JP5637806B2 - Electronic paper - Google Patents

Description

The present invention relates to an electronic paper that has excellent contrast performance and can clearly display characters and images.

In recent years, there has been a demand for a thin display device, and as one of them, an electronic paper of a system using minute spherical particles having different colors for each hemisphere, that is, a so-called twist ball has been developed.
As this twist ball type electronic paper, as shown in FIG. 2, a silicone oil layer in which a number of twist balls are arranged is used. In such an electronic paper, the twist ball has a thickness of the electronic paper. There is a problem in that the thickness of the electronic paper increases due to the configuration overlapping in the direction.
For this reason, the development of a thinner electronic paper has been made. In Patent Documents 1 and 2, an electronic paper having a separator that holds a twist ball and holding the twist ball on one plane is disclosed in Patent Document 3. There has been proposed an electronic paper of a type in which twist balls are sealed one by one in capsules filled with silicone oil and the capsules are dispersed in a resin layer and held on one plane.

JP 2004-45643 A

JP 2004-54184 A

JP 2007-183575 A

However, in the electronic paper proposed in the above-described Patent Documents 1 to 3, a portion between each of the twist balls in the separator or the resin layer is black, and a portion that is originally intended to be displayed is a gray-colored display color. The displayed characters and images have poor contrast and cannot be clearly seen.
Accordingly, an object of the present invention is to provide an electronic paper that is thin, excellent in contrast, and capable of displaying displayed characters and images clearly.

As a result of intensive studies to solve the above-mentioned problems, the present inventors are the inner surface of the opposite support (10 ′ in FIG. 2) that the user is looking at between the twist balls. As a result of finding out that it looks black because it is not exposed to light and further studying it, it was found that the above object can be achieved if the twist ball is configured to reflect the color of the twist ball. It came to be completed.
That is, the present invention provides the following electronic paper.
1. A pair of supports;
A large number of microspherical particles located between the pair of supports, each having a different color for each hemisphere and charged in a dipole state;
In the electronic paper which is a light-transmitting support that transmits visible light, the film located on the side that at least the user visually recognizes the pair of supports,
A large number of the fine spherical particles are arranged so as to be positioned on one plane between the supports, and when the electronic paper is viewed from the viewing surface side viewed by the user, the fine spherical particles are interposed between the fine spherical particles. An intermediate part where no particles exist is formed,
An electronic paper, wherein the intermediate portion is provided with a mirror reflection surface.
2. The position of the microspherical particles is fixed by a particle holding member,
The particle holding member consists of two layers of a transparent layer located on the viewing surface side and a non-transparent layer located on the opposite side of the viewing surface in the thickness direction of the electronic paper,
2. The electronic paper according to claim 1, wherein the specular reflection surface is formed at an interface between the transparent layer and the non-transparent layer.

  In the electronic paper of the present invention, so-called twist balls (microspherical particles) can be arranged on one plane, so that the entire thickness can be reduced. In addition, since the mirror-finished member is located between the twist balls, the color of the hemisphere of the twist ball located on the user side can be reflected to clearly display characters and images. For example, in the case of a white-black twist ball, the part to be displayed in white can be made white by reflecting the color of the white hemisphere, and the black part can be displayed in black as well. As a result, the contrast is excellent and characters and images can be clearly displayed. Such an effect is particularly remarkable in twist balls other than black such as white-blue.

FIG. 1 is a cross-sectional view schematically showing one embodiment of the electronic paper of the present invention. FIG. 2 is a cross-sectional view schematically showing conventional electronic paper.

DESCRIPTION OF SYMBOLS 1 Electronic paper 10,10 'support body (substrate electrode and transparent electrode), 20 microspherical particle, 30 particle holding member, 31 transparent layer, 32 non-transparent layer, 33 specular reflection surface, 40 middle part, 50 silicone oil layer

Hereinafter, the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the electronic paper 1 of the present embodiment is located between a pair of supports 10, 10 ′ and a pair of the supports 10, 10 ′. And a large number of microspherical particles 20 that are electrically charged.
Moreover, in this embodiment, a pair of support body 10 and 10 'are the support bodies 10 which are located in the visual recognition surface side which a user visually recognizes, and the transparent support body (transparent electrode) which permeate | transmits visible light, and is opposite. The support 10 'located on the side is an electrode substrate that is not transparent.
Further, the microspherical particles 20 are included in the silicone oil layer 22 and are rotatable due to the presence of the silicone oil 22.
Further, although not particularly illustrated, the periphery of each support is hermetically sealed with a frame, and the configuration of the entire electronic paper can employ the same configuration as that of a known electronic paper without any particular limitation.

  And the electronic paper 1 of this embodiment is arranged so that many micro spherical particles 20 may be located on one plane between the support bodies 10 and 10 ', as shown in FIG. When viewed from the viewing surface A side viewed by a person, an intermediate portion 40 in which no microspherical particles are present is formed between the microspherical particles 20, and the intermediate portion 40 is provided with a specular reflection surface 33. It is characterized by.

The characteristic part of the electronic paper 1 of this embodiment is demonstrated still in detail.
The positions of the microspherical particles 20 are fixed by the particle holding member 30.
The particle holding member 30 includes two layers of a transparent layer 31 located on the viewing surface A side and a non-transparent layer 32 located on the opposite side of the viewing surface A in the thickness direction of the electronic paper 1.

A transparent curable silicone rubber or the like can be used as a material for forming the transparent layer 31 in the particle holding member 30. As the material for forming the non-transparent layer, aluminum-containing curable silicone rubber or the like containing 1 to 5 parts by weight of aluminum paste or the like in curable silicone rubber with respect to 100 parts by weight of curable silicone rubber can be used. When these forming materials are used, the finally obtained transparent layer 31 and non-transparent layer 32 are both made of cured silicone rubber.
As the curable silicone rubber, those usually used for this type of electronic paper can be used without particular limitation. As the aluminum paste, a commercially available product can be used without particular limitation.

In the present embodiment, the specular reflection surface 33 is formed by an interface between the transparent layer 31 and the non-transparent layer 32 in the intermediate portion 40. In FIG. 1, the specular reflection surface 33 is shown as having a thickness in order to facilitate understanding.
In the electronic paper of this embodiment, the interface between the non-transparent layer 32 made of a cured silicone rubber mixed with aluminum and the transparent layer 31 made of a transparent cured silicone rubber has a mirror reflection function due to the presence of aluminum. A reflection surface 33 is formed.
Further, as in the present embodiment, the specular reflection surface 33 is preferably positioned above the center line 25 of the microspherical particle in the thickness direction so that the color of the upper hemisphere of the microspherical particle 20 can be reflected.
When the particle diameter of the microspherical particles 20 is 30 to 150 μm, the thickness of the non-transparent layer is preferably 10 to 100 μm, and the thickness of the transparent layer is preferably 10 to 100 μm.

In the electronic paper 1 of the present embodiment formed in this way, as with normal electronic paper, electricity is applied to a support that is an electrode according to predetermined information, and the hemisphere of a predetermined color is visually recognized by the microspherical particles 20. It can be used by rotating it so that it is located on the surface A side and displaying a desired character or image.
And since the electronic paper 1 of this embodiment is comprised as mentioned above, the color of the hemispherical part of the microspherical particle 20 located in the visual recognition surface A side reflects in the specular reflective surface 33. FIG. For this reason, the portion to be displayed in white is clearly displayed in white, so that the contrast of the entire image or the like is improved and the display is clear. In addition, when the color of the microspherical particles is a color other than black, such as white-blue, the color between the blue parts of the particles appears black, and the blue color is reflected on the specular reflection surface. Since 33 reflects, it becomes a clearer blue, and the clearness of the whole display becomes remarkable.

The electronic paper of this embodiment can be manufactured as follows, for example.
First, on a cast film such as a PET film, a curable silicone rubber containing a predetermined amount of aluminum paste (for example, 2 parts by weight with respect to 100 parts by weight of silicone rubber) has a thickness of 10 to 100 μm (in this embodiment, 50 μm). Apply as follows.
Next, the fine spherical particles 20 are sprinkled uniformly on the applied silicone rubber so as to form a single layer, and are embedded so that half of the particles are embedded in the silicone rubber. Thereafter, the non-transparent layer 32 is formed by curing (not complete curing) at 80 to 120 ° C. for 3 to 20 minutes (in this embodiment, 80 ° C. for 10 minutes).
A transparent curable silicone rubber is applied so that all protruding hemispheres of the microspherical particles are buried after curing, and cured at 80 to 150 ° C. for 60 to 300 minutes (in this embodiment, at 80 ° C. for 180 minutes) to be transparent layer 31 is formed, and the particle holding member 30 is formed.
The obtained particle holding member 30 containing the microspherical particles is immersed in silicone oil and expanded 1.1 to 1.4 times (1.2 times in the present embodiment) in the length direction. Incorporate with silicone oil. Finally, the particle holding member 30 can be obtained by sandwiching the particle holding member 30 between the electrodes as the supports 10 and 10 ′ and the transparent electrode, and sealing the periphery to form a display member.

The electronic paper of the present invention is not limited to the above-described example, and various changes can be made without departing from the spirit of the present invention.
For example, instead of forming a particle holding member with a transparent layer and a non-transparent layer, the non-transparent layer can also be formed as a transparent layer, and a mirror reflection surface can be formed by providing a metal layer between two transparent layers. The metal layer can be formed by vapor-depositing a metal on the surface of the previously formed transparent layer or applying a paint containing the metal.

  The electronic paper of the present invention is useful as various thin display devices.

Claims (1)

A pair of supports;
A large number of microspherical particles located between the pair of supports, each having a different color for each hemisphere and charged in a dipole state;
Consists of
In the electronic paper which is a light transmissive support that transmits visible light, a film located on at least a side visually recognized by the user of the pair of supports,
A large number of the microspherical particles are arranged so as to be positioned on one plane between the supports, and when the electronic paper is viewed from the viewing surface side viewed by the user, the microspherical particles are interposed between the microspherical particles. An intermediate part where no particles exist is formed,
The intermediate portion is provided with a specular reflection surface, the specular reflection surface is located above the center line of the microspherical particles in the thickness direction so as to reflect the color of the upper hemisphere of the microspherical particles ,
The position of the microspherical particles is fixed by a particle holding member,
The particle holding member consists of two layers of a transparent layer located on the viewing surface side and a non-transparent layer located on the opposite side of the viewing surface in the thickness direction of the electronic paper,
The non-transparent layer is formed of an aluminum-containing curable silicone rubber containing 1 to 5 parts by weight of aluminum paste with respect to 100 parts by weight of curable silicone rubber.
The specular reflection surface is formed at the interface between the transparent layer and the non-transparent layer.
Electronic paper characterized by that.

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