JPH02284124A - Electrophoretic display device and production thereof - Google Patents

Abstract

PURPOSE:To avert the heating of a dispersion system liquid and to easily and surely inject the dispersion system into the respective pores of spacers by using the porous spacers which can be joined to electrode plates by an induction heating. CONSTITUTION:The porous spacers 8 are provided between the electrode plates 2 and 4 disposed to face each other and the dispersion system 7 dispersed with electrophoresis particles 6 is divided to discontinuous phases and is sealed therebetween. The porous spacers 8 are selectively joined by using a hot-melt adhesive agent, such as polyamide resin, which can be adhered by the induction heating or the porous spacers 8 are formed on the electrode plate 2 or 4 by using the hot-melt adhesive agent and the spacers 8 are selectively joined thereto by the induction heating at the time of joining the porous spacers to the electrode plate 2 or 4. The sure sealing of the dispersion system into the respective pores of the porous spacers in a stable state is possible in this way without generating holes even with the dispersion system contg. a solvent of a low b. p.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a display device using electrophoretic particles, in which a dispersion system for display is divided into small sections in a discontinuous phase and a porous material is used to encapsulate the display device. When the spacer is bonded to the electrode plate, the bonding layer between the two or the porous spacer itself is made of a hot melt adhesive that can be bonded by dielectric heating. The present invention relates to an electrophoretic display device configured to reliably encapsulate the dispersion system without the risk of causing undesirable effects, and a method for manufacturing the same.

"Prior art" This type of electrophoretic display device using electrophoretic particles is
As shown in FIG. 3, two transparent glass plates 1 and 3 each have a required display electrode pattern 2.4 formed on their opposing surfaces using an appropriate transparent conductive material such as indium tin oxide.
It has a structure in which a sealing member 5, which also serves as a spacer, is disposed on the outer periphery in order to seal a dispersion system 7 in which electrophoretic particles 6 are dispersed in a liquid dispersion medium into the gap between the opposed parts.

An electrophoretic display device having such a structure has an electrode pattern 2
．． By applying a display driving voltage to the dispersion system 7 and applying an electric field to the dispersion system 7 so as to cause the electrophoretic particles 6 to be attracted to and separated from the electrode patterns 2 and 4, the distribution state of the electrophoretic particles 6 is changed. By changing the optical characteristics of the display device 7, a desired display operation of characters, symbols, figures, etc. can be performed.

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 due to unevenness in electric field strength due to uneven spacing between the two 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 eliminate such inconveniences, a porous spacer with a large number of holes is used to encapsulate the dispersed system in each hole, thereby dividing the dispersed system into small sections and encapsulating the dispersion into discontinuous phases. Such a structure is also disclosed in JP-A No. 49-32038,
JP-A-59-34518 or JP-A-59-1719
No. 30, each publication, etc. are numbered.

``Problems to be Solved by the Invention'' However, in a dispersion-divided electrophoretic display device in which a porous spacer is used to divide the dispersion into small sections into discontinuous phases, it is preferable for the prepared dispersion for display. In reality, it is not easy to reliably and skillfully encapsulate the display dispersion system without causing negative effects or leaving pores in the holes of the porous spacer. For example, in a structure in which a large number of cells for encapsulating a display dispersion system are pre-assembled between both electrodes using a porous spacer, the display dispersion system is individually injected into the hole formed by each cell. However, this method not only reduces the injection efficiency but also makes it difficult to expect complete injection of the dispersed system due to the presence of air in each hole, impairing display performance.

Therefore, one of the electrode plates has a flexible structure, and with this flexible electrode plate open, the porous spacer provided on the other electrode plate is sufficiently filled with the display dispersion system. In the case of a method in which a porous electrode plate is bonded to a porous spacer, it is effective in eliminating residual pores and improving sealing efficiency. In the bonding process, there is a need for a technique that can stably encapsulate various dispersion systems without adversely affecting the display dispersion systems composed of various compositions due to heat or the like.

"Means for Solving the Problems" The present invention provides a dispersion type electrophoretic display device using porous spacers, by providing the porous spacers with a function that allows them to be joined to electrode plates by induction heating. Electrophoresis that allows a desired dispersion system to be easily and reliably injected into the holes of a porous spacer without causing any unfavorable effects on the dispersion system while avoiding situations such as heating of the display dispersion liquid. The present invention provides a display device and a method for manufacturing the same.

For this reason, in the electrophoretic display device according to the present invention, a dispersion system in which electrophoretic particles are dispersed with a porous spacer interposed between a pair of electrode plates, at least one of which is transparent, which are arranged opposite to each other, is created in a discontinuous manner. When configuring an electrophoretic display device that is divided into phases and sealed.

The porous spacer is formed of a hot melt adhesive member that can be bonded to at least one of the electrode plates by dielectric heating, and the hot melt adhesive member is preferably a polyamide resin.

As a method for manufacturing such an electrophoretic display device, even in the case of a branch system configuration in which the display dispersion system contains a low boiling point solvent, etc., the encapsulation process can be suitably achieved.
When bonding the porous spacer to at least one of the electrode plates, the porous spacer may be selectively bonded using a hot melt adhesive such as polyamide resin that can be bonded by dielectric heating, or a similar material may be used to bond the porous spacer to at least one of the electrode plates. A preferred method is to form a porous spacer using a hot melt adhesive, and selectively bond the spacer to the other electrode plate by dielectric heating the spacer.

``Example'' The present invention will be described in further detail below with reference to one illustrated example. In Fig. 1, reference numerals 1 and 3 are transparent glass plates that serve as base materials for constructing counter electrode plates, and their opposing surfaces are made of transparent conductive material such as indium tin oxide to form the required electrode pattern. 2.4 are formed separately. A porous spacer 8 is disposed between the opposing electrode plates to divide and encapsulate one display dispersion system into small sections. It can be preformed to a desired thickness using a suitable method such as printing means, for example, with a manually available hot melt adhesive made of polyamide resin manufactured by Diabond Kogyo 4, etc. 7
is a dispersion system for display to be sealed in the holes of the porous spacer 8, which is prepared in advance by dispersing required electrophoretic particles 6 such as titanium oxide in a liquid dispersion medium. I can do it.

In the above, the porous spacer is entirely formed with hot melt adhesive, but instead of this method, the second
As shown in the figure, the porous spacer itself is made of materials other than hot melt adhesives, such as silicone rubber, urethane rubber, fluorine rubber, etc.
Using a material such as synthetic rubber such as acrylic rubber or natural rubber, it is integrally formed so that a large number of required through holes can be punched on one electrode plate side using an appropriate method such as punching, laser, or printing means as shown in the figure. Alternatively, after the photosensitive resin has been deposited, necessary through holes are arbitrarily formed by chemical dissolution means such as etching, thereby providing the porous spacer 9 and final bonding of the spacer 9 with other electrode plates. It is also possible to provide a hot melt adhesive layer 10 made of a polyamide resin similar to the above on the surface.

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 organic and inorganic pigments, dyes, ceramics, resins, etc. can be appropriately used. Further, as the dispersion medium of the 5-dispersion system 7, various dispersion media having various boiling points such as hydrocarbons, halogenated hydrocarbons, aromatic hydrocarbons, and various natural or synthetic oils can be optionally used. And, if necessary, an electrolyte for the dispersion system 7.

In addition to surfactants, metal soaps, charge control agents made of particles of resins, rubbers, oils, varnishes, compounds, etc., dispersants, lubricants, stabilizers, etc. can be added as appropriate. Furthermore, in addition to means for unifying the charge of electrophoretic particles to positive or negative or increasing the zeta potential, electrode patterns 2 of electrophoretic particles can be used.
．． It is also possible to adjust the adsorption properties for No. 4 and the viscosity of the dispersion medium as appropriate.

To manufacture the above dispersion type electrophoretic display device, 1. For example, one transparent glass plate I and a transparent electrode pattern 2.
After forming the porous spacer 8 or 9 having the above structure on the side of the electrode pattern 2 of the electrode plate, electrophoretic particles 6 such as titanium oxide are added to a liquid dispersion medium suitable for the display purpose. This porous spacer 8 or 9 is filled one-tenth with the dispersed system 7 prepared in advance. Dispersion system 7
Prepare 100 cc of hexylbenzene as a dispersion medium, dissolve 1 g of a dark blue dye made of Oil Blue BA and 0.5 g of a surfactant made of Silpan S83 in it, and add 5 g of titanium oxide as electrophoretic particles to this solvent. A dispersion system 7 is prepared in advance by dispersing.

Next, as shown in both figures, another electrode plate is placed on the porous spacer 8 or 9 so that its electrode button 4 faces the electrode pattern 2 of the electrode plate, and the electrodes of this temporarily assembled dielectric heating device are assembled. By performing the hot-melt bonding process while performing dielectric heat treatment under pressure, effective encapsulation and encapsulation for the display dispersion system 7 can be achieved without the risk of applying harmful heat to the display dispersion system 7. Therefore, it is possible to easily and quickly accomplish a complete encapsulation process of a split type dispersion system without pores in the porous spacer 8 or 9 and a process of bonding the members to each other.

"Effects of the Invention" According to the electrophoretic display device and the manufacturing method thereof according to the present invention, as explained above, a porous spacer is interposed between a pair of opposing electrode plates, at least one of which is transparent. When configuring an electrophoretic display device in which a dispersion system in which electrophoretic particles are dispersed is divided into discontinuous phases and sealed, dielectric heating is performed when joining the porous spacer to at least one of the electrode plates. Alternatively, the porous spacer itself may be formed using a hot melt adhesive that can be bonded directly to one electrode plate, and the spacer and the other electrode may be bonded together using a hot melt adhesive. Since the spacer is bonded to the plate by dielectric heating, the spacer can be bonded to the spacer without any possibility of having an unfavorable effect on various desired display dispersion systems, including display dispersion systems containing low-boiling point solvents. The dispersed system can be reliably encapsulated in the holes of the spacer in a stable state.

Therefore, since the split-type encapsulation process of a dispersion system without pores can be easily and reliably performed efficiently and in a short time, by adopting the present invention, it is possible to perform an excellent dispersion-system split-type electrophoresis process that is highly reliable and free of display defects. Display devices can be provided.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a dispersion type electrophoretic display device in which a porous spacer is directly constructed with a hot melt adhesive that can be bonded to an electrode plate by dielectric heating treatment according to an embodiment of the electrophoretic display device according to the present invention. FIG. 2 shows a dispersion similar to the above, in which the porous spacer itself is made of a material other than hot melt adhesive, and a hot melt adhesive layer is provided on the final bonding surface, according to another embodiment of the present invention. Conceptual enlarged cross-sectional configuration diagram of a system-divided electrophoretic display device,
FIG. 3 is a conceptual cross-sectional diagram of a dispersed continuous phase type electrophoretic display device having a conventional structure that does not use a porous spacer. l: 2: 3: 4: 5: 6 Near: 8: 9: 10: Transparent glass plate electrode pattern Transparent glass plate electrode pattern End spacer Dispersion system for electrophoretic particle display Futomelt porous spacer Porous spacer hot melt Adhesive layer Figure 1 Figure 2

Claims (5)

[Claims] (1) An electric 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 porous spacer. An electrophoretic display device, characterized in that the porous spacer is formed of a hot melt adhesive member that can be bonded to at least one of the electrode plates by dielectric heating. (2) The electrophoretic display device according to claim (1), wherein the hot melt adhesive member is made of polyamide resin. (3) Electrophoretic display in which a dispersion system in which electrophoretic particles are dispersed through a porous spacer is divided into discontinuous phases and sealed between a pair of opposing electrode plates, at least one of which is transparent. In the method for manufacturing the device, the porous spacer is bonded to at least one of the electrode plates using a hot melt adhesive that can be bonded by dielectric heating. Manufacturing method. (4) Electrophoretic display in which a dispersion system in which electrophoretic particles are dispersed through a porous spacer is divided into discontinuous phases and sealed between a pair of opposing electrode plates, at least one of which is transparent. In the method for manufacturing the device, the porous spacer is formed on one of the electrode plates using a hot melt adhesive, and the spacer and the other electrode plate are bonded by dielectric heating to the spacer. A method for manufacturing an electrophoretic display device characterized by: (5) The method for manufacturing an electrophoretic display device according to claim (3) or (4), wherein a polyamide resin is used as the hot melt adhesive.