JPH02284126A - Electrophoresis display device and production thereof - Google Patents

Abstract

PURPOSE:To easily and surely inject a dispersion system into the respective pores of porous spacers by constituting the spacers of a swellable member and providing the liquid pools for the dispersion system around the porous parts thereof. CONSTITUTION:The excess dispersion system is extruded while the flexible electrode plate 14 is brought into tight contact successively with the swellable porous spacers 12 by successively imparting a pressing force to the flexible electrode plate 14 side in the state of excessively supplying the dispersion system 7 for displaying to the swellable porous spacers 12 having the porous parts 16 and the dispersion system liquid pools 17. The generation of the residual holes which are display defects in the porous parts is, therefore, prevented. The evaporation of the dispersion system 7 occurring in the excessive negative pressure state generated in the respective pores by the excessive swelling of the swellable porous spacers 12 is prevented and the generation of the holes is obviated as the dispersion system 7 is supplied from the liquid pools 17 of the dispersion system. The dispersion system is surely sealed into the respective pores of the swellable porous spacers 12 in this way and the generation of the display defects is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a display device using electrophoretic particles, and more specifically, 1. In a dispersion-divided electrophoretic display device that uses one flexible electrode plate made of a resin film or the like and a porous spacer for dividing the display dispersion into small sections into discontinuous phases. By adopting a structure in which the porous portion of the porous spacer is made of a swellable material and a liquid reservoir for the display dispersion system is provided around the porous portion, the dispersion system can be easily and easily distributed in the pores of the porous spacer. The present invention relates to a dispersion type electrophoretic display device configured to be reliably encapsulated and a method for manufacturing the same.

"Prior art and its problems" This type of electrophoretic display device using electrophoretic particles is
As shown in FIG. 3, two transparent glass plates l each have required display electrode patterns 2 and 4 formed on their opposing surfaces using a suitable transparent conductive material such as indium tin oxide, respectively;
3, and a sealing member 5, which also serves as a spacer, is disposed on the outer periphery to seal a dispersion system 7 in which electrophoretic particles 6 are dispersed in a liquid dispersion medium in the gap between the opposing sides.

Such an electrophoretic display device applies a display driving voltage to the electrode pattern 2.4 and applies an electric field to the dispersion system 7 so that the electrophoretic particles 6 can be attracted to and separated from the electrode pattern 2.4. By changing the distribution state of the electrophoretic particles 6, the optical characteristics of the dispersion system 7 are changed to perform a desired display operation of characters, symbols, figures, etc.

When the dispersion system 7 is enclosed in a continuous phase with the sealing member 5 provided at the end as described above, the dispersion system 7 may be enclosed in a continuous phase due to unevenness in electric field strength due to uneven spacing between the picture electrode patterns 2, 4, etc. 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 this electrophoretic display device is repeatedly used for a long time, there is a problem that the concentration of electrophoretic particles becomes uneven in places and display unevenness occurs.

Therefore, as a means to solve this inconvenience, the dispersion system 7 is divided into small sections into discontinuous phases by using a porous spacer with a large number of through holes and enclosing the dispersion system in each hole. The enclosed structure is also disclosed in Japanese Patent Application Laid-Open No. 49-32038.
No., JP-A-59-34518 or JP-A-59-17
1930, each publication, etc. are numbered.

However, in the case of the above-mentioned known example of a dispersion-divided electrophoretic display device in which the dispersion is divided into small sections into discontinuous phases using porous spacers, when substrate films are used for both electrode plates, respectively. Since a gap is likely to be formed between the porous spacer and the electrode plate due to film deformation or the like, there is a risk that electrophoretic particles may be unevenly distributed. In addition, when both electrode plates are composed of glass plate base materials, a gap may be left between the porous spacer and the electrode plate due to the relationship between the flatness of the glass plate and the thickness distribution of the porous spacer. Therefore, even with this structure, it is not easy to prevent uneven distribution of electrophoretic particles.

Furthermore, with a cell structure in which both electrode plates and an intervening porous spacer are bonded in advance, it is extremely difficult to uniformly inject the dispersed system into the pores of the porous spacer. In addition to the various manufacturing difficulties involved, there is a high possibility that imperfections in dispersion injection may occur, resulting in display defects, and there are many issues to be solved in order to obtain a highly reliable display device. .

[Means for Solving the Problems] The present invention provides a dispersion type electrophoretic display device using a porous spacer, in which the porous spacer is composed of a swellable material and is dispersed around the pores of the porous spacer. By providing a system liquid reservoir and configuring one side of the electrode plate to be flexible, it is possible to easily and reliably inject the dispersed system into the pores of the porous spacer, and after sealing, The present invention provides an electrophoretic display device whose main purpose is to prevent air from being partially generated due to excessive swelling of a porous spacer, and a method for manufacturing the same.

To this end, according to the electrophoretic display device of the present invention, electrophoretic particles are dispersed between a pair of opposing electrode plates, at least one of which is transparent, with a swellable porous spacer interposed therebetween. In an electrophoretic display device having a structure in which a system is divided into discontinuous phases and sealed, one of the electrode plates is configured to be flexible enough to adhere to the swelling porous spacer, and the other electrode plate is made of a transparent rigid body, and the swellable porous spacer has an adhesive fixing part provided around its end region for joining with the flexible electrode plate, and the adhesive fixing part and the porous spacer. The dispersion liquid reservoir is provided between the porous spacer and the peripheral area of the porous spacer, and this structure appropriately prevents air generation in the porous space due to excessive swelling of the porous spacer. can.

In order to manufacture such a dispersion type electrophoretic display device, a flexible electrode plate and a transparent rigid electrode plate each having a desired electrode pattern formed on one side of a film member and a transparent glass plate are used. is prepared, and on the electrode pattern side of the rigid electrode plate, a porous part necessary for a porous spacer is formed with a swelling material, and a liquid reservoir of a dispersion system for display is formed in the area around the porous part. After arranging an adhesive fixing part to the flexible electrode plate and supplying an excessive amount of a dispersion system in which electrophoretic particles are dispersed to the pores of the porous spacer and the liquid reservoir, the flexible electrode plate is arranged on the porous spacer so that its electrode pattern faces the electrode pattern of the rigid electrode plate, and then a pressure is applied to the upper surface of the flexible electrode plate to remove excess dispersed system. It is preferable to include the steps of fixing the adhesive fixing part arranged around the outer periphery of the porous spacer and the flexible electrode plate while extruding the porous spacer, and sealing the dispersion system in the pores of the porous spacer. By employing such a method, it becomes possible to quickly perform a reliable injection process and a sealing process of the dispersion system into the pores of the porous spacer used in the division method of the display dispersion system.

"Examples" The present invention will be described in further detail below with reference to illustrated embodiments. In Fig. 1, 10 is a transparent glass plate as a base material for constructing a transparent rigid electrode plate, and its upper surface is coated with a transparent conductive material such as tin oxide, indium tin oxide, etc. The electrode pattern 11 is formed as appropriate. A porous spacer 12 made of a swellable material is disposed on the upper surface of this rigid electrode plate in order to divide and encapsulate the dispersed system into small sections. Furthermore, on the upper surface of the porous spacer 12,
A flexible electrode plate made of a film base material 13 on which another electrode pattern 14 is formed on the surface facing the rigid electrode plate side electrode pattern 11 is arranged.

Such a flexible electrode plate is made of the above-mentioned swellable porous spacer 12.
The dispersion system 7 supplied in excess into the pores of the flexible electrode plate is applied with a pressing force (described later) from the upper surface of the flexible electrode plate to bring it into close contact with the spacer 12, and the excess dispersion system 7 is successively pushed out. By fixing the spacer 12 with the periphery, the dispersion system 7 is completely enclosed without any air in the pores of the spacer 12 along with the action of the dispersion system liquid reservoir provided in the porous spacer 12. It is highly useful as a means for easily and quickly performing the divisional encapsulation process of the dispersion system 7 and the sealing process between the constituent members under the cooperation of the swellable porous spacer 12. porous spacer 12
As the swellable material for composing, synthetic rubber such as styrene-butadiene, isoprene, ethylene-propylene, acrylonitrilo-butadiene, chloroprene, natural rubber, or various low-crystalline resins may be used. The porous portion 16 is formed by drilling a large number of required through-holes for the porous spacer 12 in the swellable sheet material of such a member by a suitable means such as bunching or laser. It can be joined to the electrode pattern 11 side of the rigid electrode plate, as shown in FIG.

The swellable porous spacer 12 has a porous portion 1 for dividing the display dispersion system 7 into small sections into discontinuous phases and enclosing the dispersion system 7 in the above-mentioned manner.
6 is a rigid electrode plate electrode back 11 as shown in FIG.
An adhesive fixing portion is formed on the flexible electrode plate with a thickness of, for example, about 30 μm, and a dispersed liquid reservoir 17 formed with a width of approximately several millimeters is formed around the porous portion 16. 15 is provided, and 18 is a fixing adhesive therefor.

As the electrophoretic particles used in the dispersion system 7, in addition to titanium oxide and various well-known colloidal particles, fine powders of various kinds of mineral pigments, inorganic pigments, dyes, ceramics, resins, etc. can be appropriately used. Further, as the dispersion medium of the dispersion system 7, in addition to hydrocarbons, halogenated hydrocarbons, aromatic hydrocarbons, etc., various natural or synthetic oils can be optionally used. In addition to electrolytes, surfactants, and metal soaps, if necessary, the dispersion system 7 contains
In addition to a charge control agent consisting of particles of resin, rubber, oil, varnish, compound, etc., a dispersant, lubricant, stabilizer, etc. can be added as appropriate. Furthermore, in addition to making the charges of the electrophoretic particles uniformly positive or negative and increasing the zeta potential, it is also possible to appropriately adjust the adsorption of the electrophoretic particles to the electrode pattern 2.4, the viscosity of the dispersion medium, and the like.

In order to manufacture the above dispersion type electrophoretic display device, the above-mentioned swelling porous spacer 12 is provided on the side of the electrode pattern 11 of a rigid electrode plate consisting of a transparent glass plate IO and a transparent electrode pattern 11.

A dispersion system 7 prepared in advance by dispersing electrophoretic particles such as titanium oxide in a liquid dispersion medium suitable for the purpose of display is supplied in excess of the required amount to the porous portions 16 and liquid reservoirs 17. The spacer 12 is completely covered with the dispersion system 7.

Dispersion system 7 contains hexylbenzene 100 as a dispersion medium.
Prepare cc and add 1g of dark blue dye made of Oil Blue BA and 0.5g of surfactant made of Silpan S83.
A required display dispersion system was prepared in advance by dissolving 5 g of titanium oxide as electrophoretic particles in this solvent.

Next, as shown in FIG. 1, the flexible electrode plate is placed over the swelling porous spacer 12 so that its 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 swollen porous spacer 12 by sequentially applying a pressing force with a pressure roller or the like, the excess dispersion system is pushed out from the liquid reservoir 17 and the pores of the porous portion 16. The dispersion system 7 is then properly encapsulated. Therefore, if the adhesive fixing part 15 is used to fix the constituent members with the adhesive 18, the swelling porous spacer 1
2. Complete encapsulation of a split-type dispersion system without any uninjected parts and mutual bonding of members can be carried out easily and quickly.

After such divided encapsulation of the dispersion system 7, the swellable porous spacer 1
Even if the dispersion system 7 swells excessively and the dispersion system 7 evaporates due to the excessively low pressure state of the pores in the porous portion 16,
Since the dispersion system is effectively supplied from the liquid reservoir 17 and the pressure returns to normal, a good display operation without any display defects can be maintained.

When a switching test was conducted by repeatedly applying a DC voltage of 55 V between the electrode plates of the electrophoretic display device manufactured as described above, it was found that the electrophoretic particles were uneven and bubbles occurred even after 1 million switching cycles. was not observed, and display operation with good contrast continued.

"Effects of the Invention" According to the electrophoretic display device and the manufacturing method thereof according to the present invention, a flexible porous spacer having a porous portion and a dispersion liquid reservoir is provided with a display dispersion in excess. By sequentially applying a pressing force to the electrode plate side to bring the flexible electrode plate into close contact with the swollen porous spacer and extruding the excess dispersion system, there is a risk that residual pores may be generated in the porous portions, resulting in display defects. Therefore, the display dispersion system can be reliably encapsulated in the pores of the swellable porous spacer, and therefore, the injection process of the dispersion system can be carried out efficiently, easily, and reliably in a short time.

After dividing and encapsulating the dispersion system, the problem of vaporization of the dispersion system due to the excessive negative pressure state of the dispersion system in each pore due to excessive swelling of the swellable porous spacer is due to the effect of the dispersion system due to the liquid pooling of the dispersion system. This can be suitably prevented by a natural supply action.

Therefore, it is possible to ensure a display operation with good contrast without any display defects, and to provide a highly reliable dispersion type electrophoretic display device with high durability against repeated display operations.

[Brief explanation of drawings]

FIG. 1 shows a dispersed system split type structure in which a swellable porous spacer having a dispersed liquid reservoir is interposed between a transparent rigid electrode plate and a flexible electrode plate according to an embodiment of the present invention. Figure 2 is a conceptual enlarged cross-sectional configuration diagram of an electrophoretic display device. FIG. 3 is a conceptual cross-sectional diagram of a dispersed continuous phase electrophoretic display device with a conventional structure that does not use a porous spacer. be. l : 2 : 3 : 4 = 5 = 6 = 7 : 10 : l l : 12 = 13 = l4 : l5 : l6 : l7 : 18 = Transparent glass Plate electrode pattern Transparent glass Plate electrode pattern end spacer dispersion transparent glass for displaying electrophoretic particles Plate electrode pattern swelling porous spacer film base electrode pattern adhesion fixed part spacer porous dispersion liquid pool Fixing adhesive figure 2

Claims (2)

[Claims] (1) A structure in which a dispersion system in which electrophoretic particles are dispersed is divided into discontinuous phases and sealed between a pair of opposing electrode plates, at least one of which is transparent, via a swellable porous spacer. In the electrophoretic display device, one of the electrode plates is flexible enough to adhere to the swellable porous spacer, and the other electrode plate is made of a transparent rigid body, while the swellable porous spacer The porous spacer is provided with an adhesive fixing part provided around the end thereof and for joining with the flexible electrode plate, and between the adhesive fixing part and the peripheral area of the porous part of the porous spacer. An electrophoretic display device characterized in that it is configured to include a dispersed liquid reservoir. (2) Prepare a flexible electrode plate and a transparent rigid electrode plate in which a required electrode pattern is formed on each side of a film member and a transparent glass plate, and on the electrode pattern side of the rigid electrode plate, , forming a porous part necessary for the porous spacer with a swelling material, and disposing an adhesive fixing part to the flexible electrode plate in the peripheral area of the porous part via a liquid reservoir of the display dispersion system, After supplying an excessive amount of a dispersion system in which electrophoretic particles are dispersed to the porous portion of the porous spacer and the liquid reservoir, the flexible electrode plate is placed so that its electrode pattern faces the electrode pattern of the rigid electrode plate. The adhesive fixing portion is placed on the porous spacer, and then placed around the outer periphery of the porous spacer while applying pressure to the upper surface of the flexible electrode plate to push out the excess dispersion system. A method for producing an electrophoretic display device, comprising the steps of fixing and fixing the flexible electrode plate and enclosing the dispersion system in each hole of the porous spacer.