JPS6226032B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a display structure useful for a display device based on a new principle of electrically controlling reflectance and transmittance, and a display device using the same. BACKGROUND OF THE INVENTION 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 LCD device has a narrow operating temperature range, making it difficult to create a wide screen.
It had several problems that were inherently difficult to improve, such as slow response speed. In view of the above, the present inventor first applied a voltage to a display structure made of a porous body impregnated with a liquid material and held so that at least one surface faced an open space. We propose a display device that controls external light based on a new principle that utilizes the so-called electroosmotic phenomenon, which controls the liquid impregnation rate of the surface of the display structure facing the open space by moving a liquid material to the porous body in response to voltage. did. This device has a wide operating temperature range due to the use of a liquid material with a high boiling point, and uses porous paper as the display structure, making it easy to obtain a wide screen. Furthermore, external light can be controlled by electroosmotic phenomena. Since it can be saturated with a very small liquid movement of about 1 micron, it has many advantages such as an extremely fast response speed compared to liquid crystals. However, there was still room for further improvement in the contrast ratio, which is important for display devices, that is, the electrical control intensity range of external light. Based on the above background, the present invention aims to provide a display structure that is improved with the intention of increasing the contrast ratio, and a display device using the same. More specifically, the present invention includes a large number of fine openings exposed on at least one surface, which are impregnated with a liquid material and whose liquid impregnation rate is electrically controlled. The display structure made of a porous body is characterized in that a depressed portion including a plurality of the openings is provided on the surface of the porous body. Here, the porous body preferably has fine pores, gaps, and grooves of any shape that substantially penetrate from one surface to the other surface facing the other surface, and these do not necessarily have to be formed from one surface facing the other surface. No penetration into the other surface is required. In addition, the porous body can be formed of dielectric materials such as plastic, glass, metal oxides such as alumina, porcelain, and natural fibers, and these materials may be in the form of films, plates, particles, tubes, fibers, or It does not matter if it is transparent or non-transparent and whether it is colorless or colored. In the present invention, when a depression is formed on the surface of a porous body so as to include a plurality of so-called micropores having minute openings, significant light reflection and light transmission can be electrically controlled on the side slopes of the depression. This is based on what we discovered. Hereinafter, aspects of the present invention will be described with reference to Examples. FIG. 1 shows a display structure according to the present invention, and FIG. 2 shows a vertical cross-sectional structure and a power supply diagram of a display device using this structure. In addition, in the following examples, including this example, the display is appropriately enlarged for convenience of explanation, so the relative dimensions thereof do not necessarily match the description in the main text. Further, all parts of the same type are indicated by the same number. The display structure 100 is made of a membrane-like porous body 101, and the surface thereof has conical dot-like depressions 102.
There are many. The porous body 101 is, for example, a microporous membrane filter made of a transparent material made of cellulose ester such as nitrocellulose or cellulose acetate.
filter). Its thickness is 40 to 200 microns, and as illustrated in the enlarged view in Figure 3, it has ultra-fine pores 103 with an average pore diameter of about 0.1 to 1 micron penetrating from one surface to the other, and its porosity is About 50 to 80% can be used. Particularly preferred are those having an average pore diameter of about 0.22 to 0.65 microns. The dotted depressions 102 can be made, for example, by a so-called embossing method in which a halftone copper plate for letterpress printing is pressure-bonded or heat-bonded to a microporous membrane filter, as described later. The point-like depressions 102 have a triangular, square, polygonal, or conical shape, or a triangular, square, polygonal, or truncated conical shape, and the long axis of the depressions 102 on the surface of the porous body 101, the so-called pore diameter, is 10. ~40 microns, with a depth of 10 to 35 microns, and the pore diameter becomes smaller as it goes inside the porous body 101. The included angle θ of the cross-sectional ridgeline is within 130°, preferably within 90°, and the short axis of the tip of the recessed portion 102 is preferably 5
Constructs sharply within microns. The dotted depressions 102 made of such so-called embossed holes have an interval of, for example, 254 microns (100 microns).
A large number of particles are arranged regularly, ranging from 63.5 microns (400 pieces/inch) to 63.5 microns (400 pieces/inch).
On the surface of the porous body 101, electrodes 111 and 112 made of extremely thin transparent conductive films that are porous and have liquid permeability corresponding to the micropores 111 are adhered. Such a liquid permeable translucent electrode 111,1
12, a copper deposited film having a thickness of about 80 angstroms is deposited on the surface of the display structure 100 by vacuum deposition, and then dipped in an iodine solution to form a conductive film made of cuprous iodide. Still another method is to apply a thin layer of indium oxide, tin oxide, or a solid solution material thereof by a cold sputtering method.
It is possible to obtain an electrode that is transparent and permeable to liquid. In this way, by forming the depressions 102 in the porous body 100 and then constructing the electrode by vapor deposition or sputtering, a good conductive film can be formed even inside the depressions 102. The display structure 100 having the electrodes 111 and 112 covered thereon is placed on a support plate 300 made of transparent glass and covered with an electrode 200 made of a transparent conductive film such as tin oxide. The display structure 100 includes a liquid material 4 that is transparent, has approximately the same refractive index as, for example, the cellulose ester material forming the porous body 101, and has electroosmotic properties with respect to the porous body 101.
00 (shown as multiple points for convenience of explanation). When the porous body 101 is, for example, nitrocellulose (refractive index n _d =1.51), for example, n _d 1.51.
dimethyl triphenyl trimethoxysiloxane

[Formula] However, φ is phenyl group), cellulose acetate (n _d
1.47), for example, phenyltrimethoxysilane (C ₆ H ₅ Si (OCH ₃ ) ₃ ) with n _d 1.47, or a mixture of nitrocellulose and cellulose acetate (1.47<n _d <1.51). is a mixture of phenyltrimethoxysilane and dimethyltriphenyltrimethoxysiloxane, with a refractive index of 1.47<
Select an intermediate value of n _d <1.51, and set the refractive index to porous body 1.
Select approximately equal to 01. Since the display structure 100 itself is porous and air exists in the micropores 103, the materials forming the porous body 101 have different refractive indexes, that is, the mismatching of the refractive indexes causes scattering and reflection of light. It is white and opaque. However, as described above, when the transparent liquid material 400 has the same refractive index as the transparent material forming the porous body 101, the fine pores 103 of the porous body 101
When impregnated in a limited amount sufficient to completely fill the display structure 1, the refractive index mismatch is removed and the display structure 1
00 becomes transparent. Generally, when a liquid material and a solid material are brought into contact, an interfacial electric double layer is generated at the interface, and each material is charged to opposite polarities. Therefore, if the solid material is fixed and parallel to this interface, a voltage (signal)
When , the liquid material moves in the direction opposite to its charged polarity. This phenomenon is generally referred to as an electroosmotic phenomenon, and the polarity of the electroosmotic direction of the liquid material can be positive or negative depending on the correlation with the solid material. However, generally, in many cases, the liquid material is positively charged with respect to the solid material, that is, electroosmosis occurs in the negative polarity voltage direction. The aforementioned porous material 101
Similarly, in the case of the transparent liquid material 400, electroosmosis occurs in the negative polarity direction. In this way, the electrode 20
In the electrode 112 part connected to the same potential as 0,
No voltage is applied. Therefore, if the amount of liquid material 400 to be impregnated is appropriately selected, it will be retained within the porous body 101 by capillarity, and a portion will overflow through the electrode 112 to the surface of the porous body 101 and be exposed on the surface of the porous body 101. It can completely wet even the smallest openings. In this state,
The fine hole 103 facing the open space 700 is the flat part 1
04 and the depressed portion 102, the liquid material 40
0 (i.e. surface liquid impregnation rate 100%)
There is no refractive index mismatch within the micropores 103 in the surface portion. Therefore, in this portion, the display structure 100 is transparent and transmits the incident external light _L1 , producing bright transmitted light _LB. However, the electrode 111 is connected to the electrode 200 via the conducting wire 501.
In the part where a positive voltage of V ₁ is applied, the flat part 1
04 and the depressed portion 102, the liquid material 400 electroosmoses toward the negative electrode 200, and the excess liquid material 400 flows into the arrangement gap 600. Due to this electroosmosis, the liquid impregnation rate on the surfaces of the flat portion 104 and the depressed portion 102 decreases, and then air enters through the electrode 111, and the surface portions of the micropores 104 become voids. Therefore, light scattering occurs within the micropores 104 due to refractive index mismatch due to the presence of air. In particular, as illustrated in FIG. 3, the scattered reflection on the side slopes of the depressed portion 102 is significant. The reason for this is that, as shown in the figure, the input external light _L1 is incident on the flat portion 104 at a right angle, but on the recessed portion 102, it is incident at an acute angle, and the input external light L1 is incident on the display structure 100.
and that the incident external light is easily reflected to the inside of the
This is thought to be due to the fact that the effective area with respect to L ₁ has expanded, and that the surface condition of the micropores 103 is disturbed compared to the flat portion 104 due to the formation of the depressed portion 102 (for example, embossing). Therefore, in the depressed portion 102, the transmittance substantially decreases, the reflectance increases, and light is scattered and refracted.
It looks white. Transmitted output light L _D that passes through this part
becomes extremely dark. For example, when the display device shown in FIG. 2 is mounted on a slide projector and projected onto a screen, the electrode 112 has a flat portion 104 and a depressed portion 102.
have almost the same bright screen brightness, whereas in the electrode 111 part, the flat part 104
is darker than the electrode 112 portion, and the recessed portion 102 is even more markedly dark and projected in the shape of a black spot. For example, as the display structure 100, the thickness is 120 mm.
A microporous membrane filter made of nitrocellulose with a diameter of ~150 microns and an average pore diameter of micropores 103 of 0.3 microns.
A membrane filter) is used as the porous body 101, and there are dotted depressions 102 having an average major axis of 15 to 30 microns at the surface, a depth of 10 to 25 microns, and an average pore diameter of 5 microns or less at the tip of the sinkhole. Using the display structure 100 having the liquid material 40
When dimethyltriphenyltrimethoxysiloxane is impregnated as 0 and 100 to 150 V is applied as V ₁ , the screen brightness decreases to 1/1.2 to 1/2.0 at the flat part 104 of the electrode 111 compared to the 112 part of the electrode. In contrast, in the depression 102
It showed a significantly dark dot-like screen brightness of 1/15 to 1/40. The flat portion 104 of the electrode 111 corresponds to the conventional device proposed above, and the depressed portion 10 is a feature of the present invention.
2 at high density, the electrical control rate of the average external light L ₁ including the flat portion 104 is significantly improved. When the voltage V ₁ is reduced to zero, the liquid material 400 quickly moves to the open space 700 side through the fine pores 103 due to capillary action, and the same as the electrode 112 part,
That is, the display structure 100 returns to the transparent state. Light control in this type of display device is sufficient if the liquid material 400 moves about 1 micron from the open space 700 side surface. The electroosmotic degree of the liquid material can be approximately 10 ^-4 cm ² /V.Sec. in principle. Therefore, it has the excellent feature of providing a display device with an extremely fast response time of 100 microseconds or less. In the above explanation, external light is input from the support plate 300 side.
Although L ₁ was irradiated, similar transmitted light control can be achieved by irradiating from the open space 700 side. Furthermore, it is possible to control not only transmitted light but also reflected light. This is also applicable not only to this example but also to all the examples described below. In the first configuration, the material forming the porous body 101 is mixed with, for example, black or colored oil-based dyes or pigments to form the porous body 101 into a light-absorbing material such as black or colored. In the second configuration, a light-absorbing thin film such as black paint is formed on the electrode 200, or a metal vapor-deposited film such as aluminum is deposited on the electrode 200 to make it light-reflective. In the third configuration, the electrode 200 itself is formed of, for example, a black light-absorbing conductive film containing graphite powder or the like, or a light-reflecting electrode such as a metal vapor-deposited film such as aluminum. In the fourth configuration, on the surface of the support plate 300 opposite to the electrode 200, as exemplified in the second configuration,
An auxiliary film consisting of a light-absorbing film, a light-reflecting film, etc. is applied. In the fifth configuration, the support plate 300 itself is configured to have a light absorbing property such as a graphite plate, or a light reflecting property such as a metal plate such as aluminum. Note that if the support plate 300 itself has conductivity, this support plate itself can be used as the electrode 200. In this way, the display structure 100 itself is substantially formed to be light-absorbing, but the side of the display structure 100 opposite to the open space 700 is substantially
When the electrode 112 is formed to have a light reflective or light absorbing property, the portion of the electrode 112 held at an equal potential can be observed as black with respect to external light L ₁ ' from the open space 700 side, while the electrode 112 to which the voltage V ₁ is applied can be observed as black. In the 111th section, the external light L ₁ ' is diffusely reflected and scattered, especially around the depression 102, and is displayed white, resulting in a black and white display. FIG. 4 is a longitudinal cross-sectional structural view of a display device using a display structure according to another embodiment of the present invention, and a diagram showing a power supply system. The depressed portion 102 in the display structure 100 is
It can be formed into a linear shape (parallel lattice shape) as shown in FIG. 5 showing a partial top view, a short fence shape as shown in FIG. 6, or a so-called net shape in which the lines intersect as shown in FIG. 7. In both cases, the cross section of the depressed portion 102 is triangular or trapezoidal, becoming narrower toward the inside.
The cross-sectional ridgeline has a narrow angle of 130° or less, preferably has a shape of a straight line, and is formed as sharply as possible so that the width of the tip is preferably within 5 microns. The depth of the depressed portion 102 is 10 to 35 microns, and the arrangement interval in the case of a linear or short fence shape is 100 microns.
~200 microns is preferable. In the case of a mesh, it is formed into a mesh with approximately 100 to 400 lines per inch. The device shown in FIG. 4 is intended for reflective display, and the outer surface of the support plate 300 made of transparent glass or the like is coated with a light absorption layer made of black paint or the like, or a metallic luster reflection film made of vapor-deposited metal such as aluminum. An auxiliary film 210 consisting of is deposited.
The porous body 101, transparent electrodes 111, 112, and liquid material 400 forming the display structure 100 are formed in the same manner as described in FIG. 201 and 202 are transparent electrodes made of indium oxide or the like which are insulated from each other, and liquid-permeable electrodes 111,
112. The electrodes 111, 201 are connected to a DC power supply V ₃ through a conductor 501, and the electrodes 112, 201 are connected to a DC power supply V ₂ through a conductor 502, and switches S ₁ , S ₂
When is set to A, a negative voltage is applied to electrodes 201 and 202 relative to electrodes 111 and 112, respectively,
When switches S ₁ and S ₂ are set to B, they are kept at the same potential.
In the combination of the porous body 101 and the liquid material 400 described above, the liquid material 400 electroosmoses toward the negative electrode. Therefore, external light from the open space 700 side
When the switches S _{1 and} S ₂ are respectively connected to the A terminal, the liquid impregnation rate of the surface including the depressed portion 102 decreases, and L 1 is diffusely reflected and displayed white. On the other hand, when the switches S ₁ and S ₂ are respectively connected to the B terminal, the surface is impregnated with the liquid material 400 and is therefore transparent, but is displayed black due to the light absorption or metallic luster of the auxiliary film 210. Ru. Thus, in the device of FIG. 4, the DC power supply V ₂ ,
By controlling _V3 , the transparent electrode 111,
112 can be displayed independently in black and white. In this example, the electrode 200 in FIG.
Although it is insulated and separated corresponding to 11 and 112,
The transparent electrode on the open space 700 side may be a single conductive film, and the electrode on the support plate 300 side may be insulated and separated into a plurality of electrodes. In this way, at least one side of the open space 700 or the support plate 300 is formed into a 〓 shape, for example.
By separating the segments and switching and driving each segment independently, a transmissive or reflective numeric display device can be constructed. FIG. 8 is a longitudinal cross-sectional structural view and a power supply system of another embodiment of the present invention. In this example, a reflective display device is formed, but a liquid-permeable, light-transmitting electrode is not adhered to the surface of the display structure 100, and a negative electrode 203 and a positive electrode 204 are provided to the surface of the support plate. It is being Electrode 203,2
04 are connected to a variable voltage DC power source V ₄ via conductive wires 503 and 504, respectively. As the porous material, the aforementioned nitrocellulose or cellulose acetate microporous membrane filter is used. As the liquid material 400, the above-mentioned material that is electroosmotic in the direction of the negative electrode and has a refractive index almost equal to that of the porous body is used. The depressed portion 102 has a point, line, or short fence shape, and in this example, its cross section is trapezoidal. However, the short side should have sharp corners as shown in the figure. Such a cross-sectional shape often appears when a point-like recess is formed by an embossing method. The presence of such sharp corners exhibits favorable characteristics for effective light control.
On the surface of the display structure 100 opposite to the open space 700, an insulating, light-absorbing, liquid-permeable film 211 made of, for example, black ink is provided. Note that this membrane 211 has an electrode 2 on the support plate 300.
It may be applied to cover the electrodes 203 and 204, or it may be applied to the opposite surface of the support plate 300 to the surface on which the electrodes 203 and 204 are applied. In this case, the membrane 211 does not need to be permeable to liquid, and can also be a metal vapor deposited membrane such as aluminum. The support plate 300 is made of, for example, a glass plate.
The electrodes 204 and 205 are made of a metal oxide conductive film such as tin oxide or a metal evaporated film such as aluminum or gold. The electrode 203 is narrow, for example, about 100 microns, and the electrode 204 is a display electrode, so
Compared to the electrode 203, it is made wider by about 500 to 3000 microns. The gap between the electrodes 203 and 204 is made narrow to about 100 microns. When the DC voltage V ₄ is zero, the electrodes 203 and 204
Regardless of the case, the display structure 100 is wetted to the surface with the liquid material 400 and is transparent, so that the auxiliary film 211
It looks black because you will be observing it. As the voltage of V ₄ is increased, the liquid material 400 on the positive electrode 204 electroosmoses onto the negative electrode 203. Therefore, the liquid impregnation rate of the surface of the display structure 100 on the open space 700 side on the electrode 204 decreases, and the external light _L1 is diffusely reflected, making it appear white. Although the electrode 203 still appears black, since its area is small, the display structure 100 as a whole is displayed as white. If V ₄ is made zero, the liquid material 400 collected on the electrode 203
quickly diffuses onto the electrode 204 due to surface tension and capillary action, returning to the original black state. In this example, liquid material 4
00 moves on the open space 700 side surface of the display structure 100, so the micropores of the porous body do not necessarily need to penetrate between the opposing surfaces. Not limited to this example, the depth of the micropores is 700 mm in open space.
From the surface, it is sufficient that the depth is at least the depth of the sinkhole 102. FIG. 9 is a diagram showing a vertical cross-sectional structure and a power supply system of still another embodiment of the display device according to the present invention. The electrodes 201, 202 are connected to a DC voltage switching device _V5 via conductors 505, 506, and the conductors 50
A display electrode that selectively applies a negative voltage to a liquid-permeable translucent conductive film 110 connected to V ₅ through V 7; in the case of a reflective type, a black electrode made of graphite paint; In the case of a mold, it consists of a transparent electrode made of tin oxide. The recessed portion 102 provided in the display structure 100 is connected to the display electrode 20.
It is installed only in the part corresponding to 1,202. Therefore, when a negative voltage is selectively applied to the display electrodes 201 and 202, the liquid impregnation rate of the surface portion where the depressed portion 102 is disposed decreases, causing light scattering.
This has the advantage that a clear shape corresponding to the electrodes 201 and 202 can be displayed. FIG. 10 shows yet another embodiment in comparison with FIG. 9. The difference from FIG. 9 is that the display electrode is provided on the open space 700 side of the display structure, and the recessed part 102 is formed by the transparent liquid-permeable display electrode 11.
1,112. The electrode 200 on the opposite side may be divided and provided at positions corresponding to the electrodes 111 and 112, but in this example, a single conductive film is formed over the entire surface of the support plate 300. . The electrodes 300, 111, 112 are each connected to a conductive wire 5.
00, 508, 509 to the DC power supply _V6 , and the electrodes 111, 112 are connected to the electrode 200.
A DC voltage is selectively applied so that the voltage becomes a positive potential. In this voltage application state, the liquid material 400 electroosmoses in the direction of the negative electrode 200, so the electrode 11
1,112 parts selectively causes light scattering, and the desired display can be performed. In the so-called flat portion 104 where there is no depressed portion 102, no voltage is applied, and therefore,
Since the light scattering effect is also small, there is an advantage that a clearer pattern can be displayed compared to FIG. In FIGS. 9 and 10, a plurality of opposing electrodes were divided and insulated into a shape corresponding to the pattern to be displayed, and a voltage was selectively applied.
However, if necessary, both the electrodes on the open space 700 side and the support plate 300 side of the display structure 100 can be divided in accordance with the pattern shape to be displayed, and the electrodes can be operated by selectively applying a voltage. can. Therefore, it is assumed that at least one of the opposing electrodes can be divided into a plurality of parts depending on the pattern to be displayed. 11 to 13 are partially cutaway perspective views of other embodiments of the display structure according to the present invention. In FIG. 11, the surface shape of the depressed portion 102 forms a kind of diamond shape, and as it goes inside the porous body 101, its diameter decreases to form a point-like depressed portion with a sharp tip. . Note that the surface shape of the depressed portion 102 is not limited to the diamond shape shown in the figure, but may be a so-called polygon such as a triangle or even a pentagon, and a dotted depressed portion in the shape of a polygonal pyramid or a truncated polygonal pyramid whose diameter becomes smaller toward the inside. can be configured. FIG. 12 shows an example of a radial dot-like depression in which a plurality of short lines extend radially around one point. In this example, the depression 102 has a starfish-shaped shape, and similarly has a sharp point inside. Point-like depressions are formed.
In the display device according to the present invention, light control is performed by controlling the liquid impregnation rate of the side surface of the depressed portion 100. Therefore, as shown in FIGS. 11 and 12, if the shape of the depressed portion 102 is formed into a polygon or a radial point shape, the side surface area per unit point-shaped depressed portion increases and the light control effect is further improved. can be improved. FIG. 13 shows an example in which the recessed portion is composed of a plurality of recessed portions having different shapes. A so-called background pattern-type composite depression 102 is formed by a combination of an earthworm-shaped depression 102' and a circular depression 102'', each forming a hole that becomes sharper toward the inside. When configuring a display device , it may be necessary to operate over a wide range of applied voltages.If a composite depression is formed as in this example, the circular depression 102'' effectively controls light at low voltages. However, in the high voltage section, a worm-shaped depression 102'
This enables a display device that operates effectively and has a wide operating range. Although this example has two types of shapes, it is also possible to configure a composite depressed portion with multiple types of shapes, such as a combination of dotted and linear shapes. The various depressions mentioned above can be created by photoetching a protrusion corresponding to the shape of the desired depression on a copper plate used for letterpress printing, etc. using ferrous chloride, etc., and using this as an original plate. , can be easily formed by embossing a porous body. FIG. 14 is a diagram showing an example of the manufacturing process of a display structure using the above-mentioned embossing method. In FIG. A, reference numeral 1100 is an embossing original plate having convex portions 1110 corresponding to the desired shape of the depressed portion, such as a desired dot shape, line shape, short fence shape, or a combination thereof. 1100, for example, photo-etches a printing copper original plate with a thickness of about a millimeter with ferrous chloride,
Alternatively, the desired convex portions 1110 are formed on a plastic original plate for printing using an electronic engraving machine or the like. 101 is the porous body mentioned above, with a thickness of 40~
It is a microporous membrane filter made of cellulose ester with a diameter of approximately 150 microns. Reference numeral 1200 denotes an auxiliary sheet for protecting the surface of the porous body 101, which is a paper or plastic film with a smooth surface, for example, about 30 to 70 microns thick. 1300 is a rubber sheet with a thickness of about 2 to 5 mm for pressure buffering. These are overlapped as shown in Figure A, and passed between rolling rollers made of metal rollers 1410 and 1420 having a gap narrower than the thickness of the stack, as shown in Figure B. In this process, the porous body 101 is embossed to correspond to the convex portions 1110. In this case, at least one of the embossing original plate 1100 or the rollers 1410 and 1420,
When the porous body 101 made of cellulose ester is heated to as high a temperature as possible without deforming, for example, about 60°C, the porous body 101 becomes the original plate 1100.
Heat embossing is performed to obtain a good recessed part. After passing through rollers 1410 and 1420, when removing 1100, 1200 and 1300,
As shown in FIG. C, a display structure 100 having a depression 102 of a desired shape at a desired position on the surface of the porous body 101 is obtained. Note that if a convex portion corresponding to the recessed portion 102 is processed on the surface of the roller 1410 by photo etching or the like, the original plate 1100 is not necessary and the embossing can be performed directly with the roller 1410. In this way, the pressing of the porous body 101 and the mold plate 1100 and the processing of the depressed portion 102 by heating are as follows:
Attach the cumulative laminate shown in Figure A to the press device, and
Applying uniform pressure to the surface of porous body 10
This can also be done by pressing the original plate 1100 onto 1. However, the depressed portion 1 is uniform over the entire surface of the porous body 101.
02 is difficult to form, and this pressure bonding may collapse the openings on the surface of the micropores 103 of the porous body 101, which may significantly impede liquid permeability. However, the roller method described above has the advantage that a uniform and excellent display structure 100 with almost no loss in liquid permeability can be obtained. FIG. 15 is a cross-sectional structural diagram showing another method of manufacturing the display structure. Generally, microporous membrane filters made of cellulose ester, polyamide (nylon), etc. are formed by dissolving a solution of these resins in a solvent in an atmosphere with appropriate humidity and controlling the evaporation of the solvent. In this way, as shown in FIG. 15A, a template 1100 made of a copper plate or a plastic plate having a protrusion 1110 corresponding to the shape of the depression as already described in FIG. 14 is placed horizontally on the bottom of the container 1500. Deploy. On top of this, a solution 1600 of a plastic material forming a porous body is poured. When the plastic material is nitrocellulose, cellulose acetate or a mixture thereof,
For example, a solution 1600 is prepared by dissolving it in a mixed solvent of acetone and glacial acetic acid, or in the case of nylon, in a mixed solvent of ethyl alcohol and water, for example. In this case, suitable dispersants and stabilizers such as surfactants can be mixed. Further, a suitable mold release agent can be applied to the surface of the mold plate 1100. Thus, the container 1500 containing these is kept in a humidified atmosphere and the solvent is evaporated 1610. This evaporation of the solvent produces micropores 103 that penetrate in the thickness direction as shown in Figure B, and when the solvent is completely evaporated, a porous body 10 consisting of a microporous membrane filter is placed on the mold plate 1100.
1 is obtained. The average pore diameter of the micropores 103 can be adjusted within a wide range by changing the evaporation rate of the solvent, that is, the humidification of the atmosphere. When the porous body 101 is peeled off from the mold plate 1100, washed with water, etc., unnecessary chemicals are dissolved, and dried, a display structure having the required recessed portion 102 at the desired position on one surface is obtained, as shown in Figure C. 100 is obtained. In this way, the porous body 1 made of a microporous membrane filter is placed on the mold plate 1100.
According to the manufacturing method of the display structure 100 in which the display structure 100 is manufactured, as shown in the embossing method shown in FIG.
It has an excellent feature that a display structure 100 with good electroosmotic property can be obtained. In the above explanation, we mainly talked about porous materials having micropores penetrating through the thickness direction, but other materials such as cellulose ester, polyester, glass, natural fibers, etc., made by sifting short to long fibers, etc. So-called fiber papers can also be used. These allow liquid material to penetrate substantially from one surface to the other through the interstices and grooves between the fibers. The size of the depression in this case is
It is sufficient to include a plurality of gaps (short sides) between fibers. Furthermore, porous bodies include plates made of glass, metal oxides such as alumina, porcelain materials, etc., with fine pores provided therein;
Alternatively, the porous body can be constructed from a sintered body of particles of the various materials mentioned above. It is desirable that the pores, gaps, grooves, etc. that have minute openings on the surface substantially penetrate between both surfaces of the porous body, but the holes, gaps, grooves, etc. If it is deeper than the depth of the depression, it is not necessarily necessary to penetrate it. As explained above, the present invention is a porous body impregnated with a liquid material and having a large number of fine openings exposed on at least one surface of the surface, the liquid impregnation rate of the surface being electrically controlled. A display structure comprising a recessed portion including a plurality of the openings on the surface of the porous body, and a display device using this display structure, wherein the recessed portion is installed. , it becomes possible to effectively control the transmission or reflection of external light, and a display device with an improved contrast ratio can be obtained, which is extremely useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of a display structure according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional structure and power supply diagram of a display device according to the present invention using the display structure of FIG. 1, and FIG. FIG. 2 is an enlarged partial view of the device to explain its operating principle; FIG. 4 is a diagram showing the vertical cross-sectional structure and power supply system of another embodiment of the display structure according to the present invention and a display device using the same; Figures 5 to 7 are
FIGS. 8 to 10 are partial perspective views showing other embodiments of the display structure according to the present invention, and longitudinal cross-sectional structures and power supply of other embodiments of the display structure according to the present invention and a display device using the same. Diagrams showing the method, Figures 11 to 1
3 is a partial perspective view showing another embodiment of the display structure according to the present invention, FIGS. 14A to 14C are process diagrams showing a method for manufacturing the display structure according to the present invention, and FIG. 15A -C are process diagrams showing another method of manufacturing a display structure according to the present invention. 100... display structure, 101... porous body,
102... Depression, 103... Micropore, 104...
... Flat part, 110, 111, 112 ... Liquid permeable electrode, 200-204 ... Electrode, 300 ... Support, 400 ... Liquid material, 501-509 ...
Conductor, 700...open space, _V1 to _V6 ...power supply,
L ₁ ...Outdoor light, 1100...Original plate for embossing, 1410, 1420...Roller, 1500
... Container, 1600 ... Solution.

Claims (1)

[Scope of Claims] 1. Embossing in which a mold body having a convex portion corresponding to the formation of a desired depressed portion is pressed onto a membrane-like porous body composed of a microporous membrane filter made of a plastic material, and further heated. 1. A method for manufacturing a display structure, which comprises forming a depressed portion on the surface of a porous body through processing. 2. A porous body composed of a microporous membrane filter made of plastic material and a mold plate having a convex portion corresponding to the shape of the desired recessed portion are overlapped, and the mold plate is passed through a gap between the rollers. 2. The method of manufacturing a display structure according to claim 1, wherein the porous body is pressurized and further heated to form a depressed portion on the surface of the porous body. 3. A sheet-like rubber body is arranged on the side of the porous body opposite to the side on which the mold is placed, with a sheet body having a smooth surface interposed therebetween, and the cumulative body is passed through a roller gap. A method for manufacturing a display structure according to claim 1. 4 Place a solution of plastic material on the mold surface having a convex portion corresponding to the shape of the desired depression,
Forming a microporous membrane filter on the mold surface by evaporation of the solvent;
A method for manufacturing a display structure, characterized in that a porous body consisting of a microporous membrane filter having a recessed portion on its surface is obtained by peeling it from the template. 5. Impregnating a display structure with a liquid material in which a recessed portion including a plurality of the openings is provided on the surface of a porous body having a plurality of fine openings exposed on at least one surface, and The display structure is held such that the surface provided with the recessed portion faces the open space, and means is provided for applying a voltage to the display structure, and the porous body is controlled in accordance with the voltage. A display device characterized in that a liquid impregnation rate of at least a surface of the display structure facing an open space of the display structure is controlled by movement of the liquid material. 6. The display structure is installed and held on the support plate surface, and the surface of the display structure with the recessed portion on the opposite side to the support plate faces the open space. Display device according to scope item 5. 7 Having at least a pair of electrode elements adjacent to each other on the support plate surface on which the display structure is installed, and in which one electrode element is arranged in the shape of the pattern to be displayed compared to the other electrode element. A patent claim characterized in that the electrodes are formed correspondingly wide and a voltage is applied directly between the electrodes to control the liquid impregnation rate of at least the surface of the display structure corresponding to the wide electrode element. The display device according to item 5. 8. The display structure has a light-transmitting and liquid-permeable electrode on a surface having a recessed part, and is installed on a support plate having the electrode coated on the surface, and a voltage is applied between the two electrodes. A display device according to claim 6, characterized in that: 9. In the display device according to claim 8, at least one of the electrodes provided on the display structure or the support plate is composed of a plurality of mutually insulated electrode elements, and A display device comprising means for selectively applying a voltage between the electrodes or electrode elements facing each other with a narrow structure. 10 A patent characterized in that a display structure consisting of a porous body made of a translucent material and having a depression on one surface is impregnated with a liquid material having a refractive index approximately equal to that of the translucent material. A display device according to claim 5. 11 For the surface of the display structure with the recessed part,
11. The display device according to claim 10, wherein the opposite surface is substantially translucent. 12. The display according to claim 10, wherein the surface of the display structure opposite to the surface provided with the recessed portion is substantially light-absorbing or light-reflective. Device. 13. The display device according to claim 5, wherein the display structure is made of a light-absorbing or opaque material and is impregnated with a translucent liquid material. 14 Consisting of a membrane or plate-shaped porous body having a large number of micropores that penetrate substantially from one surface to the other surface, and having a depressed portion containing a plurality of the micropores on the surface of the porous body. 6. A display device according to claim 5, further comprising a display device. 15. The display device according to claim 14, wherein the porous body is a microporous membrane filter made of plastic material and having micropores. 16. The display device according to claim 15, wherein the micropores have an average diameter of 0.1 to 1 micron and a thickness of 40 to 200 microns. 17. The display device according to claim 5, wherein the recessed portion is dot-shaped. 18 The depressed portion is in the shape of a cone, a truncated cone, a triangular pyramid, a truncated triangular pyramid, a square pyramid, a truncated quadrangular pyramid, a polygonal pyramid, or a polygonal truncated pyramid, with the porous body surface as its base. 18. A display device according to claim 17, characterized in that: 19. The display device according to claim 5, wherein the depressed portion has a radial point shape with a plurality of short lines extending radially around one point. 20. The display device according to claim 5, wherein the recessed portion is linear, short shelf-shaped, or net-shaped. 21. The display device according to claim 20, wherein the depressed portion has a triangular or trapezoidal cross-sectional shape with the surface of the porous body being the base and narrowing toward the inside of the porous body. 22. The display device according to claim 17, 19, or 20, wherein the included angle of the cross-sectional ridgeline of the depressed portion is 130° or less. 23. The display device according to any one of claims 17, 19, and 20, wherein the cross-sectional edge line of the depression is on a parabolic line convex toward the depression space. 24 Claim No. 1, characterized in that the depressions are at least one of dot-shaped, linear, and short shelf-shaped, and a plurality of depressions are arranged independently and adjacent to each other. Display device according to item 5. 25. The display device according to claim 5, wherein a plurality of types of depressions having different shapes are arranged independently and regularly. 26. The display device according to claim 5, wherein the recessed portion is disposed only in a portion corresponding to a pattern to be displayed. 27 The depressions are point-like, and the major axis at the surface of the porous body is in the range of 10 to 40 microns, the depth is in the range of 10 to 35 microns, and the diameter decreases toward the inside of the porous body. A display device according to claim 16 or 18, characterized in that: 28 Claims 16, 18, 20, or 21, characterized in that the short diameter or width of the tip of the depressed portion is within 5 microns.
Display device according to any one of paragraphs. 29 In the display structure according to claim 5, the surface provided with the recessed portion is made of a single piece or a plurality of mutually insulated conductive films that are permeable to liquid and transparent. A display device characterized by having electrodes adhered thereto.