JP4839617B2 - Manufacturing method of microcapsule type electrophoretic display panel - Google Patents

Description

The present invention relates to a method for manufacturing a microcapsule type electrophoretic display panel in which deterioration of a microcapsule display layer is prevented.

  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, titanium oxide as white particles in the microcapsule is deteriorated and colored by ultraviolet rays, and at the same time, the electrophoretic properties are lowered. There was a problem.
JP 2000-221546 A

The present invention has been made under the circumstances as described above, and an object of the present invention is to provide a method for manufacturing a microcapsule type electrophoretic display panel that effectively prevents deterioration of white particles used in a microcapsule display layer due to ultraviolet rays. To do.

In order to solve the above-described problems, the present invention provides a front plate comprising a substrate having an electrode layer on a surface thereof, and a microcapsule display layer containing a transparent electrode layer and titanium oxide as white particles in order on a transparent resin film. A step of adhering the microcapsule display layer surface through a first adhesive layer, a size larger than that of the microcapsule display layer and the transparent resin film, containing an ultraviolet absorber, and forming a gas barrier layer on the surface The gas barrier layer surface of the transparent protective film having a thickness of 100 to 300 μm and the transparent resin film are protruded laterally by 1 to 2.0 mm from the side surface of the transparent resin film. A step of adhering via the second adhesive layer, and a step of filling a gap formed between the substrate and the transparent protective film with a sealing resin made of an ultraviolet curable resin. When the providing a step of irradiating ultraviolet rays to the sealing resin from the side, a method for producing a microcapsule-type electrophoretic display panel sequentially and a step of performing a post-baking.

According to the manufacturing method of the microcapsule type electrophoretic display panel of the present invention configured as described above, an ultraviolet absorber is included on the observation side from the microcapsule display layer, that is, the transparent protective film, the transparent resin film, or the touch panel. Therefore, it is possible to effectively prevent the particles in the microcapsule from being deteriorated and colored by the ultraviolet rays in the outside light.

In the method for producing a microcapsule type electrophoretic display panel of the present invention, benzophenone, benzotriazole, salicylate, and cyanoacrylate can be used as the ultraviolet absorber. The content of the ultraviolet absorber is preferably 0.1 to 20% by weight.

  As the sealing resin layer, an ultraviolet-cured acrylic resin can be used. 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.

  In addition, when UV curable acrylic resin is cured with UV, if UV absorber is included in the transparent protective film, UV light from the observation side is absorbed by the transparent protective film and does not reach the acrylic resin. It is necessary to irradiate ultraviolet rays from the side of the filled acrylic resin.

  On the other hand, when the ultraviolet absorber is contained in the transparent resin film, since the transparent resin film does not cover the acrylic resin, it is possible to irradiate ultraviolet rays from the observation side. In that case, even if the width of the acrylic resin is thick, it is possible to irradiate the entire acrylic resin with a sufficient amount of ultraviolet rays.

  Polyethylene terephthalate can be used as the transparent resin film and the transparent protective film.

  Moreover, it is also possible to interpose a gas barrier layer between the transparent protective film and the transparent resin film and the sealing resin layer. As the gas barrier layer, one kind of inorganic compound film selected from the group consisting of silicon dioxide, aluminum oxide and magnesium oxide, or a fluororesin film can be used. Such a gas barrier layer can effectively prevent the permeation of water vapor from above.

According to the present invention, since the ultraviolet protective agent is contained in the transparent protective film, the transparent resin film, or the touch panel on the observation side from the microcapsule display layer, the particles in the microcapsule are deteriorated by the ultraviolet rays in the outside light. Thus, there is provided a method for manufacturing a microcapsule type electrophoretic display panel that effectively prevents coloring and a decrease in electrophoretic properties.

  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 showing a microcapsule type electrophoretic display panel according to an embodiment of the present invention.

  As shown in FIG. 1, a front plate 2 is attached on a substrate 1. The front plate 2 has a microcapsule display layer printed on the surface of the transparent electrode layer 3 of the transparent resin film 4 made of polyethylene terephthalate having a transparent electrode layer (ITO film) 3 formed on the surface by screen printing. 5 and then the first adhesive layer 6 is formed on the surface of the microcapsule display layer 5.

  In this case, printing of electronic ink is performed on the transparent electrode layer 3 of the transparent resin film 4, but since the transparent resin film 3 is thin, operation by winding is possible, and printing of electronic ink is continuously performed. Thus, it is possible to perform with good workability.

  As the transparent resin film 4, 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 4 is preferably about 25 to 250 μm. When the film thickness of the transparent resin film 4 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 4 is too thin, the protective function of the microcapsule display layer 5 becomes insufficient even if a transparent protective film described later is provided.

  The transparent electrode layer 3 can be a common electrode having the same potential on the entire surface. The film thickness of the transparent electrode layer 3 is preferably 10 nm or more, more preferably about 100 nm in order to have sufficient conductivity.

  As the first adhesive layer 6, 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 6 is affixed to the microcapsule display layer 5 with the adhesive on the non-adhesive side of the single-sided adhesive tape, or peeled off the one release tape of the double-sided adhesive tape and applied to the microcapsule display layer 5. Can be formed. The thickness of the first adhesive layer 6 is preferably about 10 to 50 μm.

  A second adhesive layer 7 is provided on the surface of the front plate 2, that is, the surface of the transparent resin film 4 opposite to the transparent electrode layer 3. 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 protective film 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.

  The front plate 2 can be attached to the substrate 1 by, for example, removing the release paper, attaching the adhesive surface of the first adhesive layer 6 to the substrate 1, and pressing or heating. The substrate 1 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.

  2% by weight of 2- (5-methyl-2-hydroxyphenyl) benzotriazole is contained as an ultraviolet absorber on the transparent resin film 4 of the laminate constituted as described above via the second adhesive layer 7. A transparent protective film 8 is formed.

  As the transparent protective film 8, 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 protective film 8 is preferably about 100 to 300 μm. When the thickness of the transparent protective film 8 is too thin, the protective function of the microcapsule display layer 5 is insufficient, and when it is too thick, it is difficult to produce a uniform film and the visibility is also lowered.

The transparent protective film 8 has a larger size than the transparent resin film 4. As for the size of the transparent protective film 8, the edge part protrudes 1 to 2.0 mm side from the side surface of the transparent resin film .

  Thus, by making the size of the transparent protective film 8 larger than the transparent resin film 4 and projecting the end of the transparent protective film 8 from the side surface of the transparent resin film 4 to the side, An air gap is formed between the display layer 5 and the substrate 1. As described above, the width of the gap is such a length that the end of the transparent protective film 8 protrudes laterally from the side surface of the transparent resin film, and the height of the gap is the distance between the substrate 1 and the transparent protective film 8, That is, the total thickness of the first adhesive layer 6, the microcapsule display layer 5, the transparent electrode layer 3, the transparent resin film 4, and the second adhesive layer 7.

  A gap formed between the substrate 1 and the transparent protective film 8 is filled with a sealing resin. As the sealing resin, it is preferable to use 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.

  Filling the gap with the sealing resin can be performed by, for example, a general dispenser. The sealing resin filled in the gap is cured by heating or irradiation with ultraviolet rays, whereby the sealing resin layer 9 is formed.

  When an ultraviolet curable resin is used as the sealing resin, an ultraviolet absorber is contained in the transparent protective film 8, and therefore, ultraviolet irradiation for curing is not performed through the transparent protective film 8 from the observation side. It is necessary to carry out from the side, that is, from the direction of the arrow in FIG. In this case, since the width of the sealing resin to be cured is as wide as about 1.5 mm, for example, it may be difficult to uniformly cure the whole, and in that case, post baking is necessary.

  A gas barrier layer 10 may be provided on the surface of the transparent protective film 8 on the substrate 1 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 500 nm (0.02 to 0.5 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 substance may be included in the transparent 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 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 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.

  In the microcapsule type electrophoretic display panel configured as described above, since the transparent protective film 8 contains an ultraviolet absorber, it is assumed that it is used outdoors for a long period of time and irradiated with ultraviolet rays in sunlight. In addition, it is possible to effectively prevent the electrophoretic properties from being lowered at the same time as the titanium oxide particles in the microcapsule are deteriorated and discolored.

  Moreover, since it is only necessary to change only the transparent protective film 8 to a material containing an ultraviolet absorber for a normal microcapsule type electrophoretic display panel, a conventional one can be used as the front plate 2. Cost reduction is possible.

  Furthermore, since the ultraviolet absorber is not contained in the transparent resin film 4 adjacent to the transparent electrode layer 3, the ultraviolet absorber does not adversely affect the transparent electrode layer 3.

  FIG. 2 is a cross-sectional view showing a microcapsule type electrophoretic display panel according to another embodiment of the present invention.

  The microcapsule-type electrophoretic display panel according to this embodiment is different from the microcapsule-type electrophoretic display panel shown in FIG. 1 in that the transparent resin film 14 contains an ultraviolet absorber. The transparent protective film 18 does not contain an ultraviolet absorber. Other configurations are the same as those of the microcapsule type electrophoretic display panel shown in FIG.

  In the microcapsule type electrophoretic display panel according to this embodiment, since the transparent resin film 14 contains an ultraviolet absorber, the oxidation in the microcapsule is the same as the microcapsule type electrophoretic display panel shown in FIG. It is possible to effectively prevent the electrophoretic properties from being deteriorated at the same time as the titanium particles are deteriorated and discolored.

  In the microcapsule type electrophoretic display panel shown in FIG. 1, as described above, when an ultraviolet curable resin is used as the sealing resin, the transparent protective film 8 contains an ultraviolet absorber. The ultraviolet irradiation for curing needs to be performed from the side, that is, from the direction of the arrow in FIG. 1, not from the observation side through the transparent protective film 8. Since it is as wide as 5 mm, it was necessary to perform post-baking in order to uniformly cure the whole. On the other hand, in the microcapsule-type electrophoretic display panel shown in FIG. 2 according to the present embodiment, the transparent protective film 18 does not contain an ultraviolet absorber. It is possible to carry out through the transparent protective film 18 from the side, and the thickness of the sealing resin is as thin as about 0.3 mm, for example, so that sufficient curing can be performed only by ultraviolet irradiation.

  FIG. 3 is a cross-sectional view showing an example in which a microcapsule electrophoretic display panel according to still another embodiment of the present invention is applied to a touch panel.

  The touch panel according to this embodiment has a structure in which a front plate 2 is attached on a substrate 1 and a transparent protective film 28 that does not contain an ultraviolet absorber is formed on the front plate 2 via a barrier layer 10. Although it is the same as that of a touch-panel type microcapsule-type electrophoretic display panel, it is different in that an ultraviolet absorber is contained in the touch panel structure thereon.

  That is, a pair of transparent electrode layers 31, 32 are provided on the transparent protective film 28 via dot spacers 33, and a surface protective film 34 containing an ultraviolet absorber is provided on the transparent electrode layer 32. Is provided. The material of the surface protective film 34 can be the same as that of the transparent protective films 8, 18, and 28.

  In the touch panel configured as described above, when a predetermined position of the surface protective film 34 is pressed with a finger or a pen 35, the surface protective film 34 is deformed and the pair of transparent electrode layers 31 and 32 are in contact with each other. It is output.

  Also in the microcapsule type electrophoretic display panel applied to the touch panel according to the present embodiment, since the surface protective film 34 contains an ultraviolet absorber, the microcapsule type electrophoretic display shown in FIGS. Similar to the panel, it is possible to effectively prevent the titanium oxide particles in the microcapsule from being deteriorated and discolored, and at the same time, reducing the electrophoretic properties.

  In the microcapsule type electrophoretic display panel described above, the microcapsules contained in the microcapsule display layer 5 are, for example, 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. 5, an electric field is applied to the transparent electrode layer 3 on the transparent resin film 4 side and the electrode layer 21 on the substrate 1 side, the transparent electrode layer 3 is the negative electrode, and the electrode layer 21 is the positive electrode. In this case, the positively charged white particles 113 are drawn to the transparent electrode layer 3 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 3 is a positive electrode and the electrode layer 21 is a negative electrode, positively charged white particles 113 are attracted to the electrode layer 21 side, and negatively charged black particles 114 are transparent. Since it is drawn to the electrode layer 3 side, when viewed from above the transparent electrode layer 3 side, the portion looks black.

  As shown in the schematic side sectional view of FIG. 6, the microcapsule display layer 5 includes a large number of microcapsules 110, the transparent electrode layer 3 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, by using the electrode layer 21 as a common electrode (with the potential set to zero) and controlling the electric field of each address electrode on the transparent electrode 3 side (giving a positive or negative potential), 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. By providing the color filter having the color filter on the transparent electrode 3 side to which an electric field can be applied in units of pixels, color image display can be realized.

  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 5, there is no problem in display even if the position of the microcapsules 110 varies slightly. 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 3 and the electrode layer 21 thin and portable, flexibility such as paper can be provided.

  In the microcapsule type electrophoretic display panel of the present invention, since the layer on the observation side from the microcapsule display layer contains an ultraviolet absorber, the titanium oxide particles in the microcapsule are deteriorated and discolored. It is possible to effectively prevent the degradation of the properties, and therefore, it can be widely used as a display panel used in various applications, particularly outdoors for a long period of time.

1 is a cross-sectional view showing a microcapsule type electrophoretic display panel according to an embodiment of the present invention. Sectional drawing which shows the microcapsule type | mold electrophoretic display panel which concerns on other embodiment of this invention. Sectional drawing which shows the touchscreen type display panel which concerns on other embodiment of this invention. The figure which shows typically the microcapsule contained in the microcapsule display layer of the microcapsule type | mold electrophoretic display panel which concerns on one Embodiment of this 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.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... substrate, 2, 20 ... front plate, 3, 31, 32 ... transparent electrode layer (ITO film), 4, 14 ... transparent resin film, 5 ... microcapsule display layer , 6 ... 1st adhesive layer, 7 ... 2nd adhesive layer, 8, 18, 28 ... Transparent protective film, 9 ... Seal resin layer, 10 ... Gas barrier layer, 11. ..Functional layer, 21... Electrode layer, 33... Dot spacer, 34. 110 ... microcapsule, 111 ... capsule shell, 112 ... dispersion medium, 113 ... white particles, 114 ... black particles.

Claims (5)

The electrode layer surface of the substrate provided with an electrode layer on the surface, and the microcapsule display layer surface of the front plate provided with a transparent electrode layer and a microcapsule display layer containing titanium oxide as white particles in order on the transparent resin film, Adhering via an adhesive layer;
The gas barrier layer surface of the transparent protective film having a thickness of 100 to 300 μm, which is larger in size than the microcapsule display layer and the transparent resin film, contains an ultraviolet absorber, and has a gas barrier layer formed on the surface, and the transparent resin Bonding the film with the second adhesive layer so that the end of the transparent protective film protrudes 1 to 2.0 mm laterally from the side surface of the transparent resin film;
Filling a gap formed between the substrate and the gas barrier layer of the transparent protective film with a sealing resin made of an ultraviolet curable resin;
Irradiating the sealing resin with ultraviolet rays from the side ;
The manufacturing method of a microcapsule type | mold electrophoretic display panel provided with the process of performing a post-baking in order. 2. The microcapsule type electrophoretic display panel according to claim 1 , wherein the ultraviolet absorber is made of one selected from the group consisting of benzophenone, benzotriazole, salicylate, and cyanoacrylate. Manufacturing method. The method for producing a microcapsule type electrophoretic display panel according to claim 1 or 2 , wherein the content of the ultraviolet absorber is 0.1 to 20% by weight. The method of manufacturing a microcapsule type electrophoretic display panel according to claim 1 , wherein the seal resin is made of an acrylic resin. The method of manufacturing a microcapsule type electrophoretic display panel according to claim 1 , wherein the transparent resin film and the transparent protective film are made of polyethylene terephthalate.

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