JP5136614B2 - Microcapsule type electrophoretic display panel and manufacturing method thereof - Google Patents

Description

  The present invention relates to a microcapsule electrophoretic display panel having a high moisture blocking function for a microcapsule display layer and operating with stable characteristics, and a method for manufacturing the same.

  As a flat panel display device, a liquid crystal display device (LCD) is now widely used in various applications because it is thin and can be miniaturized. As another display method aiming at further thinner and lower power consumption than such an LCD, a display device using an electrophoretic phenomenon has been developed.

  As one of display devices using the electrophoresis phenomenon, a microcapsule electrophoresis system has been put into practical use. In this type of display device, positive and negatively charged white and black particles are placed in a microcapsule 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. Since the size of the microcapsule is as small as several tens μm to several hundred μm, when the microcapsule is dispersed in a transparent binder, it can be coated like ink. This ink is called electronic ink because an image can be drawn by applying a voltage from the outside.

  When this electronic ink is coated on a transparent resin film on which a transparent electrode is formed and bonded to a substrate on which an electrode circuit for driving an active matrix is formed, an active matrix display panel as shown in Patent Document 1, for example, can be obtained. it can. In general, a component in which a transparent resin film on which a transparent electrode is formed is coated with electronic ink is called a “front plate”, and a substrate on which an electrode circuit for driving an active matrix is formed is called a “back plate”.

  In the microcapsule type electrophoretic display device configured as described above, the seal on the side of the panel is not sufficient, and moisture such as water vapor enters the microcapsule display layer formed by the coating of electronic ink, and the electrical There is a problem of deteriorating the physical characteristics.

  That is, the upper surface of the panel is covered with a transparent resin film, and the lower surface is blocked with a substrate. However, since it is difficult to seal the side of the panel, the moisture that enters from the side cannot be sufficiently blocked. It was.

JP 2000-221546 A

  The present invention has been made under the circumstances as described above, effectively blocking the ingress of moisture from the side surface, and effectively preventing the deterioration of the characteristics of the microcapsule display layer due to the ingress of moisture into the microcapsule display layer. It is an object of the present invention to provide a microcapsule type electrophoretic display panel and a method for manufacturing the same.

  In order to solve the above-described problems, the present invention provides a substrate, a microcapsule display layer disposed on the substrate via a first adhesive layer, and the microcapsule display deposited on the microcapsule display layer. A transparent resin film having a transparent electrode layer on the layer side, which is deposited on the transparent resin film via a second adhesive layer, protrudes sideways from the side surface of the transparent resin film, and the transparent resin film and the microcapsule A transparent resin protective film having a size larger than that of the transparent resin film so as to form a gap between the substrate and the side surface of the display layer, an antiglare film and an antireflection film formed on the transparent resin protective film And a functional layer selected from the group consisting of a hard coat, and a water vapor blocking resin layer having a width of 1 to 1.5 mm, which is filled in the voids, and the transparent resin protective film exceeds 100 μm and is 250 μm. Less than A microcapsule type having a thickness below and containing a gas barrier material, wherein the water vapor blocking resin layer is made of an acrylic resin, a methacrylic resin or an epoxy resin cured by irradiation with heat or ultraviolet rays An electrophoretic display panel is provided.

  Further, the present invention provides a step of forming a microcapsule display layer on a transparent electrode layer of a transparent resin film having a transparent electrode layer to obtain a front plate, a surface on the side opposite to the transparent electrode layer of the transparent resin film. A step of applying the second adhesive layer, a step of cutting the front plate to which the second adhesive layer is attached to a predetermined size, and the microcapsule display layer side of the transparent resin film via the first adhesive layer A transparent resin protective film having a size larger than that of the transparent resin film and having a thickness of more than 100 μm and not more than 250 μm and containing a gas barrier substance, the second adhesive layer A step of forming a gap between the transparent resin film and the side surface of the microcapsule display layer, and forming a void between the substrate and the transparent resin film through the side surface of the transparent resin film, Acrylic resin, methacrylate A step of filling a water vapor blocking resin having a viscosity of 2000 Pa · s or less made of a resin or an epoxy resin, and curing the filled water vapor blocking resin by heating or irradiation with ultraviolet rays, and having a width of 1 to 1.5 mm Provided is a method for manufacturing a microcapsule type electrophoretic display panel, comprising a step of forming a water vapor blocking resin layer.

  According to the microcapsule-type electrophoretic display panel of the present invention configured as described above and the manufacturing method thereof, the gap formed between the substrate and the transparent resin protective film on the side surfaces of the transparent resin film and the microcapsule display layer. Is filled with a water vapor blocking resin layer, which effectively blocks the ingress of moisture into the microcapsule display layer and effectively degrades the characteristics of the microcapsule display layer due to the ingress of moisture into the microcapsule display layer. Can be prevented.

  In addition, since the transparent resin protective film is applied on the surface, the protection function for the microcapsule display layer can be greatly enhanced, and damage to the microcapsule display layer due to external impact can be effectively prevented.

  In the microcapsule-type electrophoretic display panel of the present invention, it is desirable that the water vapor blocking resin layer is composed of a thermosetting or ultraviolet curable acrylic resin. Since the acrylic resin has water vapor barrier properties and low viscosity, it can be easily filled into the gaps on the side surfaces of the transparent resin film and the microcapsule display layer.

  Moreover, the width | variety of the water-vapor-shielding resin layer with which the space | gap of the side surface of the transparent resin film and the microcapsule display layer was filled is 1-1.5 mm. By setting the width of the water vapor blocking resin layer within this range, it is possible to sufficiently prevent moisture from entering the microcapsule display layer.

Furthermore, it is desirable that the transparent resin protective film has a water vapor permeability of 0.1 g / m ² · day or less. With such a transparent resin protective film having water vapor permeability, it is possible to effectively prevent moisture from entering from above (the display surface side).

  Furthermore, it is desirable that a gas barrier layer is interposed between the transparent resin protective film and the transparent resin film and the water vapor blocking resin layer. The transparent resin protective film contains a gas barrier material. By such a gas barrier layer or gas barrier material, it is possible to effectively prevent the permeation of water vapor from above.

  The gas barrier layer or gas barrier material can be one inorganic compound selected from the group consisting of silicon dioxide, aluminum oxide and magnesium oxide, or a fluororesin.

  According to the present invention, by filling the void formed between the substrate and the transparent resin protective film on the side surface of the transparent resin film and the microcapsule display layer with the water vapor blocking resin layer, Provided is a microcapsule type electrophoretic display panel capable of effectively blocking intrusion and effectively preventing deterioration of characteristics of the microcapsule display layer due to the ingress of moisture into the microcapsule display layer. Since the microcapsule-type electrophoretic display panel according to the present invention has a transparent resin protective film attached to the surface, the protection function for the microcapsule display layer is greatly enhanced, and the microcapsule display layer due to external impact It is also possible to effectively prevent the breakage of the material.

9 is a cross-sectional view illustrating a manufacturing process of a microcapsule type electrophoretic display panel according to one embodiment of the present invention. FIG. FIG. 3 is a diagram schematically illustrating a microcapsule included in a microcapsule display layer of a microcapsule type electrophoretic display panel according to one embodiment of the present invention. The perspective view which represents typically an example of the display form of the microcapsule display layer of the microcapsule type | mold electrophoretic display panel which concerns on one form of this invention. FIG. 6 is a side cross-sectional view schematically illustrating an example of a display form of a microcapsule display layer of a microcapsule type electrophoretic display panel according to an embodiment of the present invention.

  The best mode for carrying out the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a cross-sectional view illustrating a manufacturing process of a microcapsule type electrophoretic display panel according to an embodiment of the present invention.

  As shown in FIG. 1A, first, electronic ink is applied by screen printing on the surface of the transparent electrode layer 1 of the transparent resin film 2 made of polyethylene terephthalate having the transparent electrode layer (ITO film) 1 formed on the surface. Printing is performed to form the microcapsule display layer 3. Next, the first adhesive layer 4 is formed on the surface of the microcapsule display layer 3 to obtain the front plate 5.

  In this case, printing of electronic ink is performed on the transparent electrode layer 1 of the transparent resin film 2, but since the transparent resin film 2 is thin, operation by winding is possible, and printing of electronic ink is performed continuously. Thus, it is possible to perform with good workability.

  As the transparent resin film 2, in addition to polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyethylene naphthalate, polypropylene, nylon-6, nylon-66, polyvinylidene chloride, polyethersulfone, or the like can be used. The film thickness of the transparent resin film 2 is preferably about 25 to 250 μm. When the film thickness of the transparent resin film 2 is thick, it is difficult to wind up, which adversely affects the workability of electronic ink printing. On the other hand, when the film thickness of the transparent resin film 2 is too thin, the protective function of the microcapsule display layer 3 becomes insufficient even if a transparent resin protective film described later is provided.

  The transparent electrode layer 1 can be a common electrode having the same potential on the entire surface. The film thickness of the transparent electrode layer 1 is preferably 10 nm or more, more preferably about 100 nm in order to have sufficient conductivity.

  As the first adhesive layer 4, a known pressure-sensitive adhesive or heat-sensitive adhesive can be used. These can be used in the form of a single-sided adhesive tape or a double-sided adhesive tape having release paper on the adhesive surface. That is, the first adhesive layer 4 is affixed to the microcapsule display layer 3 by sticking the non-adhesive surface of the single-sided adhesive tape to the microcapsule display layer 3 with an adhesive, or by peeling off one release tape of the double-sided adhesive tape. Can be formed. The thickness of the first adhesive layer 4 is preferably about 10 to 50 μm.

  A second adhesive layer 7 is provided on the surface of the front plate 5, that is, on the surface of the transparent resin film 2 opposite to the transparent electrode layer 1. The second adhesive layer 7 preferably has high self-holding properties and high elasticity. The second adhesive layer 7 having high elasticity can serve not only as a mere adhesive action but also as a cushion to reduce the impact received by the transparent resin protective film 8 described later. Specific materials for the second adhesive layer 7 include silicon rubber, chloroprene rubber, ethylene-propylene rubber, fluorine rubber, acrylic rubber, butyl rubber, and the like, and the film thickness is preferably 25 μm or more. . The upper limit of the thickness of the second adhesive layer 7 is not particularly limited from the viewpoint of performance, but is about 250 μm from the viewpoint of productivity.

  As described above, after the second adhesive layer 7 is formed on the front plate 5, the front plate 5 is cut into a predetermined size. As a result, the end surfaces of the front plate 5 and the second adhesive layer 7 can be aligned.

  In addition, by using the second adhesive layer 7 having high elasticity, the second adhesive layer 7 may be partially detached during the process to contaminate the apparatus or the workpiece, or the workpiece may be bonded to each other. Absent. Moreover, since a clean end surface is obtained by cutting the front plate 5 after the second adhesive layer 7 is formed, it does not adversely affect the filling of the water vapor blocking resin in the subsequent process.

  Next, as shown in FIG. 1 (b), the front plate 5 is attached to the substrate 6. Affixing can be performed, for example, by removing the release paper, adhering the adhesive surface of the first adhesive layer 4 to the substrate 6 and pressing or heating. The substrate 6 is a glass substrate or resin film provided with an electrode layer (not shown) on the surface, and the electrode layer on the surface is patterned independently for each pixel as a pixel electrode, and a thin film transistor, a signal electrode, and a scanning electrode (not shown) Can be used.

  Next, as shown in FIG. 1C, a transparent resin protective film 8 is formed on the transparent resin film 2 of the laminate obtained as described above via a second adhesive layer 7.

As the transparent resin protective film 8, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyethylene naphthalate, polypropylene, nylon-6, nylon-66, polyvinylidene chloride, polyethersulfone, or the like can be used. In particular, in order to effectively prevent moisture from entering from the upper side (display surface side), it is desirable that the water vapor permeability is 0.1 g / m ² · day or less. In addition, water vapor permeability is a value when measured with the front plate 5 side facing the sensor side of the measuring instrument.

  The film thickness of the transparent resin protective film 8 is preferably about 100 to 250 μm. When the thickness of the transparent resin protective film 8 is too thin, the protective function of the microcapsule display layer 3 is insufficient, and when it is too thick, it is difficult to produce a uniform film and the visibility is also lowered.

  The transparent resin protective film 8 is larger in size than the transparent resin film 2. The size of the transparent resin protective film 8 is desirably such that the end portion protrudes 1 to 1.5 mm laterally from the side surface of the transparent resin film. That is, the length of the end of the transparent resin protective film 8 projecting sideways from the side surface of the transparent resin film is the width of the water vapor blocking resin layer described later, and moisture penetrates into the microcapsule display layer 3. Since it is a distance, if it is 1 to 1.5 mm, it is possible to sufficiently prevent moisture from entering the microcapsule display layer 3. On the other hand, if the protruding length is less than 1 mm, it is difficult to sufficiently prevent moisture from entering the microcapsule display layer 3, and if it exceeds 1.5 mm, it is difficult to fill a water vapor blocking resin layer described later. Become.

  Thus, by making the size of the transparent resin protective film 8 larger than the transparent resin film 2 and projecting the end of the transparent resin protective film 8 from the side surface of the transparent resin film 2, the transparent resin film 2 and A gap is formed between the side surface of the microcapsule display layer 3 and the substrate 6. As described above, the width of the gap is such a length that the end of the transparent resin protective film 8 protrudes laterally from the side surface of the transparent resin film, and the height of the gap is between the substrate 6 and the transparent resin protective film 8. The distance, that is, the total thickness of the first adhesive layer 4, the microcapsule display layer 3, the transparent electrode layer 1, the transparent resin film 2, and the second adhesive layer 7.

A space formed between the substrate 6 and the transparent resin protective film 8 is filled with a water vapor blocking resin. The water vapor blocking resin that can be used is desirably a resin having a water vapor blocking function and a low viscosity so that it can be easily filled. Further, it is desirable that the resin is cured by irradiation with heat or ultraviolet rays after filling. As such a resin, a heat or ultraviolet curable acrylic resin, a methacrylic resin, an epoxy resin, or the like can be used, and it is particularly preferable to use an acrylic resin. The water vapor blocking function preferably has a water vapor transmission coefficient of 0.6 g · mm / m ² · day or less, and the viscosity is preferably 2000 Pa · s or less.

  The filling of the water vapor blocking resin into the gap can be performed by, for example, a general dispenser. The water vapor blocking resin filled in the gap is cured by heating or irradiation with ultraviolet rays, and the water vapor blocking resin layer 9 is formed.

  As described above, after the second adhesive layer 7 is formed on the front plate 5, the front plate 5 and the end surface of the second adhesive layer 7 are aligned by cutting the front plate 5 to a predetermined size. Therefore, the width of the water vapor blocking resin to be filled, that is, the seal width is uniform over the entire circumference, so that uniform sealing can be performed.

  A gas barrier layer 10 may be provided on the surface of the transparent resin protective film 8 on the substrate 6 side. As the gas barrier layer 10, an inorganic compound such as silicon dioxide, aluminum oxide, magnesium oxide, or a fluororesin can be used. The thickness of the gas barrier layer 10 can be, for example, 20 to 200 nm (0.02 to 0.2 μm) in the case of an inorganic compound film, and 0.05 to 0.2 mm (50 to 200 μm) in the case of a fluororesin film. Instead of providing the gas barrier layer 10, a gas barrier material may be included in the transparent resin protective film 8. As the gas barrier material, the material used for the gas barrier layer 10 described above can be used.

  By such a gas barrier material in the gas barrier layer 10 or the transparent resin protective film 8, it is possible to effectively prevent the permeation of water vapor from above.

  Further, a functional layer 11 having a specific function such as an antiglare film, an antireflection film, or a hard coat may be provided on the surface of the transparent resin protective film 8. The anti-glare film is a film that has irregularities on the surface and scatters external light on the irregular surface, and the anti-reflection film reflects using interference of reflected light generated at the interface between the laminated layers. It attenuates light. The hard coat is a hard resin film having a high cross-linking density and has scratch resistance similar to that of glass. These functional layers 11 can be formed by a known method using a known material.

  The microcapsule-type electrophoretic display panel obtained as described above and shown in FIG. 1C is formed between the substrate 6 and the transparent resin protective film 8 on the side surfaces of the transparent resin film 2 and the microcapsule display layer 3. Since the water vapor blocking resin layer 9 is filled in the gap formed in the microcapsule display layer, it effectively blocks moisture from entering the microcapsule display layer 3, and the microcapsule display by the moisture intrusion into the microcapsule display layer 3 is performed. The deterioration of the characteristics of the layer 3 can be effectively prevented.

  In the microcapsule-type electrophoretic display panel described above, the microcapsules included in the microcapsule display layer 3 include, for example, a methacrylic acid resin, urea resin, gum arabic or the like as a capsule shell 111 as shown in FIG. Inside, white particles 113 made of titanium oxide and black particles 114 made of carbon black are enclosed in a state of being dispersed in a highly viscous dispersion medium 112 such as silicone oil. Titanium oxide, which is a white particle 113, has a positive charge, while carbon black, which is a black particle 114, has a negative charge.

  A display body using such a microcapsule type electrophoresis system including the microcapsules 110 operates as follows.

  That is, as shown in the schematic diagram of FIG. 3, an electric field is applied to the transparent electrode layer 1 on the transparent resin film 2 side and the electrode layer 21 on the substrate 6 side, the transparent electrode layer 1 being a negative electrode, and the electrode layer 21 being a positive electrode. In this case, the positively charged white particles 113 are drawn to the transparent electrode layer 1 side, and the negatively charged black particles 114 are drawn to the electrode layer 21 side. The part looks white.

  Conversely, when the transparent electrode layer 1 is a positive electrode and the electrode layer 21 is a negative electrode, the positively charged white particles 113 are attracted to the electrode layer 21 side, and the negatively charged black particles 114 are transparent. Since it is drawn to the electrode layer 1 side, when viewed from above the transparent electrode layer 1 side, the portion looks black.

  As shown in the schematic side sectional view of FIG. 4, the microcapsule display layer 3 includes a large number of microcapsules 110, the transparent electrode layer 1 is a common electrode having the same potential, and the electric field of each address electrode of the electrode layer 21 is changed. By controlling, it is possible to display desired characters and figures as white and black pixels by moving particles in the microcapsule based on the above-described principle.

  Similarly, the electrode layer 21 is used as a common electrode (the potential is set to zero), and the electric field of each address electrode on the transparent electrode 1 side is controlled (a positive or negative potential is applied), so You may make it display a desired image by moving particle | grains.

  Various diameters of the microcapsules can be adopted. However, when a diameter of about 40 μm to about 100 μm is adopted, sufficient resolution and responsiveness can be obtained. The resolution of the display image mainly depends on the arrangement of the electrodes in the electrode layer. However, if the diameter of the microcapsules is small, the movement speed of the microcapsules in the dispersion medium increases, and as a result, the response at the time of display is excellent. There are benefits.

  In the above example, an example of monochrome (monochrome) image display has been described. However, in the case of color image display, R (red), G (green), and B (blue) colors divided in units of pixels are used. A color image display can be realized by providing the color filter having the color filter on the transparent electrode 1 side to which an electric field can be applied in units of pixels.

  A paper-like electronic display can be realized by producing a flexible material and patterning electrodes and the like on a plastic film by a printing method or a vapor deposition method. The display screen size can be created in any size according to the application and demand.

  In the microcapsule display layer 3, there is no problem in display even if the position of the microcapsule 110 is slightly changed. Therefore, it is possible to bend and use it by attaching it to a curved surface.

  In the microcapsule-type electrophoretic display panel, each particle is dispersed in a highly viscous dispersion medium. Therefore, once the electric field is applied, the position of the particle does not change even when the power is turned off. In this way, the display image does not disappear even when the display is turned off. It has non-volatility (memory property), so it is only necessary to apply an electric field at the time of initial display or rewriting, and it is necessary for display compared to a normal display device. It requires less power and can save a lot of power.

  Further, in the display panel, there is no problem in display even if the position of the microcapsules 110 is slightly changed. Therefore, by using a material that makes the entire display including the transparent electrode layer 1 and the electrode layer 21 thin and portable, flexibility such as paper can be provided.

  Since the microcapsule type electrophoretic display panel of the present invention has excellent water vapor barrier properties and moisture resistance, it can be widely used as a display panel in various applications.

  DESCRIPTION OF SYMBOLS 1 ... Transparent electrode layer (ITO film), 2 ... Transparent resin film, 3 ... Microcapsule display layer, 4 ... 1st contact bonding layer, 5 ... Front plate, 6 ... Substrate, 7 ... second adhesive layer, 8 ... transparent resin protective film, 9 ... water vapor blocking resin layer, 10 ... gas barrier layer, 11 ... functional layer, 21 ... electrode Layers 210... Microcapsules 111. Capsule shells 112. Dispersion medium 113. White particles 114. Black particles

Claims (6)

  A substrate, a microcapsule display layer disposed on the substrate via a first adhesive layer, and a transparent resin film having a transparent electrode layer on the microcapsule display layer, which is deposited on the microcapsule display layer The transparent resin film is deposited via a second adhesive layer, protrudes laterally from the side surface of the transparent resin film, and between the substrate on the side surface of the transparent resin film and the microcapsule display layer. Transparent resin protective film having a size larger than that of the transparent resin film so as to form a void, selected from the group consisting of an antiglare film, an antireflection film, and a hard coat formed on the transparent resin protective film A functional layer and a water vapor blocking resin layer having a width of 1 to 1.5 mm filled in the gap, the transparent resin protective film having a thickness of more than 100 μm and not more than 250 μm, and a gas barrier material And the water vapor blocking resin layer is made of an acrylic resin, a methacrylic resin, or an epoxy resin cured by irradiation with heat or ultraviolet rays. The microcapsule type electrophoretic display panel according to claim 1, wherein the transparent resin protective film has a water vapor permeability of 0.1 g / m ² · day or less.   3. The microcapsule type electrophoretic display panel according to claim 1, wherein a gas barrier layer is interposed between the transparent resin protective film and the transparent resin film and the water vapor blocking resin layer. .   4. The microcapsule electrophoresis system according to claim 3, wherein the gas barrier layer is one kind of inorganic compound film selected from the group consisting of silicon dioxide, aluminum oxide and magnesium oxide, or a fluororesin film. Display panel. Forming a microcapsule display layer on a transparent electrode layer of a transparent resin film having a transparent electrode layer to obtain a front plate;
Applying a second adhesive layer to the surface of the transparent resin film opposite to the transparent electrode layer;
Cutting the front plate to which the second adhesive layer is deposited into a predetermined size;
A step of attaching the microcapsule display layer side of the transparent resin film to a substrate via a first adhesive layer;
A transparent resin protective film having a size larger than that of the transparent resin film and having a thickness of more than 100 μm and not more than 250 μm and containing a gas barrier substance is formed on the transparent resin film via the second adhesive layer. A step of forming a gap between the transparent resin film and the side surface of the microcapsule display layer and the substrate so as to protrude sideways from the side surface;
Filling the void with a water vapor blocking resin having a viscosity of 2000 Pa · s or less made of acrylic resin, methacrylic resin or epoxy resin, and curing the filled water vapor blocking resin by heating or irradiation with ultraviolet rays; Forming a water vapor blocking resin layer having a width of 1 to 1.5 mm. A method for producing a microcapsule-type electrophoretic display panel. The method of manufacturing a microcapsule type electrophoretic display panel according to claim 5, wherein the transparent resin protective film has a water vapor permeability of 0.1 g / m ² · day or less.

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