JP5034268B2 - Front plate for electrophoretic display device, extraction electrode forming method and wiping device - Google Patents

Description

  The present invention relates to an electrophoretic display device front plate, a method for forming an extraction electrode thereof, and a wiping device for removing unnecessary materials including a display material and an adhesive on the extraction electrode when the extraction electrode is formed.

  As one of display devices using the electrophoresis phenomenon, a microcapsule type electrophoresis system using microcapsules as a display material has been put into practical use. In this type of display device, positive and negatively charged black particles and white particles are placed in microcapsules filled with a transparent solvent, and an image is formed by pulling up each particle to the display surface by applying an external voltage. It is. The particle size of the microcapsule is several tens μm to several hundred μm, and when the microcapsule is dispersed in a transparent binder, it can be coated like an ink.

  When this capsule is coated on a transparent base material on which a transparent electrode is formed and the base material on which an active matrix driving electrode circuit is formed is bonded, for example, an active matrix electrophoretic display device as shown in Patent Document 1 is obtained. Can do.

  Here, a transparent electrode is formed on a transparent substrate, and a component coated with a capsule on the transparent electrode is referred to as a “front plate”, and an active matrix driving electrode circuit or the like that is joined to the front plate is formed. The material is called “back plate”.

  Various defects occur in the front plate. Above all, display defects cannot be confirmed in the state where no voltage is applied unlike the coating failure in the microcapsule dispersion coating, and voltage is applied to the display material to display white, black, and if necessary. Confirmation is possible by displaying gradation. When the display defect inspection is performed after the front plate and the rear plate are joined, a loss of having to dispose of an expensive normal product of the rear plate due to a defect in the front plate occurs. Therefore, it is desirable to perform a display defect inspection at the component stage as the front plate.

  However, the front plate has only one electrode for applying a voltage to the microcapsule. Therefore, for example, an adhesive for bonding a back plate is coated on a cover film made of a base material having a conductive layer such as a PET film deposited with aluminum, and this is bonded to the front plate. The front plate is inspected for quality by applying a voltage between the conductive layers of the transparent electrode and the cover film.

The patent literature is as follows.
JP 2000-221546 A

  Using a cover film having a conductive layer, a transparent electrode for inspecting display defects on the front plate and a take-out electrode for exposing the cover film to conduct electricity must be formed. FIG. 1 is a cross-sectional explanatory view of the front plate of the present invention. A transparent electrode layer and a microcapsule layer are formed on the base film, and this and a cover film having a conductive layer on the cover film base are bonded together via an adhesive layer. At this time, the extraction electrode for each of the transparent electrode and the conductive layer of the cover film is formed as shown in FIG.

  The take-out electrode P of the conductive layer on the cover film can be taken out by processing as shown in FIG. 1, but the take-out electrode Q on the transparent electrode side has a microcapsule layer of several tens of μm on the upper layer and an adhesive layer. There are several tens of μm, the conductive base material is several tens to several hundreds of μm, and in order to form an extraction electrode, these upper layers must be removed and the transparent electrode layer must be exposed.

  Here, as a method of taking out the transparent electrode, a method of irradiating the entire area of the electrode with a laser by using a laser processing apparatus and incinerating and exposing the upper layer of the transparent electrode can be considered, but the laser output is adjusted and minimized. However, not only the upper layer but also the transparent electrode itself is destroyed. Therefore, as shown by Q in FIG. 1, it is necessary to cut only the conductive release substrate using a processing means such as a laser or a cutter, and wipe the microcapsule layer and the adhesive layer with a waste cloth, a cotton swab or the like.

  Here, wiping off the microcapsule layer and the adhesive layer on the extraction electrode is simply referred to as “electrode wiping”. Moreover, since the microcapsule layer and the adhesive layer are mixed by bonding and the adhesiveness of the adhesive is strong, it takes time and labor to wipe the mixture of the microcapsule and the adhesive. Further, when the mixture of the adhesive and the microcapsules on the extraction electrode is wiped off, there is a problem that the transparent electrode layer is wiped off at the same time.

  Further, when inspecting a display defect portion, it is desirable that the takeout electrode is not one location but two locations as shown in FIGS. 1 (a) and 1 (b). This is to make the response speed of the image display uniform over the entire surface when conducting to the electrodes on the front plate described above.

  In this case, two locations of the front plate are wiped off, and when the number of front plates increases, the time required for the electrode wiping operation increases and the labor cost increases. .

  Thus, by mechanizing the unnecessary material wiping operation comprising the display material and the adhesive in forming the extraction electrode, it is possible to reduce the time required for the electrode wiping operation and the cost such as labor costs.

  Here, as a method for wiping the electrode, a plastic brush (10) such as PET having the same size as the area of the electrode wiping portion (Q) as shown in FIG. 3 is prepared, and the brush is applied to the electrode wiping portion (Q). A method of wiping the electrode by pressing and rotating the hair (11) is conceivable. In this case, the work efficiency of wiping is better compared to manual work, but the tip of the brush is deformed when used several tens of times or more, and the mixture of the adhesive (4) and microcapsule (3) wiped off by the brush is in the vicinity. The mixture of the adhesive and the microcapsule adheres to the brush (10).

  As a result, the electrode wiping area cannot be wiped evenly over the entire surface, and the mixture of adhesive and microcapsules scattered by wiping adheres to the front plate, or the mixture of adhesive and microcapsules attached to the brush is the electrode. There was a problem of adhering around the wiping portion.

  Therefore, in order to uniformly wipe the entire surface of the electrode wiper, wipe the mixture of the adhesive and microcapsule attached to the brush each time with a cloth with a solvent attached, and then renew the brush every several tens of times. It is necessary to exchange for something. In addition, the mixture of adhesive and microcapsules scattered by wiping is sucked with a vacuum cleaner, etc., but since the adhesive has strong adhesive properties, the mixture of microcapsules and adhesive scattered by a vacuum cleaner etc. must be completely recovered. It is difficult.

  As a result, the indirect time in the electrode wiping operation increases, for example, the mixture of the microcapsules and the adhesive scattered around the area must be wiped off.

  Further, when the electrode is wiped by rotating the brush, the center of the resistance force that the wiping part receives by the rotation of the brush is the largest, so the transparent electrode is destroyed at the center of the electrode wiping part, and the substrate is exposed, or the brush rotates Therefore, there is a problem that a wiping defect occurs in which the mixture of the microcapsules and the adhesive cannot be completely removed around the electrode portion where the resistance force received by the wiping portion is the smallest.

  The present invention solves the problems of the electrode wiping method using a brush that is easily conceived, and even when the electrode wiping operation is repeated several hundred times when removing unnecessary portions for exposing the electrode take-out portion, the wiping portion The mixture of the wiped adhesive and microcapsule is completely recovered without splashing around the front plate, etc., and the mixture of the adhesive and microcapsule does not adhere to the wiping area, and the entire surface is uniform every time. An object of the present invention is to provide a method for forming a take-out electrode that can be wiped off and a wiping device using this method.

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a front plate for an electrophoretic display device comprising at least a transparent substrate, a transparent electrode, a display material, an adhesive, and a cover film. A method of forming an electrode extraction electrode,
Removing the cover film;
For a takeout electrode having an unnecessary material consisting of a display material and an adhesive, a step of pressing a stick against the takeout electrode through a nonwoven fabric;
The extraction electrode forming method is characterized by including a step of removing unnecessary materials by reciprocating sliding of the nonwoven fabric while the rod is pressed.

Further, the invention according to claim 2 is, before the step of taking out the rod and pressing it against the electrode through the nonwoven fabric,
2. The extraction electrode forming method according to claim 1, further comprising a step of pressing the bar against an extraction electrode having an unnecessary material made of a display material and an adhesive and rotating the bar.

The invention according to claim 3 is a front plate for an electrophoretic display device comprising at least a transparent substrate, a transparent electrode layer, a display material, an adhesive, and a cover film. A wiping device for removing unnecessary materials consisting of display material and adhesive on the take-out electrode after removing the cover film to form a tip having a size smaller than that of the take-out electrode A mechanism capable of pressing a rod having
To placing the nonwoven fabric on the take-out electrode, and to obtain a wiping and having a mechanism capable of reciprocally sliding the nonwoven fabric device.

  The invention according to claim 4 is characterized in that the rod is made of fluororesin or metal and the area of the tip of the rod is 50 to 98% of the area of the extraction electrode. A wiping device was used.

  The invention according to claim 5 is the wiping device according to claim 3 or 4, wherein the bar has a rotation mechanism.

  The front plate for an electrophoretic display device of the present invention will be described.

  FIG. 1 is an explanatory cross-sectional view of a full face plate according to an embodiment of the present invention. FIG. 6 is an explanatory view schematically showing the configuration of the microcapsules of display material constituting the front plate according to the embodiment of the present invention. FIG. 7 is an explanatory diagram showing an example of the display form of the image display layer constituting the information display member according to the embodiment of the present invention.

  The front plate for an electrophoretic display device of the present invention has a transparent electrode layer and a microcapsule layer formed on a transparent substrate, and a cover film having a conductive layer on the cover film substrate via an adhesive layer. Are pasted together.

  As a transparent substrate, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate, polycarbonate, polyethylene naphthalate, polypropylene, nylon-6, nylon-6.6, polyvinylidene chloride, polyethersulfone, etc. Can be used. The film thickness of the transparent substrate is desirably about 25 to 250 μm. When the film thickness of the transparent substrate is thick, winding becomes difficult. On the other hand, when the film thickness of the transparent substrate is too thin, the moisture blocking function is lowered and the protection function of the microcapsule display layer against impact is insufficient.

  The transparent electrode layer can be a common electrode whose entire surface has the same potential. As the transparent electrode forming material, indium tin oxide (ITO), indium zinc oxide (IZO) or the like can be used, and the film is formed on the substrate by a dry film forming method such as a sputtering method.

  Moreover, it is better to provide a conductive protective layer on the transparent electrode at the extraction electrode forming portion. By providing the conductive protective layer, it becomes possible to contribute to the destruction of the transparent electrode layer when wiping off unnecessary materials. Any conductive protective layer may be used as long as it has conductivity. For example, the conductive protective layer can be formed by screen printing using Ag paste.

  As the display material of the electrophoretic display device of the present invention, microcapsules can be used, and those containing microcapsules (14) as shown in the schematic diagram of FIG. 6 can be used. An example of the microcapsule (14) is a capsule shell (15) made of, for example, methacrylic acid resin, urea resin, gum arabic or the like, and white particles (17) made of titanium oxide and black particles made of carbon black. (18) is encapsulated in a state of being dispersed in a highly viscous dispersion medium (16) such as silicone oil. White particles of titanium oxide are positively charged, while black particles of carbon black are negatively charged.

  A display medium using a microcapsule type electrophoresis system including such microcapsules operates as follows.

  That is, as shown in the schematic diagram of FIG. 7, an electric field is applied to the transparent electrode layer (19) and the conductive layer with or without cover fibre (20), the transparent electrode layer (19) is the negative electrode, and the conductive layer on the cover film. When (20) is a positive electrode, positively charged white particles (17) are attracted to the transparent electrode layer (19) side, and black particles (18) are attracted to the conductive layer (20) side. When observed from above the electrode layer (19) side, the portion looks white.

Conversely, when the transparent electrode layer (19) is the positive electrode and the conductive layer (20) is the negative electrode, the positively charged white particles (17) are attracted to the conductive layer (20) side and become black. Since the particles (18) are attracted to the transparent electrode layer (19) side, when observed from above the transparent electrode layer (19) side, the portion looks black.

  The microcapsule layer (3) has a large number of such microcapsules as shown in the schematic side sectional view of FIG. 1 (c), and can be obtained by controlling the electric field of each address electrode of the transparent electrode. Can be displayed as white and black pixels.

  Moreover, as a cover film base material, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate, polycarbonate, polyethylene naphthalate, polypropylene, nylon-6, nylon-6.6, polyvinylidene chloride, polyether Sulfone or the like can be used.

  Moreover, as the conductive layer formed on the cover film substrate, a metal material such as Al can be used in addition to ITO and IZO. These are formed by a dry film forming method such as a sputtering method or a vapor deposition method.

  The transparent electrode formed on the transparent substrate, the display material, and the cover film having a conductive layer on the cover film substrate are bonded together via an adhesive layer.

  Examples of the adhesive layer include a pressure-sensitive adhesive (pressure-sensitive adhesive) and a heat-sensitive adhesive in consideration of mounting and the like.

  Examples of the former pressure-sensitive adhesive include a urethane resin pressure-sensitive adhesive composed of a urethane prepolymer obtained by reacting a polyol and a polyisocyanate in the presence of a catalyst such as hexahydrodimethylaniline and a deterioration inhibitor. be able to. As the polyol, polyester polyol, polyether polyol and the like are used, and as the polyisocyanate, aromatic polyisocyanate, aliphatic polyisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, tolidine diisocyanate, polymethylene polyphenylene polyisocyanate, Tolidine diisocyanate, naphthalene diisocyanate and the like are used. Furthermore, as the aliphatic polyisocyanate, for example, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, dicyclohexylmethane diisocyanate and the like are used.

  Examples of the latter heat-sensitive adhesive include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and unstretched polypropylene (CPP) as resins having excellent heat sealability. A polyolefin film having a thickness of about 50 μm can be suitably used.

  However, since these polyolefin resins alone may not be able to balance the adhesive strength and peel strength, for example, these polyolefin resins are further mixed with incompatible components such as polystyrene and polybutene with respect to polyolefin resins. It is also possible to extrude a melt of these mixed resins to form an easily peelable adhesive layer. It is also possible to use a hot melt adhesive made of ethylene-vinyl acetate copolymer resin or the like.

  The extraction electrode forming method on the transparent electrode side of the present invention will be described.

  As shown in FIG. 1C, in order to perform a display defect inspection, it is necessary to expose the transparent electrode and the conductive layer and form an extraction electrode. The extraction electrode P on the conductive layer side on the cover film is formed so as to extract the electrode from the transparent base material side, and the extraction electrode Q on the transparent electrode side is formed so as to extract the electrode from the cover film side.

  In the front plate for an electrophoretic display device comprising a transparent electrode, a display material, an adhesive, and a cover film on a transparent substrate, the cover film that is empty above the extraction electrode formation site is removed. As a method of removing the cover film, cutting with a laser or a cutter can be raised. When cutting with a laser or a cutter, it is necessary to prevent the transparent electrode from being damaged. A conductive protective layer may be formed on the transparent electrode at the location where the extraction electrode is formed.

  After removing the cover film, the display material and the adhesive on the take-out electrode are removed. The conceptual diagram of the wiping method in the electrode wiping process which concerns on FIG. 4 at one Embodiment of this invention was shown. FIG. 4G is a conceptual diagram of the wiping portion viewed in parallel to the B-B ′ direction. (H) is the conceptual diagram seen in parallel with the A-A 'direction.

  In order to take out the unnecessary material composed of the display material and the adhesive, the bar 12 is pressed against the take-out electrode through the nonwoven fabric 13 and reciprocated. By reciprocatingly sliding, unnecessary matter on the take-out electrode is transferred to the nonwoven fabric 13 and removed.

  In the configuration of the front plate member for electrophoretic display devices, if the adhesive film thickness is thin or the adhesive adhesive strength is weak, a bar is pressed against the take-out electrode via a non-woven fabric, and the cloth is slid back and forth in the pressed state. By doing so, the electrode can be wiped off. However, if the adhesive film is thick or the adhesive strength is strong, when the electrode is wiped by reciprocating sliding the nonwoven fabric, the adhesive on the electrode wiper and unnecessary materials on the display material are removed. In addition to wiping, there is a problem that the adhesive and display material around the electrode wiping portion are also dragged off.

  In order to prevent the adhesive and display material around the electrode wiping portion from being dragged back and forth by reciprocating sliding, the bar 12 is pressed against the extraction electrode and rotated before it is pressed against the bar and the extraction electrode through the nonwoven fabric. By rotating the rod 12, the adhesive on the take-out electrode and the adhesive on the periphery of the take-out electrode can be separated. Unnecessary materials are transferred to the rod and removed. The conceptual diagram of the wiping method in the wiping process which concerns on FIG. 5 at one Embodiment of this invention was shown.

  Further, after rotating the rod 12, the rod is pressed against the take-out electrode through the non-woven fabric, and the non-woven fabric is reciprocated to reciprocate, whereby not only the remaining unnecessary matter on the take-out electrode is wiped off. Unnecessary matter adhering to the rod when the electrode is taken out and pressed against the electrode can be removed.

  Next, the wiping device according to the present invention will be described.

  As a stick | rod in the wiping apparatus in this invention, it has a pressing mechanism for pressing a stick | rod to an extraction electrode. As a mechanism for pressing the rod, it can be pressed against the take-out electrode by the weight of the rod itself, but if the rod is made of a light material such as plastic and is lightweight, it can be pressed by attaching a weight to the rod. . Further, the bar can be taken out and pressed against the electrode by a spring.

  As the material for forming the rod, fluorine-based resin or metal can be preferably used, and the area of the tip of the rod is preferably 50 to 98% of the area of the extraction electrode.

  Moreover, it is preferable that the rod has a rotation mechanism. The rotation mechanism can be achieved by attaching a motor to a rod, for example.

In addition, as a mechanism for reciprocally sliding the nonwoven fabric, a web-shaped nonwoven fabric wound around a roll is wound around a roll to be wound up through a plurality of rolls, and the roll is wound between a supply roll and a winding roll. There is a method in which the nonwoven fabric is reciprocated on the take-out electrode by rotating. And after taking out an unnecessary thing, the unnecessary thing on a taking-out electrode can be removed by winding up a roll for a required amount and also with an unused nonwoven fabric.

  The mechanism for reciprocating and sliding the nonwoven fabric is preferably integral and movable. By making it movable, it becomes possible to provide a non-woven fabric between the extraction electrode and the rod as required.

  In the present invention, a nonwoven fabric can be used as the wiping cloth. Nonwoven fabrics can be suitably used because they are strong and do not generate dust.

  The non-woven fabric is preferably a mixture of pulp and acrylic fiber, which has fine fibers, high tensile strength, and hardly generates flaking. In order to use continuously, it is preferable to use a web-like thing having a width of 2 cm or more and a roll of about 20 m.

It is a figure which shows the front board which concerns on one Embodiment of this invention, (a) is an image display surface side by a top view, (b) shows the back surface of (a), ie, an electroconductive release side, (c) FIG. 3 is a side cross-sectional view taken along the line AA ′. It is a figure which shows the front board which concerns on one Embodiment of this invention, (d) is B-B 'side sectional drawing of FIG.1 (b). (E) is a view of the conductive release layer excised with a laser, and (f) is a view showing the state after wiping off the electrode. It is a figure which shows one Embodiment of the electrode wiping method using a brush, 10 is a wiping brush figure. It is a figure explaining the wiping method in the electrode wiping process which concerns on one Embodiment of this invention. (G) is the figure which looked at the wiping part in parallel with the B-B 'direction, applies a load from the top to a stick | rod (12), and is an idea figure which reciprocates and slides a nonwoven fabric (13) in the arrow direction. (H) is the figure seen in parallel with the A-A 'direction. It is a figure explaining the wiping method when the adhesive bond layer in the process which concerns on one Embodiment of this invention in an electrode wiping process is thick or adhesiveness is strong. It is explanatory drawing which shows typically the structure of the microcapsule which comprises the front plate which concerns on one Embodiment of this invention. It is a side view showing typically an example of a display form of an image display layer which constitutes a front board concerning one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base film 2 Transparent electrode layer 3 Microcapsule layer 4 Adhesive layer 5 Conductive layer 6 Cover film base material 7 Black particle 8 White particle 9 Brush rotating shaft 10 Brush 11 Brush hair 12 Stick 13 Nonwoven fabric 14 Microcapsule 15 Capsule shell 16 Dispersion medium 17 White particles 18 Black particles 19 Transparent electrode layer 20 Conductive release substrate AA ′ Dividing line BB ′ Dividing line P Conductive release side extraction electrode Q Transparent electrode side extraction electrode

Claims (5)

In the front plate for an electrophoretic display device comprising at least a transparent electrode, a display material, an adhesive, and a cover film on a transparent substrate, a method of forming an extraction electrode of the transparent electrode from the cover film side,
Removing the cover film;
For a takeout electrode having an unnecessary material consisting of a display material and an adhesive, a step of pressing a stick against the takeout electrode through a nonwoven fabric;
A method for forming a take-out electrode, comprising a step of removing unnecessary substances by reciprocating and sliding a nonwoven fabric while pressing the rod. Before the step of taking out the rod through the nonwoven fabric and pressing it against the electrode,
2. The extraction electrode forming method according to claim 1, further comprising a step of pressing the bar against an extraction electrode having an unnecessary material made of a display material and an adhesive and rotating the bar. In the front plate for an electrophoretic display device comprising at least a transparent electrode layer, a display material, an adhesive, and a cover film on a transparent substrate, the cover film was removed from the cover film side in order to form a transparent electrode take-out electrode Thereafter, a wiping device for removing unnecessary materials composed of the display material and the adhesive on the take-out electrode, the stick having a tip having a smaller size than the take-out electrode on the take-out electrode through the non-woven fabric. A mechanism that can be pressed against the electrode ;
To placing the nonwoven fabric on the take-out electrode, and, wiping and having a mechanism capable of reciprocally sliding the nonwoven fabric device.   4. The wiping device according to claim 3, wherein the bar is made of a fluororesin or metal, and the area of the tip of the bar is 50 to 98% of the area of the extraction electrode.   The wiping device according to claim 3 or 4, wherein the bar has a rotation mechanism.