JP2012211974A - Microcapsule type electrophoretic display device and method for manufacturing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microcapsule type electrophoretic display device achieving both of a wide viewing angle and high productivity, and to provide a method for manufacturing the device.SOLUTION: The microcapsule type electrophoretic display device is manufactured through steps of: adhering a protective film (2) to a reception layer (4) of a color ink layer (3) with an adhesive component of the reception layer (4), the ink layer formed on one surface of a transparent substrate (6); laminating an electrophoretic display layer (10) containing microcapsules (8) on a transparent electrode layer (7) formed on the other surface of the transparent substrate (6); and laminating a back face electrode substrate (18) having a pixel electrode layer (12) on the electrophoretic display layer (10) with a layer of a conductive adhesive (11) interposed therebetween.

Description

  The present invention relates to a microcapsule-type electrophoretic display device, and includes a structure in which a microcapsule in which a charged pigment is encapsulated is disposed between a pair of transparent counter electrode substrates, one of which is transparent. Further, the present invention relates to a microcapsule type electrophoretic display device that enables multicolor display by forming a color filter layer, and a method for manufacturing the same.

  In recent years, with the development of information equipment, information display has been made in various forms. As the variable information display, a CRT (cathode ray tube), a liquid crystal display, and the like are mainly used. A light-emitting display such as a liquid crystal display using a CRT or a backlight is not suitable for reading a document or the like because the load on the eyes is large when used for a long time.

  Flat panel display devices are widely used in various applications because the current liquid crystal display is thin and can be miniaturized. There is a problem that the load on the eyes is large and the optical characteristics vary greatly depending on the viewing angle.

  On the other hand, a liquid crystal display of a type that does not use a backlight has a problem that the darkness of the screen due to the use of a polarizing plate appears and the visibility is poor. Furthermore, the images displayed on these displays have no memory property and have the disadvantage that they disappear as soon as the electrical energy supply is stopped.

  In the replacement of display of portable information devices such as e-books and portable information terminals, which are expected to become more popular in the future, even when used for a long time, the load on the eyes is small, visibility is good, and power consumption is low. In addition, it is considered necessary to have image memory properties.

  Among them, electronic paper is one of display devices that are particularly attracting attention. This has the advantages of both paper and an electronic display, and has the feature that image information is retained even in a non-powered state and can be rewritten. In addition, since it is a reflective display, it has the advantages that the contrast ratio does not change and the viewing angle is wide.

  Since the electrophoretic display device for electronic paper displays characters and images by reflected light, similarly to the printed paper surface, it is suitable for work that keeps the screen on for a long time with little load on the eyes. This is based on the principle that by applying an electric field, the charged particles in the microcapsule move and display an image.

  In electrophoretic display devices for electronic paper, positively and negatively charged white particles and black particles are placed in microcapsules filled with a dispersion medium, and each particle is pulled up to the display surface by applying an external voltage to display an image. To form. Since the size of the microcapsules is as small as several tens of μm to several hundreds of μm, when the microcapsules are dispersed in a transparent binder material, they can be coated like ink. Since this ink can be displayed in black and white by applying a voltage, it is also called “electronic ink”.

  When this ink is coated on a transparent base material on which a transparent electrode is formed and a conductive adhesive layer is formed thereon, it is bonded to a substrate on which an active matrix driving electrode circuit represented by TFT is formed. An active matrix display can be obtained. Usually, 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”. When this “front plate” is bonded to the “back plate”, for example, an active matrix display as shown in Patent Document 1 can be obtained.

  In the production of the front plate, first, an ink including an electrophoretic display layer in which an additive is arbitrarily blended is formed on a transparent resin substrate on which a transparent electrode is formed, using a predetermined coating method. On the other hand, the conductive adhesive layer is separately formed on the resin substrate using the same coating method. And a front board is comprised by bonding an ink layer and a conductive adhesive layer.

On the other hand, in recent years, a multicolor display has been demanded and is being actively developed. For example, a method of performing multicolor display by attaching a color filter on an electrophoretic display device for monochrome two-color display has been announced.
For example, an electrophoretic display layer, a transparent electrode layer, and a transparent substrate are laminated on a pixel electrode substrate via an adhesive layer, and another transparent substrate on which a color filter layer is formed is pasted on the transparent substrate via an adhesive layer. Match. Furthermore, it has a structure in which a protective film is bonded to the opposite surface of the color filter layer of another transparent substrate via an adhesive layer.

  However, in the above method, it is necessary to newly provide an adhesive layer between the color filter layer and the electrophoretic display layer, and the distance is increased between the color filter layer and the electrophoretic display layer. The advantages of electronic paper, such as fading colors and wide viewing angles, will be lost.

  In addition, because the pixel electrode substrate and color filter substrate formed on separate transparent substrates are bonded together, the alignment marks and pixels are displaced due to the heat and expansion / contraction of each substrate, making it difficult to adjust the position during bonding. There is a problem that productivity is low.

  In order to solve the above problem, a method of displaying a color by forming a receiving layer on the surface of the transparent substrate opposite to the transparent electrode layer and providing an ink layer on the receiving layer can be proposed.

  However, in this case, in order to provide a protective film for the purpose of protecting the surface of the display screen from damage or dirt, it is necessary to provide it on the receiving layer via an adhesive. Since it is necessary to newly provide an adhesive layer, there are problems such as a decrease in optical characteristics and an increase in weight.

JP 2000-221546 A

  The present invention has been made to solve the above problems, and an object thereof is to provide a microcapsule type electrophoretic display device capable of achieving both a wide viewing angle and high productivity and a method for manufacturing the same.

In order to achieve the above object in the present invention, in claim 1,
A protective film is adhered to the receptor layer by the adhesive component of the receptor layer of the color ink layer formed on one surface of the transparent substrate,
Laminating an electrophoretic display layer containing microcapsules on a transparent electrode layer formed on the other surface of the transparent substrate,
An electrode substrate having a pixel electrode layer is laminated on the electrophoretic display layer via an adhesive layer;
The present invention provides a method for manufacturing a microcapsule type electrophoretic display device.

  Further, according to claim 2, there is provided a method of manufacturing a microcapsule type electrophoretic display device according to claim 1, wherein a resin material having a glass transition temperature of 30 ° C. or lower is used for the receiving layer. Is.

  3. The method of manufacturing a microcapsule electrophoretic display device according to claim 1, wherein the protective film is laminated on a surface of a color filter layer including the receiving layer. It is to provide.

  The present invention provides a method for manufacturing a microcapsule type electrophoretic display device according to claim 1, wherein the thickness of the transparent substrate is 10 μm or more and 200 μm or less. is there.

  The micro transparent substrate according to claim 1, wherein the transparent substrate is a glass substrate or a resin plate formed of polyethylene terephthalate, polyvinyl chloride, polycarbonate or the like. A method for manufacturing a capsule electrophoretic display device is provided.

In claim 6,
The protective film is adhered to the receptor layer by the adhesive component of the receptor layer of the color ink layer formed on one surface of the transparent substrate,
An electrophoretic display layer containing microcapsules is laminated on the transparent electrode layer formed on the other surface of the transparent substrate,
An electrode substrate having a pixel electrode layer is laminated on the electrophoretic display layer via an adhesive layer.
It is an object of the present invention to provide a microcapsule type electrophoretic display device.

In claim 7,
The microcapsule-type electrophoretic display device according to claim 6, wherein the receiving layer is a resin material having a glass transition temperature of 30 ° C. or lower.

Further, in claim 8,
8. The microcapsule electrophoretic display device according to claim 6 or 7, wherein the protective film is laminated on a surface of a color filter layer including the receiving layer.

In claim 9,
9. The microcapsule type electrophoretic display device according to claim 6, wherein the pixel electrode layer has a pattern for pixel alignment of a color filter layer including the receiving layer. To do.
The micro transparent substrate according to claim 6, wherein the transparent substrate is a glass substrate or a resin plate formed of polyethylene terephthalate, polyvinyl chloride, polycarbonate or the like. A capsule-type electrophoretic display device is provided.

  According to the present invention, by using a receiving layer that also serves as an adhesive, a new adhesive layer is provided on the receiving layer directly to install a protective film for the display as in the past. Since a protective film can be formed, effects such as prevention of a decrease in display brightness, a reduction in manufacturing processes, and a reduction in the thickness and weight of the display are achieved.

  Further, by forming a receiving layer including a color ink layer directly on the surface of the transparent substrate provided with a transparent electrode layer having an electrophoretic display layer, on the side opposite to the electrophoretic display layer, The color filter layer including the color ink layer and the receiving layer has a structure close to each other, so that the viewing angle can be prevented from being narrowed as compared with a display device in which the color filter layer is bonded to the electrophoretic display layer. Furthermore, since the color filter is formed with reference to the alignment pattern on the pixel electrode substrate, there is no concern about positional deviation due to expansion / contraction of the base material, and the productivity is improved.

1 is a cross-sectional view of a microcapsule type electrophoretic display device according to an embodiment of the present invention. It is a mimetic diagram of a microcapsule contained in a microcapsule display layer of a microcapsule type electrophoretic display sheet concerning 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 of a microcapsule type electrophoretic display device according to an embodiment of the present invention.

As shown in FIG. 1, the microcapsule-type electrophoretic display device (1) of this embodiment includes a color filter layer (5) in which a color ink layer (3) is provided on a receiving layer (4), and a color filter layer ( 5) Electrophoretic display comprising a protective film (2) for protecting, a transparent substrate (6) on which a transparent electrode layer (7) is formed, and microcapsules (8) enclosing colored particles having a charge and white particles A layer (10) and a back electrode substrate (18) comprising a pixel electrode layer (12) and a back substrate (13) with a conductive adhesive (11) interposed therebetween.
The pixel electrode layer (12) of the back electrode substrate (18) has a plurality of pixel electrodes (12a), a color ink layer (3) of the color filter layer (5), and a pixel electrode (12a of the pixel electrode tank (12)). ) And a pattern (12b) is formed. The electrophoretic display layer (10) is bonded to the pixel electrode layer (12) via a conductive adhesive (11).

  In the transparent substrate (6) having the transparent electrode layer (7), the electronic ink in which the microcapsules (8) and the binder resin (9) are dispersed is applied on the transparent electrode layer (7) by a predetermined coating method. Then, an electrophoretic display layer (10) is formed. The receiving layer (4) is applied to the surface of the transparent substrate (6) opposite to the transparent electrode layer (7) by a predetermined coating method.

  Since the receiving layer (4) has adhesiveness, a silicon layer is optionally added to protect the receiving layer (4) until the color ink layer (3) is formed on the receiving layer (4). A resin substrate provided with a release layer such as is provided on the receiving layer (4).

  Further, a conductive adhesive substrate is formed by applying a conductive adhesive (11) on a conductive release substrate in which a silicon layer is provided as a release layer on the surface layer of the conductive layer. The surface of the conductive adhesive (11) is bonded to the binder resin (9) of the electrophoretic display layer (10).

  In order to protect the outermost surface of the color filter layer (5) from scratches, impacts, and dirt from the outside after providing the color ink layer (3) on the receiving layer (4) to form a color filter layer (5), Bond the protective film (2). Since the receiving layer (4) also serves as an adhesive, it is not necessary to newly provide an adhesive layer when the protective film (2) is bonded.

As the resin material constituting the receiving layer (4) which also serves as an adhesive, it is preferable to use a resin component having a resin component having adhesiveness at room temperature as a main component and having a glass transition temperature (Tg) of 30 ° C. or lower.
If the glass transition temperature (Tg) of the resin material constituting the receptor layer (4) exceeds 30 ° C., the adhesive film may be weakened in the standard state, so the protective film (2) may be peeled off. In addition, bubbles may be mixed between the protective film (2) and the receiving layer (4).

  The formation of the receiving layer (4) on the transparent substrate (6) may be performed before the electrophoretic display layer (10) or after the electrophoretic display layer (10). Moreover, you may carry out after bonding the binder resin (9) of an electrophoretic display layer (10) with the conductive adhesive (11) surface of a conductive adhesive board | substrate.

  Ink jet printing, screen printing, and offset printing are suitable for the formation of the color ink layer (3) on the receiving layer (4) of the color filter layer (5).

  The thickness of the protective film 2 to be bonded to the color filter layer (5) is preferably 10 to 100 μm, and an organic polymer substrate such as polyethylene terephthalate (PET), polypropylene (PP), polycarbonate, polyimide, or acrylic resin is used. Is possible.

  The receptor layer (4) is formed by a predetermined coating method such as screen printing, offset printing, or spin coating when it is formed by a single wafer method. When the substrate is formed by a continuous method such as a roll, the receiving layer (4) is formed by a predetermined coating method such as die coating, comma coating, or gravure.

  For the receiving layer (4), urethane resin, acrylic resin, polyester resin, vinyl chloride resin or the like is used.

  As the conductive adhesive (11), a synthetic resin adhesive such as an acrylic resin or a urethane resin is suitable, and a resin that is an adhesive using a high dielectric resin is particularly preferable.

  The electronic ink in which the microcapsule (8) and the binder resin (9) are dispersed is coated on the transparent electrode layer (7) by a predetermined coating method such as screen printing, microgravure, die coater, dip coater, An electrophoretic display layer (10) is formed.

  Examples of the binder resin (9) include polymer resins such as polyurethane resin, acrylic resin, polyester resin, and acrylic urethane resin.

  By using the conductive adhesive (11) having the same components as the binder resin (9) used in the ink, the affinity of the resin interface is increased and the separation is less likely to occur, and the dielectric constant is similar. Therefore, there is an advantage that the voltage applied to the microcapsule (8) tends to be constant in terms of surface.

  For the transparent substrate (6), a material that can visually recognize the color of the display medium from the outside of the panel and has a high visible light transmittance is optimal. As the transparent substrate (6), it is possible to use an organic polymer substrate such as polyethylene terephthalate (PET), polycarbonate, polyimide, acrylic resin, or glass.

  The thickness of the transparent substrate (6) is preferably 10 μm to 100 μm. When the thickness is 10 μm or less, when the receiving layer (4) and the electrophoretic display layer (10) are formed on the transparent substrate (6), the deformation of the transparent substrate (6) is large due to a difference in expansion and contraction during the layer formation. This is because the processability is low and unevenness of the display image due to deformation tends to occur. When the thickness is 100 μm or more, the distance between the color filter layer (5) and the electrophoretic display layer (10) is widened, so that parallax occurs depending on the viewing angle, and color unevenness becomes remarkable.

  For the transparent electrode layer (7) on the transparent substrate (6), a conductive material having high light transmittance such as indium tin oxide (ITO) or indium zinc oxide (IZO) is used. Moreover, you may use the material which has electroconductivity for the transparent electrode layer (7) other than the said metal material.

  FIG. 2 is a schematic view of a microcapsule (8) included in the electrophoretic display layer (10) of FIG.

  As shown in FIG. 2, the microcapsule (8) contained in the electrophoretic display layer (10) has a capsule shell (14) made of methacrylic acid resin, urea resin, gum arabic, etc., and has a white interior made of titanium oxide. Black particles (16) composed of particles (15) and carbon black are encapsulated in a state of being dispersed in a highly viscous dispersion medium (17) such as silicone oil. The white particles (15), titanium oxide, are positively charged, while the black particles (16), carbon black, are negatively charged.

  The display body of the microcapsule type electrophoretic display device (1) having a layer formed as shown in FIG. 1 displays by applying a voltage between the transparent electrode (7) on the transparent substrate (6) and the pixel electrode layer (12). The color can be expressed by selectively applying a positive or negative voltage to the electrodes.

  As shown in the cross-sectional view of FIG. 1, the electrophoretic display layer (10) includes a large number of microcapsules (8). By controlling the direction of the electric field of the electrode layer, the microcapsules (10 8) The particles inside can be moved and displayed as white and black.

  The electrophoretic display device (1) of the present invention having the above-described structure is close to the white color of paper in terms of easiness of viewing, has a very large viewing angle, and can be used without any problem under outdoor direct sunlight.

Since each particle in the microcapsule (8) of the electrophoretic display layer (10) is dispersed in a highly viscous dispersion medium, once the electric field is applied, the position of the particle does not change even when the power is turned off. . In this way, since the display image has a memory property that does not disappear, an electric field may be applied only at the time of rewriting.
The color filter layer (5) has a pattern (12b) of the pixel electrode tank (12) that is visually recognized through the transparent substrate (6), the transparent electrode layer (7), and the electrophoretic display layer (10). It can form on a transparent substrate (6) according to a position. Thereby, the pixel position of the color ink layer (3) of the color filter layer (5) and the pixel electrode (12a) of the electrophoretic display layer (10) can be aligned to have an appropriate positional relationship.
As described above, the manufacturing method of the microcapsule type electrophoretic display device of the present embodiment is as follows.
The protective film (2) is adhered to the receiving layer (4) by the adhesive component of the receiving layer (4) of the color ink layer (3) formed on one surface of the transparent substrate (6),
An electrophoretic display layer (10) containing microcapsules (8) is laminated on the transparent electrode layer (7) formed on the other surface of the transparent substrate (6),
A back electrode substrate (18) having a pixel electrode layer (12) is laminated on the electrophoretic display layer (10) via a layer of conductive adhesive (11);
Thus, a microcapsule type electrophoretic display device was manufactured.
As a result, the protective film (2) of the color filter layer (5) is adhered using the receiving layer (4) that also serves as an adhesive, so that a new protective film for the display can be installed as in the past. Since the protective film (2) can be formed directly on the receiving layer (4) as compared with the method in which an adhesive layer is provided on and bonded to the color filter layer, This has the effect of reducing the thickness and weight of the display.
Further, the color ink layer (3) is provided on the surface of the transparent substrate (6) provided with the transparent electrode layer (7) having the electrophoretic display layer (10) on the side opposite to the electrophoretic display layer (10). By directly forming the receiving layer (4) including the electrophoretic display layer (10), the color filter layer (5) including the color ink layer (3) and the receiving layer (4) has a close structure, As compared with a display device in which a color filter layer is bonded to an electrophoretic display layer, the viewing angle can be prevented from being narrowed. Further, since the color filter is formed based on the alignment pattern (12b) in the pixel electrode layer (12), the position of the color filter layer (5) and the transparent electrode layer (7) due to the expansion and contraction of each substrate. There is no concern about deviation, and there is an effect that productivity is improved.

  The particle size was adjusted so that the microcapsules having an average particle size of 45 μm and a particle size of 30 to 60 μm were 80% or more, and the aqueous dispersion of microcapsules was adjusted so that the solid content was 45% by weight. The dispersion, a urethane binder material having a solid content of 25% by weight (CP-750, manufactured by Dainippon Ink Co., Ltd.), a surfactant, a thickener, and pure water are mixed and stirred to produce an electronic ink. Was made.

  The resin material of the receiving layer is blended in 100 parts of toluene and 100 parts of MEK in 100 parts of acrylic resin (Dianar LR-331, manufactured by Mitsubishi Rayon Co., Ltd.) having a glass transition temperature of 20 ° C. A receiving layer coating solution was obtained.

  A receiving layer coating solution was formed with a slot die coater to a thickness of 10 μm on the surface opposite to the ITO surface of the 100 μm ITO / PET substrate, and dried at 80 ° C. for 2 minutes to obtain a receiving layer. A 25 μm release substrate having a silicon layer as a release layer is formed on the receptor layer so that the release surface is on the receptor layer side. Next, the electronic ink was applied to the ITO surface side of the ITO / PET base material by the same method to form a microcapsule layer with a thickness of 23 μm.

  A conductive adhesive layer was similarly formed on the silicon surface side of a 100 μm PET substrate having a silicon layer as a release layer. The microcapsule surface and the conductive adhesive surface were bonded together with a laminator to obtain a microcapsule layer front plate.

  A microcapsule-type electrophoretic display device is obtained by laminating to the pixel electrode surface of a back electrode plate having a pixel electrode having a circuit configuration of an active matrix type driving method using a thin film transistor on a conductive adhesive surface, at a pressure of 0.5 MPa. It was.

  The laminated end portion of the pixel electrode and front plate of the obtained microcapsule type electrophoretic display device is enclosed and sealed with a UV curable sealant KJC-7805 (Shin-Etsu Chemical Co., Ltd.).

  Next, on the receiving layer, ink corresponding to each pixel was printed using an ink jet apparatus based on the alignment pattern on the pixel electrode layer. Furthermore, when a 15 μm PP film was applied as a protective film on the receiving layer, peeling of the protective film and the PP film, damage to the ink layer, and the like were not observed.

  Further, when a voltage was applied to each pixel, color display could be performed. Further, since the electrophoretic layer and the color filter layer are close to each other, no color unevenness due to parallax was observed.

  For the resin material of the receiving layer, 100 parts of toluene and 100 parts of MEK are blended in 100 parts of a polyester resin (Vylonal MD1330, manufactured by Toyobo Co., Ltd.) having a glass transition temperature of 6 ° C. After dispersion and stirring, coating of the receiving layer is performed. A liquid was obtained.

  Each layer of the front plate was laminated under the same conditions as in Example 1 to form a microcapsule type electrophoretic display device, and sealing was performed in the same manner.

  Next, on the receiving layer, ink corresponding to each pixel was printed using an ink jet apparatus based on the alignment pattern on the pixel electrode layer. Furthermore, when a 40 μm PET film was applied as a protective film on the receiving layer, no peeling of the protective film and the PET film, damage to the ink layer, or the like was observed.

  Further, when a voltage was applied to each pixel, color display could be performed. Further, since the electrophoretic layer and the color filter layer are close to each other, no color unevenness due to parallax was observed.

DESCRIPTION OF SYMBOLS 1 ... Electrophoretic display device 2 ... Protective film 3 ... Color ink layer 4 ... Receiving layer 5 ... Color filter layer 6 ... Transparent substrate 7 ... Transparent electrode layer 8 ... Microcapsule 9 ... Binder resin 10 ... Electrophoretic display layer 11 ... Conductive adhesive 12 ... Pixel electrode layer 12a ... Pixel electrode 12b ... Pattern 13 ... Back substrate 14 ... capsule shell 15 ... white particles 16 ... black particles 17 ... dispersion medium 18 ... back electrode substrate

Claims (10)

A protective film is adhered to the receptor layer by the adhesive component of the receptor layer of the color ink layer formed on one surface of the transparent substrate,
Laminating an electrophoretic display layer containing microcapsules on a transparent electrode layer formed on the other surface of the transparent substrate,
An electrode substrate having a pixel electrode layer is laminated on the electrophoretic display layer via an adhesive layer;
A method for producing a microcapsule type electrophoretic display device.   2. The method of manufacturing a microcapsule type electrophoretic display device according to claim 1, wherein a resin material having a glass transition temperature of 30 [deg.] C. or less is used for the receiving layer.   3. The method of manufacturing a microcapsule type electrophoretic display device according to claim 1, wherein the protective film is laminated on a surface of a color filter layer including the receiving layer.   4. The method of manufacturing a microcapsule type electrophoretic display device according to claim 1, wherein the thickness of the transparent substrate is 10 μm or more and 200 μm or less.   5. The microcapsule type electrophoretic display device according to claim 1, wherein a glass substrate or a resin plate formed of polyethylene terephthalate, polyvinyl chloride, polycarbonate or the like is used as the transparent substrate. Production method. The protective film is adhered to the receptor layer by the adhesive component of the receptor layer including the color ink layer formed on one surface of the transparent substrate,
An electrophoretic display layer containing microcapsules is laminated on the transparent electrode layer formed on the other surface of the transparent substrate,
An electrode substrate having a pixel electrode layer is laminated on the electrophoretic display layer via an adhesive layer.
A microcapsule type electrophoretic display device.   The microcapsule type electrophoretic display device according to claim 6, wherein the receiving layer is a resin material having a glass transition temperature of 30 ° C or lower.   8. The microcapsule type electrophoretic display device according to claim 6, wherein the protective film is laminated on a surface of a color filter layer including the receiving layer.   9. The microcapsule type electrophoretic display device according to claim 6, wherein the pixel electrode layer has a pattern for pixel alignment of a color filter layer including the receiving layer.   10. The microcapsule type electrophoretic display device according to claim 6, 7, 8, or 9, wherein the transparent substrate is a glass substrate or a resin plate formed of polyethylene terephthalate, polyvinyl chloride, polycarbonate or the like.

Images