JPH10214050A - Device and medium for image display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rotation control over display particles with an external electric field, to quicken response at the time of image display operation, and to make a high-contrast image display by forming the display particles of a polarized dielectric substance. SOLUTION: The display particles 3 are formed of white ferroelectric balls of barium titanate as a raw material and each ferroelectric ball has its upper hemispherical part colored in blue and its lower hemispherical part colored in white and is polarized so that there are more negative electric charges in the upper hemispherical part than in the lower hemispherical part. Therefore, display particles 3 which are sandwiched between an X electrode 5 and a Y electrode 6 are oriented according to the polarity of a power source 9. Namely, when the Y electrode 6 is an anode, the ball rotates so that the blue part where there are more electric charges approaches the Y electrode 6 and the ball becomes stable where the peak of the blue part is the closest to the Y electrode 6. Further, display particles 3 held between the X electrode 5 and Y electrode 7 are oriented according to the polarity of the power source 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device and an image display medium, and more particularly, to a display panel for displaying image information such as characters, graphics, and videos by rotating color-coded particles by an electric field. Alternatively, the present invention relates to a display medium such as an image display sheet.

[0002]

2. Description of the Related Art Conventionally, US Pat.
No. 4,126,854, there is known a particle rotating display for displaying an image using display particles having a configuration in which each hemisphere of a spherical substance is color-coded. Have been.

The display particles are obtained, for example, by coloring half of a spherical glass or the like with a dye or the like. Therefore, the material constituting the surface of one display particle is
Each hemisphere is configured to be different.

[0004] Here, as is well known in the field of electrochemistry and the like, an electric double layer is formed at the interface between the highly insulating liquid and the particles. Is different for each hemisphere, the chargeability in the highly insulating liquid, that is, the amount of surface charge also differs for each hemisphere.As a result, particles for display in the highly insulating liquid have
An electric dipole is formed.

[0005] Then, a highly insulating liquid in which the display particles having the above-described structure are dispersed is sandwiched between two insulating plates, and one of the insulating plates has an X electrode and the other has a Y electrode. Thus, the particle rotating display described in each of the above publications is configured.

[0006] In the particle rotating display having the above configuration, a voltage is applied between the X electrode and the Y electrode by an appropriate power supply, and the interaction between the electric field generated at that time and the electric dipole causes Image display is performed by controlling the orientation direction of the display particles.

[0007]

However, in the above-described conventional particle rotating display, the displayed image has insufficient contrast.

Specifically, when the direction of the electric field was reversed, there were many display particles whose rotation was incomplete. This is because the electric dipole moment of the display particles is small and the response to an external electric field is poor.

The reason is that the display particles are colored with a dye or the like that colors the hemisphere of the particles and form an electric dipole, so that the charge control property for obtaining a large electric dipole moment and the good coloring property are obtained. Although it is necessary to select a dye having both of the following, in reality, there is no dye exhibiting sufficient charge controllability and coloring properties, and a dye having poor charge controllability with priority given to coloring properties for image display. Must be selected, and therefore, the chargeability of the display particles in the highly insulating liquid becomes insufficient, and the electric dipole moment decreases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a display panel or a display medium which has good display control by an external electric field, has a fast response, and has a high contrast. And

[0011]

In order to achieve this object, an image display device according to a first aspect of the present invention comprises at least two types of regions having different charging properties and colors in an insulating liquid. The display particles having a surface to be formed are dispersed in an insulating liquid, and an image is displayed by rotating the display particles by controlling an electric field applied to the display particles. The particles are characterized by being composed of a polarized dielectric material.

The polarized dielectric substance is obtained, for example, by electrically polarizing a ferroelectric substance under a predetermined electric field.

The ferroelectric substance is electrically polarized by an external electric field and maintains the polarization even when the electric field disappears, and generally has a high dielectric constant. In particular,
Examples include barium titanate, lead titanate, lead zirconiaate, lead zirconate titanate, and lithium niobate.

The particles made of such a dielectric substance are electrically polarized, and at least a part of the particle surface is colored so that the particle surface is colored differently according to the polarization direction. Display particles are obtained.

In this case, since the electric dipole moment is formed by the polarization, the dye or the like used for coloring the particles does not need to consider the charge controllability, and can be selected only by the color. Therefore, display particles having a large electric dipole moment and a clear color display can be obtained, the rotation and orientation control of the display particles by an external electric field are favorably performed, and the response during the image display operation is fast, The contrast of the displayed image is also high.

Further, the image display medium according to the second aspect includes a display particle having a surface constituted by two or more regions having different charging properties and colors in the insulating liquid, and the insulating liquid. Holding the display capsule to be supported on the support, to display an image by controlling the electric field applied to the display particles and rotating the display particles,
The display particles are made of a polarized dielectric material.

The display capsule is a functional particle formed by enclosing the display particle and an insulating liquid with a wall material such as a resin. Therefore, a container or the like for holding the insulating liquid is not required, and the display capsule can be held on an arbitrary support such as paper. An image display medium having excellent properties and easy handling can be obtained.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a structure of a display device 1 as an image display device according to a first embodiment of the present invention. The display device 1 has a configuration in which image display can be confirmed from the upper side in FIG.

The display device 1 includes a panel substrate 2
, Display particles 3, insulating liquid 8, X electrode 5, Y
Electrodes 6 and 7, control power supplies 9 and 10, insulator base 11
And an insulating protective layer 12.

A large number of voids 4 are provided inside the panel base material 2, and an insulating liquid 8 is provided inside each of the voids 4.
And display particles 3 are included.

The panel substrate 2 is only required to be transparent to the extent that the coloring of the display particles 3 can be distinguished and to have sufficient strength as a panel. For example, a plastic or elastomer such as polyethylene or polystyrene may be used. Can be used.

The diameter of the void 4 formed in the panel substrate 2 is preferably about 1.5 to 2 times the average particle diameter of the display particles 3 so that the display particles 3 can rotate. .

As the insulating liquid 8, a highly insulating liquid such as silicon oil, toluene, xylene, isoparaffin and the like is suitable.

On the upper and lower sides of the panel substrate 2 in FIG. 1, an X electrode 5 and Y electrodes 6 and 7 are provided.

The X electrodes 5 are linear electrode patterns formed by arranging a plurality of the X electrodes 5 in a direction perpendicular to the paper surface of FIG.

The Y electrodes 6 and 7 are linear electrode patterns extending in a direction perpendicular to the paper surface of FIG.
It is composed of a transparent electrode such as O.

The Y electrodes 6, 7 and the X electrode 5 are configured to intersect each other at right angles or at an angle close to each other, and between the X electrode 5 and the Y electrode 6, and between the X electrode 5 and the Y electrode 7. Are connected to power supplies 9 and 10 for control. Therefore,
The intersections where the Y electrodes 6 or 7 overlap the X electrodes 5 form a so-called matrix over the entire surface of the panel substrate 2 and are driven in a time-division manner. The time division driving is performed by a driving element such as an IC (not shown).

The periphery and the lower part of the X electrode 5 are covered with an insulating substrate 11, and the periphery and the upper part of the Y electrodes 6 and 7 are covered with a transparent insulating protective layer 12.
The insulator substrate 11 may not be particularly transparent, and may be made of glass, phenol resin, or the like.
For example, synthetic resins such as polycarbonate, polystyrene, and acryl, and glass having good transparency are used.

As shown in FIG. 2, the display particles 3 are made of a white ferroelectric ball made of barium titanate having an average particle size of about 0.05 mm as a raw material, and the upper hemisphere portion of the ferroelectric ball is used. Has a blue color (hereinafter, referred to as a blue portion), a lower hemisphere portion has a white color (hereinafter, referred to as a white portion), and the upper hemisphere portion has more negative charges than the lower hemisphere portion. Is configured to be polarized.

Therefore, the display particles 3 sandwiched between the X electrode 5 and the Y electrode 6 are oriented according to the polarity of the power supply 9. That is, as shown in FIG. 1, when the Y electrode 6 is the anode, the blue portion having many negative charges rotates so as to approach the Y electrode 6, and the vertex of the blue portion is closest to the Y electrode 6. Stabilizes in state.

The display particles 3 sandwiched between the X electrode 5 and the Y electrode 7 are oriented according to the polarity of the power supply 10 as described above. That is, when the Y electrode 7 is a cathode, a white portion having a large amount of positive charges rotates so as to approach the Y electrode 7, and the apex of the white portion stabilizes in a state of being closest to the Y electrode 7.

By switching the polarities of the power supplies 9 and 10 in accordance with the image data to be displayed,
Any image can be displayed.

Here, a method for producing the display particles 3 will be described with reference to FIGS.

FIG. 3 is a diagram showing an electric polarization step.

First, the dielectric balls 24 are dispersed in an aqueous solution of polyvinyl alcohol, and this dispersion is coated on the lower electrode plate 21 by a spin coater and dried to form a coating on the lower electrode plate 21. A film 22 of polyvinyl alcohol is formed. At this time, since the volume of the polyvinyl alcohol film 22 is reduced due to the evaporation of water, as shown in FIG.
The upper half is exposed, and the lower half is supported so as to be buried in the polyvinyl alcohol film 22.

Then, while the upper electrode plate 23 is in contact with the upper half of the dielectric balls 24 applied on the lower electrode plate 21, the inside of the highly insulating liquid 26 filled in the container 28 is removed. And a power supply 25 is connected between the upper electrode plate 23 and the lower electrode plate 21 to apply a voltage of, for example, about 3 kV to 1
By applying the voltage for about 0 hours, the dielectric balls 24 are electrically polarized. After that, the upper electrode plate 23 is removed from the container 28 and dried sufficiently.

According to the above-described method, the polarization plate 20 shown in FIG. 4 in which the dielectric ball 24 polarized so that the upper part has a positive polarity and the lower part has a negative
Is obtained.

Next, as shown in FIG. 5, the polarization plate 20 is mounted on a sample table 31 of a vapor deposition apparatus 30, and a copper phthalocyanine vapor deposition material 33 having a blue color is placed on a heating plate 32. By setting the inside of the vapor deposition device 30 to a high vacuum state and heating the vapor deposition material 33 with the heating plate 32, the surface of the exposed hemispherical portion of the dielectric ball 24 is coated with blue copper phthalocyanine. A film is deposited.

After the vapor deposition, the polarization plate 32 is taken out of the vapor deposition device 30 and immersed in acetone containing a surfactant. The polyvinyl alcohol film 22 swells and softens, and the dielectric balls 24 Separated from the film.

Through the above steps, as shown in FIG. 2, display particles 3 which are electrically polarized to a large electric dipole moment and arranged in two colors along the polarization direction are obtained.

The two-part silicone rubber in which the display particles 3 obtained as described above are dispersed is formed into a plate having a thickness of 2 mm using a coating device, and is heated and cured at about 70 ° C. for about 90 minutes. . Then, the obtained silicone rubber plate is immersed in silicone oil for about 48 hours to expand the silicone rubber. The panel substrate 2 provided is obtained.

Subsequently, the panel substrate 2 is made of an insulating substrate 11 which is a glass plate on which the X electrodes 5 made of transparent electrodes are formed, and a glass plate on which Y electrodes 6 and 7 made of transparent electrodes are formed. The display device 1 is obtained by being sandwiched between a certain insulating protective layer 12.

Next, an image display medium 40 according to a second embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 6, a binder layer 42 is formed on the surface of a support 41 of an image display medium 40, and a display capsule 44 is held on the binder layer 42. Here, the display capsule 44 is held by the binder layer 42 by burying the lower hemisphere portion in the binder layer 42, and the upper hemisphere portion is exposed for image display.

The display capsule 44 is provided with the display particles 4.
3 and the highly insulating liquid 45 as inclusions, and the inclusions are sealed in a wall material such as resin.

As the support 41, various papers, plastic films, synthetic paper of paper and film, and the like are used.

As the display particles 43 and the highly insulating liquid 45, those similar to those in the first embodiment can be used.

The display capsule 44 having the above configuration is obtained as follows.

That is, the display particles 43 are dispersed in a highly insulating liquid using a surfactant or the like, and an approximately equal amount of water to which the emulsifier has been added is mixed with the dispersion. Then, an O / W emulsion is obtained by stirring, and then, from the aqueous phase side, a substance serving as the wall material, for example, a prepolymer of melamine formaldehyde resin is added, and the prepolymer is added at about 70 ° C. for 2 hours. Is cured to obtain the display capsule 44 having the above-described configuration.

The display capsule 44 thus obtained is
By dispersing the dispersion in an aqueous solution of a polymer substance such as polyvinylpyrrolidone constituting the binder layer 42, applying the dispersion to the support 41 using a coating apparatus, and drying the dispersion, the image display medium 40 shown in FIG. Is obtained.

The image display medium 40 having the above-described structure is the same as the insulator base 11 and the insulating protective layer 1 of the first embodiment.
As shown in 2, the image is displayed by rotating the display particles 43 by sandwiching between a set of plate-like members or films having electrodes formed in a matrix and applying an electric field according to an image signal. be able to.

Further, an external electric field generating device having a configuration in which two needle electrodes facing each other with a predetermined gap therebetween are arranged in a line is used, while applying a voltage corresponding to an image signal to each of the needle electrodes. By passing the image display medium 40 through the gap, an arbitrary image can be displayed on the image display medium 40. The image display medium 40 on which the image is displayed can be lightweight and portable, like printed paper or the like. It has excellent properties and is easy to handle.

The present invention is not limited to the embodiment described above, and various changes can be made without departing from the scope of the invention.

For example, the electric polarization and the coloring may be performed separately as in the above-described embodiment, or may be performed simultaneously.

The coloration of the surface of the display particles is not limited to two colors, but may be more.

[0057]

As is apparent from the above description, according to the image display device of the first aspect of the present invention, the rotation of the display particles is effectively controlled by the external electric field, and the image display operation is performed. And a high-contrast image can be displayed.

According to the image display medium of the present invention, no container or the like for holding the insulating liquid is required, and the display capsule can be held on any support such as paper. In addition, it is possible to provide an image display medium which is quick in response, can display an image with high contrast, is lightweight, has excellent portability, and is easy to handle.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a display device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of display particles used in the display device.

FIG. 3 is a diagram illustrating a method for producing the display particles.

FIG. 4 is a diagram illustrating a method for producing the display particles.

FIG. 5 is a diagram illustrating a method for producing the display particles.

FIG. 6 is a diagram illustrating a schematic configuration of an image display medium according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Display apparatus 2 Panel base material 3 Display particle 8 Insulating liquid 24 Dielectric ball 40 Image display medium 44 Display capsule

Claims (2)

[Claims] An electric field applied to display particles, wherein display particles having a surface composed of two or more types of regions having different chargeability and different colors in the insulating liquid are dispersed in the insulating liquid. An image display apparatus for displaying an image by controlling display and rotating display particles, wherein the display particles are made of a polarized dielectric substance. 2. A support for holding a display particle having a surface composed of two or more types of regions having different charging properties and colors in an insulating liquid and a display capsule containing the insulating liquid. An image display medium for displaying an image by controlling an electric field applied to the display particles and rotating the display particles, wherein the display particles are made of a polarized dielectric material. Characteristic image display medium.