JP2004126424A - Device and method for forming film, display device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film forming device whose film thickness is uniform and even, whose patterning precision is exellent and can suppress tact time, and to provide a film forming method, a display device and a manufacturing method of the display device. <P>SOLUTION: When an orientation film of a liquid crystal display device is manufactured, an ink jet head 2 of the film forming device 10 jets liquid droplets different in sizes in accordance with command signals from a computer 5 and an ink jet head driver 3. Thus, stripe-like first impact lines where the liquid droplets in first sizes are arranged and stripe-like impact lines which are arranged between the first impact lines, which complement regions between the liquid droplets of the first impact lines and in which the liquid droplets in second sizes smaller than the liquid droplets in the first sizes are are arranged formed on a substrate 7. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inkjet type film forming apparatus and a film forming method capable of achieving both uniformity of film thickness and patterning accuracy by applying droplets having different sizes. In addition, the present invention relates to a display device in which the thickness of an alignment film is made uniform and the patterning accuracy is improved by an ink-jet method of applying droplets having different sizes, and a method of manufacturing the same.
[0002]
[Prior art]
For example, when an alignment film of a liquid crystal display device is formed, it is known that the film is formed by an ink-jet method for reasons such as effective use of the material of the film and prevention of adhesion of unnecessary substances such as dust. .
[0003]
In film formation by the ink jet method, it is important to uniformly control the film thickness in order to apply the material of the film as fine droplets.
Patent Document 1 discloses a liquid crystal display element which aims at flattening the surface of an alignment film formed on a colored layer even when there is a difference in the height of a colored layer forming a color filter, and manufacturing the same. A method is disclosed.
Here, by increasing the amount of liquid droplets to be applied in a region where a thick alignment film is required, and decreasing the amount of the liquid droplet to be applied in a region where a thin alignment film is required, finally, The surface of the formed alignment film is planarized.
[0004]
Further, in Patent Document 2, when film formation is performed using an inkjet nozzle in which ejection holes for ejecting droplets are arranged in a line at a predetermined pitch, the pitch of the arrangement of the ejection holes in a certain row is changed to the row. A method for forming an alignment film, which is shifted by a half pitch from the pitch of the arrangement of the injection holes in a row adjacent to the row. According to this technique, in the above-mentioned literature, variation in the amount of overlap of droplets is suppressed, and the thickness of the alignment film formed on a flat substrate is made uniform.
[0005]
In addition, when forming a film using an inkjet method, after ejecting the material droplet, the thickness of the alignment film is measured, and the material droplet is again applied to a portion where the film thickness is less than a predetermined value using an inkjet nozzle. A coating method is known (for example, see Patent Document 3).
[0006]
[Patent Document 1]
JP-A-9-127509 (FIGS. 5 and 6)
[Patent Document 2]
JP-A-9-138410 (FIGS. 1 and 5)
[Patent Document 3]
JP-A-9-166873
[0007]
[Problems to be solved by the invention]
However, in the method described in Patent Document 1, since the amount of the droplet is changed according to the height of the colored layer, it is not possible to form a flat alignment film having a uniform thickness on a flat substrate. Can not.
Further, in the method described in Patent Literature 2, the sizes of droplets to be applied are all the same. Therefore, when the size of the droplet is increased in order to make the film thickness thinner and uniform, the droplet size is large, and the patterning accuracy when patterning the alignment film into a predetermined shape is sacrificed. Become. Conversely, when the size of the droplet is reduced, the patterning accuracy is improved, but the density of the droplet needs to be increased, and the tact time for forming the alignment film increases.
[0008]
When the film is formed while measuring the film thickness as described in Patent Document 3, the applied droplet may start drying during the measurement, and unevenness may occur when a new droplet is ejected. Is high. Further, when the substrate on which the alignment film liquid is applied is moved for film thickness measurement or droplet re-ejection, the movement may cause unevenness in the thickness of the alignment film being formed.
[0009]
Therefore, an object of the present invention is to provide a film forming apparatus having a uniform film thickness, no unevenness, good patterning accuracy, and a reduced tact time.
It is also an object of the present invention to provide a film forming method that is uniform in film thickness, does not cause unevenness, has good patterning accuracy, and can suppress tact time.
Another object of the present invention is to provide a display device in which the thickness of the alignment film is uniform and uniform, the patterning accuracy is good, and the tact time for manufacturing can be suppressed.
It is also an object of the present invention to provide a method for manufacturing a display device in which the thickness of the alignment film is uniform and uniform, the patterning accuracy is good, and the tact time can be suppressed.
[0010]
[Means for Solving the Problems]
The film forming apparatus according to the present invention comprises: a coating unit that receives a command signal, lands droplets of a raw material solution at a predetermined pitch, and applies the solution to an object, and the droplet lands on the coating unit. Control means for outputting the command signal for instructing the size of the liquid droplets, and wherein the coating means responds to the command signal so that the first landing of the stripe in which the droplets of the first size are arranged A second size droplet, smaller than the first size droplet, which is located between the line and the first landing line and complements the area between each droplet of the first landing line. This is a film forming apparatus for forming a stripe-shaped second landing line in which droplets are arranged.
[0011]
Further, the film forming method according to the present invention is characterized in that a stripe-shaped first landing line formed by landing a raw material droplet of a first size on a target at a predetermined pitch, and the first landing line And a stripe-shaped second droplet formed by landing a droplet of a second size smaller than the droplet of the first size, which complements an area between the droplets of the first landing line. 2 is a film formation method for forming a film having a predetermined thickness on the object by forming two landing lines.
[0012]
The display device according to the present invention holds an element to be aligned between a pair of substrates provided with electrodes, changes the alignment direction of the element to be aligned by applying a voltage to the electrode, adjusts the amount of light, and displays an image. A display device for displaying, wherein a first droplet of a first size is formed between a first landing line in a stripe shape and a first droplet of a raw material having a first size landed on the substrate at a predetermined pitch. A second landing in the form of a stripe formed by landing droplets of a second size smaller than the droplets of the first size, which complements an area between the droplets of the first landing line. A display device having an alignment film formed by forming lines and orienting the element to be aligned in a predetermined direction.
[0013]
Further, in the method for manufacturing a display device according to the present invention, the amount of light to be aligned is adjusted by holding the element to be aligned between a pair of substrates having electrodes and changing the alignment direction of the element to be aligned by applying a voltage to the electrodes. A method of manufacturing a display device for displaying an image by performing
A step of forming the electrode on the substrate, a first landing line in a stripe shape formed by landing a raw material droplet of a first size at a predetermined pitch on the substrate on which the electrode is formed, Dropping a droplet of a second size smaller than the droplet of the first size, which complements an area between droplets of the first landing line, between the first landing lines. Forming a second landing line in a stripe shape to form an alignment film, and assembling the pair of substrates with the surfaces on which the alignment film is formed facing each other, and forming the alignment target between the alignment films. Enclosing the element and orienting the element in a predetermined direction.
[0014]
In the present invention, the application unit causes the droplets of the raw material solution of the film to land on the object at a predetermined pitch. In the case of manufacturing a display device, the object corresponds to a substrate on which electrodes are formed, and the film corresponds to an alignment film that sandwiches an element to be aligned and aligns the element in a predetermined direction.
The application unit receives the command signal output from the control unit and changes the size of the droplet that lands on the target object.
[0015]
The coating means is disposed between a first landing line in which droplets of a first size are arranged in a stripe pattern at a predetermined pitch, and a first landing line. A stripe-shaped second landing line in which droplets of a second size smaller than the droplets of the first size are arranged at a predetermined pitch to complement the region is formed.
The first size droplet lands on the object spreads, and the second size droplet spreads to complement the area between them, thereby forming a uniform film with a uniform thickness. Is done.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings.
In the following, embodiments of the present invention will be described using a liquid crystal display device in which an alignment film is formed by an inkjet method as an example.
[0017]
First embodiment
FIG. 1 is a schematic configuration diagram of a film forming apparatus according to the first embodiment of the present invention.
The film forming apparatus 10 illustrated in FIG. 1 includes an alignment film liquid supply device 1, an inkjet head 2, an inkjet head driver 3, an XY table 4, an XY table driver 6, and a computer 5. ing.
[0018]
The alignment film liquid supply device 1 is connected to the inkjet head 2.
An ink jet head (hereinafter, abbreviated as a head) 2 corresponds to an embodiment of a coating unit in the present invention.
The head 2 is connected to a computer 5 via a head driver 3.
The head driver 3 and the computer 5 constitute one embodiment of the control means in the present invention.
[0019]
The computer 5 is also connected to the XY table 4 via the XY table driver 6.
A substrate 7 as an object on which an alignment film is to be formed is placed on the XY table 4.
The head 2 is arranged so as to face the alignment film forming surface of the substrate 7.
In this embodiment, the head 2 is fixed, and the substrate 7 on the XY table 4 is moved in a plane. However, the substrate 7 is fixed and the head 2 is moved in a plane. Needless to say, it may be in a form in which it is performed. Further, it is also possible to adopt a mode in which both the head 2 and the substrate 7 are moved.
[0020]
The alignment film liquid supply device 1 supplies an alignment film liquid, which is a raw material of an alignment film, to the head 2. As the alignment film, a film of an organic polymer material such as polyimide is used.
[0021]
The head 2 is preferably an ink jet type application unit that ejects and applies the alignment film liquid supplied by the alignment film liquid supply device from fine injection holes provided in the plurality of nozzles 20. In the present embodiment, a piezo-type inkjet head is preferably used.
The head 2 receives a command signal from the head driver 3 and applies an alignment film liquid to the substrate 7.
The detailed structure and function of the head 2 will be described later.
[0022]
The head driver 3 outputs an ejection start signal and an ejection stop signal to each nozzle 20 of the head 2 at a predetermined timing to eject the droplet.
Since it is necessary to pattern the alignment film into a predetermined shape, the timing for outputting the ejection control command signals such as the ejection start signal and the stop signal can be individually controlled for each nozzle 20 in the related art. Met. However, drive waveforms such as the pulse width, pulse number, and inclination of the command signal have been common to all nozzles 20 in the past.
On the other hand, in the present embodiment, not only the output timing of the ejection control command signal but also the driving waveform thereof can be individually controlled for each nozzle 20.
[0023]
The XY table 4 includes a table moving mechanism using, for example, a ball screw, and receives a control signal from the XY table driver 6 to move the table on which the substrate 7 is placed on the XY plane. Move.
The XY table driver 6 outputs, based on information from the computer 5, a command signal for giving an instruction such as a movement amount, a movement direction, and a movement timing to the XY table 4.
[0024]
The computer 5 cooperates with the head 2 and the XY table 4 on the basis of information such as the properties of the alignment film liquid, the patterning shape of the alignment film, and the characteristics of the head 2, and performs alignment of a predetermined thickness and shape. A command signal for driving the head 2 and the XY table 4 to form a film is output to the head driver 3 and the XY table driver 6.
[0025]
Here, the structure and function of the nozzle 20 will be described with reference to FIG. As illustrated in FIG. 2A, the nozzle 20 of the piezo-type inkjet head 2 includes a piezo element 22 in an ejection pipe 21.
The alignment film liquid from the alignment film supply device 1 is supplied to the cavity 23 inside the injection tube 21 according to the displacement of the piezo element 22.
[0026]
When a voltage is applied to the piezo element 22 in response to a command signal from the head driver 3, displacement occurs in the piezo element 22. FIG. 2B illustrates a case where the piezo element 22 extends in the vertical direction.
As shown in FIG. 2B, the ejection tube 21 is pressed and deformed by the displacement of the piezo element 22, and the alignment film liquid is discharged from the ejection hole 21a of the ejection tube 21 as a droplet Dp1.
[0027]
The size of the ejection droplet, that is, the ejection amount, depends on the shape and size of the ejection hole 21a, the shape and capacity of the cavity 23, the shape and displacement of the piezo element 22, and the waveform of the driving voltage applied to the piezo element 22. It is determined.
An example in which the ejection amount changes due to the difference in the driving waveform will be described below with reference to FIG.
[0028]
As shown in FIG. 3A, a single pulse S having one pulse is given to the piezo element 22 of the nozzle 20. At this time, the piezo element 22 is displaced such that the alignment film liquid corresponding to the area SA of the pulse S is sucked into the cavity 23 and discharged, and discharges a droplet Dp1 in an amount based on the area SA.
When discharging a droplet smaller than the droplet Dp1, for example, a double pulse W having two pulses as shown in FIG. 3B is applied to the piezo element 22.
When the first pulse W1 of the pulses W is given, the piezo element 22 is displaced so that the alignment film liquid corresponding to the area W1A is sucked into the cavity 23 and discharged. The piezo element 22 is displaced by the second pulse W2 given after the state in which the alignment film liquid is discharged, so that the droplet is pulled back from the ejection hole 21a into the cavity 23. By adding the pull-back operation, it is possible to discharge a small droplet Dp2 having a smaller amount than the droplet Dp1, even if the ejection holes 21a have the same shape and size.
[0029]
As described above, by changing the drive voltage waveform applied to the piezo element 22, in the present embodiment, the same nozzle 20 can realize droplets having a difference of about twice the amount (for example, 240 ng versus 110 ng). Can be.
By changing the capacity of the cavity 23, the shape of the piezo element 22, and the amount of displacement, it is possible to realize a larger difference.
In the present embodiment, the size of the ejected droplet can be individually controlled for each nozzle 20 by changing the pulse width and the drive voltage value of the drive voltage waveform via the head driver 3. .
By adjusting the rise and fall times of the drive waveform, the ejection amount can be more finely adjusted for each nozzle 20.
[0030]
In the first embodiment, a head 2 having an in-line type nozzle row 200 in which the above-described piezo type inkjet nozzles 20 are arranged in one direction at a predetermined pitch as shown in FIG. 4 is used.
As illustrated in FIG. 4, the pitch between the centers of the circular injection holes 21a in the nozzle row 200 is P₀And The number of the injection holes 21a in the nozzle row 200 is 2500 as an example.
[0031]
In the present embodiment, the relative position between the head 2 and the substrate 7 is set at a pitch P in the Y direction in FIG.₂The alignment film is formed on the substrate 7 by applying the liquid droplets of the alignment film raw material while shifting each other. Pitch P₂Is appropriately changed according to conditions such as the pattern of the alignment film and the size of the injection hole 21a.
When forming the alignment film, the head 2 is relatively moved in the Y direction and also moved in the X direction. The moving pitch in the X direction is the pitch P₁And As an example, the head 2 has a pitch P from the initial position PL1 in the Y direction.₂At the position PL2 moved by the distance P, the pitch P₁I know. Further pitch P in Y direction from position PL2₂At the position PL3 shifted by a distance, the head 2 moves in the X direction by a pitch P in the direction opposite to the moving direction from the position PL1 to the position PL2.₁After a minute shift, it returns to the initial position in the X direction.
When the head 2 shifts again to the position PL4 in the Y direction, the pitch P is again shifted in the X direction.₁I know.
As described above, the head 2 is shifted from the initial position by the pitch P in the X direction.₁While repeatedly shifting and returning to the initial position, the pitch P is relatively increased in the Y direction.₂Proceed while shifting. Note that the pitch P₁Is, for example, the pitch P₀1/2 of the size of
[0032]
At this time, the head driver 3 gives the pulse S and the pulse W to the head 2 alternately according to the movement of the head 2.
As an example, the head driver 3 gives a pulse S when the head 2 is located at the position PL1, and gives a pulse W when the head 2 is located at the position PL2. When the head 2 is located at the position PL3, the pulse S is given again.
[0033]
In this way, by alternately giving the command signals indicating the size of the droplet to be ejected, the size of the droplet landed on the substrate 7 is different for each landing line as shown in FIG. become.
In FIG. 4, since the droplets are ejected while moving the head 2 also in the X direction, the landing pitch of the droplets is also shifted between the landing lines.
[0034]
FIG. 5 shows a state in which the first landing line L1 formed by applying the pulse S to the droplet Dp1 on the substrate 7 is formed in a stripe shape. The droplet Dp2 is applied by applying the pulse W between the first landing lines L1, so that the second landing lines L2 are formed in a stripe shape.
The landing pitch of the droplet Dp2 on the landing line L2 is different from the landing pitch of the droplet Dp1 as described above. Therefore, the droplet Dp2 lands at a position that complements the area between the droplets Dp1 on the landing line L1.
[0035]
In this manner, the landing pitch is shifted, and the droplets having different sizes are spread and connected to each other, whereby an alignment film having a uniform film thickness is formed.
As shown in FIG. 5, when each droplet lands in a circular shape, the diameter rd1 of the large droplet Dp1 becomes smaller than the diameter rd1 of the smaller droplet Dp2, as shown in FIG. It is preferable that rd2 be at least twice, preferably three times or more, in order to form an alignment film having a uniform thickness.
According to the present embodiment, it is possible to suppress the thickness unevenness of the alignment film to within ± 5% of the reference thickness. Depending on the conditions such as environmental temperature, wettability, and composition of the alignment film solution, thickness unevenness can be suppressed to within ± 3%.
[0036]
Next, a liquid crystal display device in which an alignment film is formed using the film forming apparatus 10 of the above-described method and a method for manufacturing the same will be described below.
6 to 8 are schematic sectional views illustrating the method for manufacturing the liquid crystal display device according to the present embodiment.
[0037]
In a liquid crystal display device assembled by sandwiching liquid crystal between a pair of panels, a back panel on which a switching element used for switching display / non-display of a pixel is formed is manufactured as follows.
First, as illustrated in FIG. 6A, a display electrode 31, a switching element and a wiring 32 (not shown) are formed on a rear substrate 30.
As the back substrate 30, a glass substrate such as borosilicate glass or quartz glass is used.
As the display electrode 31, a transparent electrode such as ITO (Indium Tin Oxide) is used. The display electrode 31 is patterned on a predetermined shape for each pixel by a known method, and is formed on the rear substrate 30.
[0038]
As the switching element, a TFT (Thin Film Transistor) is preferably used, but another switching element such as a MIM (Metal Insulator Metal) may be used.
When a TFT is used as a switching element, the wiring 32 formed between the display electrodes 31 includes a gate electrode and a source electrode of the TFT. A display pixel is defined by the gate electrode and the source electrode connected to the display electrode 31.
These switching elements and wirings 32 are also formed on the back substrate 30 by a known material and a manufacturing method.
[0039]
The alignment film liquid is applied to the surface of the rear substrate 30 on which the display electrodes 31, the switching elements, and the wirings 32 are formed, using the in-line type head 2 (see FIG. 6B).
By controlling the discharge of each nozzle 20 of the head 2 and the stop of the discharge, the alignment film can be formed by patterning only on the surface 31 a of the display electrode 32.
The rear substrate 30 on which the display electrodes 32 and the wirings 32 are formed corresponds to the substrate 7 in the film forming apparatus 10.
[0040]
At this time, the alignment film liquid is applied so as to alternately form the landing lines L1 and the landing lines L2. The film of the alignment film liquid formed by spreading and connecting the applied droplets is dried and baked to form an alignment film 33 having a predetermined thickness.
[0041]
The back panel 40 is completed by performing a rubbing process on the alignment film 33 thus formed.
The rubbing treatment is to rub the surface of the alignment film 33 by rotating a rubbing roller 36 in which a rubbing cloth such as felt or cotton is wound around the roller 34 as shown in FIG. 6C.
[0042]
Next, a method for manufacturing a front panel on which a color filter layer is formed will be described.
The color filter layer 51 including the red filter 51r, the green filter 51g, and the blue filter 51b is formed on the front substrate 50 by a known method such as a dyeing method using a dye or a pigment, a dispersion method, and an electrodeposition method (FIG. 7 (d)).
As front substrate 50, for example, a glass substrate similar to rear substrate 30 is used.
As required, a black matrix is formed between the filters 51r, 51g, and 51b. The black matrix is provided for the purpose of improving contrast, preventing color mixing in a filter material, shielding light from a TFT, and the like.
[0043]
As shown in FIG. 7E, a common electrode 53 is formed on the surface of the front substrate 50 on which the color filter layer 51 is formed, with a protective film 52 interposed therebetween.
The common electrode 53 is formed by a known method such as sputtering or vapor deposition using a transparent electrode such as ITO.
[0044]
Further, as in the case of the back panel 40, an alignment film liquid is applied to the common electrode 53 by an inkjet method using the head 2, dried, and fired to form an alignment film 54. In this case, the front substrate 50 on which the common electrode 53 is formed corresponds to the substrate 7 in FIG.
The formed alignment film 54 is subjected to a rubbing process using a rubbing roller 36.
Thus, the front panel 55 is completed (see FIG. 7F).
[0045]
FIGS. 7D to 7F show a state in which the respective components are arranged toward the lower side in the figure in order to indicate that the manufacturing process is the front panel. However, when the front panel 55 is actually manufactured, it goes without saying that the front panel 55 is not necessarily manufactured in the state shown in FIGS. 7D to 7F.
[0046]
The completed rear panel 40 and front panel 55 are arranged such that the alignment films 33 and 54 face each other via the spacer 57 as illustrated in FIG.
As the spacer 57, a resin such as a melamine resin or a urea resin, or a material such as glass is used.
[0047]
As illustrated in FIG. 8H, a liquid crystal 60 is injected between the alignment films 33 and 54 by, for example, vacuum suction. At the periphery of the display area, the liquid crystal 60 is sealed by bonding the back panel 40 and the front panel 55 using a sealing agent (not shown).
Polarizing plates 62 and 64 are attached to the exposed surfaces of the rear substrate 30 and the front substrate 50, respectively.
The liquid crystal display device 70 is completed by connecting electronic components for driving to the liquid crystal panel manufactured in this manner by using, for example, a TAB (Tape Automated Bonding) method.
Note that the liquid crystal display device 70 corresponds to one embodiment of the display device of the present invention, and the liquid crystal 60 corresponds to one embodiment of the alignment element of the present invention.
[0048]
In the liquid crystal display device 70, the display electrode 31 to which the voltage is applied is selected by appropriately selecting the gate electrode and the source electrode of the TFT and applying the voltage.
An image is displayed by changing the arrangement direction of the liquid crystal molecules by the electric field applied between the selected display electrode 31 and the common electrode 54, and changing the light transmittance according to the value of the applied voltage. You.
[0049]
In the first embodiment, the landing pitch of the droplet is shifted for each landing line, and the size of the droplet is also different for each landing line.
In the case where the droplet size is the same even if the landing pitch is shifted, as in the related art, in order to make the film thickness uniform, an orientation film having a uniform film thickness is formed by spreading the droplet. In view of this, it is conceivable to improve the wettability and increase the size of the droplet. However, in this method, the patterning accuracy is deteriorated in the peripheral portion of the formation region of the alignment film.
Conversely, when small droplets are applied close to each other, the overlap between the droplets increases and the film thickness increases. In addition, the uniformity of the film thickness tends to deteriorate. Further, the tact time becomes longer and the productivity decreases.
[0050]
In the conventional method, the size of the droplet is appropriately changed. However, if the landing pitch is not shifted for each landing line, unevenness in the spread of the droplet is likely to occur. Therefore, when forming a film on a flat substrate, it is difficult to form an alignment film having a uniform thickness.
[0051]
However, in this embodiment, by applying a droplet Dp2 smaller than the droplet Dp1 to replenish the alignment film liquid in a region where the droplets Dp1 are unlikely to overlap with each other, in a region having the same wettability condition, The uniformity of the film thickness and the patterning accuracy can be controlled with high accuracy. It is possible to suppress an increase in the tact time for forming the alignment films 33 and 54, and it is also possible to improve the productivity of the liquid crystal display device 70. Further, the thickness of the alignment films 33 and 54 can be made smaller than before while maintaining uniformity.
[0052]
Second embodiment
The size of the droplet can be changed not only by changing the driving waveform of the voltage applied to the piezo element 22 but also by changing the size of the ejection hole 21a of the nozzle 20. Hereinafter, a second embodiment of the present invention in which droplets of different sizes are realized by a variable nozzle will be described.
[0053]
FIGS. 9A and 9B are cross-sectional views showing the structure of the main part of the nozzle according to the second embodiment.
The nozzle 25 shown in FIG. 9A is obtained by further attaching a piezo element 27 to the side surface of the injection pipe 21 of the nozzle 20 shown in FIG. The other configuration is the same as that of the nozzle 20, and therefore, the same components are denoted by the same reference numerals and detailed description thereof will be omitted.
[0054]
By applying a pulse C of a voltage causing a displacement to the piezo element 27, the side wall of the injection pipe 21 is pressed and slightly deformed elastically. As a result, the injection hole 21a becomes a smaller injection hole 21b.
On the other hand, the piezo element 22 is applied with a single pulse S ′ similar to the pulse S for sucking and discharging the alignment film liquid into the cavity 23. However, since the injection hole 21b is smaller than the injection hole 21a, the area of the pulse S 'is smaller than the area of the pulse S.
[0055]
As described above, by applying both the pulse S ′ and the pulse C to adjust the amount of deformation of the injection tube 21, the droplet Dp2 having the same size as that when the pulse W is applied in the first embodiment can be discharged. (See FIG. 9B).
When the application of the pulse C to the piezo element 27 is stopped, the side wall of the injection tube 21 returns to the original position, and the injection hole 21b returns to the injection hole 21a.
The application timing of the pulse S 'and the pulse C is appropriately adjusted so that the droplet Dp2 having a desired size is ejected.
[0056]
As shown in FIG. 10, the nozzles 25 are arranged in an in-line type in the head 2 as in the case of the first embodiment. The arrangement pitch of the injection holes 21a at this time is also the arrangement pitch P in the case of the first embodiment shown in FIG.₀Is the same as The number of the injection holes 21a is also, for example, 2500.
The head 2 having the in-line type nozzle row 200 using the nozzles 25 has a pitch P in the Y direction even when the alignment film is formed, as in the first embodiment.₂Deviate by one.
In the X direction, the pitch P₁If it shifts by one, the returning operation is repeated.
[0057]
At this time, for example, a pulse S is applied to the head 2 at the initial position PL1 in FIG.₂The pulse S and the pair of the pulse S 'and the pulse C are alternately applied to the head 2 such that both the pulse S' and the pulse C are applied at the position PL2 shifted by a minute.
Thus, each time the nozzle row 200 moves in the Y direction, the injection holes alternately change from the injection holes 21a to the injection holes 21b. As a result, the landing pattern formed by the discharged droplets is as shown in FIG. 5, as in the case of the first embodiment.
[0058]
The size of the circular injection hole 21a is minute, and even when the minute injection hole 21a is deformed to become the injection hole 21b, the shape can be considered to be substantially circular. At this time, the diameter r of the injection hole 21a₀Is the diameter r of the injection hole 21b.₁It is preferable that the size of the droplets Dp1 and Dp2 be at least two times, preferably three times or more.
The other points related to the film forming apparatus, the liquid crystal display device in which the alignment film is formed using the film forming apparatus, and the method of manufacturing the same are the same as those in the first embodiment, and thus the description is not repeated.
[0059]
As described above, also in the second embodiment, similarly to the first embodiment, a landing pattern in which the landing pitch of droplets is shifted for each landing line and the size of the droplet is different is realized. be able to. Therefore, the uniformity of the film thickness and the patterning accuracy can be controlled with high accuracy. Further, it is possible to suppress an increase in the tact time for forming the alignment films 33 and 54, and it is also possible to improve the productivity of the liquid crystal display device 70. Furthermore, the thickness of the alignment films 33 and 54 can be made smaller than before while maintaining uniformity.
[0060]
Third embodiment
The nozzle row of the inkjet head 2 does not need to be one, and may be plural.
In FIG. 11, as an example, the head 2 according to the third embodiment having two nozzle rows 200 and 210 is shown from the injection hole side.
[0061]
In the head 2 shown in FIG. 11, the arrangement pitch of the injection holes 21a is set in parallel with the first nozzle row 200 by the pitch P₁A second nozzle row 210 that is separated is arranged.
The injection holes of the nozzle row 200 and the injection holes of the nozzle row 210 are the same injection holes 21a, and the arrangement pitch is the same.₀It is.
The center of the injection hole 21a of the nozzle row 200 and the center of the injection hole 21a of the nozzle row 210₂Are off by minutes.
[0062]
Also in the third embodiment, when forming an alignment film using the head 2 shown in FIG. 11, droplets are ejected while shifting the head 2 by a predetermined pitch in the Y direction in the figure. The moving pitch of the head 2 is, for example, a pitch P₂It is twice as large as
Then, the head driver 3 applies the above-described pulse S to the nozzle row 200 and applies the pulse W to the nozzle row 210 to discharge the alignment film liquid.
Thereby, also in the third embodiment, the impact pattern shown in FIG. 5 can be obtained.
The other points are the same as those of the first and second embodiments, and the detailed description is omitted.
[0063]
Also in the third embodiment, the same effects as in the first and second embodiments can be obtained. In addition, since the alignment film liquid is applied two rows at a time, the tact time is shorter than in the first and second embodiments, and the productivity is improved.
When the XY table 4 is fixed and the head 2 is moved, the head 2 is moved in the X direction in order to shift the landing pitch of the droplets in the landing line L1 and the landing line L2 shown in FIG. Since there is no need, droplets can be landed with higher precision. For this reason, the uniformity of the thickness of the alignment film and the patterning accuracy can be improved.
[0064]
Fourth embodiment
In the head 2 according to the fourth embodiment of the present invention shown in FIG. 12, the nozzle row 210 of the head 2 according to the third embodiment shown in FIG. 11 is changed to a nozzle row 220 in which the injection holes 21b are arranged at a predetermined pitch. It was done.
The arrangement pitch of the circular injection holes 21b is the same pitch P as the arrangement pitch of the injection holes 21a of the nozzle row 200.₀And
In the second embodiment, the diameter of the injection hole is changed by applying the pulse C to the piezo element 27. However, in the present embodiment, the piezo element 27 is not used, and the diameter r of the injection hole 21 b of the nozzle row 220 is set.₁And the diameter r of the injection hole 21a of the nozzle row 200₀Is immutable.
[0065]
The pulse S is applied to the nozzle row 200 via the head driver 3, and the above-described pulse S ′ is applied to the nozzle row 220. As a result, the droplet Dp1 is ejected from the nozzle row 200, and the droplet Dp2 is ejected from the nozzle row 220.
Except for the above, the fourth embodiment is the same as the previous embodiments. The head 2 illustrated in FIG. 12 has, for example, a pitch P₂The raw material droplets are ejected while moving at a pitch twice as large as the above. The diameter r of the injection hole 21a₀Also, as in the case of the second embodiment, the diameter r of the injection hole 21b is₁It is preferably at least twice, preferably at least three times, from the viewpoint of discharging the droplets Dp1 and Dp2, respectively.
Other detailed description is omitted here.
[0066]
According to the fourth embodiment as well, the impact pattern shown in FIG. 5 can be obtained as before. Therefore, the same effect as in the above-described embodiment can be obtained.
In addition, in the present embodiment, the diameter r of the injection holes 21a and 21b₀, R₁Is constant, the sizes of the droplets Dp1 and Dp2 can be defined with higher precision, and the film thickness can be further uniformed.
[0067]
Fifth embodiment
The ejection amount of the head 2 varies depending on the ejection cycle, that is, the repetition frequency, even for the same head.
FIG. 13 is a graph showing the relationship between the repetition frequency and the discharge amount. In FIG. 13, the horizontal axis represents the repetition frequency [kHz], and the vertical axis represents the discharge amount [ng] for each nozzle 20.
[0068]
FIG. 13 shows that the ejection amount decreases as the repetition frequency increases. Due to the inverse relationship between the repetition frequency and the discharge amount, when a required amount of the alignment film liquid is applied over a wide range, the relative moving speed of the head 2 and the substrate 7 becomes slow and the tact time becomes long. May occur.
In order to solve this disadvantage, in the fifth embodiment, as shown in FIG. 14, a head in which a plurality of heads 2 according to the third embodiment are combined is used.
[0069]
In the head 2 shown in FIG. 14, two pairs of the nozzle row 200 and the nozzle row 210 according to the third embodiment shown in FIG. 11 are arranged in parallel.
Conditions such as the arrangement pitch of the injection holes 21a in each nozzle row and the pitch between the nozzle rows are the same as in the case of the third embodiment.
A pulse S is applied to the nozzle row 200, and a pulse W is applied to the nozzle row 210.
Thereby, even if the nozzle 2 according to the fifth embodiment is used, the impact pattern shown in FIG. 5 can be obtained.
[0070]
In the fifth embodiment, since the number of nozzles 20 for discharging the alignment film liquid is larger than in the above-described embodiment, the alignment film can be formed over a wide range at a time. Therefore, it is possible to shorten the tact time for forming the alignment film as compared with the case of the above-described embodiment.
Needless to say, the tact time can be further reduced by further increasing the number of nozzle rows to be combined.
It is needless to say that a similar effect can be obtained by using the nozzle row 220 shown in FIG. 12 instead of the nozzle row 210 and applying the pulse S ′ to the nozzle row 220.
[0071]
The above embodiment is an example for describing the present invention, and the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, different drive waveforms are given for each nozzle row, but the same drive waveform is given to each nozzle of one nozzle row in common. However, in the present invention, it is also possible to give a different drive waveform to each nozzle individually.
In the case of the piezo-type inkjet nozzle, even when the same drive waveform is given to the same one nozzle at the start of the discharge operation and after the drive is stabilized after a predetermined time from the start of the discharge, FIG. As shown, it is known that the size of the discharged droplet Dp is different.
Further, even when the same drive waveform is commonly applied to the nozzles 20 of the nozzle row in which the same nozzles 20 are arranged, the size of each droplet Dp of the landing line L3 formed by ejection is limited. It is known that there is variation for each nozzle 20 as shown in FIG.
In the present invention, by taking into account such a variation in the size of the droplet Dp, the applied drive waveform is changed for each nozzle 20 to absorb fluctuations and variations in the ejection conditions, thereby achieving higher precision formation. A membrane can be realized.
[0072]
Further, a test ejection may be performed when the head 2 is replaced, the size of the droplet Dp may be measured and observed, and the result may be fed back to be reflected in the driving parameters of the head driver 3. This makes it possible to suppress in advance the fluctuation in the size of the droplet Dp immediately after the start of the discharge operation, and to achieve effects such as stabilization of film formation quality, reduction of maintenance time, and reduction of discharge condition indexing time. it can.
Further, the present invention can be applied not only to the production of an alignment film but also to the production of any film using an inkjet method. Further, the present invention is not limited to a liquid crystal display device, and the present invention can be applied to any display device using an alignment film and a method for manufacturing the same.
[0073]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a film forming apparatus having a uniform film thickness, no unevenness, good patterning accuracy, and a reduced tact time.
It is also possible to provide a film forming method which is uniform in film thickness, does not cause unevenness, has good patterning accuracy, and can suppress tact time.
Further, according to the present invention, it is possible to provide a display device in which the thickness of the alignment film is uniform and uniform, the patterning accuracy is good, and the tact time for production can be suppressed.
Further, it is possible to provide a method for manufacturing a display device, in which the thickness of the alignment film is uniform and uniform, the patterning accuracy is good, and the tact time can be suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a film forming apparatus according to an embodiment of the present invention.
FIG. 2A is a cross-sectional view illustrating a schematic structure of a main part of a nozzle of an inkjet head according to an embodiment of the present invention, and FIG. 2B is a cross-sectional view illustrated in FIG. FIG. 4 is a cross-sectional view illustrating a state in which droplets are discharged using a nozzle.
FIG. 3A is a diagram illustrating a state in which a pulse is applied to the nozzle illustrated in FIG. 2 to discharge one droplet of a first size by applying one driving voltage; FIG. 3B is a diagram illustrating a state in which a pulse applies two drive voltages to eject a droplet of a second size.
FIG. 4 is a diagram showing the ink jet head according to the first embodiment of the present invention and the movement at the time of film formation from the side of the droplet ejection holes.
FIG. 5 is an example of a droplet landing pattern obtained by the present invention.
FIGS. 6A to 6C are cross-sectional views illustrating an example of a method for manufacturing a liquid crystal display device according to an embodiment of the present invention.
FIGS. 7 (d) to 7 (f) are cross-sectional views illustrating an example of a method for manufacturing a liquid crystal display device according to an embodiment of the present invention, following FIGS. 6 (a) to 6 (c).
FIGS. 8G and 8H are cross-sectional views, following FIGS. 7D to 7F, illustrating an example of a method for manufacturing a liquid crystal display device according to an embodiment of the present invention.
9A is a cross-sectional view illustrating a schematic structure of a main part of a nozzle of an inkjet head according to a second embodiment of the present invention, and FIG. 9B is a cross-sectional view of FIG. FIG. 3 is a cross-sectional view illustrating a state in which droplets are ejected using the illustrated nozzle.
FIG. 10 is a diagram showing an ink jet head according to a second embodiment of the present invention and the movement during film formation from the side of the droplet ejection holes.
FIG. 11 is a diagram illustrating an inkjet head according to a third embodiment of the present invention, as viewed from a droplet ejection hole side.
FIG. 12 is a diagram illustrating an inkjet head according to a fourth embodiment of the present invention, as viewed from a droplet ejection hole side.
FIG. 13 is a graph showing a relationship between a discharge repetition frequency and a discharge amount of the inkjet head according to one embodiment of the present invention.
FIG. 14 is a diagram illustrating an ink jet head according to a fifth embodiment of the present invention, as viewed from a droplet ejection hole side.
FIG. 15 (a) is a diagram showing a change in droplet size at the start of ejection and after drive stabilization when a conventional inkjet head is used, and FIG. 15 (b) is the same. FIG. 9 is a diagram showing variations in droplet size when the same conventional drive waveform is applied to a nozzle row in which nozzles are arranged.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Orientation film supply apparatus, 2 ... Ink jet head, 3 ... Ink jet head driver, 4 ... XY table, 5 ... Computer, 6 ... XY table driver, 7 ... Substrate, 10 ... Film forming apparatus, 20, 25 ... Nozzle, 21 ... Injection tube, 21a, 21b ... Injection hole, 22, 27 ... Piezo element, 23 ... Cavity 30 ... Back substrate, 31 ... Display electrode, 31a ... Electrode surface, 32 ... Wiring, 33, 54 ... Alignment film , 34: roller, 35: rubbing cloth, 36: rubbing roller, 40: rear panel, 50: front substrate, 51: color filter layer, 51r: red filter, 51g: green filter, 51b: blue filter, 52: protective film 53, common electrode, 55, front panel, 57, spacer 60, liquid crystal, 62, 64, polarizing plate, 70, liquid crystal display device, 200, 2 0,220 ... nozzle array, Dp, Dp1, Dp2 ... droplets, L1～3 ... first to third landing line

Claims (12)

Receiving a command signal, applying means for applying the solution to a target object by landing droplets of the raw material solution at a predetermined pitch,
The coating unit has a control unit that outputs the command signal that indicates the size of the landed droplet,
The application unit is configured to respond to the command signal,
A first landing line in a stripe shape in which the droplets of the first size are arranged,
A second size droplet, smaller than the first size droplet, is disposed between the first landing lines and complements the area between each droplet of the first landing line. A film forming apparatus for forming an arranged stripe-shaped second landing line. The coating means has a nozzle row in which a plurality of injection holes are arranged at equal intervals in a predetermined direction at a predetermined pitch,
When forming the first landing line, the control unit outputs the command signal for ejecting the droplets of the first size from the nozzle row to the coating unit, and the second landing line 2. The film forming apparatus according to claim 1, wherein when forming a line, the command signal for ejecting the droplet of the second size from the nozzle row is output to the coating unit. 3. The application means has a variable nozzle row in which a plurality of injection holes are arranged at regular intervals in a predetermined direction at a predetermined pitch, and the diameter of the injection holes changes according to the command signal.
When forming the first landing line, the control unit increases the diameter of the variable nozzle row and ejects the droplet of the first size to form the second landing line. 2. The film forming apparatus according to claim 1, wherein in the case, the command signal for causing the diameter of the variable nozzle row to be small and ejecting the droplet of the second size is output to the coating unit. The coating means includes: a first nozzle row in which a plurality of injection holes are arranged at regular intervals at a predetermined pitch in a predetermined direction; and the injection holes are arranged in parallel with the first nozzle row at a predetermined pitch. A second nozzle row,
The control unit is configured to apply the command signal for ejecting the droplets of the first size from the first nozzle row and ejecting the droplets of the second size from the second nozzle row. 2. The film forming apparatus according to claim 1, wherein the film is output to a means. The film forming apparatus according to claim 4, wherein the diameter of each injection hole of the second nozzle row is smaller than the diameter of each injection hole of the first nozzle row. 2. The landed droplet having a circular shape, and the diameter of the landed first size droplet is at least twice the diameter of the landed second size droplet. 3. Film forming equipment. A first droplet of a first size is disposed between a first landing line in a stripe shape formed by landing a raw material droplet of a first size on a target at a predetermined pitch, and the first landing line is arranged between the first landing line and the first landing line. Forming a second landing line in the form of a stripe formed by landing droplets of a second size smaller than the droplets of the first size to complement a region between the droplets, A film forming method for forming a film having a predetermined thickness on an object. 8. The landed droplet having a circular shape, and the diameter of the landed first size droplet is at least twice the diameter of the landed second size droplet. 9. Film formation method. A display device that holds an element to be aligned between a pair of substrates including electrodes, changes the alignment direction of the element to be aligned by applying a voltage to the electrode, adjusts the amount of light, and displays an image,
A first landing line having a stripe shape formed by landing material droplets of a first size on the substrate at a predetermined pitch, and a first landing line; A second landing line in a stripe shape formed by landing a droplet of a second size smaller than the droplet of the first size, which complements an area between the droplets, is formed and generated. And a display device having an alignment film that holds the element to be aligned and aligns the element in a predetermined direction. The display device according to claim 9, wherein the element to be aligned is a liquid crystal. A method for manufacturing a display device that holds an element to be aligned between a pair of substrates provided with electrodes, changes the alignment direction of the element to be aligned by applying a voltage to the electrode, adjusts the amount of light, and displays an image. So,
Forming the electrode on the substrate;
A stripe-shaped first landing line formed by landing, at a predetermined pitch, a raw material droplet having a first size on the substrate on which the electrode is formed, and between the droplets of the first landing line. A second landing line having a stripe shape formed by landing a droplet of a second size smaller than the droplet of the first size, which complements an area, between the first landing lines. Forming and forming an alignment film;
And assembling the pair of substrates with the surfaces on which the alignment films are formed facing each other, enclosing the element to be aligned between the alignment films and aligning the devices in a predetermined direction. The method for manufacturing a display device according to claim 11, wherein the alignment target element is a liquid crystal.

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