JPH08129194A - Color display device - Google Patents

Abstract

PURPOSE: To obtain a color display device of a reflection type capable of expressing full colors by adjusting electric fields and impressing these electric fields. CONSTITUTION: Transparent reference electrode 12a is formed on one of transparent two surfaces 11a, 11b and counter electrode 12b on the other and electrosensitive type optical functionable fluid compsns. 14 formed by incorporating electric field arranging type particles 13 into electrically insulatable media are packed into a cell 10. The cells 10 are laminated in three layers and the electric field arranging type particles in the rspective cells are repectively colored to different opaque dolors. The respective cells 10 to 30 are provided with means 15, 25, 35 for adjustably impressing the electric fields between the reference electrodes and counter electrodes of the cells.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color display device using an electrosensitive optical functional fluid composition,
In particular, the present invention relates to a reflective color display device capable of expressing a full color by adjusting and applying an electric field.

[0002]

2. Description of the Related Art Conventionally known as a color display device (hereinafter simply referred to as "color display device") capable of changing a color or an image on a display surface is an electronic display device, a neon display device, a CRT display. Examples of the device include an LED display device, a liquid crystal display device, a plasma display device, an electroluminescence display device, and a projection display device. However, all of them have insufficient brightness and poor visibility for use in bright places such as daylight outdoors. Therefore, as a color display device having high visibility even in daylight, a reflection type device having a color reflecting plate such as a rotating plate and a reversing plate is used. Among them, the rotary plate type is to show the part of the disk-shaped or wound belt-shaped rotary plate on which an image is drawn from the moving image display window of the color display device, and rotate this rotary plate continuously or intermittently. The image is changed by. Further, the reversing plate type is such that small pieces of reversing elements to which different image portions or colors are applied are arranged in a matrix on the display surface, and each reversing element can be individually reversed to two or more surfaces. The surface of each inverting element is individually controlled to express a moving image.

[0003]

In each of these conventional reflection type color display devices, which have high visibility even in a bright place, the number of images that can be displayed is limited because images are driven mechanically. There are problems that the structure is complicated, it is easy to break down, noise is generated, and it is heavy and expensive. Particularly, in the conventional reflective color display device, since the color tone of each image element cannot be changed stepwise or continuously, so-called full-color expression cannot be performed and the application is limited.
Therefore, there is a demand for a reflective full-color display device that has high visibility even in daylight and can change the color tone stepwise or continuously by an electric means.

By the way, the inventors of the present invention are conducting research on an electro-sensitive photo-functional fluid composition (hereinafter referred to as "EA fluid") having a novel electric field arrangement which has not been heretofore known. This composition is a fluid obtained by dispersing solid particles in an electrically insulating medium. When an electric field is applied to the composition, the solid particles cause dielectric polarization, and electrostatic attraction based on the dielectric polarization causes the solid particles to move in the electric field direction relative to each other. It has the property of forming a chain structure by being coordinately linked and aligned. In addition, some solid particles have electrophoretic properties, and thus exhibit a property of exhibiting an array lump structure by electrophoresing and aligning on the electrode portion when an electric field is applied.

Hereinafter, the effect of the solid particles in a fluid being oriented and arranged as described above when an electric field is applied is referred to as an electric field arrangement effect or "EA effect", and solid particles exhibiting this property in a fluid are referred to as electric field arrangement particles or It will be referred to as "EA particles".

Therefore, there has been a demand for a technique of using the EA fluid to provide a reflective full-color display device having high visibility even in daylight. The present invention has been achieved as a result of earnest research to solve the above problems, and therefore an object thereof is to use this EA fluid to gradually or continuously change the color tone of a picture element by electrical means. It is an object of the present invention to provide a reflective color display device that can be changed into

[0007]

[Means for Solving the Problems] The above problems have two transparent surfaces facing each other, a transparent reference electrode is formed inside one of the transparent surfaces, and a transparent reference electrode is formed inside the other transparent surface. An EA fluid in which cells having different counter electrodes are laminated in at least three layers such that transparent surfaces thereof overlap each other, and EA particles are contained in an electrically insulating medium between the both electrodes. The solid particles in the EA fluid filled in each cell are colored with different opaque colors, and an electric field is adjustable between the reference electrode and the counter electrode of each cell. This can be solved by providing a color display device provided with a means for doing so.

In each of the above-mentioned cells, a transparent adjacent electrode that is adjacent to the reference electrode is formed on a transparent surface on which the reference electrode is formed, and the transparent adjacent electrode is formed between the reference electrode and the adjacent electrode or between the reference electrode and the above-mentioned electrode. Means for switching and applying an electric field is preferably provided between the counter electrode and the counter electrode. The EA particles include a core body made of an organic polymer compound, E
Inorganic substance having A effect (hereinafter referred to as "EA inorganic substance")
It is preferable that the inorganic-organic composite particles are formed by a surface layer containing

[0009]

When the electric field is applied with the EA fluid interposed between the transparent electrodes, the EA particles are arranged in the direction of the electric field to form a chain, so that light is transmitted in a direction parallel to the chain. become. The degree of this light transmission can be adjusted stepwise or continuously by changing the electric field strength. Therefore, if the EA particles of the three layers of cells are each colored with one of the three different primary colors of reflection, the full color of the reflected light can be expressed by individually controlling the electric field strength of each cell.

[0010]

EXAMPLES The present invention will be described in detail below with reference to examples. (Embodiment 1) FIG. 1 shows a cross section and a circuit configuration of one image element in one embodiment of the color display device of the present invention. This image element 1 is a cell 1 having three layers.
It is composed of 0, 20, and 30. Since all of these cells have substantially the same configuration, only the cell 10 will be described in common. The cell 10 has two transparent surfaces 11a-11b facing each other.
A transparent reference electrode 12a is formed inside a, and a transparent counter electrode 12b is formed inside the other transparent surface 11b. In this example, three layers of cells 10, 20,
30 contacting transparent surfaces 11b-21a, 21b-
One transparent plate also serves as 31a. Therefore, the cells are stacked so that their transparent surfaces overlap.

Reference electrode 12a and counter electrode 12 of cell 10
An EA fluid 14 containing the EA particles 13 in an electrically insulating medium is filled between b and b. Here, the EA fluids 14, 24, 3 filled in the cells 10, 20, 30
The EA particles 13, 23, and 33 in FIG. 4 are colored in different opaque colors, yellow, red, and blue, respectively.

The EA fluid 14 contained in the cell 10 contains EA particles 13 in silicone oil which is an electrically insulating medium. The EA particles 13 are organic polymer compounds as shown in FIG. The inorganic-organic composite particles (13) are formed by a core body 51 made of a polyacrylic acid ester and a surface layer 54 containing titanium hydroxide fine particles 52 and a yellow pigment 53 which are EA inorganic substances. This EA
The reflected light of the fluid 14 appears yellow due to the color of the pigment of the EA particles 13. EA fluid 2 contained in the other cells 20, 30
4, 34 have substantially the same configuration as the EA fluid 14 except that the pigment contained in the surface layer 54 of the EA particles is a red pigment and a blue pigment instead of the yellow pigment, respectively.
The reflected light appears red and blue depending on the color of the pigment of the EA particles 23 and 33, respectively. An observer O looking at the image element 1 of this color display device from the direction of the cell 10
For bs, the image element 1 sees yellow light, which is the reflected light from the cell 10.

Reference electrode 12a and counter electrode 12 of cell 10
Wirings are drawn out of the cell from b, the counter electrode 12b is connected to, for example, the (−) side of the power supply 40, and the reference electrode 12a is connected to the output terminal 16 of the voltage regulator 15. The voltage regulator 15 is, for example, a variable resistor type in which one fixed terminal is connected to the (+) side of the power source 40 and the other fixed terminal is connected to the (−) side via a load resistance. . The voltage adjuster 15 can adjustably apply an electric field between the reference electrode 12a and the counter electrode 12b of the cell 10. The cell 20 and the cell 30 also have electric field adjusting means similar to the cell 10, and each of them can be adjusted individually.

As shown in FIG. 3, the outputs of the voltage regulators 15, 25 and 35 are adjusted to apply a high voltage between the electrodes 12a-12b of the cell 10 and the electrode 22a of the cell 20. It is assumed that a medium voltage is applied between −22b and no voltage is applied between the electrodes 32a-32b of the cell 30. At this time, the EA particles 13 in the cell 10 are arranged vertically to the electrodes 12a-12b due to the EA effect by the electric field, and as a result, the cell 10 looks transparent to the observer Obs looking from the direction of the cell 10. Since a medium voltage is applied to the cell 20, the polarization of the EA particles 23 is weak,
Therefore, only some of the EA particles form a chain, and the rest of the E particles
The particles A are kept in a randomly dispersed state. Since the number of EA particles 23 in this randomly dispersed state is smaller than that in the case where no electric field is applied, as a result, a semitransparent red color is observed from the observer Obs side. On the other hand, since no voltage is applied to the cell 30, the surface color of the cell 30 is originally opaque blue, but as a result of being mixed with the semitransparent red color of the cell 20 overlaid thereon, this image is seen from the observer Obs side. The element 1 as a whole looks like purple, which is a mixed color of blue and red.

Similarly, the medium voltage is applied to the cell 10 and the cell 20
If a high voltage is applied to the cell 30 and no voltage is applied to the cell 30, the image element 1 as a whole looks green, which is a mixed color of blue and yellow. When a medium voltage is applied to the cell 10 and no voltage is applied to the cell 20, the image element 1 as a whole looks like orange, which is a reflective mixed color of red and yellow. Further, if a medium voltage is applied to any of the cells 10, 20, and 30, yellow, red, and blue are mixed and it looks like black, and if a high voltage is applied to any of the cells 10, 20, and 30, all cells are Is transparent, a white background plate (not shown) may be placed on the back side of the image element 1 or the back side transparent plate 31b itself may be replaced with an opaque white plate.
From the s side, the image element 1 looks white as a whole. In this way, the image element 1 of this color display device can express an arbitrary color by adjusting the voltage regulators 15, 25 and 35 independently of each other. A full-color reflective color display device can be obtained by arranging them in arbitrary shapes.

(Embodiment 2) The image element in the color display device of Embodiment 2 is the same as that of Embodiment 1 except that the structure of the electrode of each cell and the electric circuit associated therewith are different. Therefore, only one cell will be described here.
FIG. 4 shows the structure of the electrodes of one cell and the electric circuit in this embodiment. One transparent surface 61 of this cell
In a, a comb-shaped transparent reference electrode 62a and a transparent adjacent electrode 62c adjacent to the comb-shaped transparent reference electrode 62c are formed in a nested manner with each other, and a counter electrode 62b is formed over the entire other transparent surface 61b of the cell. .

The electric circuit in this cell is constructed as follows. The adjacent electrode 62c formed on the transparent surface 61a and the counter electrode 62b on the other transparent surface 61b are
Each fixed terminal 63 of each changeover switch 63
a, 63b. The movable terminal 63c of the changeover switch 63 is connected to, for example, the (−) side of the power supply 40. The reference electrode 62a on the transparent surface 61a is connected to the output terminal 64a of the voltage regulator 64. This voltage regulator 64 is, for example, a variable resistor, one fixed terminal 64b of which is connected to the (+) side of the power source 40, and the other fixed terminal 64c of which is connected to the (-) side via a load resistor. ing. That is, in this electric circuit, the reference electrode 62a and the adjacent electrode 62c are changed by switching the changeover switch 63.
, Or between the reference electrode 62a and the counter electrode 62b, the adjusted electric field can be switched and applied via the voltage adjuster 64.

In combination with this electric circuit, the cell operates as follows. First, when the changeover switch 63 is connected to the counter electrode 62b side and the voltage adjuster 64 is adjusted to the high voltage side, a high voltage is applied between the reference electrode 62a and the counter electrode 62b. Therefore, the E intervening between these electrodes
The fluid A is highly electric-field arrayed to form a chain perpendicular to the transparent surface 61a, and the cell becomes transparent.

Next, the changeover switch 63 is set to the adjacent electrode 62c.
When switched to the side, a voltage is applied between the reference electrode 62a and the adjacent electrode 62c. At this time, in the EA fluid, as shown in FIG.
By arranging an electric field between the electrode and the adjacent electrode 62c,
A chain 66 parallel to the transparent surface 61a is formed, and the surface is covered by the chain 66, so that the cell becomes colored and opaque.

When the voltage regulator 64 is adjusted to a medium voltage in the course of the above-mentioned switching operation, as shown in a typical example in FIG. 6, a part of the EA particles 65 is a chain 67 perpendicular to the transparent surface 61a. As a result, the other part of the EA particles 65 forms a chain 66 parallel to the transparent surface 61a, so that the cell becomes colored and semitransparent. As a result, the reflected color of the cells in the lower layer becomes partially visible, and a mixed color is obtained. The degree of translucency depends on the chain 66 parallel to the plane and the chain 67 perpendicular to the plane.
This is controllable by the voltage regulator 64, as it depends on the production ratio of and which depends on the electric field strength.

The image element in the color display device of Example 2 is formed by stacking the above cells in three layers.
This color display device is a full-color display device having a good electric field response because the color switching is immediately performed depending on the changeover switch of each cell and the adjustment of the voltage regulator.

In the configuration of the first and / or second embodiment, the changeover switch, the voltage regulator, and the circuit configuration may be of any type as long as they can perform the corresponding functions. For example, an inverter having both the function of the changeover switch and the function of adjusting the voltage stepwise or continuously can be used. Needless to say, the polarities of the reference electrode 62a, the adjacent electrode 62c, and the counter electrode 62b in the second embodiment may be opposite. The pattern of the reference electrode 62a and the adjacent electrode 62c is comb-shaped in the second embodiment, but the pattern is not limited to this. For example, a spiral pattern or a dendritic pattern can be used as long as the patterns are configured to be adjacent to each other. It may have any shape, such as

In Example 1, E used in the three-layer cell
The colors of the A fluids 14, 24, and 34 are yellow, red, and blue, respectively, but this order is not limited to the example. Further, generally, these three colors are the three primary colors in the case of expressing a full color by reflected light, but the three colors are not limited to these depending on the purpose and the situation, and may be arbitrary different colors. Further, in order to enhance the contrast of the image, it is effective to add one layer of black cell to these three layers.

The EA fluid suitable for use in the color display device of the present invention will be described in detail below. This EA
The fluid basically comprises solid particles (EA particles) having an EA effect in an electrically insulating medium,
It can be anything. However, a particularly preferable one is, as the EA particles, as shown in FIG. 2, an inorganic substance formed by a core body made of an organic polymer compound and a surface layer containing an inorganic substance having an EA effect (EA inorganic substance) and a pigment. -It uses organic composite particles. Since the surface layer of the inorganic / organic composite particles is made of EA inorganic material, the particles as a whole have the EA effect, and the core body is made of an organic polymer compound having a relatively small specific gravity even if the specific gravity of the EA inorganic material is large. Therefore, the specific gravity of the EA particles can be approximated to that of the electrically insulating medium, and an EA fluid having good dispersibility can be obtained.

Examples of the organic polymer compound that can be used as the above core include, for example, poly (meth) acrylic acid ester, (meth) acrylic acid ester-styrene copolymer, polystyrene, polyethylene, polypropylene, nitrile rubber, Butyl rubber, ABS resin, nylon, polyvinyl butyrate, ionomer, ethylene-vinyl acetate copolymer, vinyl acetate resin, polycarbonate resin, and the like, or a mixture of two or more thereof, or their monomers or oligomers with each other, or other Examples thereof include copolymers with monomers or oligomers. Further, as the above organic polymer compound, a compound containing a functional group such as a hydroxyl group, a carboxyl group or an amino group can be used, and such an organic polymer compound containing a functional group can enhance the EA effect. Therefore, it is preferable.

The EA inorganic material suitable for use as the surface layer of the inorganic / organic composite particles is an electrosemiconductor inorganic material, an inorganic ion exchanger, silica gel, or a material obtained by subjecting at least one of them to metal doping, or a metal doping. Regardless of the presence or absence of the above, at least one of these is applied as an electric semiconductor layer on another support.

Examples of preferable electrically semiconductive inorganic materials include (1) metal oxides such as SnO ₂ and amorphous titanium dioxide (manufactured by Idemitsu Petrochemical Co., Ltd.); and (2) titanium oxide and water. Examples thereof include metal hydroxides such as niobium oxide, (3) metal oxide hydroxides such as FeO (OH) (goethite), and inorganic ion exchangers described below. Here, titanium hydroxide means hydrous titanium oxide (made by Ishihara Sangyo Co., Ltd.),
Metatitanic acid (also known as β-titanic acid, TiO (OH) ₂ ) and orthotitanic acid (also known as α-titanic acid, Ti (OH) 2
₄ ) is included.

Examples of inorganic ion exchangers include (4) hydroxides of polyvalent metals, (5) hydrotalcites, (6) acid salts of polyvalent metals, (7) hydroxyapatite, (8) ) Nasicon type compound, (9) clay mineral, (1
Mention may be made of 0) potassium titanates, (11) heteropolyacid salts, and (12) insoluble ferrocyanide. These details will be described below.

(4) Hydroxide of polyvalent metal. These compounds have the general formula MO _x (OH) _y (M is a polyvalent metal, x
Is a number greater than or equal to zero, and y is a positive number), for example, titanium hydroxide, zirconium hydroxide, bismuth hydroxide, tin hydroxide, lead hydroxide, aluminum hydroxide, tantalum hydroxide, water. Examples include niobium oxide, molybdenum hydroxide, magnesium hydroxide, manganese hydroxide, and iron hydroxide. Here, for example, titanium hydroxide means hydrous titanium oxide (also known as metatitanic acid or β-titanic acid, TiO (OH)
₂ ) and titanium hydroxide (also known as orthotitanic acid or α-titanic acid, Ti (OH) ₄ ), and the same applies to other compounds.

(5) Hydrotalcites. These compounds have the general formula M ₁₃ Al ₆ (OH) ₄₃ (CO) ₃ · 12H
It is represented by ₂ O (M is a divalent metal), and the divalent metal M is, for example, Mg, Ca or Ni. (6) Acid salts of polyvalent metals. These are, for example, titanium phosphate, zirconium phosphate, tin phosphate, cerium phosphate,
Chromium phosphate, zirconium arsenate, titanium arsenate, tin arsenate, cerium arsenate, titanium antimonate, tin antimonate, tantalum antimonate, niobium antimonate, zirconium tungstate, titanium vanadate, zirconium molybdate, selenate Examples include titanium and tin molybdate.

(7) Hydroxyapatite. These are, for example, calcium apatite, lead apatite, strontium apatite, cadmium apatite and the like. (8) Nasicon type compound. These include (H ₃ O)
Although Zr ₂ (PO ₄ ) _{3 and} the like are included, a Nasicon type compound in which H ₃ O is replaced with Na can also be used in the present invention. (9) Clay mineral. These are, for example, montmorillonite, sepiolite, bentonite and the like, with sepiolite being particularly preferred.

(10) Potassium titanates. These are general formulas aK ₂ O · bTiO ₂ · nH ₂ O (a is a positive number satisfying 0 <a ≦ 1, b is a positive number satisfying 1 ≦ b ≦ 6, and n is a positive number) , For example, K ₂ · TiO ₂
・ 2H ₂ O, K ₂ O ・ 2TiO ₂・ 2 H ₂ O, 0.5K ₂ O
・ TiO ₂・ 2H ₂ O, and K ₂ O ・ 2.5TiO ₂・ 2H
₂ O etc. Among the above compounds, a or b
A compound in which a is not an integer is easily synthesized by subjecting a compound in which a or b is an appropriate integer to an acid treatment and replacing K with H. (11) Heteropolyacid salt. These are of the general formula H ₃ AE ₁₂ O
₄₀ · nH ₂ O (A is phosphorus, arsenic, germanium, or silicon, E is molybdenum, tungsten, or vanadium, and n is a positive number), for example, ammonium molybdophosphate, and tungstophosphoric acid It is ammonium. (12) Insoluble ferrocyanide. These are represented by the following general formula. M _b-pxa A [E (CN) ₆ ] (M is an alkali metal or hydrogen ion, A is a heavy metal ion such as zinc, copper, nickel, cobalt, manganese, cadmium, iron (III) or titanium, E is an iron ( II), iron (II
I), or cobalt (II), b is 4 or 3, a is a valence of A, and p is a positive number of 0 to b / a). These include, for example, Cs ₂ Zn [Fe (C
N) ₆ ] and K ₂ Co [Fe (CN) ₆ ] such as insoluble ferrocyan compounds.

The inorganic ion exchangers (4) to (12) each have an OH group, and some or all of the ions present at the ion exchange sites of these inorganic ion exchangers are different from other ions. Those substituted with (hereinafter, referred to as a substitutional inorganic ion exchanger) are also included in the inorganic ion exchanger of the present invention. That, R-M ¹ inorganic ion exchanger described above (M ¹ represents an ion species of the ion exchange sites) is expressed as a part or all of M ¹ in the R-M ^1, the ion exchange reaction below A substituted inorganic ion exchanger in which an ionic species M ² different from M ¹ is substituted by
It is an inorganic ion exchanger in the present invention. xR−M ¹ + yM ² → Rx− (M ² ) y + xM ¹ (where x and y represent the valences of the ion species M ² and M ¹ , respectively). M ¹ varies depending on the type of the inorganic ion exchanger having an OH group, but when the inorganic ion exchanger exhibits a cation exchange property, M ¹ is generally H ⁺ , and in this case, M ² is an alkali metal or an alkali. Any of the metal ions other than H ⁺ , such as earth metals, polyvalent typical metals, transition metals or rare earth metals. When the inorganic ion exchanger having an OH group exhibits anion exchange property, M ¹ is generally O.
H ⁻ , in which case M ² is, for example, I, Cl, SCN, N
Any of anions other than OH ⁻ such as O ₂ , Br, F, CH ₃ COO, SO ₄ or CrO ₄ and complex ions.

Further, regarding the inorganic ion exchanger which has once lost the OH group due to the high temperature heat treatment but becomes to have the OH group again by an operation such as immersion in water, the inorganic ion exchanger after the high temperature heat treatment is used. Exchangers and the like are also a kind of inorganic ion exchangers that can be used in the present invention, and specific examples thereof include a Nasicon type compound such as (H ₃ O) Zr ₂
(PO ₄₎ HZr ₂ obtained by heating ₃ (PO _{4) 3} and high-temperature heat treatment of hydrotalcite (500 to 70
Heat treated at 0 ° C.) and the like. These inorganic ion exchangers can be used not only in one kind but also in many kinds simultaneously as a surface layer. It is particularly preferable to use a hydroxide of a polyvalent metal and an acid salt of a polyvalent metal as the above-mentioned inorganic ion exchanger.

An example of the metal-doped EA inorganic material (13) is antimony-doped tin oxide. Metal doping is performed when it is desired to increase the electric conductivity of the EA inorganic material. In addition, examples of (14) in which an EA inorganic substance is applied to another support as an electric semiconductor layer include, for example, inorganic particles such as titanium oxide, silica, alumina, silica-alumina, or polyethylene, polypropylene as a support. Examples of the organic polymer particles described in (1) above, to which antimony-doped tin oxide is applied as an electric semiconductor layer, and the like.

These EA inorganic substances may be used not only in one kind but also in a mixture of two kinds or more. E particularly suitable for use as the surface layer of inorganic / organic composite particles
A inorganic substances include (1) metal oxides, (2) metal hydroxides,
(3) metal oxide hydroxide, (4) polyvalent metal hydroxide,
(13) metal-doped EA inorganic material, or (14) another support on which EA inorganic material is applied as an electric semiconductor layer.

When an EA inorganic substance is used, its electric conductivity is 10 ³ Ω ^-1 / cm to 10 ^-11 Ω ^-1 / c at room temperature.
It is preferable to select one within the range of m. When the electric conductivity exceeds 10 ³ Ω ^-1 / cm, EA containing this
Excessive current can flow through the fluid, resulting in high power consumption as well as device overheating. 10 ^-11 Ω ^-1 / cm
If it is less than the above range, the EA effect is weak, so that a sufficient effect may not be obtained in some cases.

In the inorganic / organic composite particles, the weight ratio (%) of the EA inorganic substance forming the surface layer and the organic polymer compound forming the core is not particularly limited, but for example (EA inorganic substance): The weight ratio of the (organic polymer compound) is within the range of (1-60) :( 99-40), particularly (4-3).
0): It is preferably within the range of (96 to 70).
If the weight ratio of the EA inorganic substance is less than 1%, the EA effect of the obtained EA fluid is insufficient, and if it exceeds 60%, the specific gravity becomes large and stable dispersion of the EA particles becomes difficult to obtain, and it was obtained. An excessive current will flow in the EA fluid.

For coloring the EA particles, a dye or pigment may be included in the core, but since the color of the EA fluid mainly depends on the surface layer of the EA particles, as shown in FIG.
The surface layer 54 of the A particles is preferably colored. This can be realized by using the organic or inorganic arbitrary pigment 53 together with the EA inorganic substance 52 when forming the surface layer 54.

The inorganic / organic composite particles may contain components other than the above. Examples thereof include an antioxidant, a filler, a coupling agent, and carbon black for the core, and a charge control material such as carbon black or an amine compound for the surface layer.

The specific gravity of the EA particles is preferably close to that of the electrically insulating medium in order to stably disperse it in the electrically insulating medium. Generally, it is preferable that the specific gravity is about 1.0 to 2.0 in view of the relationship with the electrically insulating medium used. If the specific gravity difference between the EA particles and the electrically insulating medium is large,
In some cases, EA particles settle down by gravity in the medium and uniform dispersion may not be possible. From this point of view, the inorganic-organic composite particles using an organic polymer compound having a relatively small specific gravity for the core are
Even if the specific gravity of the EA inorganic material forming the surface layer is large, the specific gravity can be relatively reduced, which is advantageous. In the inorganic / organic composite particles, the specific gravity can be freely adjusted by selecting the type and ratio of the organic polymer compound and the EA inorganic material to be used.

The particle size and shape of the EA particles are not particularly limited, but spheres having a particle size of 0.1 μm to 500 μm, particularly 5 μm to 200 μm are preferable. If the particle size is less than 0.1 μm, not only is it inconvenient because the light reflectivity deteriorates and the material appears transparent, but the viscosity of the EA fluid containing a certain weight increases, and the responsiveness to the on / off change of the electric field is increased. Is lowered, and air bubbles are easily entrained, which is not preferable. When it exceeds 500 μm, the response corresponding to the on / off of the electric field becomes dull because the particle size is too large.
In addition, the dispersion stability is also reduced. The particle size of the EA inorganic material at this time is not particularly limited, but is preferably 0.0
05 μm to 100 μm, more preferably 0.0
It is 1 μm to 10 μm.

The inorganic / organic composite particles can be produced by various methods. As an example thereof, there is a method in which particles of a core body made of an organic polymer compound and fine particles of an EA inorganic material are carried by a jet stream and collided with each other. In this case, the EA inorganic fine particles collide with the surface of the core particles at a high speed,
It adheres to form a surface layer. Also, as another manufacturing method example,
There is a method in which the core particles are suspended in a gas and a solution of the EA inorganic material is atomized and sprayed on the surface. In this case, the solution adheres to the surface of the core particles, and then the surface layer is formed by drying.

A preferable example of the method for producing the inorganic / organic composite particles is a method of simultaneously forming the core and the surface layer. This method is, for example, when emulsion-polymerization, suspension-polymerization or dispersion-polymerization of a monomer or oligomer (hereinafter, simply referred to as “monomer”) of an organic polymer compound forming a core is performed in a polymerization medium. A method in which a pigment is present in the above-mentioned monomer or polymerization medium. Water is preferred as the polymerization medium, but a mixture of water and a water-soluble organic solvent can also be used, and an organic poor solvent can also be used. According to this method, the monomers are polymerized in the polymerization medium to form core particles, and at the same time, the EA inorganic fine particles and the pigment are layered on the surfaces of the core particles to coat the core particles to form a surface layer. .

When the inorganic / organic composite particles are produced by emulsion polymerization or suspension polymerization, most of the fine particles of the EA inorganic substance are combined by combining the hydrophobic property of the monomer and the hydrophilic property of the EA inorganic substance. It can be oriented on the surface of the core particles. According to the simultaneous formation method of the core and the surface layer, the EA inorganic particles and the pigment are densely and firmly adhered to the surface of the core particles made of the organic polymer compound, and the robust inorganic / organic composite particles are formed. .

The shape of the inorganic / organic composite particles used in the present invention is not necessarily spherical, but when the core particles are produced by a controlled emulsion / suspension polymerization method, the obtained inorganic / organic composite particles are The shape of the organic composite particles is almost spherical. The spherical shape is advantageous in that light can be scattered in all directions when the amount of transmitted light is adjusted, the flow viscosity of the EA fluid is reduced, and the responsiveness to electric field changes is enhanced.

Inorganic / organic composite particles produced by various methods as described above, particularly a method of simultaneously forming a core and a surface layer, generally have a surface layer in which all or a part of the organic polymer material or the production process is different. In some cases, the EA effect may not be sufficiently exerted because it is covered with a thin film of the dispersant, emulsifier or other additive used. This thin film of inert material can be removed by polishing the surface of the surface layer. Therefore, in the preferred EA fluid of the present invention, inorganic / organic composite particles whose surface is polished are used.

The surface of the inorganic / organic composite particles can be polished by various methods. For example, the inorganic / organic composite particles may be dispersed in a dispersion medium such as water and the mixture may be stirred. At this time, it is also possible to carry out by a method of mixing abrasives such as sand grains or balls into the dispersion medium and stirring with inorganic / organic composite particles, or by a method using a grinding wheel. For example, again
It is also possible to dry-stir with inorganic-organic composite particles, the above-mentioned abrasive, and a grinding wheel without using a dispersion medium.

A more preferable polishing method is a method of stirring the inorganic / organic composite particles by a jet stream or the like. This is a method in which the particles themselves are violently collided with each other in a gas phase and polished, and a preferable method in that an inert substance exfoliated from the surface of the particles can be easily separated by classification without the need for another abrasive. Is. In the above jet stream agitation, the type of equipment used for it,
It is difficult to specify the polishing conditions depending on the stirring speed and the material of the inorganic / organic composite particles, but generally 6000 rpm
It is preferable to stir with a jet stream at the stirring speed of 0.5 minutes to 15 minutes.

The EA fluid used in the present invention can be produced by uniformly stirring and mixing the above-mentioned inorganic / organic composite particles in an electrically insulating medium together with other components such as a dispersant. As the stirrer, any stirrer normally used for dispersing solid particles in a liquid dispersion medium can be used.

As the electrically insulating medium used for the EA fluid, any of those conventionally known as suitable for the EA fluid can be used. For example, diphenyl chloride, butyl sebacate, aromatic polycarboxylic acid higher alcohol ester, halophenyl alkyl ether, trans oil, chlorinated paraffin, fluorine oil, silicone oil or fluorosilicone oil, etc. Any fluid can be used as long as it has high strength, is chemically stable, and can stably disperse the inorganic / organic composite particles, and a mixture thereof can also be used.

The kinematic viscosity of this electrically insulating medium is 1 cSt.
It is preferably in the range of ˜3000 cSt. An electrically insulating medium having a kinematic viscosity of less than 1 cSt generally has many volatile components, which causes a problem in storage stability of the EA fluid, and a kinematic viscosity of more than 3000 cSt is not preferable because bubbles are less likely to escape. When a large amount of bubbles remain in the EA fluid, when electric field is applied, partial discharge may occur in a micro region in the bubbles to cause sparks, and there is a risk of insulation deterioration. From this viewpoint, the kinematic viscosity is within the range of 10 cSt to 1000 cSt,
Particularly, the range of 10 cSt to 100 cSt is particularly preferable.

This electrically insulating medium can be colored according to the purpose such as the overall color matching of the image element. For coloring, it is preferable to use a type and amount of an oil-soluble dye or a dispersible dye that is soluble in the selected electrically insulating medium and does not impair its electrical properties. The electrically insulating medium may further contain a dispersant, a surfactant, a viscosity adjusting agent, an antioxidant, a stabilizer and the like.

The concentration of the inorganic / organic composite particles in the EA fluid is not particularly limited, but is 0.5% by weight to.
It is preferably 15% by weight. If the concentration is less than 0.5% by weight, a sufficient EA effect cannot be obtained, and if it exceeds 15% by weight, the concentration is too high and sufficient transparency may not be obtained even when an electric field is applied.

Next, the general operating principle of this EA fluid will be described. FIGS. 7A and 7B show this operation principle, in which the transparent electrodes 71a-71b are electrically connected to the power source B via the switch Sw. This system is filled with an EA fluid in which EA particles 73 are dispersed in an electrically insulating medium 72. FIG. 7A shows a state in which the switch Sw is opened and the electric field is not applied to the transparent electrodes 71a-71b. In this state, the EA particles 73 are randomly dispersed and suspended in the electrically insulating medium 72. Therefore, when the light L enters from one electrode 71a side of this system, this light L
Is diffusely reflected on the surface of the EA particle 73, and when this system is observed from the incident side of the light L, it appears opaque. The color at this time is E
It matches the color of the A particle 73.

Next, as shown in FIG. 7B, the switch Sw
Is closed and an electric field is applied to the transparent electrodes 71a-71b,
The EA particles 73 interposed between the electrodes are transparent electrodes 71a-
71b are arranged in the direction perpendicular to the electrodes to form a chain 74. As described above, the mixing ratio of the EA particles 73 dispersed in the electrically insulating medium 72 is 15% by weight or less, particularly 1% by weight.
Since the content is 0% by weight or less, when these are arranged to form the chain 74, a gap in which no EA particles are present is formed between the chain and the electrode 71a.
The light L incident from the side passes through this gap and is transmitted through the system. Therefore, in this state, the system looks transparent. At this time E
The color of the A particles 73 cannot be seen.

When the switch Sw is opened again in this state, the electric field between the transparent electrodes 71a-71b disappears, so that the chain 74 collapses and the EA particles 73 disperse into the original random dispersion.
It returns to a floating state and the system becomes opaque. However, the speed of returning to the random state changes depending on the viscosity of the electrically insulating medium 72, the specific gravity difference between the electrically insulating medium and the EA particles, the temperature, the presence or absence of vibration, and the like. Therefore, as shown in Example 2, if a reference electrode and an adjacent electrode are formed on one surface of the cell and an electric field is applied between these electrodes, then the EA
Since the particles 73 form a chain (not shown) parallel to the electrode surface, they can be returned to be electrically opaque, and the transparent-opaque conversion can be performed quickly, so that the electric field response in the color display device of the present invention can be improved. Sex is significantly improved.

It goes without saying that the electric field strength applied between the transparent electrodes 71a-71b changes depending on the characteristics of the EA particles 73, but when this is expressed by a voltage, it is usually 0.1 kV / mm to 5.0 kV / It can be selected within the range of mm. When the EA particles are inorganic / organic composite particles, the range of 0.25 to 1.5 kV / mm is suitable.

Although it has been stated that the EA particles 73 form a chain by the application of an electric field, when the content of the EA particles in the EA fluid exceeds 1% by weight, as shown in FIG. Instead of the chain-like body, a plurality of chain-like bodies 74 are joined to each other to form a column 75 and are arranged.

In this column 75, the EA particles 73 of a plurality of chain-like bodies 74, 74, ... Are arranged so as to be in contact with each other while being displaced from each other, as shown in FIG. In this regard, the inventors have found that (+) and (-) dielectrically polarized individual EA particles 7
It is presumed that 3 is arranged so as to be attracted to each other at the opposite poles, and energy stability is obtained.

Therefore, when the content of the EA particles 73 is large, a large number of columns 75 are formed between the transparent electrodes 71a-71b, and as a result, the gaps between the columns have a large number of single chain states. It becomes wider than when it is formed, and the amount of transmitted light increases remarkably, resulting in higher transparency.

By the way, as described above, the particle size of the EA particles is within the range of 0.1 μm to 500 μm, preferably 5 μm.
The range of ˜200 μm is that the EA used in the present invention.
This is because the particles are functionally light-scattering particles or light-reflecting particles. As is well known, the wavelength of visible light is 380 nm to 780 nm, that is, 0.38 to 0.78 μm.
Therefore, in order to control the transmitted light by scattering or reflecting light of this wavelength, it is necessary that the particle diameter of the EA particles is at least 0.1 μm or more, preferably 5 μm or more. Become.

On the other hand, a particle size smaller than the wavelength of visible light that causes Brownian motion, for example, 5 nm to several 1
When ultrafine particles of 0 nm (about 0.005 to 0.02 μm) are dispersed in an electrically insulating medium, it may be possible to orient the ultrafine particles by an electric field, but the light transmission mechanism in that case. Is completely different from that in the above-mentioned example of the present invention, the ultrafine particles are dispersed and completely transmit light when no electric field is applied, and the ultrafine particles are oriented and scatter and attenuate light when an electric field is applied. , Will behave quite differently.

For example, the ultrafine particles of TiBaO ₄ can be considered as the ultrafine particles exhibiting the dielectric property. However, since TiBaO ₄ is a substance having a specific gravity in the range of 4 to 6 and is heavy, it is assumed that TiBaO ₄ is used. Even if an attempt is made to increase the particle size of the _four particles for the purpose of making them light-reflecting type, the particles become gravitationally settled in the electrically insulating medium due to the difference in specific gravity with the medium, and uniform dispersion cannot be achieved at all. In addition, the TiBaO
_In order to uniformly disperse the _four particles in the electrically insulating medium, an electrically insulating medium having a large specific gravity is required, but an electrically insulating medium having a specific gravity of about 4 to 6 does not exist. On the other hand, the inorganic-organic composite particles used in the present invention can be easily adjusted to have a specific gravity of about 1.2 as described above, and therefore, various commonly known electrically insulating media can be used.

Next, from the viewpoint of colorability, it is practically difficult to color the ultrafine particles, and even if they can be colored, the particle size is too small, so they are dispersed in an electrically insulating medium. It is not possible to perceptually develop the color of the generated ultrafine particles. Therefore, the on / off of the electric field cannot bring about the change between colored opacity and colorless transparency required in the present invention.

Test Example 1 An example of the EA fluid used in the present invention was tested for the relationship between the electric field strength and the change in transparency. Prepare two pieces of ITO glass with a thickness of 1.0 mm.
The TO surface was made to face inward and faced in parallel at an interval of 2 mm, and the peripheral portion was sealed with a resin sealing member to form a cell. This cell was provided with an opening so that the following EA fluid could be filled.

Titanium hydroxide (generic name; hydrous titanium oxide,
Ishihara Sangyo Kaisha, Ltd., C-II) 40 g, butyl acrylate 300 g, 1,3-butylene glycol dimethacrylate 100 g, and a mixture of a polymerization initiator, containing 25 g of tricalcium phosphate as a dispersion stabilizer.
It was dispersed in 0 ml of water, and suspension polymerization was carried out at 60 ° C. for 1 hour with stirring. The obtained product was filtered, washed with acid, further washed with water, and then dried to obtain inorganic / organic composite particles.

The obtained inorganic / organic composite particles were agitated with a jet airflow stirrer (Hybridizer manufactured by Nara Machinery Co., Ltd.) to obtain surface-polished inorganic / organic composite particles. The specific gravity of this thing is 1.157,
The average particle size was 13.7 μm. The inorganic / organic composite particles are uniformly dispersed in silicone oils of various kinematic viscosities (TSF451 series manufactured by Toshiba Silicone Co., Ltd.) so that the content ratios thereof are various weight%, and various EA fluid samples are obtained. Prepared.

The above-mentioned various EA fluids were filled in the above-mentioned cells, respectively, and the electric field strength (KV / m) applied to the ITO electrode was
m) was changed variously, at this time, the intensity of the light incident on the cell and the intensity of the light transmitted through the cell were detected by photosensors, respectively, and the comparison value was displayed in dBm as increased light. In this case, an increase of 3.2 dBm means a 2.09 times increase in optical power, and an increase of 4.2 dBm means a 2.63 times increase in optical power. The measurement results are shown in FIGS.

FIG. 10 shows the concentration (% by weight) of the inorganic / organic composite particles and the applied electric field strength (KV / m) when the kinematic viscosity of the silicone oil (electrically insulating medium) is 10 cSt.
The result of measuring the increasing light (dB) corresponding to the change of m) is shown. FIG. 11 shows that the silicone oil has a kinematic viscosity of 50 cS.
Similar test results for the case of t are shown. FIG. 12 shows similar test results when the kinematic viscosity of silicone oil is 100 cSt.

From the results shown in FIGS. 10 to 12, the tested particle concentrations were 0.25 kV / mm to 1.5 kV / m.
It can be seen that when the electric field strength is changed in the range of m, the dBm value of the increased light increases with the increase of the electric field strength in any case. That is, it was proved that the transparency of the cell increased as the electric field strength between the electrodes increased, and thereby the color matching of the color display device could be controlled. When the particle concentration is 1.0% by weight, the electric field strength is 3k.
Even with V / mm, the proportion of increased light is small. With this,
It is understood that the particle concentration is preferably 2.5% by weight or more.

FIG. 13 shows the results of measuring the increased light (dB) corresponding to changes in the kinematic viscosity of silicone oil and the electric field strength when the particle concentration was fixed at 5.0% by weight. FIG. 14 shows similar test results when the particle concentration is fixed at 7.5% by weight.

From the results shown in FIGS. 13 and 14, whether the particle concentration is 5.0% by weight or 7.5% by weight, the kinematic viscosity of the silicone oil (electrically insulating medium) is 10 cS.
It is shown that the control width of the transmitted light amount becomes maximum within the range of t to 100 cSt.

Next, a test example of the electric field response of the EA fluid will be shown. The above cell was filled with the EA fluid in which 7 wt% of inorganic / organic composite particles were dispersed in silicone oil having a kinematic viscosity of 10 cSt, and the change in the amount of transmitted light after applying an electric field was measured with time. The results are shown in Fig. 15. FIG.
5, the electric field was applied about 1 second after the start of measurement.

From the results shown in FIG. 15, it is clear that the amount of transmitted light of this EA fluid starts to increase immediately after the electric field is applied, reaches its maximum in 3 to 4 seconds, and then stabilizes.

FIG. 16 shows the relationship between the amount of transmitted light and the wavelength when the amount of transmitted light is measured using an EA fluid in which 4% by weight of blue colored EA particles are added to silicone oil having a kinematic viscosity of 10 cSt. . The coloring of the EA particles depends on the amount of the EA inorganic substance that constitutes the surface layer of the EA particles when the EA particles are manufactured.
It was carried out by substituting the blue pigment for weight%. In the figure, the curve indicated by E = 0 kV shows the transmission wavelength spectrum when no electric field is applied, and the curve indicated by E = 2 kV is
The transmission wavelength spectrum when a potential of 2 kV is applied to the electrodes is shown.

As is clear from the comparison of both curves in FIG. 16, the blue EA fluid that transmits a large amount of blue light having a short wavelength when no electric field is applied transmits light in a wide wavelength range when an electric field is applied. It is clear that the color changed from blue to colorless and transparent.

In FIG. 17, a dimethyl silicone oil containing 0.1% by weight of a blue dye was used as an electrically insulating medium, and the amount of transmitted light of this electrically insulating medium alone (without EA particles) was measured. The transmitted light spectrum in the case is shown. The electrically insulating medium is a medium that looks pale blue to the naked eye. In FIG. 17, as is clear from comparison between the light source spectrum and the medium spectrum, it is clear that light is absorbed in a portion other than the spectrum showing blue of a short wavelength, and from this, the electrically insulating medium is Since a large amount of blue is transmitted, it is clear that the electrically insulating medium is blue.

FIG. 18 shows the amount of transmitted light measured for an EA fluid in which 5% by weight of yellow colored EA particles were dispersed in an electrically insulating medium of dimethyl silicone oil containing 0.1% by weight of a blue dye. The transmitted light spectrum at the time of performing is shown. The means used for coloring the inorganic / organic composite particles is the same as in the above example, and a yellow pigment was used this time.

FIG. 18 shows the light source spectrum and E = 0 kV / m.
The transmitted light spectrum in the case of m and the transmitted light spectrum in the case of E = 1 kV / mm are shown, respectively. From this figure, it can be seen that what was opaque yellow-green, which is a mixed color of blue and yellow when no electric field was applied, changed to a blue transparent state that was almost colorless and transparent when an electric field was applied. Thus, it has been revealed that various variations of colors can be applied to the EA fluid, and the colors can be changed to a transparent state of a different color, a transparent state of the same color, or a colorless transparent state.

FIG. 19 shows the image element of the second embodiment shown in FIG. 4, in which one transparent surface 61a has a comb-shaped transparent reference electrode 62a and transparent adjacent electrodes 62c adjacent to each other, which are nested in each other. In a cell having a transparent electrode 61b formed on the other transparent surface 61b of the cell, a silicone oil having a kinematic viscosity of 10 cSt is used as an electrically insulating medium,
Inorganic / organic composite particles colored blue are used as EA particles 4
Fill with EA fluid added by weight% and switch 63
The effect when switching is shown.

The line in FIG. 19 shows the transmitted light spectrum when the voltage regulator 64 is adjusted to 0 potential and no electric field is applied to any of the electrodes. The line operates the voltage regulator 64 and the changeover switch 63 to operate the reference electrode 6
The transmitted light spectrum when an electric field of 2 kV is applied between 2a-opposing electrode 62b is shown. The line switches the changeover switch 63 to change the reference electrode 62a-adjacent electrode 6
The transmitted light spectrum when an electric field of 2 kV is applied between 2c is shown.

In FIG. 19, the line shows that the EA particles randomly float and disperse when no electric field is applied, and are opaque in the measurement wavelength band. The line shows that by applying an electric field between the reference electrode 62a and the counter electrode 62b, the EA particles were arranged perpendicularly to the transparent surface 61a, and as a result, light was transmitted in a wide wavelength band.
The line indicates that when an electric field was applied between the reference electrode 62a and the adjacent electrode 62c on the same plane, the EA particles were arranged parallel to this plane, resulting in blocking the transmission of light. That is, it is understood that the light transmittance can be rapidly changed by the switching operation of the electrodes.

In Tables 1 and 2, the silicone light (electrically insulating medium) having a kinematic viscosity of 50 cSt was used, the concentration of EA particles was set to 5.0% by weight, and the transmitted light when the electric field strength was changed was set to each wavelength. The measurement results are shown in.

[0085]

[Table 1]

[Table 2]

From the results shown in Table 1 and Table 2, when the color tone control is performed using the color display device according to the present invention, the range of 400 to
Uniform light transmission was obtained in a wide wavelength range of 1100 nm, and it became clear that the present invention enables uniform color tone adjustment in a wide light wavelength range. Since the wavelength range of visible light is usually set to 480 nm to 780 nm, the device of the present invention provides uniform transmitted light control performance in almost the entire visible light wavelength range and in the infrared region having a longer wavelength. It became clear to have.

[0087]

In the color display device of the present invention, the transparent reference electrode and the counter electrode are formed on the inner sides of the two opposite transparent surfaces, and the cells contain EA particles in the electrically insulating medium. Since the EA fluid is filled, the cells are laminated in three layers or more, and the EA particles in the EA fluid filled in each cell have different opaque colors,
When an electric field whose intensity is adjusted is applied to each of these cells, full color due to reflected light can be expressed. If a reference electrode and an adjacent electrode are formed on one surface of each of these cells, and a means for switching and applying a voltage between these electrodes or between the reference electrode and the counter electrode is provided, this electrode switching and Since the light transmittance of the EA fluid is immediately adjusted between transparent and opaque by adjusting the electric potential, a full-color reflective color display device having good electric field response can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view and a circuit diagram of an image device according to an embodiment of the present invention.

FIG. 2 shows E contained in the EA fluid used in the example of FIG.
Sectional drawing of A particle.

FIG. 3 is a sectional view and a circuit diagram showing one embodiment of the embodiment of FIG.

FIG. 4 is a development view and a circuit diagram showing an electrode configuration of a cell in another embodiment of the present invention.

5 is a cross-sectional view showing one operation mode in the embodiment shown in FIG.

6 is a sectional view showing another operation mode in the embodiment shown in FIG.

7A and 7B are a cross-sectional view showing the behavior of the EA fluid used in the present invention when no electric field is applied, and a cross-sectional view showing the behavior when an electric field is applied.

FIG. 8 is a cross-sectional view showing one behavior of an EA particle in an EA fluid used in the present invention when an electric field is applied.

9 is a cross-sectional view for explaining the principle of the behavior shown in FIG.

FIG. 10 is a graph showing changes in the amount of transmitted light when the kinematic viscosity of the electrically insulating medium is fixed to 10 cSt and the EA particle concentration and the applied electric field strength are changed for the EA fluid used in the present invention.

FIG. 11 is a graph showing changes in the amount of transmitted light when the kinematic viscosity of an electrically insulating medium is fixed to 50 cSt and the concentration of EA particles and the applied electric field strength are changed for the EA fluid used in the present invention.

FIG. 12 is a graph showing changes in the amount of transmitted light when the EA fluid used in the present invention has a kinematic viscosity of an electrically insulating medium fixed to 100 cSt and the EA particle concentration and the applied electric field strength are changed.

FIG. 13 shows an EA fluid used in the present invention.
The graph which shows the light amount change of the transmitted light when the A particle concentration is fixed to 5.0% by weight and the kinematic viscosity of the electrically insulating medium and the applied electric field strength are changed.

FIG. 14 shows the EA fluid used in the present invention.
The graph which shows the light amount change of the transmitted light when the A particle concentration is fixed to 7.5 weight% and the kinematic viscosity of the electrically insulating medium and the applied electric field strength are changed.

FIG. 15 is a graph showing an example of measurement of electric field response of a cell in one example of the present invention.

FIG. 16 is a graph showing a transmitted light spectrum of the cell in one example of the present invention when no electric field is applied and when the electric field is applied.

FIG. 17 is a graph showing a transmitted light spectrum of an electrically insulating medium used in an example of the present invention.

FIG. 18 is a graph showing transmitted light spectra of an EA fluid in which yellow colored EA particles are dispersed in a blue colored electrically insulating medium when no electric field is applied and when an electric field is applied.

FIG. 19 is a schematic diagram of the device of Example 2, in which no electric field is applied,
The graph which shows a transmitted light spectrum when an electric field is applied to a counter electrode and when an electric field is applied to an adjacent electrode.

[Explanation of symbols]

1 ... Image element, 10, 20, 30 ... Cell, 11a, 11
b, 21a, 21b, 31a, 31b ... Transparent surface, 12
a, 12b, 22a, 22b, 32a, 32b ... Transparent electrodes, 13, 23, 33 ... EA particles, 14, 24, 34 ...
EA fluid, 51 ... Core body, 52 ... EA inorganic substance, 53 ... Pigment, 54 ... Surface layer.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazuya Akashi 1-5-1, Kiba, Koto-ku, Tokyo Within Fujikura Ltd. 206

Claims (3)

[Claims] 1. A cell having two transparent opposite surfaces, wherein a transparent reference electrode is formed inside one of the transparent surfaces and a transparent counter electrode is formed inside the other transparent surface. , An electro-sensitive optical functionality in which at least three layers are laminated so that respective transparent surfaces are overlapped, and solid particles having an electric field arrangement effect are contained in an electrically insulating medium between both of the electrodes. The solid particles in the electro-sensitive optical functional fluid composition filled in the fluid composition and filled in the respective cells are colored in different opaque colors, and the reference electrode and the counter electrode of each cell are formed. A color display device provided with a means for applying an adjustable electric field between and. 2. A transparent adjacent electrode that is adjacent to the reference electrode is formed on a transparent surface of the reference electrode of each cell, and the transparent adjacent electrode is formed between the reference electrode and the adjacent electrode or between the reference electrode and the counter electrode. The color display device according to claim 1, further comprising: a means for switching and applying an electric field between and. 3. The inorganic-organic composite particles, wherein the solid particles are inorganic-organic composite particles formed by a core body made of an organic polymer compound and a surface layer containing an inorganic substance having an electric field alignment effect and a dye. 2. The color display device according to item 2.