JP4065450B2 - Fluid ejection device - Google Patents

Description

The present invention relates to an information-precision equipment, machine tools, FA (Factory Automation) field, such as or a semiconductor, liquid crystal, display, relates to an injection equipment of minute flow rate required by different production processes such as surface mount, , and particularly, it is suitable also as a fluid jet equipment for continuously or intermittently injecting a fluid.

Liquid discharge devices (dispensers) have been used in various fields in the past, but in response to the recent needs for downsizing and high recording density of electronic components, a very small amount of fluid material can be supplied with high accuracy and stability. Control technology is required. For example, in the field of displays such as plasma display, CRT (Cathode Ray Tube), and organic EL (electro-luminescence), instead of conventional methods such as screen printing and photolithography, phosphors or electrode materials are maskless on the panel surface. There is a great demand for direct patterning. To summarize the issues of dispensers for that,
(I) Finer discharge volume,
(Ii) Higher accuracy of discharge amount,
(Iii) Shortening the discharge time,
It is.

  Conventionally, as a liquid ejecting apparatus, an air pulse dispenser as shown in FIG. 36 has been widely used. For example, the technique is introduced in Non-Patent Document 1 and the like.

  The dispenser according to this system applies a constant amount of air supplied from a constant pressure source to the interior 601 of the container 600 (cylinder) in a pulsed manner, and a certain amount of liquid corresponding to the increase in pressure in the cylinder 600 is supplied from the nozzle 602. It is what is discharged.

  In recent years, it should be finely ejected in the field of circuit formation, which is becoming more highly accurate and ultra-fine, or in the field of manufacturing processes of picture tube electrodes and ribs such as PDP and CRT, phosphor screen formation, liquid crystal, and optical disks. Most of the fluid is a high viscosity powder fluid.

  The biggest problem is how to discharge the powdered fluid containing fine particles onto the target substrate with high reliability at high speed and high accuracy without clogging the flow path.

  For the purpose of high-speed intermittent discharge, a dispenser as shown in FIG. 37 (hereinafter referred to as a jet type for convenience) has been put into practical use. 550 is a micrometer, 551 is a spring, 552 is a piston seal member, 553 is a piston chamber, 554 is a heater, 555 is a needle, 556 is a discharge material that flows toward the sheet portion, 557 is a dot-like shape that flies from the dispenser It is a discharge material. 38A and 38B are model views showing the vicinity of the discharge portion 558 of FIG. 37, FIG. 38A shows the suction process, and FIG. 38B shows the discharge process. Reference numeral 559 denotes a spherical convex portion formed at the discharge side end of the needle 555, 560 denotes a discharge tip portion, 561 denotes a spherical concave portion formed in the discharge tip portion, and 562 denotes a discharge nozzle. Reference numeral 563 denotes a pump chamber formed by a spherical convex portion 559 and a concave portion 561.

In FIG. 38A which is an intake process, when the supply air pulse of the piston chamber 553 is ON, the needle 555 is raised against the spring 551. At this time, the suction portion 564 formed between the spherical convex portion 559 and the concave portion 561 is opened, and the discharge material 556 is filled from the suction portion 564 into the pump chamber 563. In FIG. 38B, which is the discharge process, when the air pulse is OFF, that is, when no air pressure is applied to the piston chamber 553, the needle 555 is lowered by the force of the spring 551. At this time, the suction portion 564 is in a shielding state, and the fluid in the pump chamber 563 is compressed in a sealed space excluding the discharge nozzle 562, so that high pressure is generated and the fluid flies and flows out.

  Hereinafter, taking the phosphor layer forming step of the plasma display panel as an example, the following problems of the prior art will be described.

[1] Issues with screen printing and photolithography
[2] Issues in direct patterning of phosphor layers using conventional dispenser technology

First, the above [1] will be described.
(1) Structure of Plasma Display Panel FIG. 39 shows an example of the structure of a plasma display panel (hereinafter referred to as PDP). The PDP is roughly composed of a front plate 800 and a back plate 801. A plurality of sets of linear transparent electrodes 803 are formed on a first substrate 802 which is a transparent substrate constituting the front plate 800. The second substrate 804 constituting the back plate 801 is provided with a plurality of sets of linear electrodes 805 orthogonal to the linear transparent electrodes. The two substrates are opposed to each other with a barrier rib 806 on which a phosphor layer is formed, and a discharge gas is sealed in the barrier rib 806. When a voltage equal to or higher than the threshold is applied between the electrodes of both substrates, a discharge occurs at a position where the electrodes cross each other, and the discharge gas emits light, and the emitted light can be observed through the transparent first substrate 802. An image can be displayed on the first substrate side by controlling the discharge position (discharge point). In order to perform color display by PDP, a phosphor that develops a desired color by ultraviolet rays emitted during discharge at each discharge point is formed at a position corresponding to each discharge point (barrier rib partition). In order to perform full color display, RGB (red, green, blue) phosphors are formed.

  The configurations of the front plate 800 and the back plate 801 will be described in a little more detail.

  The front plate 800 is formed of two or more pairs of linear transparent electrodes 803 in parallel on the inner surface side of a first substrate 802 made of a transparent substrate such as a glass substrate, using ITO or the like. A bus electrode 807 for reducing the line resistance value is formed on the inner surface of the linear transparent electrode 803. A dielectric layer 808 that covers the transparent electrode 803 and the bus electrode 807 is formed on the entire inner surface area of the front plate, and an MgO layer 809 that is a protective layer is formed on the entire surface area of the dielectric layer 808.

On the other hand, on the inner surface side of the second substrate 804 of the back plate 801, a plurality of linear address electrodes 805 orthogonal to the linear transparent electrodes 803 of the front plate 800 are formed in parallel by a silver material or the like. A dielectric layer 810 that covers the address electrodes 805 is formed on the entire inner surface of the back plate. On the dielectric layer 810, each address electrode 805 is isolated, and a barrier rib (partition) 806 having a predetermined height is interposed between the address electrodes in order to keep the gap distance between the front plate 800 and the rear plate 801 constant. Protrusively formed. With this barrier rib 806, cells 811 are formed along each address electrode, and phosphors 812 of RGB colors are sequentially formed on the inner surface thereof. The PDP having a cell structure includes a cell structure (not shown) having discharge points as shown in FIG. 39 one by one in an independent cell and a partition wall partitioned by a partition. In recent years, the “independent cell system” has attracted attention as a system that can improve the performance of the PDP. The reason is that by surrounding the cell with four barrier ribs in a waffle shape, light leakage between adjacent cells can be prevented and the area of the light emitter can be increased. As a result, the feature of the “independent cell method” is that the light emission efficiency and the light emission amount (brightness) can be improved and a high-contrast image can be realized. The phosphor layer formed on the cell wall is generally thickened to about 10 to 40 μm in order to improve the color development. In order to form the RGB phosphor layer, each cell is filled with a phosphor coating solution and dried to remove volatile components, thereby forming a thick phosphor on the inner surface of the cell and simultaneously discharging. A space filled with sex gas is created. In order to form such a thick phosphor pattern, the coating material containing the phosphor is a high-viscosity paste-like fluid (fluorescent material) of several thousand mPa · s to tens of thousands mPa · s with a reduced amount of solvent. Body paste) and conventionally discharged onto a substrate by screen printing or photolithography.

(2) Problems with the conventional screen printing method When the screen printing method has been adopted, the screen plate is stretched due to tension when the screen is enlarged, making it difficult to align the screen printing plate with high accuracy throughout the screen. It became. Further, when the phosphor material is filled, the material is placed on the top of the partition wall, and in the case of the “independent cell method”, there is a problem that leads to crosstalk between the barrier ribs. Therefore, in order to remove the material attached to the top part of the partition wall, a measure such as surface treatment or processing by mechanical means, for example, introduction of a polishing process is required. Moreover, the filling amount of the phosphor material changes due to the difference in squeegee pressure, and the pressure adjustment is very delicate and often depends on the skill level of the operator. Therefore, it is not easy to obtain a constant filling amount in all the independent cells over the entire area of the back plate.

(3) Problems of conventional photolithography Conventionally, photolithography has the following problems. In this method, after the photosensitive phosphor paste is press-fitted into the cells between the ribs, only the photosensitive composition press-fitted into the predetermined cells is left by the exposure and development processes. Thereafter, through a firing step, organic substances in the photosensitive composition are eliminated to form a phosphor layer pattern. In this construction method, since the paste used contains phosphor powder, the sensitivity to ultraviolet rays is low, and it is difficult to make the thickness of the phosphor layer 10 μm or more. Therefore, there is a problem that sufficient luminance cannot be obtained.

In addition, when adopting photolithography, an exposure and development process is essential for each color, but since the phosphor is contained in a high concentration in the paste coating layer, the loss of the phosphor due to development removal is large, Since the effective utilization rate of the phosphor is limited to less than 30%, there is a significant problem in terms of cost.

[2] Issues in direct patterning of phosphor layers using conventional dispenser technology Air tube type dispensers (Fig. 36), which are widely used in fields such as circuit packaging, are used for video tubes. Attempts have been made to discharge. In the case of the air nozzle type, since it is difficult to continuously discharge a high-viscosity fluid at a high speed, the fine particles are diluted with a low-viscosity fluid and discharged. In the case of the phosphor discharge of a picture tube such as PDP and CRT, the particle diameter of the fine particles is, for example, 3 to 9 μm, and the specific gravity is about 4 to 5. In this case, since the single particles are heavy, there is a problem that when the fluid flow is stopped, the fine particles are immediately accumulated inside the flow passage. Moreover, the air-type dispenser has a drawback of poor responsiveness. This drawback is due to the compressibility of the air confined in the cylinder and the nozzle resistance when the air passes through a narrow gap. That is, in the case of the air method, the time constant of the fluid circuit consisting of the cylinder volume and nozzle resistance is large, and after applying the input pulse, it takes about 0.07 to 0.1 seconds until the fluid starts to be transferred and transferred onto the substrate We must expect a delay.

  Development has been made to apply an ink jet method, which has been widely used as a consumer printer, as an industrial discharge device. In the case of the ink jet system, the viscosity of the fluid is limited to 10 to 50 mPa · s due to restrictions on the driving method and structure, and it cannot cope with a high viscosity fluid.

  In order to draw a fine pattern using an inkjet method, a low-viscosity nanopaste in which particles having an average particle size of about 5 nm are covered with a dispersant and independently dispersed has been developed. It is assumed that a phosphor layer is formed on the inner wall of the barrier rib (partition wall) of the “independent cell” of the above-described PDP using this nanopaste. However, in the process of filling the phosphor coating liquid in each cell and drying it, the coating material containing the phosphor is used to thicken the phosphor layer of about 10 to 40 μm as described above. Uses a pasty fluid with a high viscosity and a reduced amount of solvent. A low-viscosity nanopaste that can only have a low phosphor content cannot form a phosphor layer having a predetermined thickness because the absolute amount of the phosphor is insufficient. Also, in order to obtain high brightness, it is usually best to use phosphor particles with a particle size on the order of several microns. However, the fact that the phosphor particle size cannot be easily changed at this stage is also a major problem with inkjet systems. It is.

  In the case of the jet type dispenser shown in FIG. 37, it is sufficiently faster than the conventional dispenser, such as an air type or a thread groove type, in terms of discharge speed, and can handle a high viscosity fluid. In this method, fluid can be ejected intermittently by ejecting fluid from the nozzle in a state where the distance between the nozzle and the facing surface is sufficiently separated. As described above, the discharge method for causing the fluid to fly from the nozzle is difficult in the air method and the screw groove method in which a steep pulsed generated pressure cannot be generated.

  In this method, as described above, the spherical convex portion formed on the end portion of the needle 555 and the spherical concave portion formed on the discharge side are meshed with each other, so that the sealed space 563 excluding the discharge nozzle 562 is obtained. Is created, and the sealed space is compressed to generate a high pressure to cause the fluid to fly out.

  In this case, in the compression process, there is no gap in the suction part 564 between the relatively moving members (convex part and concave part), and the phosphor fine particles having an average particle diameter of 3 to 9 μm are mechanically squeezed and destroyed. . Due to various problems that occur as a result, that is, clogging of the flow passage, deterioration of the sealing performance of the suction portion 564 due to wear of members, etc., it is often difficult to apply to discharge of powdered fluid such as phosphor.

  Another problem with the above-described method is ensuring the accuracy of the absolute amount of ejection per dot, assuming continuous use for a long time. Assuming the case where the phosphor is intermittently discharged into the “independent cell” of the PDP described above, several tens of heads are required when considering the production tact during mass production. In the dispenser, the discharge amount per dot is determined by the volume of the sealed space, that is, the stroke of the needle 555 and the sealing performance of the suction portion 564. However, it is expected to be extremely difficult in practice to keep the stroke and absolute position of each needle 555 of the tens of dispensers and the sealing performance of the suction part 564 with wear constant for a long time without variation. The

"Automation Technology '93 .25 Volume 7"

  To summarize the above considerations, a method that has a possibility of replacing the screen printing method, for example, a direct patterning method that realizes the formation of an independent cell phosphor layer of PDP cannot be found at this stage.

  In order to respond to various recent demands related to micro flow rate discharge, the present inventor gives a relative linear motion and a rotational motion between the piston and the cylinder, and also provides a means for transporting the fluid by the rotational motion. Proposed a discharge method that controls the discharge amount by changing the relative gap between the fixed side and the rotation side using the JIS, and has been filed as “Fluid Supply Device and Fluid Supply Method” (Japanese Patent Application No. 2000-188899 (US Patent) Nos. 6,558,127 and 6,679,685)).

  In addition, theoretical analysis was performed for the dispenser structure disclosed in the above proposal, and an intermittent discharge method and apparatus using a squeeze effect generated by abruptly changing the gap between the piston end surface and its relative movement surface have already been proposed. (Japanese Patent Application No. 2001-110945 (US Pat. No. 6,679,685)).

  As a result of rigorous theoretical analysis, the present inventor has devised a combination of pump characteristics and pistons, and even when the gap between the piston end surface and its relative movement surface is sufficiently wide, high generated pressure equivalent to or higher than the squeeze effect (Secondary squeeze pressure) is found to be obtained. Due to the above effects, the gap between the piston end faces can be easily managed, and the total discharge amount per dot can be set by the number of rotations of the pump. Therefore, practical handling is easy, the flow rate accuracy is high, and the powder fluid On the other hand, it has already been proposed that an ultra-high-speed intermittent discharge device having high reliability can be realized (Japanese Patent Application: Japanese Patent Application No. 2002-286741 (US Application No. 10 / 673,495)).

  Following the above proposal, the present inventor found that in Japanese patent application: Japanese Patent Application No. 2003-036434 (US Application No. 10 / 776,278), the compressibility of the fluid greatly affects the generation of squeeze pressure. Based on the knowledge obtained from the analysis results derived in consideration of compressibility, we have proposed a head structure that realizes high-speed intermittent and high-speed continuous discharge.

As a result of further research under the strict contrast between theoretical analysis and experimental results using the above proposal as a stepping stone, the object of the present invention is, even when the volume of the flow passage is increased due to multi-heading, etc. and to provide a is that Fluid injection equipment obtained high response.

  In order to achieve the above object, the present invention is configured as follows.

According to the first aspect of the present invention, there is provided a fluid replenishing device including a thread groove shaft, and a rotation transmission device that rotationally drives the thread groove shaft about the shaft center, and a suction port that introduces fluid.
  A piston part having a piston and an axial drive device for moving the piston in the piston axial direction, and having a discharge port for discharging the fluid;
  In a fluid ejection device comprising a flow passage connecting the fluid supply device and the piston part,
  There is provided a fluid ejecting apparatus in which a gap is formed between the piston and a surface facing the side surface of the piston, and a convex portion is provided on a surface facing the side surface of the piston.

The following effects can be obtained by the fluid ejecting apparatus using the present invention.
1. Conventionally, intermittent discharge and continuous discharge with ultra-high-speed response, which was difficult with air and thread groove types, are possible.
2. Since the flow passage from the suction port to the discharge passage can be kept non-contact at all times, and a sufficiently large flow passage area can be taken, it is possible to deal with powder particles mixed with fine particles with high reliability.
3. Furthermore, the dispenser as an example of the embodiment of the present invention can have the following characteristics.
(I) High-viscosity fluid, which was difficult with the inkjet method, can be discharged at high speed.
(Ii) A very small amount can be discharged with high accuracy.

  If the present invention is used for, for example, PDP, phosphor discharge of a CRT display, a dispenser for circuit formation, formation of a microlens, etc., the advantages can be fully exhibited, and the effect is tremendous.

  Before continuing the description of the present invention, the same parts are denoted by the same reference numerals in the accompanying drawings.

  Embodiments according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a model diagram showing a fluid ejecting apparatus according to a first embodiment of the present invention.

Reference numeral 1 denotes a thread groove pump portion which is an example of a fluid supply device, and 2 denotes a piston portion which generates a squeeze pressure. Reference numeral 3 denotes a thread groove shaft having a thread groove 6 on the outer peripheral surface, and is housed so as to be movable in the rotational direction with respect to a housing 4 as an example of a casing. The thread groove shaft 3 is rotationally driven as indicated by an arrow 5 by a rotation transmission device 5A such as a motor. 6 is a thread groove formed on the relative movement surface of the thread groove shaft 3 and the housing 4, and 7 is a compressive fluid introduced into the thread groove pump section 1 by air pressure (auxiliary pressure) P _sup generated by the auxiliary pressure generator 7A. It is a suction port of a compressive fluid for doing this. A piston 8 is moved in the axial direction as indicated by an arrow 9 by an axial driving device 9A such as a piezoelectric actuator. Reference numeral 10 denotes an end surface of the piston 8, 11 denotes a fixed-side facing surface thereof, and 12 denotes a discharge nozzle as an example of a discharge port attached to the housing 4. The piston end surface 10 and the fixed-side facing surface 11 are two surfaces that relatively move in the gap direction. A space formed by these two surfaces 10 and 11 and the housing 4 becomes a discharge chamber.

  13 is a thread groove shaft end, 14 is a piston outer periphery, and 15 is a flow passage connecting the thread groove shaft end 13 and the piston outer periphery. The piston part 2 is always supplied with a discharge fluid 16 through a flow passage 15 by a thread groove pump part 1 which is an example of a fluid supply device.

The axial drive device 9A is provided in the housing 4 along the axial direction of the piston 8 and changes the relative position in the axial direction between the members 8 and 4. By this axial direction drive device 9A, the gap h between the piston end surface 10 and the opposed surface 11 can be changed. When the minimum value of the gap h of the piston end surface 10 is h = h _min , in one example of the first embodiment, h _min is sufficiently large, for example, h _min = 245 μm is set.

When the gap h is changed at a high frequency, the second squeeze effect described later (Japanese Patent Application: Japanese Patent Application No. 2002-286741 (US Application No. 10 / 673,495)), which will be described later, Fluctuating pressure is generated in the discharge chamber 17 which is a gap between the piston end surface 10 and the opposed surface 11. Reference numeral 18 denotes a throttle as an example of a fluid resistance portion formed on the piston portion 2 side of the flow passage 15. Further, in the central portion of the discharge chamber 17, a portion located at 19 is an upstream side of the discharge nozzle 12 (an opening of the discharge nozzle), and a gap formed by the screw groove 6 of the screw groove shaft 3 and the housing 4 is a screw groove. It will be called chamber 20. A constant amount of fluid is continuously supplied to the discharge chamber 17 by the thread groove pump unit 1. The application example according to the first embodiment of the present invention is an A / D conversion of a continuous flow (Analog flow) supplied from a pump into an intermittent flow (Digital flow) using a secondary squeeze effect. This is based on the idea that fluid can be intermittently discharged at high speed while the gap h between the piston end surface 10 and the fixed-side facing surface 11 is kept sufficiently large.

[1] Theoretical analysis (1-1) Derivation of basic equation Now, the present invention can obtain a lot of knowledge from the basic equation of a squeeze pump (tentative name) as the principle. First, the case where the fluid is incompressible will be described.

  This basic formula derivation method has already been proposed by the present inventor in Japanese Patent Application: Japanese Patent Application No. 2002-286741 (US Application No. 10 / 673,495).

  When a viscous fluid is present in a narrow gap between opposing planes and the gap distance changes with time, the fluid pressure is the Reynolds equation in the following polar coordinate with a squeeze action term Is obtained by solving

  In equation (1), P is pressure, μ is the viscosity coefficient of the fluid, h is the gap between the opposing surfaces, r is the radial position, and t is time. The right side is a term that provides a squeeze action effect that occurs when the gap changes. 2A is a top view of the apparatus, FIG. 2B is a diagram showing symbols of pressure and flow rate at various points of a dispenser as an example of a fluid ejecting apparatus, and FIG. 2C is an enlarged view of the piston portion 2 of FIG. 2B.

  The subscript i in each symbol indicates the value at the position of the opening 21 of the discharge nozzle 12 in FIG. 2C, and the subscript o indicates the value located at the lower end of the piston outer peripheral portion 14 inside the discharge chamber 17. .

として、式（1）の両辺を積分すると、

さらにもう一回積分すると、

以下、未定定数c₁, c₂を求める。r= r_i は吐出ノズル１２の吐出室側開口端の位置を示す。開口部２１は円錐形状に深く抉られているため、r<r_iの範囲では圧力は一定とみなすことができる。 r=r_iにおける圧力勾配dP/drと流量Q_iの関係は（ここで、Q_iは、吐出ノズル１２の開口部２１の位置における流体の流量を意味する。）、

式（4）を式（2）に代入すると未定定数c₁が求まる。

And integrating both sides of equation (1),

If you integrate one more time,

Hereinafter, undetermined constants c ₁ and c ₂ are obtained. r = r _i denotes the position of the discharge chamber-side opening end of the discharge nozzle 12. Since the opening 21 is gouged deep into a cone shape, a pressure in the range of r <r _i can be regarded as constant. relationship of the pressure gradient dP / dr and the flow Q _i in r = r _i (in this case, Q _i denotes the flow rate of the fluid at the openings 21 of the discharge nozzle 12.),

Substituting equation (4) into equation (2) Determined constant c ₁ is obtained.

Substituting Equation (5) into Equation (3), c ₂ is obtained from the boundary pressure condition P = P _{1 at} r = r ₀ (in the following equation, p ₁ means the pressure P ₁ on the piston side) .) Here, r ₀ is the radius of the piston located at the lower end of the piston outer peripheral portion 14 inside the discharge chamber 17 in FIG. 2C.

  Substituting Equations (5) and (6) into Equation (3), the pressure P = P (r) at an arbitrary position in the radial direction is obtained.

Q_i=P_i/R_nを式（8）に代入して整理すると、

ここで、吐出ノズル１２のノズル半径をr_n、ノズル長さをl_nとおくと、吐出ノズル抵抗Ｒ_ｎは、

また、R_Pは、吐出ノズル１２の開口部（図２Ｃの２１）とピストン外周部（図２Ｃのピストン外周部１４）の間（吐出口と前記相対移動面の一例としてピストンの外周部を繋ぐ半径方向の流通路）の流体抵抗である。 If the pressure at r = r _i is P = P (r _i ) (where r _i is the radius of the piston at the position of the opening 21 of the discharge nozzle 12 in FIG. 2C).

Substituting Q _i = P _i / R _n into equation (8)

Here, _assuming that the nozzle radius of the discharge nozzle 12 is r _n and the nozzle length is l _n , the discharge nozzle resistance R _n is

_RP connects between the opening of the discharge nozzle 12 (21 in FIG. 2C) and the piston outer periphery (piston outer periphery 14 in FIG. 2C) (the discharge port and the outer periphery of the piston as an example of the relative movement surface). (Radial flow path) fluid resistance.

また、r=r₀における、ピストン端面１０の圧力勾配dP/drと流量Q=Q_iの関係から、

ねじ溝ポンプ部１の内部抵抗をR_sとしたとき、ねじ溝ポンプ部１の吐出側圧力P₂は、

上式においてP_S0は流体補給装置の圧力であり、ねじ溝ポンプ部１の最大発生圧力P_maxと、材料である吐出すべき流体をねじ溝６に供給するためのエアー補助圧力P_supの和（P_S0= P_sup＋P_max）に相当する。式（12）〜式（14）から、

式（15）のピストン部側の圧力P₁を式（9）に代入して整理すると、流体の圧縮性を考慮しない場合の吐出ノズル１２の開口部圧力（吐出圧力）P_iが求まる。

Here, when the discharge side pressure of the thread groove pump part 1 is P ₂ and the fluid resistance of the throttle 18 formed in the flow path 15 connecting the thread groove pump part 1 and the piston outer peripheral part 14 is R _r , The flow rate Q ₀ is

In addition, from the relationship between the pressure gradient dP / dr of the piston end face 10 and the flow rate Q = Q _i at r = r ₀ ,

When the internal resistance of the thread groove pump part 1 is R _s , the discharge side pressure P ₂ of the thread groove pump part 1 is

In the above equation, P _S0 is the pressure of the fluid replenishing device, and is the sum of the maximum generated pressure P _max of the thread groove pump unit 1 and the air auxiliary pressure P _sup for supplying the fluid to be discharged as material to the thread groove 6. This corresponds to (P _S0 = P _{sup +} P _max ). From Equation (12) to Equation (14),

When the pressure P ₁ of the piston portion side of the equation (15) to organize into Equation (9), the opening pressure (discharge pressure) of the discharge nozzle 12 when not taken into consideration the compressibility of the fluid P _i is obtained.

Here, the primary squeeze pressure P _squ1 and the secondary squeeze pressure P _squ2 are defined as follows.

The primary squeeze pressure P _squ1 is changed between the piston end surface 10 and the fixed side facing surface 11 by abruptly changing the gap h between the piston end surface 10 and the fixed side facing surface 11 which is the relative movement surface thereof. This is due to the well-known squeeze effect, and a pressure proportional to the piston speed dh / dt and inversely proportional to the cube of the gap h is generated. The secondary squeeze pressure does not depend on the absolute value of the gap h, but is proportional to the piston speed dh / dt and proportional to the sum of the internal resistance R _{s of} the screw pump (screw groove pump part 1) and the resistance R _r of the throttle 18 To do.

(1-2) as basic equations derived above in consideration of the compressibility of the fluid, the method of deriving basic equations for guiding the discharge pressure P _i is already Japanese Patent Application: Japanese Patent Application No. 2002-286741 ( Similar to that described in the specification of US application Ser. No. 10 / 673,495). According to the following research (Japanese Patent Application: Japanese Patent Application No. 2003-036434 (US Application No. 10 / 776,278)), which was conducted while strictly comparing the theoretical value and the actual measurement value of the discharge pressure, in the following cases It has been found that the compressibility of the discharge fluid has a great influence on the “sharpness” of high-speed intermittent discharge.

(I) When the frequency of intermittent discharge is increased (ii) In the case of multi-head (iii) When the influence of bubbles mixed in the discharge fluid cannot be ignored (iv) When high elastic material is used Plural pistons with independent injection devices When the multi-head structure is used, the total volume of the flow path connecting each piston part and the thread groove pump part which is an example of the fluid replenishing device is larger than that of the stand-alone type (1 piston + 1 nozzle type). I must. In this case, if the fluid has a slight compressibility, the influence cannot be ignored. The influence of the fluid capacitance determined by the compressibility of the fluid and the total volume of the flow passage on the “sharpness” of fluid discharge becomes more significant as the frequency of intermittent discharge is higher. The compressibility of the fluid is greatly affected by, for example, air bubbles. Particularly in the case of a high-viscosity fluid, bubbles once mixed in the fluid cannot be easily defoamed. Also, certain adhesives such as rubber solutions, plastics, latexes, etc. have a low elastic modulus, and it is necessary to consider compressibility.

Now, the present inventor conducted a theoretical analysis in consideration of the compressibility of a fluid material in a previously proposed (Japanese Patent Application: Japanese Patent Application No. 2003-036434 (US Application No. 10 / 776,278)),
(I) Conditions for realizing high-speed intermittent discharge;
(Ii) a condition for sharply blocking the end of the continuous discharge line;
It has been found that (i) and (ii) can be realized by selecting parameters and operating conditions of the components of the dispenser. From this analysis result, it is known that the volume size V _s of the flow passage connecting the thread groove pump part and the piston part, which is an example of the fluid supply device, has a great influence on the discharge response. When the dispenser of the existing proposal (Japanese Patent Application: Japanese Patent Application No. 2003-036434 (US Application No. 10 / 776,278)) is composed of, for example, a multi-head and the number of heads is increased, the flow passage volume increases. For this reason, there is a problem that the responsiveness of discharge is lowered. To solve this problem, the proposed Japanese patent application: Japanese Patent Application No. 2002-286741 (US Application No. 10 / 673,495), Japanese Patent Application: Japanese Patent Application No. 2003-036434 (US Application No. 10/7766) 278) is not mentioned.

  The present invention provides a solution to this point. In the flow passage that connects the thread groove pump portion and the piston portion, which is an example of the fluid supply device, an opening that is sufficiently narrow in the vicinity of the piston portion as compared with other flow passages. A “throttle” is formed as an example of a fluid resistance portion having a portion. This “throttle” eliminates the delay in response caused by the volume on the fluid supply device side.

  The following is a theoretical analysis that explains the principles and effects of the present invention.

Assume two fluid capacitances C _h1 (= V _s1 / K) and C _h2 (= V _s2 / K) having volumes V _s1 and V _s2 across the throttle 18. K is the bulk modulus of the fluid. In FIG. 2B, the volume V _s2 is the sum (V _s2) of the volume V _{s11 of} the portion filled with the fluid of the thread groove pump portion 1 and the volume V _s22 of the flow passage 15 to the thread groove shaft end portion 13 and the throttle 18. = V _s11 + V _s22 ), which indicates the volume of the gap surrounded by the broken line 22. The volume V _s1 is the volume of the gap from the throttle 18 to the discharge chamber 17 and indicates the volume of the gap surrounded by the broken line 23. A compressibility analysis model in consideration of these two fluid capacitances is shown in FIG. Fluid flow rate Q ₃ flowing out from the aperture 18 is intended to flow branches to the fluid capacitance C _h1 side and piston side.

ピストン部側に流入する流体の流量Q₁は、

流体キャパシタンスC_h1側に流入する流量Q₂は、

したがって、絞り１８から流出した流量Ｑ_３は、

絞り１８を通過する流体の流量Ｑ_３と、ねじ溝ポンプ部１の吐出側圧力P₂とピストン部側の圧力P₁との圧力差P₂−P₁の関係から、

また、ピストン部側の圧力P₁と吐出ノズル１２の開口部圧力（吐出圧力）P_iの関係から、

Q_i=P_i/R_nを式（23）に代入すると、

式（22）と式（25）を式（21）に代入して整理すると、ピストン部側の圧力P₁に関する一階の微分方程式が次のように得られる。

The flow rate Q ₁ of the fluid flowing into the piston side is

The flow rate Q ₂ flowing into the fluid capacitance C _h1 side is

Therefore, the flow rate Q ₃ flowing out from the throttle 18 is

And the flow rate Q ₃ of the fluid passing through the aperture 18, the relationship between the pressure difference P ₂ -P ₁ and the pressure P ₁ on the discharge side pressure P ₂ and the piston side of the screw groove pump section 1,

Further, from the relationship of the opening pressure (the discharge pressure) P _i of the pressure P ₁ and the discharge nozzle 12 of the piston side,

Substituting Q _i = P _i / R _n into equation (23),

By substituting Equation (22) and Equation (25) into Equation (21) and rearranging, the first-order differential equation relating to the pressure P ₁ on the piston portion side is obtained as follows.

但し、T₁は吐出側の時定数、Q_squ2は吐出室の容積変化を示す。

However, T ₁ represents the time constant on the discharge side, and Q _squ2 represents the volume change of the discharge chamber.

_P ^* squ2 corresponds to secondary squeeze pressure when while considering the compressibility of the fluid and the diaphragm R _r provided in the discharge chamber near.

上式から圧力P₂に関する一階の微分方程式が次のように得られる。 Pressure P ₂ on the thread groove pump side is

From the above equation, a first-order differential equation for the pressure P ₂ is obtained as follows.

However, T ₂ is the time constant of the thread groove pump portion 1 side.

The pressures P ₁ and P ₂ can be obtained by solving the equations (26) and (30) as simultaneous differential equations. Further, the discharge pressure P _i is obtained by substituting the pressure P ₁ in the formula (24).

(1-3) Equivalent Circuit Model Based on the above analysis results, the relationship between the pressure generator and the load resistance is represented by an equivalent electric circuit model as shown in FIG. Is a ^{_{Q * squ2 = P * squ2 /}} R r in Figure 4.

[2] Embodiments (2-1) Specific Embodiments FIG. 5A and FIG. 5B show a fluid ejecting apparatus according to a first embodiment of the present invention. FIG. 6 is an enlarged view of the piston portion.

  Reference numeral 50 denotes a thread groove pump portion, and 51 denotes a thread groove shaft, which is accommodated so as to be movable in a rotational direction with respect to a housing 52 as an example of a casing. The thread groove shaft 51 is rotationally driven by a motor 53 which is an example of a rotation transmission device. Reference numeral 54 denotes a screw groove formed on the relative movement surface of the screw groove shaft 51 and the housing 52, and 55 denotes a fluid inlet.

  Reference numeral 56 denotes a piston portion, 57 denotes a piston, and 58 denotes a piezoelectric actuator that is an example of an axial drive device 9A for the piston 57.

  59 is an end surface of the piston 57, 60 is a fixed side facing surface, and 61 is a discharge nozzle. The piston end surface 59 and the fixed-side facing surface 60 form a discharge chamber 62 (corresponding to 17 in the analysis model in FIG. 3) that is two surfaces that move relative to each other in the gap direction.

The piezoelectric actuator 58 changes the relative position in the axial direction between the piston 57 and the fixed member. The piezoelectric actuator 58 can change the gap h between the piston end surface 59 and its fixed-side facing surface 60. 63 is a thread groove shaft end of the thread groove shaft 51, 64 is a piston outer periphery of the piston 57, 65 is a lower plate, 66 is a flow passage connecting the thread groove shaft end 63 and the piston outer periphery 64, It is formed between the lower plates 65. A fluid 67 to be discharged is always supplied to the piston outer peripheral portion 64 through a flow passage 66 by a thread groove pump portion 50 which is an example of a fluid supply device. Reference numeral 68 denotes a throttle as an example of a fluid resistance portion provided in the vicinity of the piston outer peripheral portion 64 of the flow passage 66 (corresponding to the throttle 18 as an example of a fluid resistance portion having a fluid resistance R _r in the analysis model of FIG. 3). It is. As shown in Table 1, the throttle 68 according to the first embodiment is configured with a passage width w = 2 mm, a passage depth b = 0.097 mm, and a passage length l = 4 mm. Each of the flow paths 66 is configured to be sufficiently small.

(2-2) Analysis result of the embodiment The analysis result of the pressure when the dispenser which is an example of the fluid ejecting apparatus according to the embodiment of the present invention is configured under the conditions of Tables 1 and 2 is shown below. . Note that the values of the two fluid capacitances with volumes V _s1 and V _s2 across the flow path are C _h1 (= V _s1 /K)=0.421 mm ⁵ / kg, C _h2 (= V _s2 /K)=1.02 Assuming mm ⁵ / kg. FIG. 7 is a driving waveform of the piston, and shows the piston displacement (displayed as the dimension of the gap h) with respect to time. 8A is an analysis result of the discharge pressure P _i, is a graph indicating a discharge pressure with respect to time. In FIG. 8A, in addition to the pressure waveform when the restrictor 68 is formed (solid line graph), the pressure waveform when the restrictor 68 is not formed (dotted line graph), that is, when R _r → 0, is compared. Show. From FIG. 8A, when the throttle 68 is formed, the peak pressure P _max = 13 Mpa, and an extremely high pressure necessary for flying the fluid is generated. Further, when forming the aperture 68, the negative pressure P _min <0 immediately after the discharge, and immediately after the discharge, the fluid that flows out of the discharge nozzle and does not fly and remains near the tip of the discharge nozzle again, Sufficient negative pressure necessary for suction inside the discharge nozzle is generated.

  8B and 8C are image diagrams showing the behavior of the discharge fluid that has flowed out of the discharge nozzle 61 with and without the restriction 68. FIG. 8B shows the case where the diaphragm resistance is not applied, and FIG. 8C shows the case where the diaphragm 68 is arranged and the diaphragm resistance is applied. Reference numeral 69 denotes a substrate as an example of a discharge target disposed facing the discharge nozzle 61, and reference numeral 70 denotes a fluid to be discharged after flowing from the discharge nozzle 61 to the substrate 69.

In the case of FIG. 8B, since the maximum generated pressure, that is, the generated peak pressure P _max of the thread groove pump portion 1 is low, the discharged fluid 70 that has flowed out from the discharge nozzle 61 is fluid mass at the tip of the discharge nozzle 61 due to the influence of surface tension. It adheres to the substrate 69 without dropping.

Figure 9 is a waveform of the discharge-side pressure P ₂ of the screw groove pump portion is a graph showing the discharge-side pressure P ₂ of the thread groove pump portion side with respect to time. Compared with the waveform of the pressure P ₁ on the piston portion side in FIG. 8A, the amplitude of the pressure waveform is small, P _max = 3.0 MPa, P _min = 0.9 MPa, and no negative pressure is generated.

From this result, the sensitive squeeze pressure generated on the piston side by the action of the low-pass filter by the throttle 68 and the fluid capacitances C _h1 and C _h2 is not sufficiently propagated to the upstream side (thread groove pump side). Recognize. That is, the throttle 68 disposed in the vicinity of the piston portion 56 has an effect of keeping the discharge pressure and the negative pressure having a sharp peak pressure only in the vicinity of the piston portion 56.

  FIG. 10 compares the discharge pressure waveforms when only the flow path depth b of the throttle is changed without changing other specifications, and shows the discharge pressure with respect to time using the throttle depth as a parameter. It is a graph.

Here, the conditions required for high-speed intermittent discharge include the following points.
(I) A high peak pressure can be obtained during discharge.
(Ii) A sufficient negative pressure is generated after the end of discharge.
(Iii) The discharge pressure has recovered to the supply pressure by the end of the suction process.

  The discharge pressure waveform is evaluated from the points (i) to (iii).

絞りの深さb=0.220mmの場合、P_max=6.5MPaと低く、また吐出終了後に発生する負圧レベルも小さい。絞りの深さb=0.097mmの場合、P_max=13MPaに上昇し、かつ十分に大きな負圧が発生している。絞りの深さb=0.046mmの場合、P_max=15MPaと上昇するが、負圧発生のレベルは若干低下し、また吸入工程終了時（次のステップの吐出開始時t=0.0945s）でも、圧力は供給圧に回復していない。前記解析結果から、前記（ｉ）〜（ｉｉｉ）を同時に満足させる最適な絞り抵抗が存在することがわかる。 The fluid resistance R _r of the throttle in this case is

When the aperture depth b = 0.220 mm, P _max is as low as 6.5 MPa, and the negative pressure level generated after the end of discharge is small. When the aperture depth b is 0.097 mm, P _max is increased to 13 MPa, and a sufficiently large negative pressure is generated. When the throttle depth b = 0.046mm, P _max increases to 15MPa, but the level of negative pressure generation decreases slightly, and even at the end of the inhalation process (at the start of discharge of the next step t = 0.0945s) The pressure has not recovered to the supply pressure. From the analysis results, it can be seen that there is an optimum aperture resistance that satisfies the above (i) to (iii) at the same time.

In the first embodiment, the ratio of the volumes V _s1 and V _s2 of the two fluid capacitances provided with the throttle 18 in the flow passage 15 is as follows: V _s1 / V _s2 = C _h1 / C _h2 = 0.421 / 1.02 = 0.413 _Yes , V _s1 <V _s2 . By providing a throttle 18 having a throttle resistance R _{r in} the vicinity of the discharge chamber 17, as can be seen from the comparison between the waveforms of the pressures P ₁ and P ₂ (FIGS. 8A and 9), the discharge side (piston part 2 side). Is dynamically separated from the fluid supply device side (for example, the thread groove pump portion 1 side). As a result, the volume V _s2 on the fluid supply device side does not significantly affect the response of the discharge pressure. This effect of the fluid ejection device according to the first embodiment of the present invention is that a plurality of piston portions 2 are provided and the number of the flow groove 15 connected to the thread groove pump portion 1 and each piston portion 2 of the fluid supply device is increased. This becomes noticeable in the case of a head (described later).

If the time constant on the piston portion side is set to T ₁ ≦ 30 ms, it is advantageous in terms of responsiveness as compared with the conventional dispenser, and can be applied to many applications.

(2-3) Other methods for forming aperture resistance (second and third embodiments)
(Second Embodiment)
FIG. 11A shows a fluid ejecting apparatus according to a second embodiment of the present invention, and shows a case where an aperture resistance is formed between the outer peripheral portion of the piston and its opposing surface. The structure on the thread groove pump portion side, which is not shown in FIG. 211A, is the same as that of the previous embodiment.

300 is a piston, 301 is an outer periphery of the piston, 302 is a lower plate, 303 is a flow passage connecting the end of the thread groove shaft and the outer periphery of the piston 301, and 304 is a throttle formed between the piston outer periphery 301 and the lower plate 302. (In the analysis model of FIG. 3, it corresponds to the diaphragm 18 having the fluid resistance R _r ). 305 is an end surface of the piston 300, 306 is a fixed-side facing surface, 307 is a discharge nozzle, 308 is a discharge chamber, and 309 is an opening end on the piston portion side of the flow passage 303. Reference numeral 311 denotes a discharge portion that has a nozzle 307 and is detachably fixed to the lower plate 302 by a plurality of bolts 312.

The throttle 304 is formed between the piston outer peripheral portion 301 and the lower plate 302 on the side close to the discharge chamber 308. Therefore, the volume V _s1 (that is, the fluid capacitance _{Ch 1} ) of the space formed by the lower end portion of the piston 300 and the fixed-side facing surface 306 can be reduced, thereby further improving the responsiveness.

  FIG. 11B shows a fluid ejecting apparatus according to a modified example of the second embodiment of the present invention, and shows a case where an aperture resistance is formed in a discharge portion that can be attached and detached from the outside.

350 is a piston, 351 is a piston outer peripheral part, 352 is a lower plate, 353 is a flow path connecting the thread groove shaft end part and the piston outer peripheral part 351, 354 is a throttle formed between the piston outer peripheral part 351 and the lower plate 352 ( In the analysis model of FIG. 3, it corresponds to the diaphragm 18 having the fluid resistance R _r ). 355 is an end surface of the piston 350, 356 is a fixed-side facing surface, 357 is a discharge portion that is detachably fixed to the lower plate 352 by a plurality of bolts 357a, 358 is a discharge nozzle, 359 is a discharge chamber, 360 is a flow passage Open end. The throttle 354 is formed between the piston outer peripheral portion 351 and the discharge portion 357 on the side close to the discharge chamber 359. Therefore, the volume V _s1 (that is, the fluid capacitance C _h1 ) of the space on the discharge side can be reduced, and the plurality of bolts 357a are loosened and only the discharge portion 357 is removed from the lower plate 352 without disassembling the dispenser body. The discharge unit 357 that can form the diaphragm 354 having the most appropriate diaphragm resistance is selected in accordance with the discharge conditions (in other words, the inner diameter is different from the diaphragm 354 of the discharge unit 357 previously attached. The selected other discharge portion 357 can be attached to the lower plate 352 again by tightening the plurality of bolts 357a (by replacing with another discharge portion 357 having the restriction 354).

In any of the above embodiments or modifications, the throttle 354 may be formed between the end surface 355 of the piston 350 and the open end 360 of the flow passage 353 between the piston outer peripheral portion 351 and the facing surface. Further, the convex portion for forming the diaphragm 354 may be formed on either one or both of the piston side (shaft side) and the fixed side (housing side) that houses the piston.

(Third embodiment)
FIG. 12A shows a fluid ejecting apparatus according to a third embodiment of the present invention, and shows a case where a piston tip has a tapered shape and a throttle is formed in the vicinity of a discharge chamber. 12B is a cross-sectional view taken along line AA in FIG. 12A.

250 is a piston, 251 is a piston outer peripheral portion, 252 is a lower plate, 253 is a flow passage connecting the screw groove shaft end portion and the piston outer peripheral portion 251, and 254 is between the piston outer peripheral portion 251 and the lower plate 252 (of the flow passage 253 (In the analytical model of FIG. 3, corresponding to the diaphragm 18 having the fluid resistance R _r ). 255 is a conical end surface of the piston 250, 256 is a fixed side facing surface formed in a tapered shape (in a mortar shape), 257 is a discharge nozzle, and 258 is a discharge chamber. Reference numeral 261 denotes a discharge portion that has a nozzle 257 and is detachably fixed to the lower plate 252 by a plurality of bolts 262. Thus, since the fluid can be more smoothly guided to the discharge nozzle 257 by making the space between the piston end surface 255 and the fixed-side facing surface 256 tapered, the powder fluid is used as the fluid. Troubles such as nozzle clogging can be avoided.

[2] Fourth embodiment in the case of a multi-head The dispenser of the above-described embodiment described above is a piston such as a piezoelectric actuator that is an example of a pump unit that is an example of a fluid supply device and an axial drive device 9A. This is a single head configured with one driving unit. In contrast, in the following fluid ejecting apparatus (dispenser as an example) according to the fourth embodiment of the present invention, a measure for further improving the production cycle of the head will be described.

  For example, in the case of a PDP panel, the phosphor layers formed on the front plate / back plate are formed by a screen printing method, a photolithography method, or the like.

  In order to solve the above-mentioned problems related to the screen printing method or the photolithography method, there is a strong demand for realizing a direct drawing method (direct patterning) using a dispenser. However, even when the phosphor layer is formed on the panel surface of the front plate or the back plate using a dispenser, a production tact equivalent to that of the screen printing method is desired.

  When the fluid ejecting apparatus according to the embodiment of the present invention is used and applied to a process of intermittently discharging a phosphor into a box-type cell, the above-described discharge process conditions, (i) the discharge amount per dot is In addition to constant, (ii) constant period, and (iii) ultra-high speed ejection, “being a multi-head” is a necessary condition.

  13A and 13B show a fluid ejecting apparatus according to a fourth embodiment of the present invention, which has a multi-head. FIG. 13C is an enlarged view of the vicinity of the piston portion of FIG. 13B.

  Reference numeral 150 denotes a thread groove pump portion, and 151 denotes a thread groove shaft, which is housed so as to be movable in a rotational direction with respect to a housing 152 as an example of a casing. The thread groove shaft 151 is rotationally driven by a motor which is an example of the rotation transmission device 153. Reference numeral 154 denotes a screw groove formed on the relative movement surface of the screw groove shaft 151 and the housing 152, and 155 denotes a fluid inlet. 156a to 156f are six piston portions having the same structure as shown in FIG. 13C, 157a to 157f are six pistons of the piston portions 156a to 156f, and 158a to 158f are respective pistons of the six pistons 157a to 157f. Six piezoelectric actuators 159a to 159f, which are examples of the axial driving device 9A that is a driving unit, are six discharge nozzles. Reference numeral 160 denotes a lower plate, and 161 denotes a common flow passage connected to the thread groove shaft end portion 162. The common flow passage 161 passes through six individual flow passages 163a to 163f to each of the six piston outer peripheral portions 164a to 164f. Fluid is supplied. These flow passages 161, 163 a to 163 f are formed between the housing 152 and the lower plate 160. Reference numerals 164a to 164f denote piston outer peripheral portions, and reference numerals 165a to 165f denote diaphragms formed between the piston outer peripheral portions 164a to 164f and the respective facing surfaces. In the piston portions 156a to 156f, piezoelectric actuators 158a to 158f having the same structure and pistons 157a to 157f driven independently by these actuators 158a to 158f are arranged. From the thread groove pump section 150, fluid is supplied to the discharge chambers of the piston sections 156a to 156f via the common flow path 161 → the individual flow paths 163a to 163f → the restrictors 165a to 165f.

  As shown in the fourth embodiment, if a pump unit 1 which is an example of a fluid replenishing device and the piston units 156a to 156f are separated to form an injection device, a plurality of piston units 156a are formed from one set of pump units 1. By dispensing and replenishing fluid to ˜156f, a discharge head having multi-nozzles capable of discharging in synchronization can be realized.

  FIG. 13B shows a simplified example of a control block diagram of the fluid ejection device according to the fourth embodiment. 166 is a command signal generator that gives a driving method for the piezoelectric actuators 156a to 156f, 167 is a control controller, 168a to 168f are six drivers that are driving power sources for the six piezoelectric actuators 156a to 156f, and 169 is a position A position from a linear scale provided on a stage 179 (see FIG. 13C) on which a target such as a substrate to be ejected is held and moved in two orthogonal directions with respect to the fixed multi-head. Indicates information. Based on command signals such as rising and falling waveforms, intermittent periods, amplitudes, minimum gaps, etc. of the six pistons 157a to 157f determined in advance, and a linear scale that detects the relative speed and relative position of the injection device and the substrate The six piezoelectric actuators 156a to 156f are driven by the six drivers 168a to 168f independently and synchronously as necessary based on the position information 169 of the control unit 167. The fluid supplied from the two thread groove pump sections 150 is synchronized with the discharge nozzles 159a to 159f of the six piston sections 156a to 156f via the common flow path 161, the individual flow paths 163a to 163f, and the restrictors 165a to 165f. Discharged.

  As shown in the above fourth embodiment, if the multi-head configuration in which a plurality of piston parts are arranged with respect to one set of pump part which is an example of a fluid replenishing apparatus, the whole apparatus is greatly reduced in size. it can. FIG. 14 shows an equivalent electric circuit in the case of a multi-head.

  Normally, there is a limit to downsizing the pump unit, which is an example of a fluid replenishing device, but the piston drive unit can be applied to a small piezoelectric actuator, etc. Can be small enough.

In addition, in the case of the multi-head to which the present invention is applied, each of the piston drive units is provided with an independent diaphragm (diaphragm resistance R _r ).
(I) A secondary squeeze pressure (equation (28)) proportional to the size of the throttle resistance R _r can be independently generated in each discharge chamber.

(Ii) The time constant T ₁ on the discharge side is proportional to the fluid capacitance C _h1 (= V _s1 / K), that is, the volume V _{s1 of the} discharge chamber, and therefore has a great influence on the discharge response. ₁ (Expression (27)) can be made sufficiently small.

In the case of a multi-head, as can be seen from the diagram of FIG. 13A, the volume V _s2 on the fluid supply device side increases as the number of heads increases. That is, V _s1 << V _s2 . Therefore, the time constant T ₂ on the fluid supply device side also increases and T ₁ << T ₂ , but does not significantly affect the response on the discharge side.

      (Iii) Since there is no restriction on the number of multi-heads, productivity can be improved.

The size of the diaphragm resistance R _r of the diaphragm provided in each head unit may be changed depending on the location. For example, in order to make the discharge amount more uniform, the size of the throttle resistances of the throttles 165a and 165f at a distance from the thread groove pump unit 150 is determined in consideration of the difference in resistance of the flow path. The aperture resistance of the diaphragm 165c or 165d at a short distance from the section 150 may be smaller.

Further, the multihead shown in FIG. 13A and FIG. 13B as an example may be used as a subunit, and a plurality of these subunits may be combined to form an injection device.

In the application examples of the first to fourth embodiments of the present invention described above, only the secondary squeeze pressure is obtained in a region where the influence of the primary squeeze pressure is small by setting the gap between the piston end faces sufficiently large. , The continuous flow (analog flow) supplied from the fluid supply device is A / D converted into an intermittent flow (digital flow) and intermittently discharged. In this case, the discharge amount per dot does not depend on the stroke and displacement of the piston, and the operating point flow rate Q _C (= P _c / R) determined by the pressure flow characteristic of the pump, which is an example of the fluid supply device, and the discharge nozzle fluid resistance. _n ) (see FIG. 35A). Therefore,
The discharge amount per dot is constant,
Constant period,
Super high-speed intermittent discharge.

  The present discharge method provides a very powerful means for the discharge process that simultaneously requires (i) to (iii).

For example, this is effective when R, G, B phosphors are intermittently discharged into a box-type cell on the back plate of a plasma display panel (hereinafter referred to as PDP panel) that performs color display. In the case of a PDP panel, box-type cells are arranged on the panel with high precision and geometric symmetry in a grid pattern. In this case, a certain amount of material may be applied into the cell at the same time interval at a high speed, which is very different from the case where it is widely used in circuit formation. That is, the application example of the embodiment of the present invention pays attention to the “geometric symmetry” of the discharge target, and replaces this symmetry with the “periodicity of time”, thereby discharging several milliseconds. It achieves ultra-high-speed intermittent ejection on the order or 1 millisecond or less.

[3] Reason why the intermittent discharge amount is determined by the operating point of the thread groove pump unit (3-1) Basic concept The dispenser as an example of the fluid ejecting apparatus according to the embodiment of the present invention performs intermittent discharge per dot. The amount can be set by adjusting the pressure and flow characteristics of the fluid replenishment device. The reason will be described below.

ねじ溝ポンプ部側は、絞りと容積のローパスフィルタの効果によって、圧力変動が十分小さくなっていると仮定すると、

Q_i=P_i/P_nであるため、

但し、

また、Ａは（Ｒ_ｒＳ_ｐｈ_ａ）／（Ｒ_ｎ＋Ｒ_ｒ）を意味し、ｕはｈ／ｈ_ａを意味する。 When the minimum piston end face clearance h _min is set sufficiently large, from Equation (11), when h → ∞, R _p → 0, Equation (17) to P _squ1 → 0, Equation (24) to P _i = P ₁ Therefore, equation (26) is

Assuming that the pressure fluctuation is sufficiently small due to the effect of the throttle and volume low-pass filter on the thread groove pump side,

Since Q _i = P _i / P _n ,

However,

Also, A is means _{(R r S p h a)} / (R n + R r), u denotes the _h / h _a.

The first term on the right side of Equation (35) is the flow rate determined by the intersection (operating point) of the pressure / flow rate characteristics and load resistance of the thread groove pump part (an example of a fluid supply device). The second term is a fluctuating flow rate generated by the secondary squeeze pressure. FIG. 15 assumes a piston displacement h (period P) with respect to time. FIG. 16 shows the differential dh / dt (velocity) of the displacement of the piston with respect to time. That is, the second term on the right side of Equation (35) is a periodic function having alternating positive and negative values. FIG. 16 obtains a Fourier series coefficient in consideration of the odd function [f (t) = − f (−t)]. Here, b _n means a Fourier coefficient, n means an nth harmonic, and p means a period.

したがって、

式（38）を強制入力項とする定常振動状態における線形１次微分方程式（式35）の特殊解は、良く知られているように、振幅B_nと位相φ_ｎを有する正弦波の和となる。したがって、式(３５)を解いて得られる流量Q_iは、ねじ溝ポンプ部の流量Q_i1と第２次スクイーズ圧力によって発生する変動流量Q_i2の和（Q_i= Q_i1+ Q_i2）である。この流量Q_iを周期Pの区間で積分した値が、１ドット当たり吐出流量Q_Sとなる。

Therefore,

As is well known, the special solution of the linear first-order differential equation (Equation 35) in the steady-state vibration state using the equation (38) as a forced input term is the sum of a sine wave having an amplitude B _n and a phase φ _n. Become. Therefore, the flow rate Q _i obtained by solving the equation (35) is the sum (Q _i = Q _i1 + Q _i2 ) of the flow rate Q _i1 of the thread groove pump section and the variable flow rate Q _i2 generated by the secondary squeeze pressure. is there. A value obtained by integrating the flow rate Q _i in the period P is the discharge flow rate Q _S per dot.

式(３９)の右辺第２項において、個々の正弦波を周期Pで積分した値は0となる。したがって、第２次スクイーズ圧力によって発生する変動流量は、１ドット当たり吐出流量には影響を与えず、ねじ溝ポンプ部の動作点流量Q_c（右辺第１項）だけで決まることが分かる。この場合、たとえば電源不安定が要因でピストンの振幅が変動しても、すなわち、第２次スクイーズ圧力の値が変動しても１ドット当たり吐出流量には影響を与えない。但し、この結果は、時間に対するピストンの変位の微分dh/dt（速度）が、正負の値を交互にもつ周期関数で、かつ奇関数[f（t）=-f（-t）]である場合、すなわち、ピストンの下降時間T_dと上昇時間T_aが等しく、下降前と上昇後のピストン変位の値が等しい場合に成り立つ条件である。

In the second term on the right side of Equation (39), the value obtained by integrating the individual sine waves with the period P is zero. Therefore, it can be seen that the fluctuating flow rate generated by the secondary squeeze pressure does not affect the discharge flow rate per dot and is determined only by the operating point flow rate Q _c (first term on the right side) of the thread groove pump section. In this case, for example, even if the piston amplitude fluctuates due to power supply instability, that is, even if the value of the secondary squeeze pressure fluctuates, the discharge flow rate per dot is not affected. However, this result shows that the differential dh / dt (velocity) of the displacement of the piston with respect to time is a periodic function having alternating positive and negative values and an odd function [f (t) =-f (-t)]. In other words, this is a condition that holds when the piston descent time _Td and the ascending time _Ta are equal and the piston displacement values before and after the descent are equal.

Therefore, in the dispenser as an example of the fluid ejecting apparatus according to the embodiment of the present invention, if an input waveform (for example, FIG. 15) that satisfies the above condition is given and the piston is driven, a more stable intermittent discharge is realized. it can.

(3-2) Specific Analysis Example Specific analysis results for verifying the above consideration are shown below.

The analysis conditions are the same as those in Tables 1 and 2 described above, FIG. 17 shows the displacement waveform of the piston with respect to time, and FIG. 18 shows the discharge flow rate with respect to time. No. 1 in Table 3 is a value obtained by integrating the flow rate waveform of FIG. 18 from time t = 0.025 s to t = 0.031 s. No. 2 is a value calculated by setting the first term on the right side of Equation (39) as the period P = 0.031-0.025. Both agree very well, and it can be seen that an intermittent discharge flow rate per dot can be obtained from the operating point flow rate Q _c of the thread groove pump section regardless of the secondary squeeze pressure.

[4] Other Embodiments (4-1) Using a Two-Degree-of-Freedom Actuator In the first to fourth embodiments described above, the thread groove pump part and the piston part, which are examples of fluid supply devices, are separated. It is a case where it is configured. In addition to the fluid ejecting apparatus according to the embodiment of the present invention, a head structure including a previously proposed giant magnetostrictive element and a two-degree-of-freedom actuator driven by a motor (for example, the proposed Japanese Patent Application No. 2000-188899 (US Patent No. 6,558,127 and 6,679,685)), or a head structure in which the thread groove pump portion and the piston portion are coaxially formed (for example, the previously proposed Japanese Patent Application No. 2001-110945 (US Pat. No. 6,679)). , 685)). 19 to 20 show a fluid ejecting apparatus according to a fifth embodiment of the present invention. FIG. 19 is a model diagram showing the principle of the fifth embodiment of the present invention. A piston 401 is housed in a housing 402 as an example of a casing on the fixed side so as to be movable in an axial direction and a rotation method. The piston 401 is driven independently in the axial direction indicated by the arrow 403 and the rotational direction indicated by the arrow 404 by the axial driving device 403A and the rotation transmitting device 404A. Reference numeral 405 denotes a thread groove formed on the relative movement surface of the piston 401 and the housing 402, and reference numeral 408 denotes a discharge fluid supplied between the piston 401 and the housing 402. Reference numeral 409 denotes a disk-shaped large-diameter portion provided on the discharge-side end surface of the piston 401, and a diaphragm 410 is formed between the housing 402 and the large-diameter portion 409. Reference numeral 411 denotes a discharge side end face of the piston 401, and 412 denotes a fixed side facing face thereof. The piston end surface 411 and the fixed-side facing surface 412 are two surfaces that relatively move in the gap direction. Reference numeral 413 denotes a discharge unit, and 414 denotes a discharge nozzle.

In this case, the volume V _s1 of the flow passage is equal to the volume of the gap 415 between the piston end surface 411 and the fixed-side facing surface 412. Further, the volume V _s2 is equal to the volume of the gap 416 between the screw groove 405 and the housing 402. When this structure is used, since the volume of the flow passage can be made small, both the time constant on the discharge side (formula (27)) and the time constant on the thread groove pump part side (formula (31)) can be made small. For this reason, it is greatly advantageous to increase the discharge response.

  FIG. 20 shows a configuration of the entire dispenser to which the fluid ejecting apparatus according to the embodiment of the present invention is specifically applied.

  101 is a first actuator composed of a giant magnetostrictive element and functions as an example of the axial drive device 403A, 102 is a main shaft that is linearly driven by the first actuator 101, and 103 houses the first actuator 101. It is a housing as an example of a casing. A pump unit 104 that houses the main shaft 102 is attached to the lower end (front side) of the housing 103.

  A motor 105 is a second actuator that is given a rotational motion to the main shaft 102 and functions as an example of the rotation transmission device 404A. 106 is a cylindrical giant magnetostrictive rod composed of giant magnetostrictive elements, and 107 is a magnetic field coil for applying a magnetic field in the longitudinal direction of the giant magnetostrictive rod 106. Reference numerals 108 and 109 denote rear and front permanent magnets for applying a bias magnetic field to the giant magnetostrictive rod 106. Rear and front permanent magnets 108 and 109 are arranged so as to hold the giant magnetostrictive rod 106.

  110 is disposed on the rear side of the giant magnetostrictive rod 106, the rear side yoke is a yoke material of the magnetic circuit, 111 is disposed on the front side of the giant magnetostrictive rod 106, the front side rod also serving as the yoke material, and 112 is a magnetic field coil This is a cylindrical yoke material disposed on the outer periphery of 107. That is, the giant magnetostrictive rod 106, the magnetic field coil 107, the permanent magnets 108 and 109, the rear side yoke 110, the main shaft 102, and the yoke material 112 can control the expansion and contraction of the giant magnetostrictive rod 106 in the axial direction by the current applied to the magnetic field coil. An actuator (first actuator 101) is configured.

  113 is a bias spring of the giant magnetostrictive rod 106, 114 is a bearing for supporting the main shaft 102 so as to be rotatable and movable in the axial direction, and 115 is a displacement sensor for detecting axial displacement of the main shaft 102. Reference numerals 116 and 117 denote bearings.

Reference numeral 118 denotes a piston, which is housed so as to be movable in the axial direction and the rotational direction with respect to a lower housing 119 which is a fixed side and forms a part of an example of the casing. 405 is a thread groove formed on the relative movement surface of the piston 118 and the lower housing 119, 410 is a throttle formed between the lower end of the piston 118 and the lower housing 119, 122 is a suction port, and 414 is a discharge nozzle.

(4-2) Method for Variable Time Period of Intermittent Discharge Hereinafter, as the fluid ejecting apparatus according to the sixth embodiment of the present invention, when the time interval of intermittent discharge is not constant, the first to first aspects of the present invention. A method of applying a dispenser as an example of a fluid ejecting apparatus according to any of the five embodiments will be described. For example, when the solder is discharged onto the electrode of the circuit board, the discharge time interval is usually random.

  FIG. 21 shows a case where the same discharge amount is discharged to four dots (A, B, C, and D points) on the substrate. FIG. 22 shows the number of rotations of the thread groove shaft with respect to time, and FIG. 23 shows the discharge pressure waveform. Since the distance between the dots is different, if the moving time of the stage 179 that holds the substrate and moves it in the XY directions, which are two orthogonal directions, is constant, the discharge time interval will be different. As the dispenser, for example, the structure used in the first embodiment (FIG. 5B) is used.

In the case of the dispenser according to the first embodiment, the discharge amount per dot basically does not depend on the stroke and displacement of the piston, and the pressure flow characteristics and load of the thread groove pump unit 50 which is an example of a fluid supply device. The fact that it can be determined by the operating point flow rate Q _C determined by the resistance (see FIG. 35A) is used.

さらに、ｔ＝0.3secの点Bで吐出終了後、ｔ＝0.4secの点Cで吐出するまで、ねじ溝ポンプ部５０の回転数をN=100→200rpmに急上昇させる。ｔ＝0.3secの点Bからｔ＝0.4secの点Cの間の時間間隔は0.1秒であり、前回吐出と比べてタクトは1/2になるが、流量（すなわち回転数）が２倍になるため、総流量Q_sは同一となる。 After the discharge is completed at the point A at time t = 0.1 sec, the rotational speed of the thread groove pump unit 50 (see FIG. 5B) is rapidly decreased from N = 150 to 100 rpm. From the thread groove pump section 50, a flow rate Q _n corresponding to N = 100 rpm is supplied to the discharge chamber 62 (see FIG. 6). Therefore, the total flow rate Q _{s of the} fluid supplied to the discharge chamber 62 between the point A at t = 0.1 sec and the point B at t = 0.3 sec (time interval is 0.2 sec) is

Further, after the discharge is completed at the point B of t = 0.3 sec, the rotational speed of the thread groove pump unit 50 is rapidly increased from N = 100 to 200 rpm until the discharge is performed at the point C of t = 0.4 sec. The time interval between the point B at t = 0.3 sec and the point C at t = 0.4 sec is 0.1 second, and the tact is halved compared to the previous discharge, but the flow rate (ie, rotation speed) is doubled. Therefore, the total flow rate Q _s is the same.

  Therefore, the fluid filling state in the discharge chamber 62 at the point A at t = 0.1 sec and the point B at t = 0.3 sec is the same condition, and the same discharge amount can be discharged per shot.

  In a normal discharge process, since the intermittent discharge time interval is programmed in advance, the flow rate (the number of rotations) of the thread groove pump portion 50 of the fluid supply device may be controlled in accordance with this time interval. Alternatively, as shown in Table 4, an intermittent discharge time interval may be divided into required time ranges and set in several cases, and the corresponding rotation speed may be set only in the same case. If this method is used, the operation | work which calculates rotation speed with respect to a time interval is simplified.

As the motor that rotationally drives the thread groove pump unit 50, a pulse motor, a DC servo mode, or the like may be used. When the total discharge flow rate Q _s (or dot diameter) is changed depending on each point, the number of revolutions may be controlled similarly.

(4-3) Method of achieving ultra-low flow rate Fig. 24A shows the ultra-low flow rate (for example, fluid with a flow rate of about 20 to ³⁰ pl (10 ^-6 mm ³ ) can be discharged). The dispenser as an example of the fluid injection apparatus concerning 7th Embodiment of this invention is shown.

  If the dispenser as an example of the fluid ejecting apparatus according to the seventh embodiment of the present invention is used, intermittent discharge and continuous discharge with an ultra-small flow rate can be realized. For example, in the manufacturing process of a semiconductor wafer, the demand for a quality assurance process increases as the device becomes highly functional and miniaturized, which increases the manufacturing cost. As part of an improvement method that simplifies the quality assurance process, efforts have been made to achieve electrical insulation by discharging a resin material to the electrode portion of a defective chip using a dispenser.

For this purpose, for example, a very small amount of high-viscosity material of about 20-30 pl (10 ⁻⁶ mm ³ ) is raised above the depth of the container in a container of about 30 μm in length, 100 μm in width, and about 5-7 μm in depth. A technique for intermittent discharge in a curved shape is required.

  If an ink jet system is used, since 2 to 3 pl per shot is usually easy, there is no problem in terms of discharge amount. However, the material viscosity that can be handled by the ink jet is a low-viscosity fluid of about several tens mPa · s at the most, and there is a problem that the thickness of the discharge shape (swelled shape) cannot be obtained.

Assume that the above-described jet dispenser is used to intermittently discharge a very small amount of about 20 to 30 pl. In the case of this method, it is possible to handle a high viscosity fluid, but there is a limit to the minute flow rate because it is a positive displacement type that creates a sealed space between two members. In the case of the positive displacement type, when the piston area is S _p and the piston stroke is h _st , the volume S _p × h _st pushed out by the piston is the discharge amount. In order to discharge 30 pl per shot, for example, when the piston is configured with a piston diameter of Φ0.1 mm, it is necessary to accurately control the piston position so that the piston displacement is 3 to 4 μm. Therefore, it is expected to be extremely difficult in practical use.

For the dispenser as an example of a fluid ejecting apparatus according to the seventh embodiment of the present invention, as described above, the discharge amount per dot piston area S _p, rather than determined by the piston stroke h _st, fluid It can be adjusted by setting the pressure and flow rate characteristics (see FIG. 35A) of a replenishing device (for example, a thread groove pump part). The role of the piston is only to convert a continuous flow into an intermittent flow, and if the flow rate of the fluid replenishing device is reduced, a sufficiently large piston diameter and stroke can be set so as to be practically easy to handle.

  FIG. 24A shows a fluid ejecting apparatus according to the seventh embodiment of the present invention, and FIG. 24B is an enlarged view of a portion C in FIG. 24A. Reference numeral 450 denotes a thread groove pump portion, and reference numeral 451 denotes a thread groove shaft, which is housed so as to be movable in a rotational direction with respect to a housing 452 as an example of a casing. The thread groove shaft 451 is inclined with respect to the axial direction of the piston 457. The thread groove shaft 451 is rotationally driven by a motor 453 which is an example of a rotation transmission device. Reference numeral 454 denotes a thread groove formed on the relative movement surface of the thread groove shaft 451 and the housing 452, and reference numeral 455 denotes a fluid inlet (indicated by a chain line).

456 is a piston portion, 457 is a piston having a small-diameter shaft 457a at its tip, 458 is a piezoelectric actuator which is an example of an axial drive device for the piston 457, 459 is a discharge nozzle, 460 is a thread groove pump portion 450 and a piston portion 456. An annular flow passage 461 that communicates with each other, and a throttle 461 provided in the vicinity of the small-diameter shaft 457a at the tip of the piston 457 (corresponding to the throttle 18 having the fluid resistance R _r in the analysis model of FIG. 3).

The volume V _s1 of the flow passage 460 of this structure is equal to the volume of the gap between the end surface of the small-diameter shaft 457a of the piston 457 and the mortar-shaped fixed side facing surface 459a. Further, the volume V _s2 is equal to the volume of the gap between the thread groove 454 and the housing 452. When this structure is used, the volume of the flow passage 460 can be made small, so that the time constant T ₁ (formula (27)) on the discharge side and the time constant T ₂ (formula (31)) on the screw groove pump side are Both become small, and the response of discharge can be greatly enhanced.

As described in the seventh embodiment, when changing the rotational speed of the thread groove shaft 451 in order to vary the discharge tact, the time constant T ₂ on the thread groove pump part side can be reduced because the discharge amount accuracy This is a great advantage. The reason is that the discharge amount can be instantaneously changed with respect to the change in the rotational speed of the thread groove shaft 451. This effect is the same in the case of continuous discharge. If this structure is used, for example, the line width of the discharge line can be changed instantaneously while the continuous line is being discharged.

[5] Application Example to PDP Phosphor Discharge As shown in FIG. 25, a dispenser as an example of the fluid ejecting apparatus according to the seventh embodiment of the present invention having a multi-nozzle has a relative relationship on the substrate. Suppose a process in which a phosphor is implanted into an independent cell of a PDP while moving to. Here, the relative movement of the dispenser on the substrate means that the dispenser is fixed and the stage 179 (see FIG. 13C) that holds the substrate moves relative to the fixed dispenser and the substrate is held. This means that the stage is fixed and the dispenser moves relative to the fixed substrate (see FIG. 40).

  Reference numeral 850 denotes a second substrate constituting the back plate, and 851 denotes an independent cell formed by barrier ribs. The independent cell 851 is composed of RGB independent cells 851R, 851G, and 851B into which phosphors of RGB colors are implanted. As the phosphor 852, an R color (red) phosphor 852R, a G color (green) phosphor 852G, and a B color (blue) phosphor 852B are used.

Here, attention is focused on only one nozzle 853 (corresponding to the discharge nozzle in the present specification. More specifically, for example, corresponding to the discharge nozzle 257 in FIG. 12A). In this construction method in which the phosphor 852 is ejected from the dispenser nozzle 853 into the independent cell 851, as shown in the enlarged view of FIG. 26A, the distance H between the tip of the discharge nozzle 853 and the barrier rib apex 854 is sufficiently large. Need to keep big. The reason is as follows. For example, in the case of one embodiment, the volume of the PDP independent cell 851 is V = 0.65 mm (vertical) × 0.25 mm (horizontal) × 0.12 mm (depth) ≈0.02 mm ^3. It is necessary to fill the phosphor 852 with a paste of the phosphor 852. This is because, as described above, a thick phosphor layer is formed on the inner wall of the independent cell after the volatile matter in the phosphor coating liquid is removed through the filling and drying process of the phosphor coating liquid. Because it is necessary to do.

FIG. 26B and FIG. 26C are image diagrams of a process in which the phosphor 852 is driven into the independent cell 851 using this dispenser. As an example, the piston shape and the arrangement method of the throttle use the fluid ejection device according to the above-described third embodiment of the present invention. FIG. 26B shows an inhalation process, and FIG. 26C shows an ejection process. 250 is a piston, 251 is a piston outer peripheral portion, 252 is a housing as an example of a casing, 253 is a flow passage connecting a screw groove shaft end and the piston outer peripheral portion 251, and 254 is formed between the piston outer peripheral portion 251 and the housing 252. Aperture. 255 is an end face of the piston 250, 256 is a fixed side facing surface formed in a tapered shape (conical shape), 657 is a fluid supply device side, and 258 is a discharge chamber. In the third embodiment in which the space between the piston end surface 255 and its fixed-side facing surface 256 is tapered, the powder fluid can be guided to the discharge nozzle 257 more smoothly. Therefore, the nozzle 257 when using the powder fluid is used. There are few troubles such as clogging. Further, since the restrictor 254 is disposed in the vicinity of the discharge chamber 258, the volume (V _s1 ) of the discharge chamber 258 that affects the responsiveness can be made small, and a sharp fluid discharge becomes possible. Needless to say, this effect is effective for various powder fluid discharge processes other than phosphor discharge, regardless of intermittent discharge or continuous discharge.

  Now, at the stage where the paste of the phosphor 852 is driven into the independent cell 851, the high-viscosity paste is not filled quickly into the entire container, which is a cell, due to its poor fluidity. The meniscus has a shape in which the paste is filled into the container-like independent cell 851 from above while maintaining a shape that is raised above the barrier rib apex 854. Therefore, the meniscus is not flattened even when the discharge of the paste into the target cell 851 is completed. When the tip of the discharge nozzle 257 comes into contact with the raised meniscus of the phosphor 852 in the middle of the paste discharge, the paste adheres to the tip of the nozzle 257, so that the fluid flowing out of the nozzle 257 flows into the tip of the nozzle 257. Under the influence of fluid soul, it causes various troubles. Therefore, it is necessary to maintain a sufficient distance H between the tip of the discharge nozzle 257 and the barrier rib apex 854.

  In the third embodiment, H ≧ 0.5 mm is necessary in order to prevent fluid attachment at the nozzle tip. Furthermore, if H ≧ 1.0 mm, fluid adhesion prevention is sufficient, and reliable intermittent discharge over a long period of time can be achieved.

In a state where the gap H between the tip of the discharge nozzle 257 and its opposite surface is kept sufficiently large and the flow path gap sufficiently larger than the powder particle size is maintained while flying high viscosity powder fluid, The method of shooting at high speed in the “independent cell” is enabled by a dispenser as an example of the fluid ejecting apparatus according to the third embodiment of the present invention. To summarize the characteristics of the fluid ejection device according to the third embodiment of the present invention,
(1) Applicable to high viscosity fluids in the order of thousands to tens of thousands mPa · s (cps).
(2) Clogging does not occur even with a discharge material containing a powder diameter of several μm or more.
(3) Intermittent discharge can be performed with a short cycle of msec order or less.
(4) Discharge fluid can fly over a long distance from the discharge nozzle by 0.5-1.0mm or more.
(5) The discharge amount per dot can be secured with high accuracy.
(6) Multi-head is easy and the structure is simple.

  The above (1) to (6) are also necessary conditions for achieving the independent cell type phosphor layer by direct patterning using a dispenser instead of the conventional screen printing method and photolithography method. Hereinafter, the reason why the above (1) to (6) are necessary conditions and the reason why this dispenser has the above characteristics will be supplemented a little.

The reason why the above (1) is required for forming the phosphor layer is that, as described above, the phosphor layer is thickened on the rib wall surface after the discharge and drying, so that the phosphor layer is thickened. This is because it is necessary to use a paste-like fluid having a high viscosity with a reduced amount of solvent as the coating material containing the. Further, one of the reasons why the present invention can cope with a high viscosity fluid of the order of several thousand to several tens of thousands mPa · s (cps), specifically, 5,000 to 100,000 mPa · s, is related to the embodiment of the present invention. In the fluid ejecting apparatus, the thread groove pump portion is used as an example in the fluid supply device, and the pumping pressure for pumping high-viscosity fluid to the piston portion side (discharge chamber) can be easily obtained by this thread groove pump portion. . Further, when a high viscosity fluid is used, a large discharge pressure is generated because the squeeze pressure is proportional to the viscosity. When the generated pressure is P _i = 10 MPa, for example, the piston diameter D ₀ = 3 mm from Table 1, the axial load applied to the piston f = 0.0015 ² × π × 10 × 10 ⁶ ≈70 N. In this embodiment, an electromagnetic strain actuator having a large load resistance that can withstand the load is used on the piston side.

The reason why (2) is required for forming the phosphor layer is that, as described above, in order to obtain a high brightness of the display, phosphor fine particles having a particle size on the order of several microns are usually optimal. Because. The reason why the dispenser as an example of the fluid ejecting apparatus according to the embodiment of the present invention is less likely to be clogged in the flow passage is that the secondary squeeze pressure can be used, and the piston that is most easily clogged and its piston This is because the minimum value h _min of the gap between the opposing surfaces can be set sufficiently larger than the particle size of the powder, for example, h _min = 50 to 150 μm or more.

The reason why the above (3) is required for achieving the independent cell type phosphor layer by direct patterning is as follows. For example, in the case of a 42 inch wide PDP, if the number of pixels is 852 RGB × 480, the number of independent cells = 3 × 408960≈1.33 million. Assuming time T _P = 30 sec allowed for the discharge process of the phosphor, the 100 nozzles attached to the fluid ejecting apparatus, a one shot per time _{T S = 30 × 100/1230000} ≒ 0.0024sec. This value is 1/100 or less of the response of conventional air type and thread groove type dispensers. Therefore, when considering mass productivity, there is a need for a quick response dispenser that far exceeds the conventional type.

One of the reasons why the dispenser as an example of the fluid ejecting apparatus according to the embodiment of the present invention can realize the above (3) is that the gap h _min of the piston end surface can be set large, for example, 50 to 150 μm or more. In the fluid filling process (suction process in the state where the piston is raised) of the thread groove pump part which is an example of the fluid supply device, the thread groove pump part is connected to the discharge chamber (for example, 17 in FIG. 1). This is because the fluid resistance of the flow path can be minimized. Since the fluid resistance R _P (kgs / mm ⁵ ) of the flow path along the radial direction connected to the discharge nozzle is small, the filling time can be shortened even in the case of a highly viscous fluid having poor fluidity.

Further, in the present dispenser, an electromagnetic strain actuator using a piezoelectric element having a high responsiveness of 0.1 msec or less, a giant magnetostrictive element, or the like can be effectively used. The stroke of the electromagnetic strain actuator is limited to about 30 to 50 μm at a practical level. However, since the secondary squeeze pressure is used in this embodiment, a large pressure can be generated even when the gap h _min is large. As can be seen from the equation (12), the secondary squeeze pressure does not depend on the absolute value of the gap h but depends only on the differential dh / dt (speed) of the gap h. Therefore, by making use of the advantages of an electromagnetic strain actuator that can obtain a large speed dh / dt, a discharge pressure having a high peak of 5 to 10 MPa or more can be easily obtained with a sharp and short period.

If this dispenser is used, intermittent discharge of fluid can be realized at a level on the order of msec or less, so even if the substrate is run in a continuous state, sufficiently independent dots can be discharged onto the substrate. In one example of the above-described embodiment, even if the stage moving speed on which the substrate is mounted is set to U _s = 300 to 500 mm / s, intermittent fluid discharge can be performed independently at a predetermined position. Although depending on the “sharpness” of the material to be discharged, if the stage moving speed U _s > 100 mm / s, the stage (see, for example, 179 in FIG. 13C) can be surely driven with a large amount of material to be discharged even in the continuous running state. The material can be intermittently discharged.

  The reason why the above (4) is necessary for forming the phosphor layer by direct patterning is that, as described above, the contact between the phosphor meniscus raised above the top of the barrier rib and the tip of the ejection nozzle in the middle of ejection This is because it is necessary to prevent this. The reason why (4) can be realized is that, as described above, the dispenser is sensitive to the high-speed response of the electromagnetic strain actuator, and discharge pressure having a high peak of 5 to 10 MPa or more is easy. It is because it can be obtained. Using a high peak pressure that overcomes the surface tension of the nozzle tip, it is possible to fly over a long distance even in the case of a high viscosity fluid.

  The reason (5) is required is that the accuracy of the phosphor filling amount in the independent cell is required, for example, about ± 5%. The reason (5) can be realized is that the discharge amount per dot in the intermittent discharge of this dispenser basically does not depend on the stroke of the piston, the absolute position, and the viscosity of the discharged fluid. This is because it is determined only by the pressure flow rate characteristic of a certain thread groove pump part and the flow rate at the operating point of the fluid resistance of the discharge nozzle and the number of discharges per unit time. Specifically, when a thread groove pump unit is used in a pump which is an example of a fluid supply device, a predetermined discharge amount per dot can be set only by changing the intermittent frequency and the rotation speed of the thread groove shaft.

  In the case of a conventional dispenser, the piston stroke, absolute position, and discharge fluid viscosity all have a great influence on the discharge amount, and therefore must be strictly managed. For example, in the case of an air dispenser, the discharge amount is inversely proportional to the fluid viscosity.

  The reason why (6) is required is that, in the case of direct patterning, it is necessary to mount at least several tens of heads on the fluid ejecting apparatus. In order to be able to replace the conventional construction method, maintenance performance comparable to the screen printing method and the photolithography method is required.

  The reason why the above (6) can be realized is that, in the present fluid ejecting apparatus, the fluid discharge amount per dot in the intermittent discharge can be insensitive to the stroke and absolute position of the piston as in the case (5). This is because, for example, the configuration of the piston portion 56) in FIG. 5B can be simplified. In other words, with a conventional dispenser, such as high-precision machining of the relatively moving members (for example, the piston 8 and the housing 4 in FIG. 1), accurate alignment between the members during assembly, and ensuring absolute accuracy of the piston stroke, etc. These required process controls are not so much required with this dispenser. Therefore, the entire multi-head that independently drives a plurality of pistons can be greatly simplified.

  Conventionally, the phosphor layer formation of the PDP independent cell method that had to rely on the screen printing method can be performed by the direct patterning by the fluid ejecting apparatus according to the embodiment of the present invention. As described above, in the case of the conventional screen printing method, when the phosphor material is filled, the material is placed on the top portion of the rib partition wall, so that the “independent cell method” has a problem that leads to crosstalk between the barrier ribs. . Therefore, a measure such as introducing a mechanical processing means for removing the material attached to the top portion of the rib partition wall, for example, a polishing step is essential. In the case of screen printing, due to the nature of the construction method, it is highly possible that the material is placed on the top of the rib partition wall on the entire panel surface, and it is necessary to process the top of all the ribs. However, when the attached material is removed, the fine powder scatters in each cell, which is a major factor that deteriorates the quality of the product. Although it is possible to remove the scattered fine powder by vacuum, electrostatic attraction or the like, it is difficult to restore all of the 1 million or more independent cells to a clean state. Even with direct patterning, there is a possibility that the material is placed on the top portion of the rib partition wall, but the ratio is sufficiently small when compared with screen printing. Therefore, the mechanical processing for removing the material adhering to the top portion of the rib partition wall may be only a part of the panel surface. In the above embodiment, 4/5 or more of the phosphor deletion processing is performed on all the independent cells. It is unnecessary. Even when allowance is anticipated, 2/3 or more phosphor deletion processing is unnecessary.

As described above, the features (1) to (6) of the present dispenser can, of course, be greatly utilized in processes other than the PDP phosphor discharge. For example, the present invention can greatly exert the effect in a fluid ejection process required for “under fill”, “SMT (Surface Mounting Technology)”, “die bonding”, “solder paste” and the like in the field of circuit formation.

[6] Regarding the actuator unit In the above-described embodiment, the piston is driven by a piezoelectric actuator (for example, 56 in FIG. 5B) which is a kind of an electrostrictive element as an example of the axial driving device.

As described above, since the secondary squeeze pressure can be used in this dispenser, a large discharge pressure can be generated even when the gap h _min between the piston end faces is set sufficiently large. For this reason, the disadvantages of the magnetostrictive element having a limited stroke size are not limited in the present invention, and only the advantages of the electrostrictive element having a high response (high speed) can be utilized. Since the gap h _min can be set sufficiently large, the time for filling the piston end face with the high viscosity fluid can be shortened. Therefore, in the dispenser as an example of the fluid ejecting apparatus according to the embodiment of the present invention, the use of the electrostrictive element as an example of the axial direction driving apparatus greatly contributes to the improvement of the responsiveness (productivity) as the ejecting apparatus. It is.

For example, when the present invention is applied to a process of intermittently discharging phosphors in a PDP box-type cell, the conditions of the discharge process, (i) the discharge amount per dot may be constant, (ii) the period is constant (Iii) If the feature of this head is that the discharge flow rate does not depend on the stroke and displacement of the piston, as an example of an axial drive device, resonance instead of a piezoelectric actuator A type of electrostrictive element can be used. As the piezoelectric vibrator, various types such as a disk type, a prismatic type, a cylindrical type, and a Langevin type can be used. In this case, since the load for driving the piston can be greatly reduced, the heat generation of the element can be reduced, and the actuator portion can be greatly simplified. The resonance frequency of the system may be determined using a mechanical resonance point including the mass of the piston and the rigidity of the portion supporting the piston and the electromagnetic strain element. When this resonance type vibrator is used for a multi-head, as a method of correcting the flow rate difference between the heads, a semi-fixed fluid throttle resistor may be provided in the middle of the flow path as will be described later.

[7] Application to Continuous Discharge Now, in this specification, “intermittent discharge” of fluid or “continuous discharge” of fluid is defined from the shape of the discharge pattern of the fluid immediately after being discharged onto the substrate. To do. As shown in FIG. 27A, when the width of the pattern perpendicular to the relative movement direction of the discharge nozzle and the substrate (arrow in FIG. 27A) is a, and the length along the movement direction is b, The case of ≒ b is referred to as “intermittent discharge”. Alternatively, when the discharge pattern is formed in a form substantially proportional to the inner shape of the discharge nozzle, the “intermittent discharge” is similarly used. For example, when the inner surface of the discharge nozzle has an elliptical shape, the pattern of “intermittent discharge” is still an elliptical shape. Basically, the knowledge and device obtained in the present invention can be applied regardless of intermittent discharge or continuous discharge.

  On the other hand, as shown in FIG. 27B, when the width of the pattern perpendicular to the relative movement direction is a and the length along the movement direction is b, “a continuous discharge” is set when a <b. .

The present invention can also be applied to continuous discharge (that is, in the case of a << b) as in the case of drawing a phosphor screen stripe or electrode lines on the display surface. The biggest problem with high-speed continuous discharge is high-quality discharge at the beginning and end of the drawing line. In particular,
(I) At the start of discharge, “thinning”, “cut” or the like does not occur at the start point of the discharge line.
(Ii) Similarly, at the end of ejection, no “overweight”, “reservoir”, etc. occur at the end point of the ejection line.

In order to realize the above (i) and (ii), a start / end control method using a squeeze pressure has already been proposed. 28, 29, 30 the piston of the displacement h respectively against time t, pumping pressure P _p of the thread groove pump portion, the characteristic of the discharge pressure P _i.

Using the fact that the piston driven by the magnetostrictive element can move at high speed,
(I) At the start of discharge (t = t _A ), the piston is lowered and simultaneously the rotation of the motor of the thread groove pump portion is started.
(Ii) At the end of discharge (t = t _B ), the piston is rapidly raised and the rotation of the motor of the thread groove pump section is stopped.

K_S は比例ゲイン定数であり、ピストン有効面積（相対移動する２つの部材の相対移動面の一例としてのピストンの有効面積）をS_p=π（r₀ ²-r_i ²）とすれば、

吐出側（ピストン側）時定数T_１は、

図３１にピストンの変位入力波形h（t）を示す。前記２つの部材の相対移動面例えばピストンがストロークh_st移動するのに要する時間をT_st（s）とし、0≦t≦T_stのときは、ピストン変位はランプ関数h（t）=（h_st/T_st）t+h_minであり、t>T_stのときは、一定値h（t）=h_st+h_minを保つ。 In the (ii), the conditions a negative pressure is generated in the discharge pressure P _i, that is, the condition that the P _min <0, the following is obtained. If the minimum clearance h _min of the piston end face is set sufficiently large, from Equation (11), when h → ∞, from Equation (11) to R _p → 0, from Equation (17) to P _squ1 → 0, from Equation (24) Since the discharge pressure P _i ≈P ₁ , the equation (26) is

K _S is a proportional gain constant, and assuming that the piston effective area (effective area of the piston as an example of the relative movement surface of the two members that move relative to each other) is S _p = π (r ₀ ² −r _i ² ),

Constant T ₁ when the discharge side (piston side)

FIG. 31 shows a displacement input waveform h (t) of the piston. The relative movement surface of the two members, for example, the time required for the piston to move the stroke h _st is T _st (s), and when 0 ≦ t ≦ T _st , the piston displacement is the ramp function h (t) = (h _st / T _st ) t + h _min , and when t> T _st , the constant value h (t) = h _st + h _min is maintained.

t>T_stのとき、

したがって、時間領域（0≦t≦T_st）では、式（41）の右辺の第２項（強制入力項）はステップ入力となるため、P_i=P_i0を初期条件（t=0）とすれば、

式(１７)において、ピストンが降下（隙間が減少：h_st＜0）するとき、すなわちh_st=-|h_st|のとき、t=T_stにおいて吐出圧力は最大値となる。 The differential dh / dt of the piston displacement is, as shown in FIG. 32, when 0 ≦ t ≦ T _st

When t> T _st

Therefore, in the time domain _{(0 ≦ t ≦ T st)} , the second term of the right side of the equation (41) (forced input section) is a step input, the P _i = P _i0 and initial conditions (t = 0) if,

In Expression (17), when the piston descends (gap decreases: h _st <0), that is, when h _st = − | h _st |, the discharge pressure _{reaches the} maximum value at t = T _st .

逆に、ピストンが上昇（隙間が増大：h_st＞0）するとき、すなわちh_st=|h_st|のとき、t=T_stにおいて吐出圧力は最小値となる。

Conversely, when the piston rises (gap increases: h _st > 0), that is, when h _st = | h _st |, the discharge pressure becomes the minimum value at t = T _st .

Now, the maximum value (formula (47)) and the minimum value (formula (48)) of the discharge pressure depend on the initial value P _i = P _i0 of the pressure.

  Hereinafter, the maximum value and the minimum value of the discharge pressure are obtained when the intermittent discharge cycle is sufficiently long, or when the start and end of the continuous discharge line are shut off and opened.

In this case, since the discharge pressure has reached a steady state, it is determined by the PQ characteristic of the thread groove pump section and the throttle resistance R _r + discharge nozzle resistance R _n when the piston starts to rise and when it starts to descend. the following operating point pressure P _C is the initial value P _i0. If flow path resistance R _t can not be ignored, as _{R r → R r + R t} , it may be determined the operating point pressure.

最小圧力は、

但し、

したがって吐出線の終端を遮断できる条件、すなわち、P_imin<0となる条件は、

P _{C in} equation (49) is when h _min is sufficiently large. Therefore the maximum pressure is

The minimum pressure is

However,

Therefore, the condition that can block the end of the discharge line, that is, the condition that _Pimin <0,

  The conditions for drawing the end of the discharge line with high quality have been described above. In order to draw the discharge line with high quality, the piston descending curve should be selected so that an appropriate positive pressure is generated when the piston descends so that the fluid can be discharged smoothly by overcoming the surface tension of the fluid at the nozzle tip. That's fine.

  The above-described device for achieving sharp intermittent cutting can be applied to continuous discharge. For example, the above-described devices such as a method of forming a throttle (an example of a fluid resistance portion), a position where the throttle is formed, a piston tip having a tapered shape, and a thread groove shaft that is inclined with respect to the piston shaft are continuously used. Even in the case of discharge, it is effective.

Further, if the relative traveling speed between the discharge nozzle and the substrate is decreased, a pseudo continuous line can be drawn when high-speed intermittent discharge is performed. Even in this case, all of the above-described devices for realizing sharp intermittent discharge can be utilized.

[8] Conditions for long-distance flight ejection (part 1)
Whether or not the discharge fluid can be discharged and discharged in a state where the distance between the discharge nozzle tip and the substrate is sufficiently maintained is the magnitude of the kinetic energy that can overcome the surface tension acting on the fluid at the discharge nozzle tip, i.e. It depends on the flow velocity of the fluid when passing through the internal passage of the discharge nozzle. If a steep peak pressure is generated in the discharge chamber, the flow velocity of the fluid passing through the discharge nozzle also has a sharp peak. If the peak value of the flow velocity (the maximum flow velocity of the fluid) is v _max (also expressed as V _max , both are the same), the larger the peak velocity value v _{max of the} flow velocity, the easier the fluid will fly. However, if the peak value v _{max of the} flow velocity is too large, the fluid after passing through the nozzles is in a scattered state, so that it is difficult to discharge microscopic dots. Therefore, there are practically an upper limit value and a lower limit value for the peak value v _max of the flow velocity.

Here, assuming high-speed intermittent flight discharge, an approximate expression of the peak value v _max of the flow velocity is obtained.

Assuming that the minimum piston end clearance h _min is set to a sufficiently high level, for example, h _min = 1 to 2 mm, R _p → 0 when h → ∞ from equation (11), P _suq1 from equation (17) → 0, discharge pressure P _i ≒ P ₁ from equation (24). Hereinafter, the maximum peak pressure P _max is obtained in the same manner as in section [7] in which the discharge pressure at the start and end of continuous discharge is obtained. In the formula (47), in the case of intermittent flight discharge, since the maximum peak pressure P _max >> P _i0 , P _max ≈P _st . Therefore, the approximate expression v ^* _max is obtained as follows. However, the time constant T ₁ on the discharge side is obtained from the equation (43). Here, the area of the opening of the discharge port to S _n.

The results of the experiment, when the peak value v ^* _max flow rate was set in the range of _{^{5m / s <v * max <}} 30m / s, immediately after the piston drops, the fluid without remaining in the discharge nozzle tip, fly from the discharge nozzle In addition, it is known that it can be discharged onto the substrate without scattering.

In order to prove the validity of the equation (54), the peak value v _{max of the} flow velocity obtained by strict numerical analysis of the simultaneous differential equation of the equations (26) and (30) under the conditions of Tables 1 and 2 Table 5 shows the result of comparing the approximate solution v ^* _{max according} to Equation (54). However, T _st = T _d . From the results in Table 5, it can be seen that the peak value v _{max of the} flow velocity can be evaluated with sufficient accuracy using the equation (54).

[9] Conditions for long-distance flight discharge (part 2)
As the volume V _s1 on the piston portion side is reduced with the fluid resistance portion interposed therebetween, the time constant T ₁ on the discharge side can be reduced and the discharge nozzle passage flow velocity v _max having a high peak value can be obtained. FIG. 33A shows, as an example, the discharge nozzle passage flow velocity V with respect to time when only the piston portion side volume V _s1 is changed under the conditions described in Tables 1 and 2.

From FIG. 33A, it can be seen that by setting V _s1 <40 mm ³ , v _max > 5 m / s can be achieved, and the flight conditions can be satisfied.

The lower limit value of the volume V _s1 is determined by arranging the throttle resistance (for example, the throttle 304 in the second embodiment) as close as possible to the end surface of the piston (for example, the end surface 305 of the piston 300 in the second embodiment). Can be small. The size of the piston diameter can be selected according to the application, but if the outer diameter Φ3 mm is selected within the practical range and the minimum piston gap h _{min is} 50 μm, V _s1 = 1.5 ² × 3.14 × 0.05 = 0.35 mm ³ is a lower limit value of V _s1 that can be practically used.

33B to 33D are image diagrams showing how the discharge state changes depending on the range of the discharge nozzle passage flow velocity v _max . 500 is a piston (for example, equivalent to the piston 57 in FIG. 8A), 501 is a diaphragm (for example, equivalent to the diaphragm 68 in FIG. 8A), 502 is a discharge nozzle (for example, equivalent to the discharge nozzle 61 in FIG. 8A), 503 is from the discharge nozzle 502 A discharge fluid (for example, corresponding to the fluid 70 in FIG. 8A), 504 is a substrate (for example, corresponding to the substrate 69 in FIG. 8A) immediately after flowing out.
FIG. 33B shows a case where v _max ≦ 5 m / s, and the discharge fluid 503 does not fly and a fluid mass is generated at the tip of the discharge nozzle 502. FIG. 33C shows the case of 5 m / s <v _max <30 m / s. FIG. 33D shows a case where v _mas ≧ 30 m / s, and the fluid 503 after passing through the nozzle is in a scattered state.

[10] Other supplementary explanations (10-1) Process conditions to which the present invention can be applied effectively [5]. As described in an example in “Application Example to PDP Phosphor Discharge”, the dispenser as an example of the fluid ejecting apparatus according to the embodiment of the present invention can cope with, for example, the following process conditions.

(1) Applicable to high viscosity fluids in the order of thousands to tens of thousands mPa · s (cps). There is no restriction on the lower limit of the viscosity. In order to differentiate the characteristics of the present invention, compared with the ink jet method, it can be applied to a fluid having a viscosity of 100 mPa · s or more to which the ink jet method cannot be applied.
(2) Applicable to fluids containing powder with a powder diameter φd <50 μm. The flow path between the two moving members is completely non-contact mechanically. Of course, the lower limit of the powder diameter is not limited.
(3) The intermittent discharge cycle T _P is 0.1 to 30 ms.
(4) Flying discharge is possible with a gap H ≧ 0.5mm between the discharge nozzle and the substrate.

(10-2) Additional features of fluid ejecting apparatus to which the present invention is applied Hereinafter, features of the fluid ejecting apparatus to which the present invention is applied will be additionally described.

(I) The discharge amount Q _s is not easily affected by the viscosity of the discharge fluid.
In the equation (16), the fluid resistances R _n , R _p , and R _s are proportional to the viscosity μ. If the pressure P _s0 of the fluid replenishing device is _{equal to the} maximum pressure P _{max of the} thread groove pump section, the pressure P _s0 is proportional to the viscosity μ. Since the flow rate Q _i = P _i / R _n , the denominator / numerator viscosity μ of the flow rate Q _i is canceled. Therefore, the discharge amount of this dispenser is basically independent of the viscosity. Usually, the viscosity of a fluid varies greatly logarithmically with temperature. The insensitivity to the temperature change is a very advantageous feature in configuring the discharge system.

(Ii) High reliability against clogging in the flow path of the powder fluid.
If the present invention is applied, since the opening area of the flow passage from the suction port of the pump to the discharge nozzle can be made sufficiently large, the reliability with respect to the powder fluid is high. In particular, since the gap h between the piston end faces, which is a flow path connected to the discharge nozzle, can be made sufficiently large, it is extremely advantageous for preventing clogging of powder (for example, a particle size of 7 to 9 μm in the case of a phosphor).

  Hereinafter, a method for setting the gap h will be described.

In the case of the dispenser as an example of the embodiment of the present invention, as described above, two pressures are generated due to the variation in the gap of the relative movement surface (for example, the gap h in FIG. 6). One of them is due to a known squeeze effect, and is a primary squeeze pressure that is proportional to the piston speed dh / dt and inversely proportional to the cube of the gap h. The other is a secondary squeeze pressure generated in proportion to dh / dt and the sum of the throttling resistance R _r and the internal resistance R _s of the fluid replenishing device due to the variation in the gap interval.

Here, the minimum value or average value of the fluctuating gap h is h ₀ .

1 setting range of h ₀ of the discharge amount Q _s per dot strongly affected by the primary squeeze pressure ₀ <h 0 <h _x, the discharge quantity Q _s is insensitive to changes in the gap h ₀ a when the setting range of h ₀ and the h _0> h _x, by setting the gap h ₀ in the range of h _0> h _x, will utilize only the secondary squeeze pressure.

  When only the secondary squeeze pressure is used, the following effects can be obtained.

(I) The discharge amount is not easily affected by the amplitude and position accuracy of the piston driven by the actuator. Moreover, even if the gap h drifts due to thermal expansion, the discharge amount is not easily affected. Therefore, high discharge amount accuracy can be obtained.
(Ii) Since the gap h _min of the discharge portion flow passage that is most likely to be clogged can be made sufficiently large, high reliability can be obtained for the handling of the powder fluid.

Method of obtaining this h _x analytically, hereinafter, supplementary explanation. The flow rate Q _i (= P _i / R _n ) for the gap h ₀ (which may be h _min ) is obtained using the above-described equation (16). This Q _i (= P _i / R _n ) is integrated in one cycle to obtain a total flow rate Q _s per dot. In the range of 0 <h ₀ <h _x , Q _s increases proportionally, and in the range of h ₀ > h _x , Q _s converges to a constant value. That is, the intersection of the curve envelope in 0 <h ₀ <h _x and the straight line in h ₀ > h _x may be set as h _x . The relationship between Q _s and h ₀ may be obtained experimentally.

Alternatively, if it is necessary to finely adjust the flow rate of each head in a multi-head configuration, by using it together with the output flow rate setting method (adjusting the flow rate with the number of revolutions) of the thread groove pump unit as an example of a fluid supply device The minimum gap (for example, h _min = 50 μm in FIG. 6) may be set in the vicinity of h _min ≈h _x where the gradient of the discharge amount with respect to the gap is smooth.

The fact that the flow rate can be adjusted where the gap is large is the most significant feature of the present invention. In the case of discharging a powder fluid such as a phosphor or an adhesive containing fine particles, the minimum clearance δ _min of the flow path may be set larger than the maximum value φd _max of the fine particle diameter.

(Equation 59)
δ _min > φd _max (55)

As a result of many experiments, if the groove depth h ₀ of the thread groove pump part is sufficiently larger than the particle diameter φd _max , the powder fluid flows along the groove part. It is known that the gap δ _r between the fixed-side facing surfaces does not need to be so large. When the gap of the aperture (for example, 304 in FIG. 11 and 254 in FIG. 12A) where δ _r is the smallest gap in this dispenser is set to the following conditions, the powder is almost completely obtained. Can prevent clogging.

(Equation 60)
δ _r > 5 × φd _max (56)

For example, if the particle diameter φd has a distribution of 1 to 10 μm, the aperture gap may be set to δ _r > 50 μm.

As described above, in the embodiment of the present invention, the thread groove type pump unit is used as an example of the fluid supply device. In order to realize the present invention, the pump can be applied to other types of pumps than the thread groove type, but in the case of the thread groove type, various parameters (radial gap, thread groove angle, groove depth, groove and ridge) constituting the thread groove. By changing the ratio, etc., it is advantageous in that the maximum generated pressure P _max , the maximum flow rate Q _max , and the internal resistance R _s (= P _max / Q _max ) can be freely selected. Further, in the case of the thread groove type pump section, the flow passage can be configured in a completely non-contact manner, which is advantageous when handling powder fluid. In the case of the thread groove type pump section, the internal resistance R _s can be increased and the constant flow rate characteristic can be stably maintained.

If the flow passage (for example, 66 in FIGS. 5A and 5B) connecting the thread groove pump portion and the piston portion side as an example on the fluid supply device side is short, the entire flow passage is made into an orifice-shaped restrictor (throttle resistance R _r ). It is good.

  In addition, the form of the thread groove pump part as an example of the fluid supply apparatus in the fluid ejecting apparatus according to the embodiment of the present invention is not limited to the thread groove type, and other types of pumps can be applied. For example, a Mono type, a gear type, a twin screw type, or a syringe type pump called a snake pump can be applied. Alternatively, a pump that simply pressurizes the fluid with high-pressure air may be used.

  FIG. 34 is a model diagram in the case where a gear type is used for a fluid replenishing device in the fluid ejecting apparatus according to the embodiment of the present invention, 700 is a gear pump, 701 is a flow passage, 702a, 702b, and 702c are piezoelectric types, for example. An axial drive device composed of an actuator or the like, 703a, 703b, and 703c are pistons, and 704a, 704b, and 704c are throttles as an example of a fluid resistance unit provided near the piston.

The maximum flow rate Q _max and the maximum pressure P _max of the gear pump 700 are usually obtained theoretically. If this is difficult, the pressure / flow rate characteristics (PQ characteristics in FIG. 35A) are experimentally obtained. Also good. Further, the relationship between the pump pressure and the flow rate is not necessarily linear, and the PQ characteristic connecting the maximum pump pressure P _max and the maximum flow rate Q ^* _max may be a curve. In this case, the internal resistance R _{s of the} pump draws the tangent line of the PQ characteristic at the operating points P _c and Q _c , and the intersection of the x axis is P _max and the intersection of the Y axis is Q _max , R _s = P _max / Q _{It is sufficient} to apply the theory of this research as _max .

The fluid resistances R _n and R _p are usually obtained from well-known theoretical formulas (for example, formulas (10) and (11)). However, if the shape is complicated, numerical analysis may be used or may be obtained experimentally. good. In the case of an orifice whose length of the throttle portion is short with respect to the inner diameter, the linear resistance equation (for example, Equation (10)) does not hold, but in this case, linearizing around the operating point to make the apparent fluid resistance Good.

The viscosity of the discharged fluid often depends on the shear rate. For example, when the fluid passes through the thread groove pump portion and when it passes through the discharge nozzle, the shear rate applied to the fluid is different. In this case, the relationship between the viscosity of the discharged material and the shear rate is obtained in advance by experiments, and the viscosity in each flow passage may be applied from the shear rate applied to the fluid. By this method, the fluid resistances R _n , R _p , R _s , R _{r and the} like can be obtained.

Various forms can be used for the diaphragm resistance R _r provided in the vicinity of the discharge chamber.

  FIG. 35B to FIG. 35D show several examples of apertures that are difficult to clog. FIG. 35B is a view in which the peripheral wall surface protrudes in a ring shape to form a diaphragm. FIG. 35C is a diagram in which the upper part of the peripheral wall surface protrudes greatly downward to form a diaphragm. FIG. 35D is a diagram in which the peripheral wall surface protrudes into a ring shape having a V-shaped cross section to form a diaphragm.

  The piston constituting the piston drive part or the piston part and the cross-sectional shape of the opposing surface may not be circular. The piston may have a rectangular cross-sectional shape. In this case, the radius of a circle having an equivalent area is taken as the average radius.

  The hole shape of the discharge nozzle may not be a perfect circle. For example, when the phosphor layer is formed in an independent cell of the PDP, if the independent cell is rectangular, it is preferable that the hole shape of the discharge nozzle is an ellipse.

  In the pump according to the present embodiment that handles an extremely small flow rate, the stroke of the piston may be on the order of several tens of microns at most, and even if an electromagnetic strain element such as a super magnetostrictive element or a piezoelectric element is used, the limit of the stroke is a problem. Don't be.

  In addition, when a high viscosity fluid is discharged, a large discharge pressure is expected to be generated due to the squeeze action. In this case, since an axial drive device that drives the piston requires a large thrust against high fluid pressure, an electromagnetic strain actuator that can easily generate a force of several hundred to several thousand N is preferably used. Since the magnetostrictive element has a frequency response of several MHz or more, the piston can be linearly moved with high response. Therefore, the discharge amount of the high-viscosity fluid can be controlled with high response and high accuracy.

  As the inner surface shape of the piston and the housing that houses the piston, a cylindrical shape is used in the embodiment. In addition to this method, for example, bi-reflex piezoelectric elements used in ink jet printers and the like are used to form two surfaces that move relative to each other, and a discharge fluid is supplied to a fluid supply device in a discharge chamber formed between the two surfaces. It may be configured to supply.

If the responsiveness is sacrificed, a moving magnet type, moving coil type linear motor, electromagnetic solenoid, or the like may be used for the axial direction driving device for driving the piston. In this case, the stroke restriction is eliminated.

  The perspective view of FIG. 40 shows the overall configuration to which the dispenser that is the fluid ejection device according to the embodiment of the present invention can be applied. The Z-axis direction conveying device includes a master pump (thread groove pump) 1155A (for example, 13B) and a piston portion 1155B (for example, corresponding to 156a to 156f in FIG. 13A and FIG. 13B) is mounted.

  Reference numeral 1150 denotes a PDP panel as an example of a substrate that is held on a stage or a panel support member and is a target to be ejected. A pair of Y-axis direction conveyance devices 1151 and 1152 are provided across both sides of the panel 1150. It has been. Further, the X-axis direction transport device 1153 is mounted on the Y-axis direction transport devices 1151 and 1152 so as to be movable by a pair of Y-axis direction transport devices 1151 and 1152 in the Y-Y ′ direction. Further, a Z-axis direction conveyance device 1154 is mounted on the X-axis direction conveyance device 1153 so as to be movable by the X-axis direction conveyance device 1153 in the arrow X-X ′ direction. The Z-axis direction conveying device 1154 includes a master pump (thread groove pump) 1155A (for example, corresponding to 153 in FIG. 13B) and a piston drive unit 1155B composed of a plurality of pumps (for example, corresponding to 156a156f in FIGS. 13A and 13B). Is mounted so as to be movable in the vertical direction (Z-axis direction) by a Z-axis direction conveying device 1154. Accordingly, the stage or panel support member that holds the panel 1150 is fixed, and the dispenser moves with respect to the fixed panel 1150 to discharge the fluid.

  It is to be noted that, by appropriately combining any of the various embodiments, the effects possessed by them can be produced.

  It should be noted that US application Nos. 10 / 673,495 and 10 / 776,278 and US patent publications US Pat. Nos. 6,558,127 and 6,679,685 cited in the present specification include The technical contents related to the technique in the above cited part are described, and the contents of the above US application and US patent publication are included herein.

  Although the present invention has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various variations and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as being included therein, so long as they do not depart from the scope of the present invention according to the appended claims.

  A fluid ejecting method, a fluid ejecting apparatus, and a display panel according to the present invention are, for example, an adhesive, a clean solder, a phosphor, an electrode material, grease, paint, hot, in a production process in the field of electronic components, home appliances, displays, and the like. It is applicable to intermittent dispensing and supply of various liquids such as melts, chemicals, and foods at high speed and with high accuracy.

It is a partial cross section front view which shows the model of the example of application of the fluid injection apparatus for enforcing the fluid injection method concerning 1st Embodiment of this invention. It is a top view of the fluid ejection. It is a partial cross section front view of the fluid ejecting apparatus showing symbols of pressure and flow rate at each location. It is an expanded sectional front view of a piston part. It is a partial cross section front view which shows the analysis model at the time of considering the compressibility of the fluid. It is a figure which shows the equivalent electric circuit model of the said application example of this invention. 1 is a top view illustrating a fluid ejection device according to a first embodiment of the present invention. It is a partial cross section front view which shows the fluid injection apparatus concerning 1st Embodiment of this invention. It is an expanded sectional front view of the piston part of FIG. 5B. It is a graph which shows piston displacement with respect to time. It is a graph which shows the discharge pressure with respect to time. It is an image figure which shows the outflow state from the discharge nozzle of the fluid in the case of not restrict | squeezing. It is an image figure which shows the outflow state from the discharge nozzle of the fluid at the time of restrict | squeezing. It is a graph which shows the thread groove under pressure with respect to time. It is a graph which shows the discharge pressure with respect to time which used the depth of an aperture | throttle as a parameter. It is a partial cross section front view which shows the fluid injection apparatus concerning 2nd Embodiment of this invention. It is a partial cross section front view which shows the fluid injection apparatus concerning the modification of 2nd Embodiment of this invention. It is a partial cross section front view which shows the fluid injection apparatus concerning 3rd Embodiment of this invention. It is sectional drawing of the AA line of FIG. 12A. It is a top view which shows the multi-head type fluid injection apparatus concerning 4th Embodiment of this invention. It is a partial cross section front view of the fluid injection apparatus concerning 4th Embodiment of FIG. 13A. FIG. 13B is an enlarged view of the vicinity of the discharge port of the fluid ejection device according to the fourth exemplary embodiment of FIG. It is a figure which shows the equivalent electrical circuit model of the fluid injection apparatus concerning 4th Embodiment of this invention. It is a figure which shows piston displacement with respect to time. It is a figure which shows the differentiation of the piston displacement with respect to time. It is a graph which shows piston displacement with respect to time. It is a graph which shows the discharge pressure with respect to time. It is a figure which shows the fluid injection apparatus concerning 5th Embodiment of this invention, and is an expanded sectional front view of a piston part. It is a section front view showing the whole fluid ejecting device concerning a 5th embodiment of the present invention. It is a figure which shows the dot by which the fluid was discharged on the board | substrate by the fluid injection apparatus concerning 6th Embodiment of this invention. It is a graph which shows the rotation speed of the thread groove with respect to time in the fluid injection apparatus concerning 6th Embodiment. It is a graph which shows the discharge pressure with respect to time in the fluid injection apparatus concerning 6th Embodiment. It is front sectional drawing which shows the fluid injection apparatus concerning 7th Embodiment of this invention. It is an expanded sectional view of the C section of Drawing 24A. It is a perspective view supposing the process which implants fluorescent substance in the independent cell of PDP with the fluid injection apparatus concerning the said embodiment. FIG. 26 is a partially enlarged perspective view of FIG. 25. It is an image figure of the inhalation process when a fluorescent substance is driven into an independent cell by the fluid ejecting apparatus according to the embodiment. It is an image figure of a discharge process when a fluorescent substance is driven into an independent cell by the fluid ejecting apparatus according to the embodiment. It is a figure which defines intermittent discharge in the fluid ejecting apparatus concerning the embodiment. It is a figure which defines continuous discharge in the fluid ejecting apparatus concerning the embodiment. It is a graph which shows piston displacement with respect to time in the fluid ejection device concerning the embodiment. It is a graph which shows the pumping pressure with respect to time in the fluid ejecting apparatus according to the embodiment. It is a graph which shows the discharge pressure with respect to time in the fluid injection apparatus concerning the embodiment. It is a graph which shows piston displacement with respect to time in the fluid ejection device concerning the embodiment. It is a graph which shows the differentiation of the piston displacement with respect to time in the fluid injection device concerning the embodiment. It is a graph which shows the flow velocity which passes the discharge nozzle with respect to time in the fluid injection apparatus concerning the said embodiment. In the fluid ejecting apparatus according to the embodiment, it is an image diagram illustrating a discharge state when the maximum fluid flow velocity is v _max ≦ 5 m / s depending on the range of the discharge nozzle passage flow velocity. In the fluid ejecting apparatus according to the embodiment, it is an image diagram showing a discharge state when the maximum fluid flow velocity is 5 m / s <v _max <30 m / s. In the fluid ejecting apparatus according to the embodiment, it is an image diagram illustrating a discharge state when the maximum fluid flow velocity is v _max > 5 m / s. It is sectional drawing which shows the case where a gear pump is used in the fluid injection apparatus concerning the said embodiment of this invention. It is a figure which shows the PQ characteristic of the pump of FIG. It is a figure which shows one form of the aperture_diaphragm | restriction used with the fluid ejection apparatus concerning the said embodiment of this invention. It is a figure which shows another form of the aperture_diaphragm | restriction used with the fluid ejection apparatus concerning the said embodiment of this invention. It is a figure which shows another form of the aperture_diaphragm | restriction used with the fluid injection apparatus concerning the said embodiment of this invention. It is a figure which shows the conventional air pulse system dispenser. It is a figure which shows the structure of the conventional jet type dispenser. It is an enlarged view of the piston part in the suction process of the conventional jet type dispenser. It is an enlarged view of the piston part in the discharge process of the conventional jet dispenser of FIG. 38A. It is a figure which shows an example of the structure of a plasma display panel. It is a perspective view which shows the whole schematic structure of the fluid injection apparatus of the said embodiment of this invention.

Explanation of symbols

1, 50, 150, 450 Thread groove pump part 2, 56, 156a to 156f, 456 Piston part 3, 51, 151, 451 which is an example of fluid supply device Thread groove shaft 3a, 6, 54, 120, 154, 405 , 454 Thread groove 4, 103, 152, 252, 402, 452 Housing as an example of casing 5A, 153, 404A Rotation transmission device 7, 55, 122, 155, 455 Suction port 7A Auxiliary pressure generator 8, 57, 118 , 157a to 157f, 250, 300, 350, 401, 457, 500 Piston 9A, 403A Axial drive device 10, 11 Two surfaces that move relative to each other (piston end surface, fixed side facing surface)
12 Discharge port 13, 63, 162 Thread groove shaft end portion 14, 64, 164a to 164f, 251, 301, 351 Piston outer peripheral portion 15, 66, 253, 303, 353, 460 Flow passage 17, 62, 258, 308, 359 Discharge chamber 18, 68, 121, 165a to 165f, 254, 304, 354, 410, 461, 501 One example of a fluid resistance portion 20 Screw groove chamber 21 Discharge nozzle opening 53, 453 Motor 58, 158a to 158f , 458 Piezoelectric actuator 59, 60 Two surfaces that move relatively (piston end surface, fixed side facing surface)
61,123,159a to 159f, 257,307,358,414,459,502 Discharge nozzle 65,160,252,302,352 Lower plate 67,70,408,503 Fluid to be discharged 69,504 Example of discharge target Substrate 101 First actuator 102 Main shaft 104 Pump part 105 Second actuator 106 Giant magnetostrictive rod 107 Magnetic coil 108, 109 Permanent magnet on the rear side and front side 110 Rear side yoke 111 Front side rod 112 Yoke material 113 Bias spring 114, 116, 117 Bearing 115 Displacement sensor 119 Lower housing 161 Common flow path 163a to 163f Individual flow path 166 Command signal generator 167 Control controller 168a to 168f Driver 169 Position information 179 Stages 255, 256 Relatively moving two surfaces (piston end surface, fixed side facing surface)
305, 306 Two relatively moving surfaces (piston end surface, fixed side facing surface)
309, 360 Open end of flow passage 355, 356 Two surfaces that move relatively (piston end surface, fixed side facing surface)
261, 311, 357, 413 Discharge part 262, 312, 357a Bolt 409 Large diameter part 411, 412 Two surfaces that move relatively (piston end surface, fixed side facing surface)
415 Gap between piston end surface and fixed side facing surface 416 Gap between screw groove and housing 657 Fluid supply device side 700 Gear pump 701 Flow passage 702a, 702b, 702c Axial drive device 703a, 703b, 703c Piston 704a, 704b, 704c Restriction 850 Second substrate 851 Independent cell 851R, 851G, 851B RGB independent cell 852 phosphor 852R, 852G, 852B RGB phosphor 853 nozzle 854 Barrier rib apex

Claims (1)

  A fluid supply device comprising a thread groove shaft, and a rotation transmission device that rotationally drives the thread groove shaft about the shaft center, and a suction port for introducing fluid;
  A piston part having a piston and an axial drive device for moving the piston in the piston axial direction, and having a discharge port for discharging the fluid;
  In a fluid ejection device comprising a flow passage connecting the fluid supply device and the piston part,
  A fluid ejecting apparatus, wherein a gap is formed between the piston and a surface facing the side surface of the piston, and a convex portion is formed on the surface facing the side surface of the piston.

Images