JP2777729B2 - Electrophoretic display device and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using electrophoretic particles, and more specifically, to one flexible electrode plate made of a resin film or the like, and a display device. In a dispersion type electrophoretic display device using a porous spacer for dividing the dispersion system into small sections into a discontinuous phase, the porous portion of the porous spacer is formed of a swellable member, Dispersion-split electrophoresis in which a dispersion system for display is disposed around the perforated portion so that the dispersion system can be easily and reliably sealed in each hole of the porous spacer. The present invention relates to a display device and a method for manufacturing the same.

"Prior art and its problems" As shown in FIG. 3, this type of electrophoretic display device using electrophoretic particles has indium oxide and
Two transparent glass plates 1 and 3 on which required display electrode patterns 2 and 4 were separately formed using an appropriate transparent conductive member such as tin were provided, and electrophoretic particles 6 were dispersed in a liquid dispersion medium. It has a structure in which a sealing member 5 also serving as a spacer is provided at an outer peripheral portion so as to enclose the dispersion system 7 between the opposing gaps.

Such an electrophoretic display device has electrode patterns 2, 4
By applying an electric field to the dispersion system 7 to change the distribution state of the electrophoretic particles 6 so that the electrophoretic particles 6 can be adsorbed and separated from the electrode patterns 2 and 4 by applying a display driving voltage to the dispersion system. A change in the optical characteristics of No. 7 causes a desired display operation of characters, symbols, figures, etc. to be performed.

In the case where the dispersion system 7 is formed in a continuous phase by the sealing member 5 provided at the end as described above, the dispersion system 7 is caused by non-uniform electric field strength due to uneven spacing between the two electrode patterns 2 and 4. As a result, the electrophoretic particles 6 move in a direction parallel to the electrode pattern surface, causing a bias in the concentration distribution of the electrophoretic particles. As a result, when the electrophoretic display device is used repeatedly for a long time, the concentration of the electrophoretic particles locally increases. There is a problem that the display becomes uneven or display unevenness occurs.

Therefore, as a means for solving such inconvenience, the dispersion system 7 is divided into small sections into a discontinuous phase by enclosing the dispersion system in each of the through holes using a porous spacer having a large number of through holes. Structures for encapsulation are also known in JP-A-49-32038, JP-A-59-34518 and JP-A-59-171930.

However, in the case of the above-described known example of a dispersion-division-type electrophoretic display device in which a dispersion system is divided into small sections by using a porous spacer, a substrate film is used for both electrode plates. In this method, a gap is easily formed between the porous spacer and the electrode plate due to deformation of the film or the like, and there is a possibility that the uneven distribution of the electrophoretic particles may occur. In addition, when both electrode plates are made of a glass plate substrate, there is a portion where a gap is left between the porous spacer and the electrode plate due to the relationship between the flatness of the glass plate and the distribution of the thickness of the porous spacer. So
Even with this structure, it is not easy to prevent the uneven distribution of the electrophoretic particles.

Furthermore, in the case of a cell structure in which both electrode plates and the interposed porous spacer are bonded in advance, it is extremely difficult to uniformly inject the dispersion into each hole of the porous spacer. In addition to various manufacturing difficulties associated with the above, there is a possibility that incomplete portions of the dispersion injection may occur and display defects may occur, and a problem to be solved in obtaining a highly reliable display device is: Many.

[Means for Solving the Problems] The present invention relates to a dispersion type electrophoretic display device using a porous spacer, wherein the porous spacer is composed of a swellable member and dispersed around the porous portion. By providing a liquid reservoir for the system and making one of the electrode plates flexible, it is possible to easily and surely inject the dispersion into each hole of the porous spacer, and after sealing. Another object of the present invention is to provide an electrophoretic display device whose main purpose is to prevent generation of an air portion due to excessive swelling of a porous spacer, and a method of manufacturing the same.

Therefore, according to the electrophoretic display device of the present invention, at least one of the transparent electrophoretic particles is dispersed via a swellable porous spacer between a pair of opposedly arranged electrode plates configured to be transparent. In an electrophoretic display device having a structure in which a system is divided into a discontinuous phase and sealed, the one electrode plate is configured to be flexible so as to be able to adhere to the swellable porous spacer, and the other electrode plate is formed. Is formed of a transparent rigid body, while the swellable porous spacer is provided in an end peripheral region thereof and is bonded and fixed to the flexible electrode plate; and the adhesive fixed portion and the porous spacer And a dispersion liquid reservoir provided between the porous region and the peripheral region of the porous portion. With such a configuration, air generation in the porous portion due to excessive swelling of the porous spacer is suitably prevented. it can.

Then, in order to manufacture such a dispersed system electrophoretic display device, a flexible electrode plate and a transparent rigid electrode plate each having a required electrode pattern formed on one surface of each of a film member and a transparent glass plate are provided. Is prepared, on the electrode pattern side of the rigid electrode plate, a porous portion necessary for a porous spacer is formed of a swellable member, and a peripheral region of the porous portion is provided through a liquid reservoir of a display dispersion system. After disposing an adhesive fixing portion with the flexible electrode plate and excessively supplying a dispersion system in which electrophoretic particles are dispersed in the porous portion of the porous spacer and the liquid reservoir, the flexible electrode plate Is disposed on the porous spacer so that the electrode pattern faces the electrode pattern of the rigid electrode plate, and then a pressing force is applied to the upper surface of the flexible electrode plate to form an extra dispersion system. The above-mentioned adhesive disposed around the outer periphery of the porous spacer while being extruded It is preferable that the method includes a step of fixing the fixed portion and the flexible electrode plate and enclosing the dispersion system in each hole of the porous spacer. It is possible to quickly perform a reliable injection process and a sealing process of the dispersion system on each hole of the porous spacer used in the system division method.

"Example" Hereinafter, the present invention will be described in more detail with reference to the illustrated example. In FIG. 1, reference numeral 10 denotes a transparent glass plate as a base material for forming a transparent rigid electrode plate, the upper surface of which is made of a transparent conductive material such as tin oxide, indium oxide and tin. The electrode pattern 11 is appropriately formed. On the upper surface of this rigid electrode plate, a porous spacer 12 made of a swellable member is provided in order to divide the dispersion system into small sections and enclose it, and further, on the upper surface of the porous spacer 12, A flexible electrode plate made of a film substrate 13 having another electrode pattern 14 formed on the surface facing the rigid electrode plate-side electrode pattern 11 is provided. In such a flexible electrode plate, the dispersion system 7 excessively supplied to each hole of the swellable porous spacer 12 is brought into close contact with the spacer 12 by applying a pressing force described below from the upper surface of the flexible electrode plate. While the excess dispersion system 7 is sequentially extruded while performing the fixing process between the flexible electrode plate and the periphery of the spacer 12, the function of the liquid pool of the dispersion system provided with the porous spacer 12 and the operation of the spacer 12 It is suitable as a structure for completely encapsulating the dispersion system 7 without an air portion in each hole. It is highly useful as a means for easily and quickly performing the sealing process. Porous spacer
As the swellable member for constituting 12, a synthetic rubber or a natural rubber such as styrene-butadiene-based, isoprene-based, ethylene-propylene-based, acrylonitrilo-butadiene-based, or chloroprene-based resin or various resins having low crystallinity are used. The porous portion 16 in which a large number of necessary through holes for the porous spacer 12 are formed in the swelling sheet-like material of such a member by an appropriate means such as a punch or a laser is shown in FIG.
As shown in the figure, the rigid electrode plate is joined to the electrode pattern 11 side,
Alternatively, the swellable member may be formed directly and integrally with the electrode pattern 11 side by printing means or spraying means.

The swellable porous spacer 12 is a porous portion 16 for dividing and enclosing the display dispersion system 7 into small sections in a discontinuous phase in the above-described manner.
Is formed on the electrode pattern 11 of the rigid electrode plate with a thickness of, for example, about 30 μm as shown in FIG.
A liquid pool of a dispersion system formed with a width of approximately several millimeters 17 around the area 17
There is provided an adhesive fixing portion 15 with the flexible electrode plate via
18 is a fixing adhesive for that purpose.

The electrophoretic particles used in the dispersion system 7 include various organic and inorganic pigments, in addition to titanium oxide and various known colloid particles.
Fine powders such as dyes, ceramics and resins can be used as appropriate. The dispersion medium of the dispersion system 7 includes a hydrocarbon,
In addition to halogenated hydrocarbons and aromatic hydrocarbons, various natural or synthetic oils and the like can be optionally used. And the dispersion system 7
If necessary, in addition to electrolytes, surfactants, metallic soaps, as well as charge control agents consisting of particles such as resins, rubbers, oils, varnishes, compounds, etc., appropriately add dispersants, lubricants or stabilizers, etc. it can. Furthermore, in addition to unifying the charge of the electrophoretic particles to be positive or negative, increasing the zeta potential, it is also possible to appropriately adjust the adsorptivity of the electrophoretic particles to the electrode patterns 2 and 4 and the viscosity of the dispersion system.

In order to manufacture the electrophoretic display device of the dispersion system split type, the swelling porous spacer 12 provided on the electrode pattern 11 side of a rigid electrode plate composed of a transparent glass plate 10 and a transparent electrode pattern 11, A dispersion 7 prepared in advance by dispersing electrophoretic particles such as titanium oxide in a suitable liquid dispersion medium so as to be optimal for the purpose of display is supplied to the porous portion 16 and the liquid reservoir 17 in excess of a required amount. The spacer 12 is completely covered with the dispersion system 7.

Dispersion system 7 is 100 cc of hexylbenzene as a dispersion system.
Prepare 1 g of dark blue dye consisting of oil blue BA
And 0.5 g of a surfactant consisting of Sylvan S83 were dissolved, and 5 g of titanium oxide was dispersed as electrophoretic particles in this solvent to prepare a required display dispersion system in advance.

Next, as shown in FIG. 1, the flexible electrode plate is superposed on the swelling porous spacer 12 such that the electrode pattern 14 faces the electrode pattern 11 of the rigid electrode plate, and the upper surface of the flexible electrode plate is As the flexible electrode plate is brought into close contact with the swellable porous spacer 12 by sequentially applying a pressing force to the swelling porous spacer 12, an excess dispersion system is extruded from each hole of the liquid reservoir 17 and the porous portion 16. Then, the dispersion system 7 is properly sealed.
Therefore, the adhesive 18
When the fixing is performed by the above, the complete encapsulation processing of the divided dispersion system without the non-injection into the swelling porous spacer 12 and the bonding processing between the members can be easily and quickly performed.

After such divided encapsulation of the dispersion system 7, the swollen porous spacer
Even if the dispersion 12 is excessively swollen and the dispersion system 7 is vaporized due to the excessively low pressure state of each hole in the porous portion 16, an effective supply of the dispersion system from the liquid reservoir 17 is performed. Since the pressure returns to the normal value, a favorable display operation without display defects can be maintained.

When a switching test was performed by repeatedly applying a voltage of 55 V DC between the electrode plates of the electrophoretic display device manufactured as described above, even after a lapse of 1 million times of switching, bias of the electrophoretic particles and generation of bubbles were observed. No display operation with good contrast was maintained.

[Effects of the Invention] According to the electrophoretic display device and the method of manufacturing the same according to the present invention, the swelling porous spacer having the porous portion and the dispersion liquid pool is supplied with the display dispersion system in an excessively supplied state. Excessive dispersion is extruded while sequentially applying a pressing force to the electrode plate side to bring the flexible electrode plate into close contact with the swelling porous spacer, thereby possibly causing a residual void serving as a display defect in the porous portion. In addition, the display dispersion system can be reliably enclosed in each hole of the swellable porous spacer, and therefore, the injection processing of the dispersion system can be performed efficiently and easily in a short time.

After dividing and enclosing the dispersion, the problem of vaporization of the dispersion caused by excessive negative pressure of the dispersion in each hole due to excessive swelling of the swelling porous spacer is due to the effect of the dispersion by the liquid pool of the dispersion. It can be suitably prevented by a suitable supply action.

Accordingly, it is possible to ensure a display operation with good display without display defects and to provide a highly reliable and reliable distributed electrophoretic display device with high durability against repeated display operations.

[Brief description of the drawings]

FIG. 1 is a dispersed system split type in which a swellable porous spacer having a liquid reservoir in the dispersed system is interposed between a transparent rigid electrode plate and a flexible electrode plate according to one embodiment of the present invention. FIG. 2 is a conceptual enlarged cross-sectional configuration diagram of the electrophoretic display device. FIG. 2 shows a porous portion for dividing and enclosing a dispersion system on the electrode pattern side of a rigid electrode plate, and a liquid reservoir of the dispersion system provided in a peripheral region thereof. FIG. 3 is a plan view of a swellable porous spacer having an adhesive fixing portion, and FIG. 3 is a conceptual cross-sectional view of a dispersion type continuous phase type electrophoretic display device having a conventional structure without using a porous spacer. is there. 1: Transparent glass plate 2: Electrode pattern 3: Transparent glass plate 4: Electrode pattern 5: End spacer 6: Electrophoretic particles 7: Dispersion system for display 10: Transparent glass plate 11: Electrode turn 12: Swollen porous spacer 13: Film substrate 14: Electrode pattern 15: Adhesive fixing part 16: Porous part of spacer 17: Dispersion liquid pool 18: Fixing adhesive

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Mori 757 Tenhoki, Kusazaki-cho, Inashiki-gun, Ibaraki Japan Nippon Mektron, Inc. Kutron Co., Ltd. Minami-Ibaraki Plant (58) Fields surveyed (Int. Cl. ⁶ , DB name) G02F 1/167 G09F 9/37

Claims (2)

(57) [Claims] 1. A dispersion system in which electrophoretic particles are dispersed via a swellable porous spacer between a pair of opposedly arranged electrode plates, at least one of which is transparent, is divided into a discontinuous phase and sealed. In the electrophoretic display device having the structure described above, the one electrode plate is configured to be flexible so as to be able to adhere to the swellable porous spacer, and the other electrode plate is configured by a transparent rigid body. The swelling porous spacer is provided in the peripheral region of the end portion thereof, and is provided between the adhesive fixing portion for joining with the flexible electrode plate and the peripheral region of the porous portion of the porous spacer. An electrophoretic display device comprising: a dispersion liquid reservoir provided. 2. A flexible electrode plate having a required electrode pattern formed on one surface of each of a film member and a transparent glass plate and a transparent rigid electrode plate are prepared. In addition, a porous portion necessary for the porous spacer is formed of a swellable member, and an adhesive fixing portion with the flexible electrode plate is provided around the porous portion via a liquid reservoir of a display dispersion system. Then, after excessively supplying a dispersion in which electrophoretic particles are dispersed in the porous portion of the porous spacer and the liquid reservoir, the flexible electrode plate faces the electrode pattern of the rigid electrode plate. The adhesive is disposed on the outer periphery of the porous spacer while applying a pressing force to the upper surface of the flexible electrode plate to push out an excessive dispersion system. The fixing part and the above-mentioned flexible electrode plate are fixed, and the porous Preparation of an electrophoretic display device having the step of sealing the dispersions in each hole of the support.