JPS6213667B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display device that modulates and controls external light by electrically changing reflectance and transmittance to display numbers, characters, figures, images, etc.

On the surface of a porous body having a large number of fine openings exposed on at least one surface, preferably having fine pores, gaps, etc. through which liquid can penetrate from one surface to the other surface, the above-mentioned A display structure is formed by providing a depressed portion including a plurality of openings and coating a liquid-permeable and translucent electrode, and impregnating the display structure with a liquid material, The present inventor has already proposed a display device based on the principle of controlling the reflectance or transmittance of the porous body by electrically controlling the liquid impregnation rate of the surface containing the porous body.

The above-mentioned display device controls the liquid impregnation rate of the depressed portion by electroosmosis, for example, and substantially controls the transmittance and reflectance of external light. By selectively making the surface opaque and preventing unnecessary light transmission or reflection, a display device with a high contrast ratio can be obtained.

The depressions have shapes such as dots, lines, short fences, and other shapes, and their cross sections become narrower as they get deeper into the porous body. be done.

The porous body is made of a dielectric material that is transparent, opaque, or colored, and the liquid material to be impregnated is preferably transparent, and when the dielectric material is transparent, the refractive index is approximately equal. To be elected. When the porous body is made of a translucent dielectric material, it is useful as a transmission or transmission projection or reflective display device, and when the porous body is made of an opaque or colored dielectric material, it can be used as a reflective display device. . As the porous material, plastic, glass, porcelain, metal oxide materials, etc. can be used, and the porous material has a large number of fine openings exposed on at least one surface, and is at least as deep as the depression provided. It is sufficient that there are fine holes, gaps, etc. that allow the liquid material to penetrate into the inside of the container.

Typically, the porous material used is a microporous membrane filter made of cellulose ester that allows liquid to pass through from one surface to the other. Therefore, in consideration of the heat resistance of the membrane filter, as the liquid-permeable, light-transmitting conductive film, a cuprous iodide film is formed by vacuum-depositing copper and iodizing it with an iodine solution.

In order to maintain liquid permeability, the iodide primary conductive film is usually 80 Å so as not to block the fine openings on the surface of the porous material, and to maintain good translucency.
It is made extremely thin.

However, as described above, there are still points to be improved in the display structure.

The first problem is the surface resistance of a liquid-permeable, light-transmitting conductive film. For example, the sheet resistance of the above-mentioned conductive film made of cuprous iodide is often about 10KΩ/portion, and when configuring a wide screen display device,
The resistance is too high to be used as an electrode. Also,
The conductive film is easily damaged during operation.

The second problem is that the light transmittance of the depressed portion decreases. In the case of a transmission projection display, the dielectric material forming the porous body and the impregnated liquid material are chosen to be transparent and to have approximately equal refractive index. Therefore,
The depressed portion is transparent and exhibits high light transmittance when no voltage is applied. However, when a conductive film made of cuprous iodide is provided, the light transmittance decreases due to the mismatch in the refractive index, and the image is colored brown when projected. For example, when the porous body is made of cellulose ester, its optical refractive index is in the range of 1.47 to 1.51, whereas cuprous iodide has an extremely high optical refractive index of about 2.34, which is a significant mismatch in refractive index.

In view of the above, the present invention aims to provide an improved and even new display structure and display device that solves the first and second problems mentioned above.

A display structure according to the present invention is characterized in that an electrode made of conductive ink is selectively coated and adhered to the surface side of the porous body, leaving the above-mentioned depressed portion; This is in a display device that uses this.

Hereinafter, aspects of the present invention will be described based on Examples. FIG. 1 is a partial perspective view of an embodiment of a display structure according to the present invention. For convenience of explanation, similar parts are indicated by the same numbers not only in this example but also in the following examples, and each part is enlarged as appropriate, so the relative dimensions thereof do not necessarily match the explanation in the main text. It is assumed that the Further, although the various inks applied are partially impregnated into the porous surface or the coated surface, they are shown as a laminate.

In the figure, reference numeral 100 denotes a display structure, in which conical or truncated cone-shaped point depressions 120 are provided on the surface of a membrane-like porous body 110. The porous body 110 can be made of fibers such as plastic or glass, sintered bodies of glass particles, porcelain, etc., but the most preferred is a microporous membrane filter made of cellulose ester such as nitrocellulose, cellulose acetate, or a mixture thereof. (Micro-
porous membrane filter). Porous body 1
Reference numeral 10 is transparent when configuring a transmissive display device, and is black or colored or opaque when configuring a reflective display device.

The thickness of the porous body 110 made of a microporous membrane filter is, for example, 40 to 200 microns, and the average pore diameter substantially penetrating from one surface to the other is 0.1 to 1 micron, with openings on both sides. It has micropores 111 with a porosity of about 50 to 80%. Point-like depression 120
For example, the average diameter at the surface portion is 15 to 30 microns, the depth is 10 to 25 microns, and includes a plurality of micropores 111. The average diameter of the tip of the sinkhole is preferably 3 microns or less, not only in this example but also in the case described below. A large number of depressions 120 are arranged at intervals of about 254 microns (100 pieces/inch) to 63.5 microns (400 pieces/inch).

The depressions 120 are formed by etching a copper plate for letterpress printing into the desired shape of the depressions 120, such as dots, short fences, or lines, and applying pressure or heat to the microporous membrane filter that forms the porous body 110. It can be made using a so-called embossing method that uses pressure welding.

In this way, copper is deposited on the surface of the porous body provided with the depressed portion 120, and then immersed in an iodine solution,
Liquid-permeable transparent conductive film 130 with a thickness of about 80 Å
be coated with. A depression 120 is formed on the conductive film 130.
An electrode 140 made of conductive ink is selectively applied and adhered to the electrode 140, except for the electrode 140 made of conductive ink.

The display structure as in this example is impregnated with a liquid material made of a derivative such as silane, siloxane, or naphthalene containing at least one of alkyl and alkoxy functional groups. Therefore, conductive ink 1
40 must be selected so as not to be attacked by the liquid material.

Furthermore, when the porous body 110 is made of a plastic material such as cellulose ester, it is necessary to prevent it from being dissolved or corroded by the solvent (diluent) of the conductive ink.

As a result of considering the above, we found that conductive ink 1
Although cellulose esters such as nitrocellulose and cellulose acetate can be used as the main binder in 40, the best main binder for almost all purposes has been polyamide resin. Moreover, the best ink solvents were alcohols such as heptyl alcohol and octyl alcohol. Ink 1
The conductive particles that provide conductivity to the sinkhole 40 are electrochemically stable and opaque except for the sinkhole 120.
Graphite was best for utilizing effective electrical light control of sinkhole 120, and silver was best as far as electrical conductivity was concerned.

Therefore, the conductive particles are configured to contain at least one of graphite and silver particles. The selective application and adhesion of the conductive ink 140 onto the translucent conductive film 130, leaving the depressed portions 120, is carried out by transfer from a roller that has applied solvent-diluted conductive ink to the surface, as will be described later. and drying several times. Conductive ink 140 in display structure 100 thus obtained
The sheet resistance is less than 1Ω/mouth when the conductive particles are silver,
In the case of graphite, the resistance is 100 to 200Ω/hole, which is much lower than the 10KΩ/hole when using only the transparent conductive film 130, and a good electrode can be formed.

However, the electrode 140 made of conductive ink is opaque. Therefore, when the display structure 100 is used as a transmissive display device, the opaque electrode 140 blocks light transmission except for the recessed portion 120. The transmitted light is then limited to the recessed portion 120 where effective electrical control is performed. Therefore,
In combination with the low resistance of the electrode 140 made of conductive ink and the effect of blocking transmitted light, it is possible to realize a display device that is far more stable and highly sensitive than conventional display structures.
Regarding the electrochemical stability and opacity of the conductive ink 140 when impregnated with liquid, the one using graphite particles as the conductive particles was the best. However, those using silver particles are far superior to the above as far as conductivity is concerned. However, if the liquid material is not chosen properly, it tends to be electrochemically attacked, and this problem, combined with opacity, can be ameliorated by incorporating graphite particles. Therefore, it is desirable that the conductive ink contains at least graphite particles selected from graphite and silver particles as conductive particles.

FIG. 2 is a partial perspective view of another embodiment of the display structure according to the present invention. In this example, it is particularly suitable for use as a transmissive display device.
In order to more completely block light transmission in areas other than the recessed part 120, opaque ink 150 is selectively applied to the recessed part 120, and then conductive ink 140 is applied thereon. Opaque ink 1
Ink No. 50 uses carbon black fine powder as an opaque material, and its main binder is preferably polyamide resin for the same reason as in opaque ink No. 140, and alcohols such as heptyl alcohol and octyl alcohol are preferred as the ink solvent. , selective adhesion can be achieved by transfer from a roller, leaving the depression 120 behind.

Usually, the conductive particles of the conductive ink 140 include scaly graphite particles with an average particle size of 4.5 to 10μ;
Relatively large conductive particles such as silver particles having a particle size distribution of about 0.2 to 10 μm (peak particle size of 0.5 to 3 μm) or a mixture thereof are used to increase conductivity. Therefore, when only the conductive ink 140 is applied, light transmission may not be completely blocked. However, carbon black powder can be made extremely small in particle size to less than 1 micron. Therefore, compared to the above-mentioned conductive ink, it has a much higher shielding rate and is excellent in light blocking properties. Furthermore, the presence of the opaque ink 150 allows for much better adhesion than directly coating the surface of the translucent conductive film 130, and the synergistic effect with the conductive ink 140 provides light blocking properties. also shows excellent effects.

FIG. 3 is a partial perspective view of another embodiment of the display structure according to the present invention. In this example, unlike the previous embodiment, the conductive film 130 is not present in the recessed part 120 at all, and the recessed part 120 serves as an electrode.
Conductive ink 140 is only selectively applied to all but zero.

In this example, the depression 120 is of a short fence type, but as in FIGS.
I do not care. In the case of a short fence type or a linear shape, the width of the open surface is, for example, 25 to 50 microns, the depth is 20 to 50 microns, and the width of the light end is sharp, within 3 microns. In the case of a short fence type, the length can be freely selected as appropriate, and the lengths do not necessarily have to be the same. The conductive ink 140 is constructed in the same manner as described with reference to FIGS. 1 and 2, and is selectively transferred and deposited by transfer from a roller except for the recessed portions 120.

Similar to FIGS. 1 and 2, the display structure 100 in this example is provided with a support having an electrode on the surface opposite to the surface to which the conductive ink 140 is applied, and
The display structure 100 is impregnated with a liquid material and operated by applying a voltage between the conductive ink 140 and the support side electrode. Even if there is no electrode such as the conductive film 130 in the depressed portion 120, a voltage is effectively applied within the depressed portion 120 due to the end effect of the conductive ink 140, and the electroosmotic phenomenon causes the depressed portion 12 to
The liquid impregnation rate of the 0-side slope 121 is controlled, and the light reflectance and light transmittance can be substantially electrically controlled.

Thus, according to this embodiment, the transparent electrical film 130
Since this is not necessary, manufacturing is easier than in FIGS. 1 and 2, and furthermore, by using the conductive ink 140, an electrode with low resistance can be constructed. Depression part 12
Since the conductive film 120 is not present in the 0, the movement of the liquid on the side slope 121 is not inhibited. Furthermore, the above-mentioned mismatch in refractive index between the material forming the porous body 110 and the impregnated liquid material and the transparent conductive film 130 is eliminated. Therefore, the porous body 110 was made of a transparent dielectric material and impregnated with a liquid material having a refractive index substantially equal to that of the porous body 110. In a transmission type display device, the light transmittance is increased, coloring to brown can be prevented, and a bright and clear transmitted light image can be displayed.

FIG. 4 is a partial perspective view of another embodiment of the display structure according to the present invention, and FIG. 5 is a partial perspective view of a display device according to the present invention using the display structure 100 of FIG. This is a diagram showing an embodiment, and is shown in a vertical cross-sectional structural view taken along line A-A' in FIG. 4.

In this example, the recessed portion 120 is illustrated as having a dot shape. Of course, it can also be configured in the form of a short fence or in the form of a line (parallel grid). The depressed portion 120 is the display portion 14
1' and 142' are provided in a limited manner depending on the pattern. The opaque ink 150 is applied to the entire surface of the porous body 110 by transfer from a roller, leaving the depressed portions 120. Conductive ink 141, 142
are the electrode extension parts 1 on the opaque ink 150.
Display portions 141' and 14 including 41'' and 142''
2', leaving recesses 120 selectively applied by transfer from a roller (offset printing), which are insulated from each other so that a voltage can be applied selectively. In this way,
The display structure 100 is installed on a support plate 300 made of transparent glass having a transparent electrode 300 made of tin oxide or the like deposited on its surface.

The example shown in FIG. 5 shows a case where a transmission type display device is configured, and as the porous body 110, for example, as described above, a microporous membrane filter made of nitrocellulose, cellulose acetate, or a cellulose ester mixture thereof is used. do.
The display structure 100 is impregnated with an electro-osmotic liquid material 400 having a refractive index substantially equal to that of the material forming the porous body 110 (indicated by multiple points for convenience of explanation) to match the refractive index. Measure. The porous body 110 is made of nitrocellulose (refractive index nd
1.51), the liquid material 400 is, for example, nd
1.51 dimethyltriphenyltrimethoxysiloxane ( However, φ is a phenyl group) In the case of cellulose acetate (nd1.47), nd1.47
phenyltrimethoxysilane (C ₆ H ₅ Si
(OCH ₃ ) ₃ ), or in the case of a mixture of nitrocellulose and cellulose acetate (1.41<nd<1.51), the above-mentioned liquid materials should be mixed appropriately, or α-methylnaphthalene (nd1.61) should be used. The refractive index matching of 1.47<nd<1.51 is achieved by appropriately mixing a high refractive material such as silane with a low refractive material such as phenyltrimethoxysilane.

As described above, the porous body 110 impregnated with the liquid material 400 becomes transparent. Therefore, the conductive ink 141 short-circuited with the electrode 300 by the conducting wire 50n
In order to wet the liquid material 400 up to the side slope 121' of the recessed part 120 by capillary action, the bright transmitted output light L _2T is transmitted to the input external light L ₁ at the recessed part 120. arise.

On the other hand, in the area where the conductive ink 142 is applied, a negative voltage V _B is applied to the electrode 300 via the conductive wire 502.
is applied. In the above configuration, the porous body 1
10, the liquid material 400 electroosmoses toward the negative electrode.

Therefore, the liquid material 400 on the slope 121'' on the side of the depression 120 is drawn into the interior as illustrated in the figure. Therefore, the impregnation rate of the liquid material 400 on the slope 121'' on the side of the depression 120 decreases, and the air is absorbed by that amount. This causes a refractive index mismatch. Therefore, due to the presence of the rough porous side slopes of the porous body 110, the input external light _L1 is scattered, and the transmitted output light _L2B is reduced. Opaque ink 1 is applied to the area other than the depressed portion 120.
50 and further the presence of conductive ink 142 prevents light transmission.

The transmitted light L _2B is limited to that through the recessed portion 120, allowing effective electrical light control.
For example, in the above configuration, the thickness of the porous body 110 is
When it is 120 microns, the voltage V _B is 100 to 150V,
A contrast ratio of about 20, ie, L _2T /L _2B , is obtained. When V _B is reduced to zero, the side slope 121'' is wetted by capillary action and instantly returns to the same light transmitting state as the conductive ink 141. When used as a reflective display device, the electrode 300 is The conductive ink may be constructed to be light reflective, such as an aluminum vapor-deposited electrode. In this case, the conductive ink 141 part appears black, while the 142 part appears white due to the scattering and reflection of external light. Forming the porous body 110 When the dielectric material is black or another color, the color of the dielectric material is displayed in the conductive ink 141 part, and white reflective display can be performed in the 142 part.

FIG. 6 is a vertical cross-sectional structural view of an embodiment of the display structure according to the present invention, which is a further improvement of the display structure shown in FIG. In addition, as in Fig. 5, A- in Fig. 4
The cross-sectional structure of the portion corresponding to A' is shown.

The purpose of this embodiment is to display a desired pattern more clearly and uniformly in the apparatus shown in FIG. What is different from FIG. 4 is that the conductive ink 141, 142 is selectively deposited leaving the recessed portion 120, and the opaque ink 150 is selectively deposited in the area where conductive ink is not present. It is coated with an oil repellent 160.
The oil repellent 160 is not chemically or electrochemically attacked by the liquid material 400 used, and exhibits good oil repellency, and the diluting solvent of the oil repellent 160 prevents the porous body 110 and the opaque material. ink 15
0. It is desirable that the conductive inks 141 and 142 are at least not significantly attacked. When the porous body 110 is a cellulose ester and the liquid material 400 is as described above, a fluorocarbon-based anion, a cation, or a neutral surfactant can also be used, but they are not necessarily strong electrochemically.

The most suitable for general purpose are, for example, poly-111, 111
- Fluorine-based polymers such as pentadecafluorooctyl methacrylate are dissolved in xylene hexafluoride or fluorocarbon (Freon)-based solvents.

The surface tension of the polymer coating is about 11 dynes/cm, which is extremely low compared to the liquid material 400, and it has strong oil repellency as well as water repellency, and is not soluble in most solutions. The solvent does not dissolve cellulose ester or polyamide resin. The display structure 100 shown in FIG. 6 was obtained by transfer-coating a coating agent made of the above-mentioned polymer solution by, for example, a roller coating method and drying the solvent at an appropriate temperature of about 60°C. .

When the display structure 100 in FIG. 6 is configured as a display device in the same way as in FIG. 5 in this way, the oil repellent 16
0 can prevent the liquid material 400 from flowing out or moving in the direction along the surface of the display structure 100 on the side having the depressed portion 120. Therefore, the distribution of the impregnated amount of the liquid material 400 in the two-dimensional direction in the plane direction is kept almost constant, and a pattern can be displayed with clear, uniform, and stable motion.

Furthermore, in the case of transparent display, oil repellent 160
Therefore, the applied portion is not wetted by the liquid material 400, causing a refractive index mismatch, and input external light is scattered and diffusely reflected, making it substantially opaque to transmitted light.

Therefore, the opaque ink 150 is omitted and the conductive ink 141, 142 is directly applied to the surface of the porous body 110.
may be applied, and then the oil repellent 160 may be applied. In this case, the oil repellent is directly applied to the areas where the conductive ink is not present.

4 to 6 have been explained above using a 2-segment display device as an example, but in order to configure a numeric display device, it is configured into 7 segments based on the same concept, and voltage is selectively applied to each segment. It is sufficient to perform a pulse operation with voltage polarity such that the liquid material 400 is sucked into the porous body 110.

FIG. 7 is a process diagram showing an embodiment of the method of applying conductive ink according to the present invention in comparison with the display structure shown in FIGS. 4 and 6.

In FIG. A, 110 is a microporous membrane filter made of cellulose ester as described above, and its surface is pre-embossed with dots, lines, short lines, etc., in predetermined positions corresponding to a predetermined display pattern. A fence-like depression 120 is provided. Furthermore, black opaque ink 150 is applied to the depressed portion 120, leaving it in place. This porous body 110
is placed on a support plate 610 made of flat glass or the like,
Adhesive tape 620 such as vinyl tape is attached to both ends of the tape.
and fix it on the support plate 610.

Next, as shown in Figure B, a printing roller 70 made of rubber or the like is applied.
0, conductive ink diluted with solvent 80
0 is very thinly applied to the electrode extensions 113, 114 and a shape corresponding to the desired pattern to be displayed, aligned, and quickly transferred before the solvent evaporates. After repeating this process 2 to 3 times, it is dried at an appropriate temperature of about 60°C to evaporate the solvent. This forced solvent evaporation renders the deposited conductive ink porous, contributing to favorable operation. If the resistance value is high, repeat the above operations and steps until the desired resistance value is obtained.
The diluted conductive ink 800 on the roller 700 is
The recessed portion 112 and the non-display portion 1112 are selectively transferred. The hardness of the roller 700 is important for such precise transfer. If it is too soft, it will be applied to the inside of the recessed part 120, while if it is too hard, it will damage the porous body 110 or inhibit the uniformity of transfer. A good roller was a rubber roller with a hardness of 30 degrees.

The above has described transfer by manual roller coating, but offset printing using a printing machine is effective for more precise and mass production. The conductive ink uses conductive particles made of silver, graphite, or a mixture thereof as described above, and uses polyamide resin as the main binder. Diluent solvents are relatively slow to evaporate when using manual methods;
A mixed solvent of heptyl alcohol and octyl alcohol is used.

When using an offset printing machine, hexyl alcohol, amyl alcohol, etc., which evaporate relatively quickly, are used. The preferred ink viscosity is about 150 to 300 poise.

The porous body 110 selectively coated with the conductive ink as described above is removed by peeling off the tape 620.
By appropriately cutting off unnecessary parts, a completed display structure 100 as shown in Figure C can be obtained. No conductive ink is applied to the non-display portion 112, but electrodes 141 and 142 made of conductive ink that are connected to the electrode extension portions 113 and 114 and insulated from each other are applied.

Note that when silver particles are used as conductive particles in a conductive ink, the silver particles may be chemically attacked. Therefore, overcoating with so-called electrode protection ink is required. Plastic materials are suitable for the overcoating process. For example, polyamide resin is dissolved in alcohol in the same manner as described for the conductive ink, and the electrode 141,
Similarly, the roller 7 is applied on top of the conductive ink such as 142.
By transferring from 0.00, it is possible to selectively adhere the recessed portion 120 while leaving the recessed portion 120. Further, the above-mentioned oil repellent 160 can be similarly applied by transfer from the roller 700. In any of these cases, forced evaporation of the solvent by heating to about 60° C. is preferable to form each porous layer.

FIG. 8 is a partial perspective view of another embodiment of the display structure according to the present invention, showing an example of overcoating with the electrode protection ink. Further, a linear example of the recessed portion 120 consisting of a parallel lattice is shown. 140 is a conductive ink containing silver particles and graphite particles, and on top of that,
Electrode protection ink 170 made of polyamide resin etc.
is applied by transfer from a roller.

In this case, the electrode protection ink 170 can be replaced with the opaque ink 150 described above. In this case, the opaque ink 150 also has the role of protecting the electrodes and blocking the transmission of light from unnecessary parts, and has the advantage of being simplified in terms of manufacturing technology. Therefore, although it has been explained up to now that the opaque ink 150 is always inserted between the conductive ink 140 and the porous body 110, it may also be provided on the conductive ink 140 as in this example. Moreover, it can be provided so that it exists between the conductive ink 140 and the porous body 110, and also above the conductive ink. The same applies to the case of FIG. 4 described above, and the above can be similarly applied to all embodiments.

Electrode protection ink 170 or opaque ink 150 is applied to the electrode extension portion 115 for electrical contact.
is not applied. After making electrical contact with the outside using a lead wire or the like, apply 170 or 150 if necessary.

As described above, the present invention is a display device in which electrodes made of conductive ink are selectively coated and deposited on the surface of a porous body while leaving depressions, and it is possible to have a low-resistance electrode structure. At the same time, it is possible to realize a display device that is extremely easy to manufacture, can increase the transmittance of the depressed portion, and can provide stable and clear display, and is extremely useful industrially.

Obviously, various implementations and modifications may be made without departing from the spirit of the invention. The present invention is intended to include these as well.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of one embodiment of the display structure according to the present invention, FIG. 2 is a partial perspective view of another embodiment of the display structure according to the present invention, and FIG. 3 is a partial perspective view of a display structure according to the present invention. FIG. 4 is a partial perspective view of still another embodiment of the display structure according to the invention; FIG. 5 is a partial perspective view of still another embodiment of the display structure according to the invention; FIG. FIG. 6 is a diagram illustrating a longitudinal cross-sectional structure and a power supply system of an embodiment of a display device according to the present invention using a display structure according to the present invention. 7A, B, and C are diagrams showing the manufacturing process of the display structure according to the present invention, and FIG. 8 is a longitudinal cross-sectional structural view of the display structure according to the present invention. FIG. 2 is a vertical cross-sectional structural diagram of one embodiment. 100...Display structure, 110...Porous body, 12
0... Concave portion, 130... Liquid-permeable transparent conductive film, 140, 141, 142... Electrode made of conductive ink, 150... Opaque ink, 160... Oil repellent, 170... Electrode protective ink, 200... Supporting group material, 300...electrode, 400...liquid material, 501,
502... Conductor wire, 610... Support plate, 700... Roller, 800... Ink material.

Claims (1)

[Scope of Claims] 1. A porous body surface having a large number of fine openings exposed on at least one surface is provided with a depressed portion including a plurality of the openings, and is impregnated with a liquid material. A display structure is provided in which the liquid impregnation rate of the surface of the porous body including the depressed portion is electrically controlled, and an electrode made of conductive ink is selected while leaving the depressed portion on the surface side of the porous body having the depressed portion. A second electrode is installed on the side opposite to the surface to which the electrode made of conductive ink of the display structure is adhered, and the display structure is impregnated with a liquid material, and the display structure is impregnated with a liquid material. 1. A display device characterized in that a voltage is applied between an electrode made of ink and a second electrode to control the liquid impregnation rate at least in the depressed portion. 2. A display device according to claim 1, characterized in that an electrode made of conductive ink is directly deposited on the surface of the porous body, leaving a depressed portion. 3. In the display device according to claim 1, in the display structure, opaque ink is selectively deposited on the surface of the porous body having a depression, leaving the depression. A display device characterized in that an electrode made of conductive ink is selectively deposited on the top thereof, leaving the recessed portion. 4 In the display device according to claim 1, the display structure has a translucent and liquid-permeable conductive film coated on the surface of the display structure including the inner surface of the recessed part, and this A display device characterized in that an electrode made of conductive ink is selectively deposited on a conductive film, leaving the recessed portion. 5. In the display device according to claim 1, the display structure has a translucent and liquid-permeable conductive film coated on the surface of the display structure including the inner surface of the recessed part, and , Opaque ink is selectively deposited on this conductive film, leaving the recessed portions, and electrodes made of conductive ink are selectively deposited on the opaque ink, leaving the recessed portions as well. A display device characterized by: 6 Opaque ink is selectively deposited on the surface of a porous body having depressions at positions corresponding to one or more patterns to be displayed, leaving the depressions, and a single object made of conductive ink. Alternatively, a plurality of electrodes are selectively attached to positions corresponding to a single pattern or a plurality of patterns to be displayed, respectively connected to the electrode lead-out portions, and leaving the recessed portions. Characteristic Claim No. 3
The display device according to item 1 or 5. 7. The display device according to claim 2, wherein opaque ink is selectively applied onto the electrode made of conductive ink except for the recessed portion. 8. On the surface of a porous body having depressions in portions corresponding to one or more patterns to be displayed, so as to include respective portions corresponding to the patterns,
In addition to being connected to the electrode extension part, one or more electrodes made of conductive ink are selectively applied leaving the depression part, and further, at least a part of the electrode extension part and the depression part are attached. 2. The method according to claim 1, wherein an opaque ink is applied over the electrode made of the conductive ink and the surface of the other porous body to which the electrode is not applied. Display device. 9. The display device according to claim 1, wherein the electrode made of conductive ink is opaque. 10. The display device according to claim 9, wherein the conductive ink contains conductive particles of at least one of graphite and silver. 11. The display device according to claim 10, wherein the main binder of the conductive ink is a polyamide resin. 12. The display device according to claim 1, wherein an electrode protection ink is selectively deposited on the electrode made of the conductive ink, leaving the recessed portion. 13. The display device according to claim 12, wherein the electrode protection ink is opaque. 14. In the display device according to claim 1, an oil repellent is selectively applied and adhered to the opposite surface of the electrode made of the conductive ink with respect to the porous body, leaving the recessed portion. A display device characterized by a shikoto. 15. In the display device according to claim 1, the second electrode is a transparent electrode attached to a transparent support, and the display structure is installed on the surface of the transparent electrode. and the porous body is formed from a translucent dielectric material, and the liquid material impregnated is translucent and has a refractive index substantially equal to that of the translucent dielectric material. display device. 16. In the display device according to claim 1, the electrode made of conductive ink is composed of a plurality of electrodes separated from each other, and a gap between each of the plurality of electrodes and the second electrode is provided. A display device comprising means for selectively applying a voltage to.