JP2008233306A - Microcapsule-type electrophoretic display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microcapsule-type electrophoretic display panel in which a display image can be rewritten and which is useful for contra-vision. <P>SOLUTION: The microcapsule-type electrophoretic display panel includes: a first substrate 1 having a transparent electrode; a second substrate 11 having a transparent pattern electrode disposed so as to face the first substrate; and a display medium interposed between the first substrate and the second substrate. The display medium contains colored microcapsules 110 having electrophoretic particles enclosed therein and uncolored transparent micro spheres 115 having no electrophoretic particles enclosed therein, in a dispersion medium, and the display panel displays an image by changing optical reflection characteristics of colored microcapsules 110 by application of an electric field and has a see-through property due to uncolored transparent micro spheres 115. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a microcapsule type electrophoretic display panel, and more particularly to a microcapsule type electrophoretic display panel useful for a see-through type image display device (contravision).

  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 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 of μm to several hundreds of μm, and when the microcapsule is dispersed in a transparent solvent, 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”.

  Here, as a display method of the active matrix electrophoretic display device, the single-sided display on the front plate side is generally used for the bonded front plate and back plate, but both of them can be obtained by using a transparent electrode circuit on the back plate. Screen display is also possible.

  Further, the active matrix electrophoretic display device is expected to be used as an advertising medium such as a bulletin board and a signboard because it has a feature of being a display medium with low power consumption and a rewritable display medium.

Here, the contrast vision is to provide a see-through plate having a different degree of see-through indoors and outdoors so that a message or the like can be displayed to the outside although the view is not obstructed from the inside.
JP 2000-221546 A

  Currently, switching of display images is a characteristic required for advertising media such as contravision. In particular, Contravision is used as an advertising medium in various places such as street windows, taxis, and buses, but it is necessary to replace the contravision to switch advertisements.

  Therefore, by using an active matrix electrophoretic display device for this contra-vision, it is expected as a new advertising medium that can always display a new message to the outside. However, when an active matrix electrophoretic display device is used, the microcapsule layer used for the front plate is not transparent because the microcapsules are spread without gaps, and the line of sight from indoors to the outdoors is blocked. .

  The present invention solves such problems, and a microcapsule-type electrophoretic display panel useful for contravision in which a display image can be rewritten by using a transparent active matrix electrophoretic display device. The purpose is to provide.

According to the first aspect of the present invention, a first substrate having a transparent electrode, a second substrate having a transparent pattern electrode disposed opposite to the first substrate, and a display medium interposed between the first and second substrates The display medium includes colored microcapsules in which electrophoretic particles are encapsulated in a dispersion medium and non-colored transparent microspheres in which electrophoretic particles are not encapsulated, and the colored microcapsules are applied by applying an electric field. This is a microcapsule-type electrophoretic display panel that displays by changing the optical reflection characteristics of the capsule and has transparency by the non-colored transparent microsphere.
The invention according to claim 2 is the microcapsule type electrophoretic display panel according to claim 1, wherein the colored microcapsules and the non-colored transparent microspheres have a particle size of 20 to 70 μm. .
The invention described in claim 3 is characterized in that the non-colored transparent microsphere is formed of a material having transparency selected from the group consisting of glass and transparent resin. The microcapsule type electrophoretic display panel.
The invention according to claim 4 is the microcapsule electrophoresis according to any one of claims 1 to 3, wherein the first substrate and the second substrate are formed of a glass substrate or a resin film. It is a formula display panel.
The invention according to claim 5 is the microcapsule type according to any one of claims 1 to 4, wherein the quantity ratio of the non-colored transparent microspheres to the colored microcapsules is 0.4 to 1. It is an electrophoretic display panel.

  According to the first aspect of the present invention, the display medium includes colored microcapsules in which electrophoretic particles are encapsulated in a dispersion medium and non-colored transparent microspheres, and optical reflection characteristics of the colored microcapsules by application of an electric field. In addition, the display can be changed and the transparency of the non-colored transparent microsphere can provide a function as a contravision that can rewrite the display image.

  According to the second aspect of the present invention, the colored microcapsules and the non-colored transparent microspheres are changed from 20 μm to 70 μm in size so that the colored microcapsules and the non-colored transparent microspheres are interposed between the first substrate and the second substrate. Spheres can be spread in a single layer.

  According to invention of Claim 3, it becomes possible to select the material of the non-colored transparent microsphere according to the objective.

  According to the fourth aspect of the present invention, a display medium having excellent strength can be formed by using a glass substrate, and a flexible display panel can be formed by using a resin film.

  According to the invention described in claim 5, by setting the quantity ratio of the non-colored transparent microspheres to the colored microcapsules to be 0.4 to 1, the message display to the outdoors and the good visibility from the indoors are combined. A display panel can be formed.

  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, a microcapsule layer 3 is formed on the surface of the transparent electrode layer 1 of the first substrate composed of the transparent electrode layer 1 and the transparent resin film 2 on the surface. Next, the adhesive layer 4 is formed on the surface of the microcapsule layer 3 to obtain the front plate 5.

  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 too thin, the protective function of the microcapsule layer 3 is insufficient. The transparent electrode layer 1 can be a common electrode having the same potential on the entire surface.

  As the 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 adhesive layer 4 is formed by applying the non-adhesive surface of the single-sided adhesive tape to the microcapsule display layer 3 with an adhesive, or peeling off one release tape of the double-sided adhesive tape and applying it to the microcapsule display layer 3. I can do it. The thickness of the adhesive layer 4 is preferably about 10 to 50 μm.

  Next, as shown in FIG.1 (b), the front plate 5 is affixed on the board | substrate 6 (2nd board | substrate) which has a transparent pattern electrode. Affixing can be performed, for example, by peeling the release paper, adhering the adhesive surface of the adhesive layer 4 to the substrate 6 having a transparent pattern electrode, and pressing or heating. The substrate 6 having a transparent pattern electrode is a glass substrate or a resin film having an electrode layer (not shown) on the surface, and the surface electrode layer is independently patterned for each pixel as a pixel electrode, and a transparent thin film transistor (not shown) , Signal electrodes, and scanning electrodes can be used.

  In the microcapsule-type electrophoretic display panel described above, the colored microcapsules 110 in which the electrophoretic particles are enclosed in the dispersion medium included in the microcapsule display layer 3 are, for example, as shown in FIG. Resin, gum arabic, or the like is used as a capsule shell 111, inside which white particles 113 made of titanium oxide and black particles 114 made of carbon black are dispersed in a highly viscous dispersion medium 112 such as silicone oil. It has been done. 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 panel using a microcapsule type electrophoresis system including colored microcapsules 110 in which electrophoretic particles are encapsulated in such a dispersion medium and non-colored transparent microspheres 115 in which electrophoretic particles are not encapsulated is as follows. To work.

  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 11 on the substrate 6 side, and the transparent electrode layer 1 is formed as shown on the left side of FIG. When the negative electrode and the electrode layer 11 are used as the positive electrode, 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 11 side. When observed from above the one side, the portion looks white. The portion of the non-colored transparent microsphere 115 that does not enclose the electrophoretic particles is transparent. Conversely, as shown on the right side of FIG. 3, when the transparent electrode layer 1 is a positive electrode and the electrode layer 11 is a negative electrode, positively charged white particles 113 are drawn to the electrode layer 11 side and negatively charged black particles Since 114 is drawn to the transparent electrode layer 1 side, the portion looks black when observed from above the transparent electrode layer 1 side.

  The microcapsule layer 3 includes a large number of colored microcapsules 110 enclosing electrophoretic particles and non-colored transparent microspheres 115 not encapsulating electrophoretic particles, and the transparent electrode layer 1 is used as a common electrode having the same potential. By controlling the electric field of each address electrode of the layer 11 and moving the particles in the microcapsules based on the above-described principle, a desired character or figure can be displayed as white and black pixels.

  Various diameters can be adopted for the colored microcapsules 110 and the non-colored transparent microspheres 115. When a diameter of about 20 μm to about 70 μm is used, a single capsule layer is obtained.

  Various materials can be used for the non-colored transparent microspheres depending on the purpose, but it is preferably formed from a material having transparency selected from the group consisting of glass and transparent resin. Further, if the first substrate and the second substrate are made from glass substrates, a display medium having excellent strength can be formed, and if made from a resin film, a flexible display panel can be formed.

  Examples of the present invention will be described below.

  When producing a microcapsule-type electrophoretic display panel according to the manufacturing process shown in FIG. 1, the quantity ratio of the non-colored transparent microspheres not encapsulating the electrophoretic particles to the colored microcapsules encapsulating the electrophoretic particles is set to 0 to In the range of 2, it was changed by 0.2. In order for the contra vision to have the characteristics, a transmittance of 30% to 65% is required in visible light. Therefore, the visible light transmittance of the display panel obtained under these manufacturing conditions was measured.

  Among the obtained display panels, those having a visible light transmittance of 30% to 65% are non-colored transparent microspheres that do not encapsulate electrophoretic particles relative to colored microcapsules that encapsulate electrophoretic particles. It was produced under the condition of a quantity ratio of 0.4 to 1.

  Next, in order to confirm the transparency of the display panel having a visible light transmittance of 30% to 65%, when the display panel was viewed through the light source, the light source could be visually observed. Therefore, it was confirmed that the microcapsule type electrophoretic display panel of the present invention has a function as a contra vision.

  The microcapsule type electrophoretic display panel of the present invention is useful for contra vision.

It is sectional drawing which shows the manufacturing process of the microcapsule type | mold electrophoretic display panel of this invention. It is the figure which showed typically the coloring microcapsule of the microcapsule type | mold electrophoretic display panel of this invention. It is explanatory sectional drawing of the microcapsule display layer driven by an electrophoresis system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent electrode layer 2 Transparent resin film 3 Microcapsule layer 4 Adhesive layer 5 Front plate 6 Substrate 11 Electrode layer 110 Colored microcapsule 111 Capsule shell 112 Dispersion medium 113 White particle 114 Black particle 115 Uncolored transparent microsphere

Claims (5)

  In a display panel comprising: a first substrate having a transparent electrode; a second substrate having a transparent pattern electrode disposed opposite to the first substrate; and a display medium interposed between the first and second substrates. The display medium includes colored microcapsules in which electrophoretic particles are encapsulated in a dispersion medium and non-colored transparent microspheres in which electrophoretic particles are not encapsulated, and changes the optical reflection characteristics of the colored microcapsules by applying an electric field. A microcapsule-type electrophoretic display panel that performs display and has transparency through the non-colored transparent microsphere.   2. The microcapsule electrophoretic display panel according to claim 1, wherein the colored microcapsules and the non-colored transparent microspheres have a particle size of 20 to 70 μm.   The microcapsule-type electrophoretic display panel according to claim 1 or 2, wherein the non-colored transparent microsphere is formed of a material having transparency selected from the group consisting of glass and transparent resin. .   The microcapsule type electrophoretic display panel according to claim 1, wherein the first substrate and the second substrate are made of a glass substrate or a resin film.   The microcapsule-type electrophoretic display panel according to claim 1, wherein a quantity ratio of the non-colored transparent microspheres to the colored microcapsules is 0.4 to 1.

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