JP2002006345A - Image display medium and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display medium and an image display device in which picture quality, controlling property, reliability and storage property can be improved. SOLUTION: The image display medium 30 has a display substrate 10 having an electrode 11 formed on one surface and a back substrate 14 having an electrode 13 formed on the surface facing the display substrate 10, both substrates disposed facing each other through a spacer 16. First particles (black particles) 18 and second particles (white particles) 20 are sealed in the space between the display substrate 10 and the back substrate 14. Gap electrodes 12 are erected adjacent to the spacer 16 on both ends of the electrode 13. Therefore, the intensity of the electric field on both ends of the image display medium 30 is enhanced, the first particles 18 and second particles 20 can be moved at a lower voltage as a result. Thus, even when an all-purpose handy power supply such as a dry cell is used, image display can be carried out and the medium can be easily commercialized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display medium and an image display apparatus, and more particularly, to an image display medium that can be repeatedly rewritten and an image display apparatus that displays an image on the image display medium.

[0002]

2. Description of the Related Art Conventionally, Twisting Ba has been used as a sheet-like image display medium which can be repeatedly rewritten.
ll Display (two-color separate particle rotation display),
Image display media such as electrophoresis, magnetophoresis, thermal rewritable media, and liquid crystals having memory properties have been proposed.

Among such image display media, a thermal rewritable medium and a memory liquid crystal are excellent in image memory, but cannot display a sufficient white image on a display surface like paper. Is displayed, there is a problem that it is difficult to visually confirm the distinction between the portion where the image is displayed and the portion where the image is not displayed, that is, the image quality is deteriorated.

An image display medium using electrophoresis or magnetophoresis has a memory property of an image and is a technique in which colored particles are dispersed in a white liquid. The black display forming the display portion has a problem that the white liquid always enters the gaps between the colored particles, so that the display becomes grayish and the image quality is deteriorated.

[0005] Further, since a white liquid is sealed inside the image display medium, when the image display medium is removed from the image display apparatus and handled roughly like paper, the white liquid is removed from the image display medium. There was a problem that it could leak out.

[0006] Also, Twisting Ball Di
Spray also has a display memory property, and oil exists only in cavities around particles inside an image display medium, but since it is almost in a solid state, it is relatively easy to form a sheet.

However, even if the hemispherical surfaces painted white are completely aligned on the display side, the light rays that enter the gap between the spheres are not reflected and are lost inside, so that the coverage is 100% in principle. However, there is a problem that the white display cannot be performed and the image is slightly grayed.

In addition, since the particle size is required to be smaller than the pixel size, fine particles having different colors must be manufactured for high-resolution display. There was also the problem that technology was required.

On the other hand, in order to solve the above problems,
As a display technology using toner, a conductive coloring toner and white particles are sealed between opposing electrode substrates, and charges are injected into the conductive coloring toner via a charge transport layer provided on the electrode inner surface of the non-display substrate. The charged electrically conductive toner moves to the display substrate facing the non-display substrate due to the electric field between the electrode substrates, and the conductive colored toner adheres to the inside of the display-side substrate to form the conductive colored toner. 2. Description of the Related Art An image display medium for displaying an image based on a contrast between toner and white particles has been proposed.

Recently, a method using not only conductive colored toners but also insulating or semiconductive colored particles,
A method of directly injecting a charge from an electrode without providing a charge transport layer, a method of applying a charge to particles by frictional charging, and the like have been proposed. It is known that such a display technique using toner or particles is excellent in that the image display medium is entirely formed of a solid, and the display between black and white can be switched by 100% in principle.

[0011]

However, conventional image display media using toners and particles are only designed to be sandwiched between flat plates such as a glass substrate which has been subjected to a conductive treatment, and sufficient performance has been established. Had not been. In particular, the physical structure of the image display medium to hold toner and particles, the electrode structure of the image display medium to achieve optimal driving, control of the charged state of the particles, etc.
There is a problem that a portion that strongly affects the image quality, controllability, reliability, and storability of the image display medium is not sufficient, and a sufficient image display cannot always be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has as its object to provide an image display medium and an image display device capable of improving image quality, controllability, reliability, and storability.

[0013]

In order to achieve the above object, according to the first aspect of the present invention, a pair of substrates are provided so as to be movable between the pair of substrates by an applied electric field. In an image display medium including a plurality of types of particle groups having different colors and charging characteristics while being encapsulated, an application electrode for applying the electric field, and an application electrode provided between the pair of substrates, and the application electrode And a gap electrode for changing an electric field due to the electric field applied by the method.

According to the present invention, between the pair of substrates,
A plurality of types of particle groups having different colors and charging characteristics are enclosed. By generating an electric field between the pair of substrates according to the image information, particles of different colors can be moved between the substrates according to the charged polarity of the particles, and an image can be displayed. Note that the pair of substrates can be formed of an insulating resin or a glass substrate, at least one of which is, for example, one of transparent, translucent, and colored and transparent. Also,
In addition to insulating particles, conductive, hole-transporting, and electron-transporting particles can be used as the particles.

In such an image display medium, an application electrode for applying an electric field is provided between a pair of substrates. The application electrode may be provided on one of the pair of substrates, or may be provided on each of the pair of substrates. In addition, a gap electrode for changing an electric field due to an electric field generated between the pair of substrates applied by the application electrode is provided between the pair of substrates.

Thus, the electric field strength at the position where the gap electrode is provided can be further increased, so that driving can be performed with low power. A plurality of gap electrodes may be provided. Thereby, the electric field strength can be further increased.

Note that a local electric field can be formed at the position where the gap electrode is provided by bringing the gap electrode close to the pair of substrates. Thus, a desired electric field intensity can be obtained by changing the position, shape, type, quantity, and the like of the gap electrode.

Further, since the electric field strength can be increased, it is possible to prevent particles from being deposited on the lower side even when the image display medium is used leaning against it. Further, it is possible to suppress the particles from being fixed to the substrate and the image quality from being deteriorated due to the particles being attached to each other. Therefore, stable image display can be performed over a long period of time.

Such an image display medium can be displayed as an image by an image display device provided with voltage control means for applying a voltage according to image information between the gap electrode and the application electrode.

Further, an application electrode is provided on each of a pair of substrates,
A gap electrode may be arranged between the application electrodes for a reference potential. In this case, between one application electrode and the gap electrode,
By controlling the voltage applied between the other application electrode and the gap electrode in the same manner, the same image can be displayed on both surfaces of the image display medium.

A plurality of gap electrodes are provided between the application electrodes,
By controlling the voltage applied between one applied electrode and the gap electrode and between the other applied electrode and the gap electrode independently of each other, different images may be displayed on both surfaces. .

According to a fifth aspect of the present invention, a plurality of types of substrates are sealed between the pair of substrates so as to be movable between the pair of substrates by an applied electric field, and different in color and charging characteristics. A particle group, and an image display medium comprising: a pair of application electrodes provided between the pair of substrates, and at least one of the application electrodes is provided separately from the substrate;
It is characterized by having.

According to the present invention, one of the pair of application electrodes is provided separately from the substrate. This application electrode is
For example, a grid-like electrode can be used. In this case, when the particles are moved by the applied electric field and adhere to the application electrode, there are particles that pass through the lattice and adhere to the substrate side, and because the particles hide the application electrode, the particles are directly visible,
Image quality can be improved.

Such an image display medium can be displayed as an image by an image display device provided with voltage control means for applying a voltage according to image information between a pair of application electrodes.

Also, the pair of application electrodes may be integrated via an insulating member. Thereby, the structure of the image display medium can be simplified.

With such an image display medium, an image can be displayed by an image display device provided with voltage control means for applying a voltage according to image information between a pair of application electrodes and a gap electrode.

The gap electrode can be used not only for displaying images but also for controlling the charging of particles. That is, by moving the particles and frictionally charging them, or by directly injecting charges from the gap electrode, the particles charged incorrectly by repeated development can be properly charged. At this time, it is also possible to selectively extract particles charged incorrectly and perform the processing.

Further, it is also possible to use the gap electrodes for controlling the transport and distribution of particles. As a result, the non-uniform distribution of particles generated during or after the manufacture of the image display medium, uneven distribution of particles induced by external force such as gravity, or vibration, and contamination of a display image due to a partial defect of the image display device are repaired. It is also possible to do.

Therefore, stable image quality can be maintained for a long time without restriction on the installation location of the image display medium.

Further, for the gap electrode, for example, at least a part of a sheet inserted between a pair of substrates can be used, so that it can be designed and manufactured independently of the substrate. Further, even when a plurality of types of gap electrodes are provided, it is only necessary to provide a plurality of sheets, and the design can be easily changed simply by changing the order of the sheets.

The gap electrode may be made of particles, so that it can be designed and manufactured independently of the substrate, and can be mixed and sealed with particles for development, thereby facilitating manufacture. . Further, the frequency of contact with the particles for development is improved, and the driving and charging control of the particles are facilitated.

As the gap electrode, a member provided between the substrates, for example, a part of a film coated on a spacer can be used. Thus, it is only necessary to coat a part of the spacer, and there is no need to separately provide a gap electrode. In addition, a desired electric field can be formed by arranging a plurality of types of electrode components on the film surface or by arranging a plurality of electrode components in a depth direction such as a multilayer structure.

[0033]

[First Embodiment] A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an image display medium 30 according to the present embodiment. As shown in FIG. 1, an image display medium 30 includes a display substrate 10 having an electrode 11 formed on one surface and a back substrate 14 having an electrode 13 formed on a surface facing the display substrate 10 having a spacer 16. The first particles (black particles) 18 and the second particles (white particles) 20 are sealed in a space between the display substrate 10 and the rear substrate 14.

The gap electrodes 1 are provided at both ends of the electrode 13.
2 stands upright adjacent to the spacer 16.

The display substrate 10 is made of, for example, a PET (polyethylene terephthalate) film.
For example, it is composed of an ITO electrode. The back substrate 14 is made of, for example, a PET film like the display substrate 10 and
Is made of, for example, aluminum. The electrode 11 is a voltage applying means 1
5 and the electrode 13 and the gap electrode 12 are grounded. As the gap electrode 12, for example, a material obtained by evaporating a metal on nylon can be used.

Here, assuming that the first particles 18 are negatively charged and the second particles 20 are positively charged,
When a positive DC voltage is applied to the electrode 11 of the display substrate 10 by, for example, the voltage applying means 15, the first particles 18 move toward the display substrate 10 because the first particles 18 are negatively charged, and the second particles 20 Since it is positively charged, it moves to the rear substrate 14 side.

In this state, the voltage applied to the electrode 11 is 0 V
In this case, the first particles 18 are held on the display substrate 10, and the second particles 20 are held on the back substrate 14.

When a negative DC voltage is applied to the electrode 11 by the voltage applying means 15, the first particles 18 move toward the back substrate 14 because the first particles 18 are negatively charged, and the second particles 20 Since it is positively charged, it moves to the display substrate 10 side.

In this state, when the voltage is applied to 0 V,
The first particles 18 are held on the back substrate 14 and
The second particles 20 are held on the display substrate 10.

As described above, a plurality of types of particle groups having different colors and charging polarities can be moved between substrates by applying a voltage between the substrates, so that a voltage corresponding to image information is applied between the substrates. By doing so, a desired image can be displayed.

FIG. 2 shows that the electrodes 11 and
The state of the electric field generated when a predetermined voltage is applied to the electrode 13 is shown by electric flux lines 22. Further, FIG. 3 shows the state of an electric field generated when the predetermined voltage is applied to a conventional image display medium, that is, the image display medium 100 in which the gap electrode 12 is not provided, by electric lines of force 24.

As shown in FIG. 3, in the conventional image display medium 100, the lines of electric force 24 are substantially parallel. Therefore, the electric field strength at the position of γ shown in FIG. 3 is almost the same at any position as shown in FIG. 4C.

On the other hand, the image display medium 3 according to the present invention
In the case of 0, since the gap electrode 12 is provided between the electrode 11 and the electrode 13, not only between the electrode 11 and the electrode 13 but also between the electrode 11 and the gap electrode 12 as shown in FIG. An electric field is also formed. Thereby, α, β shown in FIG.
4A and 4B, the electric field intensity at both ends of the image display medium 30, that is, at the position where the gap electrode 12 is provided, becomes stronger.

Therefore, compared with the conventional image display medium 100, the first particles 18 and the second particles 20 are formed at a lower voltage.
Can be moved. For this reason, an image can be displayed even when a general-purpose simple power supply such as a dry battery is used, and commercialization is facilitated. Further, since there is no need to apply a high voltage, danger such as electric shock can be reduced. Further, in the conventional image display medium 100, when the image is displayed with the image display medium 100 placed vertically, the first particles 18 or the second particles 20 tend to accumulate on the lower side. The image display medium 30 includes the gap electrode 12
As a result, a stronger electric field is formed at both ends of the image display medium 30, so that the particles can easily move, and the first particles 18 and the second particles 20 can be prevented from accumulating on the lower side.

Further, by changing or adding the position of the gap electrode 12, a stronger electric field can be formed at each position. Therefore, an image can be formed only by disposing the gap electrode 12 in accordance with the image. Therefore, by arranging the gap electrodes 12 according to the image, the load on the driving device for driving the image display medium can be reduced, and an inexpensive and highly decorative image display medium can be obtained.

In the present embodiment, the gap electrode 12 is connected to the electrode 13. However, the present invention is not limited to this, and the gap electrode 12 is not connected to the electrode 13, and each electrode has an independent structure. An electric field may be formed by an electric potential. In this case, a voltage may be applied to the gap electrode 12 independently. Further, instead of displaying an image on the display substrate 10 side, an image may be displayed on the rear substrate 14 side.

[Second Embodiment] Next, a second embodiment of the present invention will be described. The same parts as those of the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 5, in the image display medium 31 according to the second embodiment, not only the gap electrodes 12 are formed on both ends of the image display medium 31, but also a plurality of gap electrodes 12 are provided together with the spacer 16 at the center. Is provided. The electrode 13 is not formed on the rear substrate 14.

As described above, by providing a plurality of gap electrodes 12 not only at both ends but also at the center of the image display medium 31, and by narrowing the gap between the gap electrodes 12, it is possible to form a strong electric field at a narrow gap. it can. That is, α in FIG.
As shown in FIG. 6, the electric field strength can be increased at small intervals. Therefore, since it is not necessary to form an electrode on the rear substrate 14 side, a simple configuration can be achieved, and the manufacturing process can be simplified.

Further, since a strong electric field is formed in the vicinity of the display substrate 10, the first particles 18 and the second particles 20 sealed between the display substrate 10 and the rear substrate 14 are prevented from being biased. And high-quality image display can be realized.

For example, as shown in FIG. 7, in a case where the image display medium 31 is used leaning against the image display medium 31,
Must be vertical, the first particles 18 and the second particles 20 are liable to be deposited on the lower side by gravity, and the like.
Are provided not only at both ends but also at the center to form a strong electric field at a narrow interval, so that each particle is moved even if the first particles 18 and the second particles 20 are deposited on the lower side by gravity. And an image can be displayed satisfactorily.

Since an image can be displayed without providing the electrode 13 on the rear substrate 14, the spacer 16 and the rear substrate 14 are separated from each other as in an image display medium 34 shown in FIG. The first particles 18 and the second particles may be configured so that the first particles 18 and the second particles 20 are exchanged from the gap between the spacer 16 and the back substrate 14, that is, refreshable.

Thus, the irregularly charged first particles 18
Alternatively, only the first particles 18 or the second particles 20 that have discharged the second particles 20 and are appropriately charged can be used for image display, and good image display can be performed. Further, the deteriorated first particles 18 or second particles 20
Can be exchanged, which facilitates recycling. Further, by changing the colors to be displayed by replacing the first particles 18 and the second particles 20 with particles of different colors, or by adjusting the amounts of the first particles 18 and the second particles 20, the concentration can be reduced. Can be switched, and various extended functions can be realized.

[Third Embodiment] Next, a third embodiment of the present invention will be described. The same parts as those of the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 9, in the image display medium 36 according to the third embodiment, the gap electrodes 12 have, for example, a lattice shape, and are arranged at a substantially intermediate position between the electrodes 11 and 13. .

Then, the voltage applied between the gap electrode and the electrode 11 and the gap electrode 12
The voltage applied between the electrode 13 and the electrode 13 is controlled by the voltage applying means 15. Thereby, the same image can be displayed on the display substrate 10 side and the rear substrate 14 side.

As described above, the display substrate 10 and the rear substrate 14 can be treated equivalently by disposing the gap electrode 12 at a substantially intermediate position between the electrode 11 and the electrode 13 and setting the reference potential. The display can be easily performed.

The gap electrode 12 is increased by at least one, and the voltage applied between the gap electrode 12 and the electrode 11 and the voltage applied between the gap electrode 12 and the electrode 13 are separately controlled. Different images may be displayed on both sides. Thereby, the front surface and the back surface can be used separately.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described. The same parts as those of the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 10, the image display medium 38 according to the fourth embodiment has, for example, grid-like electrodes 11 provided slightly apart from the display substrate 10.

As described above, since the electrode 11 is separated from the display substrate 10, it is possible to prevent the first particles 18 and the second particles from sticking to the display substrate 10 and becoming dirty. This can prevent the image from deteriorating.

Since the particles on the back substrate 14 pass around the display substrate 10 through the grid of the electrodes 11, the electrodes 11
Is concealed, and higher image quality can be achieved.

Further, since no electrode is provided on the display substrate 10, a material which is difficult to conduct the conductive treatment can be used for the display substrate 10, and the selection of the material is facilitated. Further, it is possible to equip already installed places such as walls and windows with an image display function as an additional function.

In the above description, the display substrate 10 to the electrode 11
However, the configuration may be such that electrodes are provided on the display substrate 10 and the electrodes 13 are separated from the rear substrate 14.

Further, as in the image display medium 40 shown in FIG.
3 may be separated. Thus, the back substrate 14 can be made of a material that is difficult to conduct the conductivity, and the material can be easily selected. Further, since the particles on the display substrate 10 pass around the rear substrate 14 through the grid of the electrodes 13 on the rear substrate 14, the electrodes 13 on the rear substrate 14 are hidden, and an image is displayed on the rear substrate 14. In this case, high image quality can be obtained.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described. The same parts as those of the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 12, in the image display medium 42 according to the fifth embodiment, the electrodes 11 and 13 are
It is configured to be bonded via an insulating member 17 having the same shape as 1 and 13. The electrodes 11, 13 and the insulating member 17 are, for example, in a grid shape and each surface is non-parallel to the display substrate 10 and the back substrate 14, that is, a shape having a predetermined angle. It is preferable that the insulating member 17 be made of a material having a strength that can prevent deformation of the electrodes 11 and 13. Electrodes 11, 13
The voltage applied during this time is controlled by the voltage applying means 15.

Further, as in an image display medium 44 shown in FIG. 13, a structure in which grid-shaped and planar electrodes 11 and 13 are bonded by an insulating member 17 having a similar shape may be adopted.

As described above, the display substrate 10 and the back substrate 1
No electrodes need to be provided on the substrate 4, and the electrodes are integrated, so that the distance between the display substrate 10 and the rear substrate 14 can be freely designed, and the structure for supporting the electrodes can be simplified. it can. Accordingly, the image display medium can be effectively used in the case where the shape of the image display medium needs to be designed variously or in the use of a toy or the like that requires impact durability.

As shown in FIGS. 12 and 13, the first particles 18 and the second particles 20 are previously applied to the electrodes 11 and 13.
May be attached. Accordingly, it is possible to prevent the work space from being contaminated due to poor distribution of particles and scattering of the particles, which are problems that are likely to occur inside the image display medium in the particle enclosing process in the manufacturing process.

As described above, the display substrate 10 and the rear substrate 14
Since one gap electrode 12 is provided between them, the durability during use can be significantly improved.
In addition, it can be used like paper, such as bending or folding, and can also be used for wearable applications, such as cutting or pasting.

[Sixth Embodiment] Next, a sixth embodiment of the present invention will be described. The same parts as those of the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 14, in an image display medium 46 according to the sixth embodiment, an insulating member 17 having, for example, a grid-like convex portion is formed on an electrode 13 formed on a back substrate 14. Then, a grid-like electrode 11 is formed on each convex portion of the insulating member 17. The voltage applied between the electrode 11 and the electrode 13 is controlled by the voltage applying means 15.

As described above, by providing the grid-like electrodes 11 on the insulating member 17 having the grid-like protrusions, FIG.
As shown in FIG. 4, particles used for display adhere to the electrode 11, and particles not used for display adhere to the concave portion of the insulating member 17. Therefore, the particles not used for display are concealed by the particles attached to the gap electrode 11, so that the image quality can be improved.

[0076]

As described above, according to the present invention,
It has an excellent effect that image quality, controllability, reliability, and storability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image display medium according to a first embodiment.

FIG. 2 is a diagram for describing an electric field in the image display medium according to the first embodiment.

FIG. 3 is a diagram for explaining an electric field in a conventional image display medium.

4A is a diagram showing an electric field intensity at a position α in FIG. 2, FIG. 4B is a diagram showing an electric field intensity at a position β in FIG. 2, and FIG. 4C is an electric field at a position γ in FIG. It is a figure showing intensity.

FIG. 5 is a diagram for explaining an electric field in an image display medium according to a second embodiment.

FIG. 6 is a diagram showing an electric field intensity at a position α in FIG. 5;

FIG. 7 is a sectional view of an image display medium according to a second embodiment.

FIG. 8 is a sectional view of an image display medium according to a second embodiment.

FIG. 9 is a sectional view of an image display medium according to a third embodiment.

FIG. 10 is a sectional view of an image display medium according to a fourth embodiment.

FIG. 11 is a sectional view of an image display medium according to a fourth embodiment.

FIG. 12 is a sectional view of an image display medium according to a fifth embodiment.

FIG. 13 is a sectional view of an image display medium according to a fifth embodiment.

FIG. 14 is a sectional view of an image display medium according to a sixth embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 display substrate 11, 13 electrode 12 gap electrode 14 back substrate 15 voltage applying means 16 spacer 17 insulating member 18 first particle 20 second particle 30 image display medium

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiro Yamaguchi 430 Green Tech Nakai, Nakai-cho, Ashigara-gun, Kanagawa Inside Fuji Xerox Co., Ltd. (72) Inventor Shota Oba 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. ) Inventor Ken Matsunaga 430 Green Tech Nakai-cho, Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture Fuji Xerox Co., Ltd. F-term (reference) 5C080 AA16 BB05 DD29 DD30 EE26 FF03 JJ02 JJ05 JJ06

Claims (8)

[Claims] 1. A method comprising: a pair of substrates; and a plurality of types of particle groups that are sealed between the pair of substrates so as to be movable between the pair of substrates by an applied electric field and that have different colors and charging characteristics. An image display medium, comprising: an application electrode for applying the electric field; and a gap electrode provided between the pair of substrates and for changing an electric field due to the electric field applied by the application electrode. An image display medium characterized by the following. 2. The image display medium according to claim 1, wherein said gap electrode is brought close to said pair of substrates. 3. The image display medium according to claim 1, comprising a plurality of said gap electrodes. 4. The device according to claim 1, wherein said application electrodes are provided on said pair of substrates, respectively, and said gap electrode is disposed between said application electrodes for a reference potential. Item 2. The image display medium according to Item 1. 5. A semiconductor device comprising: a pair of substrates; and a plurality of types of particle groups that are sealed between the pair of substrates so as to be movable between the pair of substrates by an applied electric field and have different colors and charging characteristics. An image display medium, comprising: a pair of application electrodes provided between the pair of substrates and at least one of the application electrodes is provided separately from the substrate. 6. The image display medium according to claim 5, wherein said pair of application electrodes are integrated via an insulating member. 7. An image display device for displaying an image on an image display medium according to claim 1, wherein a voltage according to image information is applied between said gap electrode and said application electrode. An image display device comprising voltage control means. 8. An image display device for displaying an image on the image display medium according to claim 5, wherein the voltage control means for applying a voltage according to image information between the pair of application electrodes. An image display device comprising: