JPS6336512B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color display device that electrically controls light reflectance and light transmittance.

2. Description of the Related Art Conventionally, liquid crystal display devices have been widely used as so-called passive displays for displaying characters, figures, images, and the like. However, this type of display device has several problems that are essentially difficult to improve, such as a narrow operating temperature range, difficulty in producing a wide screen, and slow response speed.

Against the background of the above-mentioned problems, the inventors of the present invention
We have previously proposed a display device based on a new principle that improves these problems. This device scatters external light by controlling the liquid impregnation rate on the surface of a porous material using electroosmosis, and controls the substantial light reflectance and light transmittance of external light. A display structure including a porous body made of a film or a plate-shaped light-transmitting dielectric material having a large number of fine openings exposed on the surface of the display structure has a refractive index substantially equal to that of the light-transmitting dielectric material. A composite body impregnated with a translucent liquid material is placed on a support substrate surface such that one surface portion having the opening faces the space, and means for applying a signal voltage to the composite body is provided. The display device is configured to control the liquid impregnation rate of at least the porous surface facing the space by moving the liquid material with respect to the porous body in response to the signal voltage.

A pair of electrodes for applying a signal voltage to the composite may be arranged adjacent to each other insulated between the composite and the support substrate, and one electrode may be arranged adjacent to the composite and the support substrate. The other electrode located between the porous material and the other electrode may be provided on the surface of the composite, that is, the porous material, on the opposite side to the supporting base material. By providing a plurality of these pairs of electrodes and selectively applying a signal voltage to these electrodes, numbers, characters, figures, images, etc. can be displayed in transmission or reflection.

The porous body forming the display structure is, for example, a membrane or plate-shaped body made of glass material instead of plastic material. On the surface of this porous body,
An electrode consisting of a light-transparent, liquid-permeable conductive film such as indium oxide for applying a signal voltage can be deposited.

In addition, on the surface of the porous body opposite to the supporting base material, depressions in the form of dots, lines, strips, nets, etc. containing a plurality of the fine openings are provided to scatter light from outside light. The effect can be improved. In this case, the electrode made of the conductive film can be adhered to the surface of the porous body including the inner wall of the depression. In this case, an opacity-forming agent such as opaque ink or oil repellent is coated on the surface of the porous body while leaving the depressions, and external light control through the depressions can be effectively utilized. Furthermore, an electrode can be formed by coating and depositing a necessary opaque ink or opaque forming agent such as an oil repellent while leaving the recessed portion, and then selectively depositing graphite conductive ink or the like thereon. In this case, the electrode made of the conductive film can be removed and replaced with an electrode made of conductive ink. When constructing a transmissive display device, the supporting substrate is a transparent supporting substrate such as a transparent glass plate, and the pair is adhered thereon and inserted between the composite and the supporting substrate. One of the electrodes can be formed of a transparent conductive film such as tin oxide. When constructing a reflective display device, light reflecting or absorbing properties are imparted to the supporting base material and further to the electrodes deposited thereon. In this case, the supporting base material is made of a metal material such as aluminum, and can also have an electrode effect. Alternatively, the electrodes deposited on the surface of the supporting base material may be made of a metal vapor-deposited film such as aluminum, or
Opaque electrodes such as graphite conductive ink may also be used.

Examples of the multi-permeable material include cellulose acetate (light refractive index n _d = 1.47) and nitrocellulose (n _d = 1.51).
or mixed esters thereof (1.47<n _d <1.51)
It is made of transparent dielectric material such as 40~200mm thick.
Micron, has micropores with an average pore diameter of 0.1 to 1 micron that penetrate substantially through the thickness, and a porosity of 50
~80% microporous membrane filters are preferred. As the translucent liquid material to be impregnated, a material having a refractive index almost equal to that of the translucent dielectric material forming the porous body and good electroosmotic property is selected. For example, γ-methacryloxypropyltritri A mixture of methoxysilane (n _d =1.43) and a-methylnaphthalene (n _d =1.62) with matched refractive index is obtained. This mixed liquid material exhibits highly sensitive electroosmotic properties, particularly in microporous menglen filters made of cellulose acetate.

The depressions provided on the surface of the porous body can be easily formed by embossing the porous body made of the above-mentioned plastic material. It has a triangular or trapezoidal shape, becomes narrower with depth, has an average aperture or width at the tip of 3 microns or less, has a depth of 10 to 25 microns, and is preferably arranged at a density of about 100 to 400 pieces per inch.

Various passive displays have been proposed in the past, such as liquid crystal displays and electrochromic display devices, but there are various limitations and difficulties in colorizing them. It was difficult to display. Therefore, it is difficult to display any color, and its development has become a major research topic.

In view of the above-mentioned technical problems, the present invention has developed a color display device that can freely select not only the three primary colors but also a wide range of colors, based on the display device using the electroosmotic development proposed above. The purpose is to provide.

In the color display device of the present invention, in the display device described above, at least one of the opposing main surfaces of the porous body or the surface of the supporting base material on which the composite body is installed is transparent. A display device characterized by coating and adhering a photosensitive color ink.

Further, in the above device, a depressed portion including a plurality of the openings is formed on the main surface of the porous body facing the space, and at least a surface of the depressed portion of the main surface of the porous body is transparent. A color display device characterized in that a color ink is coated and adhered thereto.

Furthermore, in the above device, the porous body is made of a plastic material, a translucent color ink is applied to the surface of the porous body, and the depressed portion is formed by embossing on the applied ink,
A color display comprising a display structure in which at least one of an electrode made of an opaque ink, an uneven brightness forming agent such as an oil repellent, or a conductive ink is selectively applied leaving the recessed part. It's in the device.

In the color display device of the present invention, particularly in transmissive display operation, the substantial light transmittance to external light is determined by light scattering related to the liquid impregnation rate on the surface,
It is determined by reflection, and transmitted light is determined by the spectral transmittance of the applied translucent color ink. Therefore, by selecting the color of the color ink, any color of transmitted light can be obtained, and a high-purity color transmission display can be performed while the polarized light causes birefringence as in a liquid crystal display device.

Hereinafter, the present invention will be explained in detail with reference to Examples. FIG. 1 is a diagram showing a longitudinal cross-sectional structure and a power supply system of an embodiment of a color display device according to the present invention.

In the figure, 100 is a composite, 200 is a first electrode 301 whose surface is made of a transparent conductive film such as tin oxide,
This is a supporting base material made of a transparent glass plate or the like on which second electrodes 302 are adhered in a parallel grid pattern. The first electrode 301 and the second electrode 302 forming a pair are connected to a signal voltage source 500 that generates positive and negative pulses via conducting wires 401 and 402, respectively, and a DC pulse signal voltage is applied to the composite body 100 via the above-mentioned two electrodes. applied.

The composite body 100 includes a porous body 110 and a space 60
Opaque forming agent 15 made of black opaque ink or oil repellent is coated on the surface opposite to electrode 301 and electrode gap 302.
1. A display structure made of translucent color ink C coated corresponding to the electrodes 302 is coated with a translucent material having a refractive index substantially equal to that of the translucent dielectric material constituting the porous body 110. It is constructed by impregnating it with a photosensitive liquid material 111 (shown as a dot in the figure for convenience).

As described above, the porous body 110 is made of, for example, cellulose acetate (n _d =1.47), has fine pores with an average pore diameter of about 0.5 microns that penetrate substantially between the opposing main surfaces, and has a thickness of about 120 microns. A microporous membrane filter is used. Although the cellulose acetate that forms this porous body 110 is transparent, the inside of the micropores are hollow and has a refractive index n _d =1, whereas the dielectric material that forms the porous body 110 has a refractive index n _d =1.47. The refractive indexes of these elements are in a mismatched state, and the external light L ₁ is not scattered or reflected, so the color is white and almost no transmitted light L ₂ is generated. In this state, for example, when the liquid mixture of γ-methacryloxypropyltrimethoxysilane and a-methylnaphthalene with n _d =1.47 is impregnated as the transparent liquid material 111, the mismatch in the refractive index is removed, The composite 100 becomes transparent.

Therefore, when external light L ₁ is irradiated from the space 600,
In the area corresponding to the electrode 301, the opacity forming agent 1 is applied.
51, but in the part of the composite 100 corresponding to the electrode 302, it passes through the translucent color ink C and bright transmitted light _L2 is obtained, and the color is up to the spectral transmittance of the color ink C. It becomes a fixed colored light. Note that the same effect can be obtained even if the irradiation is performed from the supporting base material 200 side. This color can be freely selected by selecting the color ink.

In the figure, for example, the width of the electrodes 301 and 302 is 500 microns, the gap 303 is 200 microns, and the signal source 500 sends a negative DC pulse signal with an amplitude of about 100 volts to the first electrode 301 and the second electrode 302. In the material configuration described above, the transparent liquid material 111 is supplied from the first electrode 301 which is the negative electrode.
electroosmosis in the direction of . Therefore, the second electrode 302
The liquid impregnation rate of the translucent liquid material 111 in the composite 100 in the portion corresponding to the space 6 decreases, especially in the space 6.
In the surface portion 112 facing 00, the openings of the micropores become a kind of exposed state, resulting in a so-called hollow state (ie n _d 1) in which the liquid material 111 is extremely reduced. Therefore, due to the mismatch in the refractive index between the porous body portion and the micropores, the external light L ₁ is scattered near the surface 112, and the transmitted color light L ₂ becomes dark.
This reduction in transmitted color light _L2 occurs in response to the amplitude of the applied signal voltage.

On the other hand, when this signal voltage is removed, the first electrode 3
The liquid material 111 gathered on the 01 side moves back to the second electrode 302 side due to surface tension, the liquid impregnation rate of the surface portion 112 increases again, the refractive index mismatch is removed, and bright colored transmitted light L ₂ is obtained.
In this case, the polarity of the signal voltage is reversed and the first electrode 3
When a negative signal voltage is applied to the second electrode 302 with respect to 01, the movement and return of the liquid is promoted by electroosmosis, and bright transmitted color light _L2 is quickly obtained, allowing transmission control of monochromatic color light. .

More effective transmitted light control can be achieved by providing dot-shaped, linear, strip-shaped, or net-shaped depressions on the surface of the porous body facing at least the space 600 corresponding to the electrode 302 forming the display section, as described above. Furthermore, this can be realized by selectively coating and depositing an opaque forming agent such as an opaque ink or an oil repellent while leaving the depressions on the surface of the porous body.

Opaque forming agent 151, translucent color ink C
A material is selected that is chemically stable with respect to the translucent liquid material 111, and is preferably formed to be permeable to liquid in order to facilitate the movement of the liquid material 111.

Although an ionic surfactant can be used as the oil repellent as the opacity forming agent 151, a nonionic surfactant is selected from the viewpoint of electrochemical stability. The most preferred oil repellent is, for example, poly 111,111-
Preferably, a fluorine-based polymer such as pentadecafluorooctyl methacrylate is dissolved in a xylene hexafluoride or hydrogen fluoride-based solvent that does not dissolve the porous body 110, and these coatings are
It has strong oil repellency due to surface tension as low as dynes/cm. The surface of the porous body 110, on which these are applied thinly so as not to fill the minute openings, is not wetted by the liquid material 111, does not transmit transmitted light due to light scattering, and is substantially opaque to transmitted light. form.

The black opaque ink and translucent color ink C constituting the opacity forming agent 151 have a polyamide resin as the main binder in the material composition, and heptyl alcohol, octyl alcohol, etc. that do not dissolve the porous body 110 as the ink solvent. Gravure ink using alcohol is used, and after printing, coating, and adhering to a predetermined position on the surface of the porous body 110, the ink solvent is rapidly evaporated at a high temperature of about 60°C to make it porous. Constructed to be liquid permeable. Translucent color ink C
As such, a so-called transparent color gravure ink is preferably used.

In addition, in FIG. 1, the opaque forming agent 151 was applied to the part corresponding to the first electrode 301, but
The opacity forming agent 151 is limited to a portion corresponding to the electrode gap 303, and a translucent color ink that is different from the translucent color ink applied to the portion corresponding to the second electrode 302 is applied to the portion corresponding to the first electrode 301. Color inks can also be applied.

For example, red corresponds to electrode 301, electrode 302
When a blue translucent color ink is applied correspondingly to the electrode 30 when no signal voltage is applied,
Red transmitted light L2 is obtained in the first part and blue transmitted light _L2 is obtained in the second part of the electrode 300, so that when combined, it becomes magenta. When a negative signal voltage is applied to the electrode 302 with respect to the electrode 301, a blue transmitted light L2 is obtained, and when a negative signal voltage is applied to the electrode 301 side, a red transmitted light _L2 is obtained.
Multi-color transmitted light control is possible. Note that in this example, the pair of electrodes 301 and 302 are connected to the signal power source 500 all at once, but they constitute three pairs of electrode groups, and corresponding to these electrode groups, blue, green,
By applying translucent color ink of the three primary colors of red and selectively applying signal voltages to these electrode groups, it is possible to control transmitted light in all colors.

Note that at least one of the opacity forming agent and the transparent color ink can be applied to the surface of the porous body on the side of the space 600, and can also be applied to the surface of the support base material 200 on which the electrodes are installed. In the latter case, it is desirable that the opacity forming agent be an opaque ink.

FIG. 2 is a longitudinal cross-sectional partial structural view of another embodiment of the color display device according to the present invention.

In this example, red R, green G, and blue B inks made of translucent color ink such as gravure ink are applied thinly in strips in advance to the surface of the porous body 100, and liquid-permeable printing is performed. Further, an opaque forming agent 150 such as black ink is applied between the strips of color ink R, G, and B, and then a linear depression 120 is formed in the center of each of the strips of color ink R, G, and B in the same manner as described above. Along with embossing,
Similarly, a linear depressed groove 122 for electrode separation is embossed in the center of the band-shaped opacifying agent 150.

Next, conductive ink such as graphite or silver is applied to the surface of the porous body 110 by offset printing or roller coating. The display electrodes 143, 144, and 145 made of the obtained conductive ink are insulated by the depressed grooves 122 that remain without being coated with the conductive ink. In this way, this display structure is connected to the transparent electrode 30.
0 on a translucent support base material coated with
A composite body 110 is formed by impregnating the porous body 110 with a translucent liquid material 111 that allows refractive index matching.

The display electrodes 143, 144, 145 and the transparent electrode 300 are connected to power supply terminals Y _R , Y _G , Y _B , and X _O , respectively, and signal power supplies are selectively applied to X _O and Y _R , Y _G , and Y _B, respectively. When a DC voltage is applied from , the liquid impregnation rate of the slope surface of the recessed part 120 coated with color inks R, G, and B is controlled according to the applied voltage, and the liquid impregnation rate with respect to external light L ₁ is controlled. The transmission of each transmitted light L _R , L _G , and L _B is controlled.

For example, the porous body 110 and the transparent liquid material 11
1 as in the above-mentioned material configuration example, the liquid material 1
11 is electroosmotic in the direction of the negative electrode, so electrode 1
When a negative signal voltage is applied to the electrode 300 for 43, 144, 145, the color ink R,
The liquid impregnation rate of the surface of the depressed portion 120 coated with G and B decreases, and the transmitted light L _R , L _G , with respect to the external light L _{1 decreases} .
L _B decreases. When no signal voltage is applied,
The polarity is reversed and the display electrode 14 is reversed to the electrode 300.
When a negative signal voltage is applied to 3, 144, 145, etc., the liquid impregnation rate increases and becomes saturated, and bright transmitted light _LR , _LG , _LB is obtained. The color of the transmitted light corresponds to color ink R, G, _B.
(red), L _G (green), and L _B (blue).

The conductive ink forming the electrodes 143, 144, 145 is selected from one that does not dissolve in the liquid material 111 used. For the liquid material 111 in the above example, a graphite conductive ink whose main binder is a polyamide resin and whose solvent is an alcohol-based solvent such as heptyl alcohol or octyl alcohol gives good results.

Note that in this embodiment, the electrode 300 is formed of a single conductive film, but the display electrodes 143 and 14
It is also possible to construct a full-color transmissive color display device by dividing the light into complex parts corresponding to each of the 4,145 colors and selectively applying signal voltages.

FIG. 3 is a longitudinal cross-sectional structural view of still another embodiment of the color display device according to the present invention.

This embodiment is illustrated in connection with FIG.
Color ink, like red ink R and green ink G in the figure, can be installed on the opposite surface of the porous body 110 at a position corresponding to the installation surface of the recessed part 120. Furthermore, like the blue ink B, it can be installed on the surface of the support base material 200 on which the electrode 300 corresponding to the part where the recessed part 120 is located is covered. Further, an opacity forming agent such as black ink for preventing light transmission through the depressed grooves 142 may be applied to a position corresponding to 142 on the opposite side of the porous body 110, as illustrated at 150' in the figure. , and an opaque forming agent 15 corresponding to the recessed groove 142'.
0'', it can be installed on the support base material 200.

In addition, in Fig. 3, each color ink R,
A single depression 120 existed for G and B, but when the display area is formed of multiple depressions, each color ink must be applied over the entire area of the display area. Good.

The above description has been about a transmissive color display device, but in a reflective color display device, the electrode 200 in FIGS. Good. In this case, when observed with external light irradiated from the space side, if the liquid impregnation rate on the surface of the recessed part 120 is high, it will appear black, and if the liquid impregnation rate is low, light scattering will occur and the color ink will change color. Reflected light can be observed.

As described above, the color display device according to the present invention is a display device that utilizes electroosmosis of liquid in a porous body, and the coloring is performed using translucent ink such as gravure ink. , applied to the surface of the porous body on the side located in the space, applied to the surface of the porous body on the opposite side, or applied to the surface of the support base material that supports the display structure. This can be achieved by any method. The reflection and scattering of external light is controlled on the surface of the porous body facing the space, and the coloring is determined by the color of the translucent ink applied.

Such a color display device can be realized in either transmissive or reflective operation, and has a much wider degree of freedom in color selection than various conventional passive display devices, making it an industrially viable option. , extremely useful.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of a color display device according to the present invention, FIG. 2 is a sectional view of another embodiment, and FIG. 3 is a sectional view of still another embodiment. 100...Composite, 110...Porous body, 11
1... Translucent liquid material, 120... Recessed part, 12
2... Recessed groove for electrode separation, 143, 144, 14
5,300,301,302... electrode, 200...
...Supporting base material, 150, 150', 150'', 151
... Opaque forming agent, 401,402 ... Conductive wire, 5
00... Signal voltage source, 600... Space, C, R,
G, B... Translucent color ink, X _O , Y _R , Y _G ,
Y _B ...Power supply terminal.

Claims (1)

[Scope of Claims] 1. A film or plate-shaped porous body made of a light-transmitting dielectric material and having a large number of fine openings exposed on at least one surface, and A composite body impregnated with the porous body and a translucent liquid material having approximately the same refractive index is placed on the supporting base material surface such that one porous body surface portion having the opening faces the space. The liquid material is moved relative to the porous body in response to the voltage, and at least the surface of the porous body on the side facing the space is heated. In a display device in which the liquid impregnation rate is controlled to control the light transmitted through the composite, either one of the opposing surfaces of the porous body or the surface of a supporting base material on which the composite is installed. A color display device characterized in that a translucent color ink is coated and adhered to the surface of at least one of the above. 2. In the color display device according to claim 1, a depression including a plurality of the openings is formed on the surface of the porous body on the side facing the space, and the surface of the depression includes: A color display device characterized by being coated with translucent color ink. 3. In the color display device according to claim 1, the porous body is made of a plastic material, a translucent color ink is coated on the surface of the porous body, and an embossing process is performed on the coated ink. The recessed portion is formed, and at least one of an opaque ink, an opaque forming agent such as an oil repellent, or an electrode made of conductive ink is selectively applied leaving the recessed portion. color display device.