JP2733680B2 - Electrophoretic display device and method of manufacturing the same - Google Patents

Description

The present invention relates to a display device using electrophoretic particles,
The use of one flexible electrode plate made of a resin film or the like and a heat-fusible porous spacer for dividing the dispersion into discrete sections into discrete phases allows the dispersion to be formed in each hole of the spacer. The present invention relates to an electrophoretic display device configured to be reliably enclosed and a method of manufacturing the same.

2. Description of the Related Art As shown in FIG. 4, an electrophoretic display device of this type using electrophoretic particles has a required display electrode pattern using an appropriate transparent conductive member such as indium tin oxide on the opposing surfaces. Two transparent glass plates 1 and 3 formed separately from each other
And a sealing member 5 also serving as a spacer function is provided at an outer peripheral portion so as to enclose a dispersion system 7 in which electrophoretic particles 6 are dispersed in a liquid dispersion medium between the opposing gaps. The electrophoretic display device having such a structure includes electrode patterns 2 and 4
A voltage is applied to the display system to apply a display driving voltage, and an electric field is applied to the dispersion system 7 to change the distribution state of the electrophoresis particles 6 so that the electrophoretic particles 6 can be adsorbed and separated from the electrode patterns 2 and 4. The optical characteristics are changed to perform desired display operations of characters, symbols, figures, and the like.

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 means for solving such inconvenience, as shown in FIG. 5, a dispersion system is sealed in each through-hole by using a porous spacer 8 having a large number of through-holes. Is also disclosed in Japanese Patent Application Laid-Open Nos. Sho 49-32038, 59-34518 or 59
It is known from the publications of -171930.

[Problems to be Solved by the Invention] However, in the case of the above-described known example of the dispersion-type divisional electrophoretic display device in which the dispersion system is divided into small sections by using a porous spacer, When each of the substrate films is used as a plate, a gap is easily generated between the porous spacer and the electrode plate due to deformation of the film or the like, so that there is a possibility that uneven distribution of the electrophoretic particles may occur.

On the other hand, when both electrode plates are made of a glass plate substrate, 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. Since a portion is generated, it is not easy to prevent uneven distribution of the electrophoretic particles even with this structure.

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 provides a dispersion-separated type electrophoretic display device using a porous spacer, in which the porous spacer is provided with an adhesive layer that can be thermally fused, and the electrode plate is An object of the present invention is to provide an electrophoretic display device in which one is made flexible so that a dispersion system can be easily and reliably injected into each hole of a porous spacer, and a method for manufacturing the same.

Therefore, in the electrophoretic display device of the present invention, a dispersion system in which electrophoretic particles are dispersed via a porous spacer between a pair of opposedly arranged electrode plates at least one of which is transparent. Is divided into small sections in a discontinuous phase and sealed therein. In the electrophoretic display device, one of the opposed electrode plates is made flexible, and the other electrode plate is made of a transparent rigid body. And a hot-melt adhesive layer capable of being thermally fused to at least the flexible electrode plate with respect to the porous spacer interposed between the two electrode plates. The porous spacer which is bonded to the electrode plate by heat fusion is formed by laminating an adhesive layer made of a sheet-like hot-melt adhesive such as a polyamide system on both sides of a film member such as a polyethylene film. Can be used.

Such an electrophoretic display device first prepares 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, and prepares an electrode of the rigid electrode plate. After excessively supplying a dispersion system in which electrophoretic particles are dispersed to a heat-fusible porous spacer disposed on the pattern side, the flexible electrode plate is replaced with an electrode pattern of the rigid electrode plate. The flexible electrode plate is disposed on the porous spacer so as to face the surface of the flexible electrode plate. A method of completely sealing the dispersion system in each hole of the porous spacer by adopting a method of sealing and holding the dispersion system in each hole of the porous spacer by thermally fusing the spacer and the flexible electrode plate. And the electrode plate of this spacer And bonding process is reliably and quickly performed against.

"Example" Hereinafter, the present invention will be described in more detail with reference to the illustrated example. In FIG. 1, reference numeral 1 denotes a transparent glass plate as a base material for constituting a transparent rigid electrode plate, and a required electrode pattern 2 is formed on the upper surface thereof using a transparent conductive material such as indium tin oxide. It is formed appropriately. On the upper surface of the rigid electrode plate, a heat-sealable porous spacer 8 for dividing and enclosing the dispersion system into small sections is provided, and 10 is provided on both surfaces of the spacer 8. Is a hot melt adhesive layer.
As shown in FIG. 3, for example, the heat-fusible porous spacer 8 is formed by laminating a polyamide-based hot-melt adhesive layer 10 on both sides of a spacer film member made of a polyethylene film. A large number of required through holes 11 can be formed by means such as a punch or a laser.

On the upper surface of such a heat-fusible porous spacer 12, a flexible electrode plate made of a film base material 9 having another electrode pattern 4 formed on the surface facing the above-mentioned rigid-side electrode pattern 2 is provided. Is arranged so as to be about 70 μm. However, the flexible electrode plate is heated by pressing the dispersion system 7, which has been excessively supplied to each hole of the porous spacer 8, from the upper surface of the flexible electrode plate. And the excess dispersion system 7 is sequentially extruded while being brought into close contact with the spacer 8, and the flexible electrode plate and the spacer 8 are subjected to thermal fusion bonding, so that each hole of the porous spacer 8 is formed. This is for completely encapsulating the dispersion system 7 having no voids, and is suitable as a means for easily and quickly performing the division encapsulation process of the dispersion system 7 and the sealing process between the constituent members.

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 medium.

In order to manufacture the above-described electrophoretic display device of the dispersed system, a porous spacer 8 which can be thermally fused to the side of the electrode pattern 2 of the rigid electrode plate composed of the transparent glass plate 1 and the transparent electrode pattern 2 is heated. After adhering, the dispersion system 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 spacer 8 in excess of a required amount, and the dispersion is supplied in excess. The spacer 8 is completely covered with the dispersion system 7. Dispersion system 7 is prepared by dispersing 100 g of hexylbenzene as a dispersion medium, dissolving 1 g of dark blue dye consisting of oil blue BA and 0.5 g of surfactant consisting of Sylvan S83, and dissolving titanium oxide as electrophoretic particles in this solvent. 5g
To prepare this dispersion system in advance.

Next, as shown in FIG. 2, the flexible electrode plate is overlapped with a heat-fusible porous spacer 8 such that the electrode pattern 4 faces the electrode pattern 2 of the rigid electrode plate. When a heating pressing force is applied to the upper surface of the device by using a heating roller 12 or the like, and the sealing process is sequentially performed from one end thereof, the flexible electrode plate is sufficiently pressed against the porous spacer 8 and hot. The excess dispersion system, which has been bonded to the melt adhesive layer 10 by heat fusion and is excessively supplied to the porous spacers 8, is extruded from the holes 11 of the spacers 8 so that the dispersion system 7 can be properly encapsulated. Will be This makes it possible to easily and quickly perform the process of completely encapsulating the divided dispersion system having no pores in the porous spacer and the process of joining members together.

When a switching test was performed by repeatedly applying a voltage of 70 V DC between the electrode plates of the electrophoretic display device manufactured as described above, no deviation of the electrophoretic particles was observed even after 1 million switching operations. A display operation with good contrast was obtained.

[Effects of the Invention] As described above, the electrophoretic display device according to the present invention is applicable to an electrophoretic display device in which a dispersion system is divided into discontinuous phases into small sections using a porous spacer and sealed between electrode plates. In
One of the two electrode plates is made flexible and the other is made of a rigid body, and a heat-fusible porous spacer is interposed between the two electrode plates. By applying a heating pressing force to the flexible electrode plate side in a state where the flexible electrode plate is disposed on the supplied heat-fusible porous spacer, an excess dispersion system is extruded and the porous plate is made porous. The dispersion system can be reliably encapsulated in each hole of the porous spacer while performing the thermal fusion bonding between the spacer and the flexible electrode plate. Therefore, the divisional encapsulation processing of the dispersion system having no pores can be efficiently performed in a short time. Easy and reliable.

Since the process of enclosing the dispersion system into the heat-fusible porous spacer and the process of bonding the electrode plates can be performed simultaneously, the process can be simplified.

Such an electrophoretic display device, combined with its simple configuration, is extremely advantageous as a method for completely enclosing the dispersion system in each hole of this kind of porous spacer.

Therefore, by employing the electrophoretic display device and the method of manufacturing the same according to the present invention, it is possible to provide a dispersion-division-type electrophoretic display device having no display defects, high contrast, and excellent display reliability.

[Brief description of the drawings]

FIG. 1 is a perspective view of a dispersion-separated electrophoretic display device having a heat-fusible porous spacer between a transparent rigid electrode plate and a flexible electrode plate according to an embodiment of the present invention. FIG. 2 is a conceptual enlarged cross-sectional configuration diagram, FIG. 2 is a diagram for explaining a process of enclosing a dispersion system and a process of thermally fusing an electrode plate to a porous spacer according to the method of the present invention, and FIG. FIG. 4 is a conceptual partially enlarged perspective view of a heat-fusible porous spacer, FIG. 4 is a conceptual cross-sectional view of a dispersed continuous-phase type electrophoretic display device having a conventional structure without using a porous spacer,
FIG. 5 is a conceptual cross-sectional view of a dispersed continuous phase type electrophoretic display device according to a conventional structure using a porous spacer. 1, 3: transparent glass plate 2, 4: electrode pattern 5: end spacer 6: electrophoretic particles 7: display dispersion system 8: porous spacer 9: film substrate 10: hot melt adhesive layer 11: multiple transparent Hole 12: Heating roller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Tadakuma 757 Tenhoki, Kusazaki-cho, Inashiki-gun, Ibaraki Japan Inside the Mektron Co., Ltd. Minami-Ibaraki Plant (72) Inventor Takashi Mori 757 Tenhoki, Kusazaki-cho, Inashiki-gun, Ibaraki Japan Mektron Co., Ltd. Minami-Ibaraki Factory

Claims (6)

(57) [Claims] 1. A structure in which a dispersion system in which electrophoretic particles are dispersed via a 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, one of the opposed electrode plates is made flexible, and the other electrode plate is made of a transparent rigid body, and the porous material interposed between these two electrode plates is provided. An electrophoretic display device comprising a spacer and at least a hot-melt adhesive layer heat-fusible with the flexible electrode plate. 2. The heat-fusible porous spacer comprises a film member, a hot-melt adhesive layer formed on both sides of the film member, and a large number of through holes formed in the sheet material. The electrophoretic display device according to claim 1, wherein: 3. 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 provided, and are disposed on the electrode pattern side of the rigid electrode plate. After excessively supplying the dispersion in which the electrophoretic particles are dispersed to the mounted heat-fusible porous spacer, the flexible electrode plate is turned so that its electrode pattern faces the electrode pattern of the rigid electrode plate. The porous spacer and the flexible electrode plate are heated while applying a heating pressing force to the upper surface of the flexible electrode plate to push out an excess dispersion system. A method for manufacturing an electrophoretic display device, wherein the dispersion system is sealed and held in each hole of the porous spacer by fusing. 4. The method according to claim 3, wherein the rigid electrode plate and the porous spacer are joined in advance. 5. The heat-sealing process of the porous spacer and the flexible electrode plate is performed by a heating pressing force of a heat roller sequentially applied from one end of the upper surface of the flexible electrode plate. 3) or (4), a method for manufacturing an electrophoretic display device. 6. The method for manufacturing an electrophoretic display device according to claim 3, wherein a hot-melt adhesive layer is formed on one or both surfaces of the porous spacer.