JP2003091025A - Display element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display element by which the same gradation display is enabled between pixels even when an area for one pixel is reduced and also to provide its manufacturing method. SOLUTION: The display element is provided with a light permeable display side baseboard 1 and a non-display side baseboard 2 opposite to the baseboard 1, stores at least colored fluid 3 and a gel 4 deformed in response to an electric field between the baseboards 1 and 2 and performs display by adjusting an incident light through the use of the deformation of the gel 4 by the electric field and allowing it to exit. The density of a colored object is fixed in the colored fluid 3 and the thickness of the gel 4 stored in a thickness direction which is formed by the display side baseboard 1 and the non-display side baseboard 2, is changed by the electric field so that a distance obtained when the incident light passes through the colored fluid 3 is adjusted.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Currently, as a display device, a self-luminous type such as a CRT, a plasma display, an EL display, a fluorescent display tube and the like, and a non-luminous type such as a liquid crystal display utilizing reflected light and transmitted light. , And they are put into practical use. In recent years, due to the development of information systems,
VDT (Visual Data Te) for a long time
However, a non-emission type display screen is desirable in consideration of fatigue. For this reason, liquid crystal displays have recently become widespread as a force to replace CRTs. However, the liquid crystal display has a narrow viewing angle and the contrast of light and dark is not sufficient.

In order to solve such a problem, for example, Japanese Unexamined Patent Publication Nos. 61-149926, 63-13021 and 9-1600811 deform (swell / swell) in response to an external stimulus.
There has been proposed a display element that uses a polymer gel that contracts or bends, and adjusts incident light by the deformation of the polymer gel to perform display. This kind of display element
The polymer gel absorbs the solvent by external stimuli such as temperature, electric field, light, pH, ion concentration, and solvent composition, and swells, or discharges the solvent and contracts, or bends. Then, the incident light is adjusted for each pixel to display the contrast, thereby performing display. Unlike a liquid crystal display, such a system has a wide viewing angle and does not require a deflector or the like, and thus has an advantage of high light utilization efficiency and brightness.

FIG. 1 shows an example of a display element using gel. Referring to FIG. 1, this display element includes a light-transmissive display-side substrate 1 and a non-display-side substrate 2 that faces the display-side substrate 1, and includes the display-side substrate 1 and the non-display-side substrate 2. At least a colored liquid 3 and a gel 4 that deforms in response to an electric field are housed in the space, and the incident light is adjusted by utilizing the fact that the gel 4 deforms (swells / contracts or bends) due to the electric field. Then, the display is performed by emitting the light.

In FIG. 1, reference numerals 5 and 6 are electrodes for generating an electric field, and the electrode 5 is transparent. Further, in the configuration of FIG. 1, light is, for example, an arrow X.
In this case, when the gel 4 has no light transmissivity, or when the electrodes 6 and the substrate 2 are not transparent, this display element becomes a reflection type display element, Make the gel 4 light transmissive,
When the electrodes 6 and the substrate 2 are transparent, this display element becomes a transmissive display element. Regardless of whether this display element is a reflection type or a transmission type, this display element has a gel 4 and a liquid 3 arranged between a pair of substrates 1 and 2 at least one of which is transparent, and the gel 4 is formed by an electric field. By utilizing the phenomenon that swells and contracts, the incident light is adjusted for each pixel to provide contrast, thereby performing display.

At this time, for example, if the gel 4 is colored white and the liquid 3 is colored black, or conversely, the gel 4 is colored black and the liquid 3 is colored white, black-and-white display is possible. Also, gel 4 or liquid 3
Color display is possible by coloring the three primary colors of RGB instead of black, and a color filter can be used.

Also, in this example, depending on the type of gel 4, the electric field is turned on only when the gel 4 is contracted, or the electric field is turned on only when the gel 4 is extended, and no electric field is applied in other cases. Depending on the type of 4, the electric field is such that the electrode 5 on the display side substrate 1 side becomes an anode and the electrode 6 on the non-display side substrate 2 side becomes a negative electrode when the gel 4 shrinks, and the electrode on the display side substrate 1 side when the gel 4 extends. 5 is a negative electrode, and the electrode 6 on the non-display side substrate 2 side
A driving method in which an electric field is applied so as to serve as an anode is also possible, and a method of applying a voltage opposite thereto is also possible.

In the example of FIG. 1, two pixels P of the display element are shown.
In the pixel P1, the electric field is OFF, the gel 4 swells, and the area between the display-side substrate 1 (transparent electrode 5) and the non-display-side substrate 2 (electrode 6) is shown. Shows that only gel 4 is used. On the other hand, in the pixel P2, the electric field is ON, the gel 4 contracts, and the colored liquid 3 exists between the display-side substrate 1 (transparent electrode 5) and the gel 4. Here, when the display element is a reflective display element, assuming that the gel 4 is white and the colored liquid 3 is black, the incident light is reflected by the surface of the gel 4 or the surface of the electrode 6 in the pixel P1. Then, the pixel P1 looks white to the observer. In addition, in the pixel P2, since the colored liquid 3 exists immediately below the transparent electrode 5, the observer can see the pixel P2.
Looks black.

[0009]

By the way, in the display device as shown in FIG. 1, the shape of the gel 4 is conventionally controlled in order to perform gradation display (specifically, the surface of the display side substrate 1). (The area of the gel 4 that contacts the surface of the transparent electrode 5 is changed).

However, in this case, as the area of one pixel becomes smaller, the area of contact of the gel 4 with the display side substrate 1 becomes smaller in order to obtain the number of gradations, resulting in variations in the size of gel preparation. It has been found by the inventor of the present application that it is greatly affected and it becomes difficult to display the same gradation between pixels.

It is an object of the present invention to provide a display element and a method of manufacturing the same that enable the same gradation display between pixels even when the area of one pixel is reduced.

[0012]

In order to achieve the above object, the invention according to claim 1 is a display-side substrate having a light-transmitting property,
There is a non-display side substrate facing the display side substrate, between the display side substrate and the non-display side substrate, at least a colored liquid and a gel that deforms in response to an electric field are housed, and the gel is an electric field. In a display element that performs display by adjusting incident light by utilizing the deformation by
Incident light passes through the colored liquid by changing the thickness of the gel contained in the thickness direction formed by the display-side substrate and the non-display-side substrate by the electric field when the concentration of the colored liquid in the colored liquid is constant. It is characterized in that it is configured to adjust the distance.

According to a second aspect of the present invention, in the display element according to the first aspect, at a position inscribed in the display side substrate,
The gel which is not deformed by the electric field is arranged, and the gel which is deformed by the electric field is arranged on the side opposite to the display side substrate of the gel which is not deformed by the electric field.

According to a third aspect of the present invention, in the display element according to the first or second aspect, among the display-side substrates for the colored liquid contained between the display-side substrate and the non-display-side substrate, It is characterized by low surface wettability.

The invention according to claim 4 is the display element according to claim 3, characterized in that the surface of the display-side substrate which is in contact with the colored liquid is subjected to a liquid generating process.

According to a fifth aspect of the invention, in the display element according to any one of the first to fourth aspects,
It is characterized in that a gel that does not deform according to an electric field is arranged at a position inscribed in the non-display side substrate.

According to a sixth aspect of the invention, in the display element according to the fifth aspect, the gel that is not deformed by an electric field is
It is characterized by being a conductive gel.

According to a seventh aspect of the invention, in the display element according to the sixth aspect, the conductive gel contains a conductive polymer.

The invention according to claim 8 is the display element according to any one of claims 1 to 7, wherein:
The gel inscribed in the display-side substrate is colored.

According to a ninth aspect of the invention, in the display element according to any one of the first to eighth aspects,
The coloring liquid is black and the gel inscribed in the display side substrate is colored white.

The invention according to claim 10 has a light-transmissive display side substrate and a non-display side substrate facing the display side substrate, and between the display side substrate and the non-display side substrate. In a method of manufacturing a display element, which contains at least a colored liquid and a gel that deforms in response to an electric field, adjusts and emits incident light by utilizing the fact that the gel deforms due to an electric field, , Said gel is a chemical gel,
It is characterized in that the chemical gel is produced in a physical gel matrix.

The invention according to claim 11 is the same as claim 1.
In the method of manufacturing a display element described in No. 0, the temperature at the time of producing the chemical gel is characterized by being equal to or lower than the temperature at which the physical gel becomes a sol.

The invention according to claim 12 is the same as claim 1
The method for manufacturing a display element according to claim 0 or claim 11 is characterized in that the chemical gel is produced and then the physical gel is made into a sol.

The invention according to claim 13 is the same as claim 1.
The method for manufacturing a display element according to any one of claims 0 to 12, characterized in that the chemical gel is produced by light.

The invention of claim 14 is the same as claim 1
The method of manufacturing a display element according to any one of claims 0 to 13, characterized in that the chemical gel is manufactured in a dot matrix shape on the substrate.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment As described above, in the display device as shown in FIG. 1, conventionally, the shape of the gel 4 is controlled to perform gradation display (specifically, the display side substrate). 1 surface (surface of transparent electrode 5)
The area of the gel 4 that contacts the
In this case, as the area of one pixel becomes smaller, the number of gradations is increased, so that the area in which the gel 4 contacts the display-side substrate 1 becomes smaller, which is greatly affected by the variation in the size of gel production. It becomes difficult to display the same gradation between pixels.

As a result of studies for solving such a problem, the inventor of the present application has found that in the display element as shown in FIG. 1, the coloring matter concentration of the coloring liquid 3 is constant and the display side substrate 1 and the non-display side are not displayed. By changing the thickness of the gel 4 housed in the thickness direction formed by the side substrate 2 by the electric field,
It has been found that the above problems can be solved by adjusting the distance that incident light passes through the colored liquid 3.

That is, the display element according to the first embodiment of the present invention has a light-transmissive display-side substrate 1 and a non-display-side substrate 2 facing the display-side substrate 1. At least the colored liquid 3 and the gel 4 that deforms in response to an electric field are housed between the non-display side substrate 2 and the incident light is adjusted by utilizing the deformation of the gel 4 by the electric field. In a display element that performs display by emitting light, the concentration of the colored material in the colored liquid 3 is constant, and the gel 4 housed in the thickness direction formed by the display-side substrate 1 and the non-display-side substrate 2 is used.
The distance through which the incident light passes through the colored liquid 3 is adjusted by changing the thickness of the colored liquid 3 by an electric field.

As described above, by adjusting the distance that the incident light passes through the colored liquid 3,
Gradation display can be performed.

In the display element of the first embodiment, even if there is some variation in the gel production conditions, gradation display can be performed more uniformly. This is because the display element of the first embodiment does not perform gradation display based on the area in which the gel 4 is in contact with the substrate 1 (in the present invention, the gel 4
Of the projected area (the area where the gel 4 is in contact with the display-side substrate 1 (transparent electrode 5) is constant) and the light absorption capacity of the liquid 3 existing outside the gel 4 is used for gradation display. This is because it is achieved by using a method whose fundamental principle is different.

In other words, the gradation display of the present invention enables gradation display by controlling the distance A through which the light passes through the liquid 3 when focusing on the pixel P2 in FIG. . The distance A can be achieved by controlling the expansion / contraction rate of the gel 4. The expansion and contraction rate of the gel 4 can be achieved by controlling the electric field strength and the electric field application time. The transmittance of the liquid 3 used for visible light (black and white display: wavelength of displayed color in color display) is the transmittance for the minimum controllable stretching distance of the gel 4 in the case of transmission type display. 0.9
5 to 0.75 is preferable, and 0.9 to 0.85 is more preferable. In the case of reflective display, the transmittance is preferably 0.975 to 0.87, more preferably 0.95 to 0.92. If the transmittance is smaller than these ranges, the number of gradations that can be displayed is reduced, and if the transmittance is larger than these values, the expansion / contraction distance of the gel 4 for expressing the gradations is set large. Therefore, the cell gap becomes large, which is disadvantageous in terms of thickness, weight, and cost as a display element.

As described above, in the first embodiment of the present invention, in the display device as shown in FIG. 1, the coloring matter concentration of the coloring liquid 3 is constant, and the display side substrate 1 and the non-display side substrate 2 are By changing the thickness of the gel 4 accommodated in the thickness direction formed by the electric field by the electric field, the distance that the incident light passes through the colored liquid 3 is adjusted, so that the area of one pixel can be reduced. Even in this case, it is possible to display the same gradation between pixels.

Second Embodiment A second embodiment of the present invention is to improve the accuracy of gradation display (to provide a display element having a uniform pixel size).
Is intended. In the present invention, for example, in a reflective display element, the projected area of the gel 4 when viewed from the display side substrate 1 (the area where the gel 4 is in contact with the display side substrate 1 (transparent electrode 5)) is important. . The inventor of the present application has examined the size of the pixel in the ON state under the same conditions in the display element having the configuration as shown in FIG. 1, and as shown in FIG. 2A or 2B (see FIG. 2 (a) is a diagram showing an example in which a gel that contracts by an electric field is used as the gel 4, and
FIG. 2B is a diagram showing an example in which a gel that swells by an electric field is used as the gel 4, and the size of the projected area (that is, pixel) of the gel 4 when viewed from the display side substrate 1 side. It turns out that is different. It is considered that this is due to variations in gel preparation conditions, variations in applied voltage, variations in cell gap, and the like.

The inventor of the present application, as a result of studies to solve this problem, found that a gel that is not deformed (swelled / contracted or bent) with respect to an electric field is arranged at a position inscribed in the display-side substrate 1 and It has been found that the above problems can be solved by disposing a gel that does not deform (swell / contract, or bend) on the side opposite to the display-side substrate 1 of the gel that does not deform (swell / contract or bend). It was

That is, the display element of the second embodiment of the present invention, as shown in FIG. 3, is deformed with respect to the electric field at a position inscribed in the display side substrate 1 in the display element of the first embodiment. A gel 14 that does not deform is arranged, and a gel 24 that deforms due to an electric field is arranged on the side of the gel 14 that does not deform against an electric field, opposite to the display-side substrate 1.

In other words, in the display element of FIG. 3, the display-side substrate 1, the gel 14 that is not deformed by the electric field, and the gel 24 that is deformed by the electric field are the display-side substrate 1, the gel 14 that is not deformed by the electric field, and the electric field. Gel that deforms by 24
Are arranged in this order from the display side substrate 1 side.

With such a structure, even if the gel 24 under the gel 14 which is not deformed by an electric field expands or contracts, the projected area of the gel when viewed from the surface of the display side substrate 1 can be kept more uniform. It will be possible. That is, it is possible to improve the accuracy of gradation display (provide a display element having a uniform pixel size).

It is to be noted that the gel which does not deform by the electric field is ideally one which does not deform at all, but the amount of deformation in the cell is smaller than that of the gel which deforms by the electric field in the present invention. I wish I had it. Specifically,
The gel 14 that is not deformed by the electric field is ideally one that is not deformed at all, but when the amount of deformation in the cell is smaller than that of the gel that is deformed by the electric field in the present invention, The undeformed gel 14 is
It is also possible to select from gels that are deformed by an electric field. Preferably, the gel 14 that is not deformed by an electric field and the gel 24 that is deformed by an electric field are preferably made of the same series of materials (for example, an acrylate material). In this case, the affinity (adhesiveness) at the interface between the gel 14 that is not deformed by the electric field and the gel 24 that is deformed by the electric field can be improved, and the durability of the device can be improved. Most preferably, a polyacrylamide cross-linked gel can be used as the gel 14 that is not deformed by an electric field, and a gel 24 that is deformed by an electric field has a polymer ion part such as sodium acrylate in an acrylamide material. Cross-linked gels obtained by copolymerizing materials can be used.

The thickness of the gel that is not deformed by the electric field and the thickness of the gel that is deformed are as follows: when the liquid enters between the display side substrate and the upper surface of the gel at the time of gel contraction (ON state shown in FIG. 3) and at the time of gel extension. It is necessary to make the thickness of the gel so that a sufficient contrast can be obtained between when is in contact with the display side substrate surface (OFF state shown in FIG. 3). The thickness should be appropriately set depending on the type of gel and the liquid to be used, and cannot be generally determined. However, when the gel contracts due to the electric field, a gap (a liquid enters the gap between the gel and the display-side substrate surface) It is preferable to set the thickness of the liquid crystal between the substrates so that the average transmittance of visible light of 400 nm to 700 nm of the liquid contained between the substrates is 50% or less in order to obtain the contrast of the display element.

FIG. 4 shows that the gel that is not deformed by the electric field (upper gel) 14 is deformed, but this is not the deformation by the electric field, but the gel that is deformed by the electric field (lower gel). The drawing shows the state of being deformed by being dragged by the contracting force of 24. Therefore, the thickness of the gel 14 that is not deformed by the electric field is preferably set to a thickness that allows the deformation of the gel 24 that is deformed by the electric field due to the contracting force to be relaxed without reaching the upper portion of the gel 14 that is not deformed by the electric field.

As a method for producing the gel 14 which is not deformed by an electric field and the gel 24 which is deformed by an electric field, for example, a pre-solution of the gel 24 which is deformed by an electric field is applied to a substrate and then energy such as heat or ultraviolet rays is applied. The gel film can be prepared by forming a gel film, then applying a pre-solution of the gel 14 which is not deformed by an electric field, and applying energy such as heat or ultraviolet rays to the gel film. At this time, if it is light, the shape can be controlled by passing it through a photomask, and if it is heat, the shape can be controlled by focusing light or something having a minute spot such as a laser. Further, as the gel produced at this time, it is preferable to use a chemical gel which is stable against the external environment. Further, it is more preferable to use the production method using a physical gel described later.

As described above, in the second embodiment of the present invention, in the display element of the first embodiment, the display side substrate 1 is used.
Since the gel 14 that does not deform with respect to the electric field is arranged at the position inscribed in, and the gel 24 that deforms with the electric field is arranged on the side of the gel 14 that does not deform against the electric field opposite to the display side substrate 1. Thus, it is possible to improve the accuracy of gradation display (provide a display element having a uniform pixel size).

Third Embodiment Further , the third embodiment of the present invention is intended to improve the contrast. Since the present invention performs display by utilizing the colored liquid outside the gel, when the gel is inscribed in the display side substrate, the colored liquid enters between the display side substrate and the gel. It is preferable not to come. In the past, when the gel and the display-side substrate were brought into contact with each other, a part of the liquid remained between the gel and the display-side substrate, and there was a problem that sufficient contrast could not be obtained.

The inventor of the present application, as a result of studies to solve this, reduces the wettability of the surface of the display side substrate (transparent electrode) with respect to the liquid contained in the display side substrate and the non-display side substrate. It has been found that the above problems can be solved.

That is, the display element of the third embodiment of the present invention is the same as the display element of the first or second embodiment,
The wettability of the inner surface of the display side substrate 1 with respect to the colored liquid 3 contained between the display side substrate 1 and the non-display side substrate 2 is low.

Here, the low wettability means that the display side substrate 1
It is desired that the contact angle of the surface contacting the liquid 3 with respect to the liquid 3 is a receding contact angle of 50 ° or more. As shown in FIG. 5, the contact angle is the angle θ of the angle between the surface of the droplet and the surface of the substrate that includes the droplet, and the receding contact angle is The liquid was dropped and wetted, and then the liquid was absorbed, and the angle of the liquid droplets remaining at that time was measured by enlarging it with an optical system.

As a method of lowering the wettability between the display-side substrate and the liquid contained between the substrates, the wettability is adjusted by surface-treating the substrate surface in contact with the liquid or providing a new layer. And a second way of choosing the combination of substrate and solvent. To explain the first method in more detail, first, it is possible to make the surface of the substrate in contact with the liquid hydrophobic if the liquid used is hydrophilic or hydrophilic if the liquid is lipophilic. Hydrophobicization of the substrate
For example, it can be achieved by providing a polymer layer containing a hydrophobic group such as an alkyl group, or by carrying out a surface treatment using a coupling agent such as a silane type or a titanium type. Hydrophilization can be achieved by providing a polymer layer containing a hydrophilic group such as a sulfonic acid group, a carboxyl group, a hydroxyl group, an amino group, and a cyano group. Furthermore, if any liquid is treated to generate liquid, regardless of the type of liquid,
It is preferable because it can be used in a wider range. In this case, liquefaction can be achieved by, for example, providing a polymer layer having a fluorinated alkyl group, a siloxane group, or the like, but is not particularly limited as long as the desired lyophobic property is obtained. As the polymer having a fluorinated alkyl group, polyvinyl fluoride,
Fluorine-based resins such as polyvinylidene fluoride, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer are mentioned. Examples of the polymer having a siloxane group include silicone resins such as dimethyl silicone, methylphenyl silicone, silicone amino modification, epoxy modification, carboxyl modification, methacryl modification, phenol modification, and alkyl modification. . The surface of the substrate can be liquefied by dissolving or dispersing these polymers in a solvent and immersing the substrate. In addition, sol-gel method, biosol method, CVD,
The liquefied layer may be formed by vacuum deposition, ion plating, or the like.

As described above, the display element of the third embodiment of the present invention is the same as the display element of the first or second embodiment, and is housed between the display side substrate 1 and the non-display side substrate 2. Since the wettability of the inner surface of the display-side substrate 1 with respect to the colored liquid 3 present is low (specifically, the surface of the display-side substrate 1 in contact with the colored liquid 3 has been subjected to a liquid generation process). , The contrast can be improved.

Fourth Embodiment The fourth embodiment of the present invention is intended to improve the durability of repeated display. The inventor of the present application is
For example, in the display device having the configuration of FIG. 1, when the repeated display characteristics were examined, when the gel 4 was repeatedly expanded and contracted,
From the portion of the contact surface B between the electrode 6 and the gel 4, the gel 4 and the electrode 6
It was found that the peeling of the gel 4 caused the gel 4 to float in the liquid 3 and the accurate display was hindered (the floating gel moved from its original position or abnormal contrast occurred). This phenomenon is such that the expansion and contraction of the gel 4 actually occurs in the vicinity of the electrode 6, and when contracting, the state is as shown in FIG. 6, so stress is generated at the interface between the electrode 6 and the gel 4, It is considered that they will eventually peel off.

The inventor of the present application has conducted a study to solve this problem, and as a result, by arranging a gel that does not deform (swell / contract or bend) in response to an electric field, at a position inscribed in the non-display side substrate 2. It has been found that an element having excellent repeated display characteristics can be obtained.

That is, the display element of the fourth embodiment of the present invention is, in the display element of any of the first to third embodiments, deformed at a position inscribed in the non-display side substrate 2 in accordance with an electric field. It is characterized by placing a gel that does not.

FIG. 7 shows an example of such a display element. In the display element of FIG. 7, the non-display side substrate 2, the gel 34 that is not deformed by the electric field, and the gel 44 that is deformed by the electric field are not deformed by the non-display side substrate 2 or the electric field from the non-display side substrate 2 side. The gel 34 and the gel 44 that is deformed by an electric field are arranged in this order.

Although it is not clear why such a structure improves the repetitive display characteristics, it is probably that the material is a hard non-deformable material such as the non-display side substrate 2 and an inorganic material (in the case of glass), In contrast to the organic material, which is deformable by an electric field, the adhesiveness is insufficient, and thus the adhesive is peeled off due to the stress of deformation. In the fourth embodiment, both the material that does not deform and the soft organic material (34) are used. It is considered that by sandwiching the gap between them, the stress due to the deformation of the gel 44 which is deformed by the electric field can be relaxed inside the gel 34 which is not deformed by the electric field without being directly transmitted to the electrodes 6 and the substrate 2.

It should be noted that the gel which is not deformed by the electric field as used herein does not need to be one which is not deformed at all, as long as the deformation amount is smaller than the deformation amount of the gel deformed by the electric field. It is effective in improving the repeated display characteristics. Specifically, the gel 34 that is not deformed by the electric field does not need to be one that does not deform at all, and the amount of deformation is smaller than that of the gel that is deformed by the electric field. In particular, the gel 34 that is not deformed by the electric field can be selected from gels that are deformed by the electric field. Preferably, the gel 34 that is not deformed by an electric field and the gel 44 that is deformed by an electric field are preferably made of the same series of materials (for example, an acrylate material). In this case, the affinity (adhesiveness) at the interface between the gel 34 that is not deformed by the electric field and the gel 44 that is deformed by the electric field can be improved, and the durability of the device can be improved. Most preferably, a polyacrylamide cross-linked gel is used as the gel 34 that is not deformed by an electric field, and a material having a polymer ion portion such as sodium acrylate is copolymerized with an acrylamide material as the gel 44 that is deformed by an electric field. Crosslinked gels can be used.

The thickness of the gel that is not deformed by the electric field and the thickness of the gel that is deformed are as follows: when the liquid enters between the display-side substrate and the upper surface of the gel during gel contraction (ON state shown in FIG. 7) and during gel extension. It is necessary to make the thickness of the gel so that a sufficient contrast can be obtained between when is in contact with the display side substrate surface (OFF state shown in FIG. 7). The thickness should be appropriately set depending on the type of gel and the liquid to be used, and cannot be generally determined. However, when the gel contracts due to the electric field, a gap (a liquid enters the gap between the gel and the display-side substrate surface) It is preferable to set the thickness of the liquid crystal between the substrates so that the average transmittance of visible light of 400 nm to 700 nm of the liquid contained between the substrates is 50% or less in order to obtain the contrast of the display element.

As described above, the display element according to the fourth embodiment of the present invention is the display element according to any one of the first to third embodiments, in which a position corresponding to the non-display side substrate 2 is inscribed, depending on the electric field. Since the gel 34 that is not deformed due to the arrangement is arranged, the durability of repeated display can be improved.

Fifth Embodiment Further, the fifth embodiment of the present invention is the same as the display device of the fourth embodiment, except that the gel 34 which is not deformed by an electric field is used.
Is conductive.

The stretching speed (response speed) of the gel is higher as the electric field strength is higher. However, since the gel generally does not have sufficient conductivity, for example, in the display element of FIG. 7, the electric field strength (E1) applied between the uppermost end of the gel and the transparent electrode 5 of the display side substrate 1 is increased. Is smaller than the electric field intensity (E0) originally applied between the electrodes 5 and 6 (see FIG. 8).

FIG. 9 is a diagram showing an example of the structure of the display element of the fifth embodiment. In the example of FIG. 9, the portion of the gel 34 that is not deformed by the electric field is conductive. According to this configuration, when the gel 34 that is not deformed by the electric field is conductive and has sufficient conductivity, E0 = E
8, and when the thickness of the inside of the cell is the same in the configuration of FIG. 8 and the configuration of FIG. 9, a larger electric field than that in the configuration of FIG. 8 can be applied to the gel deformed by the electric field. The response speed can be improved.

In fact, the inventor of the present application, in a display element in which a gel 34 which is not deformed (swelled / contracted or bent) according to an electric field is arranged at a position inscribed in the non-display side substrate 2,
When the response speed was evaluated, deformation (swelling /
If the gel 34 that does not contract or bend) is conductive,
It was found that the response speed was better.

As described above, in the display element of the fifth embodiment, since the gel 34 which is not deformed by the electric field is the conductive gel in the display element of the fourth embodiment, the response speed can be improved.

To make the gel conductive, a method of mixing a conductive substance into the gel can be used. The conductive gel is
After dispersing the conductive substance in the liquid state before gelation,
It can be produced by gelling. As the conductive substance that can be used at this time, a metal, a metal oxide, a metal nitride, or a conductive organic substance can be used. More specifically, Au,
Metal particles of Pt, Ag, Cu, Fe, Al, Ti, etc., I
n ₂ O ₃ , SnO ₂ , ZnO, CdO, TiO ₂ , In ₂ O ₃
-Sn, oxides such as SnO ₂ -Sb, TiN, ZrN
Examples thereof include organic substances such as nitrides, graphite, conductive polymers, etc., but they are required to be electrochemically stable under an applied electric field. As the shape, fine particles are preferable. Among these conductive materials, it is preferable to use a conductive polymer material. This is because they are the same organic substance and therefore have a good affinity with the gel as the matrix, and can stably exist as a complex. In addition, although it is a liquid before gelation, it is preferable to use a conductive polymer also from the viewpoint of gel synthesis, because dispersion and stabilization can be more easily performed in this liquid state. The conductive polymer used for the composite is not particularly limited, and examples thereof include polymers such as hetero five-membered ring compounds, condensed polycyclic compounds and amine compounds. More specifically, polypyrrole, polythiophene, polyphenylene, polyazulene, polyaniline, polydiphenylbenzidine, polyisothionaphthene and derivatives thereof can be exemplified, and more preferably polyaniline and its derivatives, polypyrrole because of high conductivity and stability. And its derivatives, polythiophene and its derivatives, and most preferably polyaniline, polypyrrole and poly (3-methylthiophene). Since these compounds are used in a conductive state, it goes without saying that they are in a doped state. Furthermore, it is preferable to use a polymer dopant which is difficult to be undoped by an applied electric field as an ion species which is a dopant.

As a method of producing a gel which is not deformed by an electric field and a gel which is deformed by an electric field, for example, a gel pre-solution which is not deformed by an electric field is applied to a substrate and then energy such as heat or ultraviolet rays is applied to the gel. There is a method of forming a film, then applying a pre-solution of gel that is deformed by an electric field on it, and applying energy such as heat and ultraviolet rays to form a gel film. At this time, if it is light, the shape can be controlled by passing it through a photomask, and if it is heat, the shape can be controlled by condensing light or by using something having a minute spot such as a laser. Further, as the gel produced at this time, it is preferable to use a chemical gel stable to the external environment. Further, it is preferable to use a production method using a physical gel described later.

Sixth Embodiment A sixth embodiment of the present invention is a light-transmissive display side substrate,
There is a non-display side substrate facing the display side substrate, between the display side substrate and the non-display side substrate, at least a colored liquid and a gel that deforms in response to an electric field are housed, and the gel is an electric field. In the method of manufacturing a display device that performs display by adjusting the incident light by utilizing the deformation by, the gel is a chemical gel, and the chemical gel is produced in a physical gel matrix. It has a feature.
That is, the gel used for display is a chemical gel, and the chemical gel is produced in a physical gel matrix.

That is, the inventor of the present application has studied the improvement of the shape controllability during gel preparation. As a result, the gel used for display is a chemical gel, and by producing the chemical gel in a physical gel matrix, It has been found that the shape controllability during gel preparation can be improved.

Here, the chemical gel is formed in such a manner that the solvent is incorporated into the three-dimensional network structure of the polymer, but since the network structure is a chemical bond, it has no processability after being manufactured. Therefore, in order to produce a chemical gel having a desired shape, a mold having a desired shape is prepared and a gelation reaction is carried out in the mold to obtain the desired shape. However, this method is difficult because the mold is not peeled off from the gel and the gel is damaged. The idea of applying a chemical gel to a display element has existed in the past (Japanese Patent Laid-Open Nos. 61-149926 and 63-130).
21, JP-A-9-160081), for example, JP-A-63-
In 13021, a monomer solution state before gelation is applied on a substrate, and the monomer in the solution is photopolymerized through a dot matrix mask to obtain a dot matrix chemical gel. . According to this method, a dot-matrix gel can be obtained, but since the liquid remains on the substrate until it is irradiated with light, there is a drawback that evaporation, handling, and deformation of the liquid surface due to air flow are likely to occur. Further, as the liquid becomes thicker, it becomes difficult to accurately control the shape of the gel due to the disturbance of the monomer in the liquid.

The present invention solves such a problem. The concept of the manufacturing method of the present invention will be described. First, prepare a system that can form a physical gel, and then, in the system at a temperature above the sol transition temperature of the physical gel (that is, in a fluid state), a monomer that forms a chemical gel (usually a monofunctional monomer). And a polyfunctional monomer), and if necessary, a reaction initiator (photoinitiator, thermal initiator), and if necessary, a solvent, an additive, etc. are added to obtain a uniform state. In this state, the temperature is lowered below the temperature at which the physical gel is transformed. This allows the system to gel and be treated as an apparent solid. If light is applied in this state (polymerization is photoinitiated), the reaction occurs only where the light hits,
A chemical gel will be produced. That is, the shape of the chemical gel can be controlled by controlling the position where the light is applied.
Further, if a light source having a minute spot such as a laser beam is used as light, fine processing is possible. Further, if light is collected using a lens and the temperature is raised locally (in the case where the polymerization is initiated by heat), the chemical gel is generated only at the place where the temperature rises. That is, the shape of the chemical gel can be controlled by controlling the light collecting position.

In this way, it becomes possible to control the shape of the chemical gel using the physical gel matrix. Furthermore, if the physical gel thus produced is heated to a temperature above the temperature at which the physical gel undergoes sol transition, the physical gel becomes sol again, that is, it becomes fluid.
On the other hand, in the portion where the chemical gel is generated, the organic substances bond with each other chemically (covalent bond), and thus remain in a gel state, that is, a solid state even when the temperature is raised. In this state, the chemical gel is taken out, or the physical gel is washed away, so that only the shape-controlled chemical gel can be obtained.

The gel in the present invention means a state in which a solvent is incorporated in the three-dimensional network structure.

The physical gel used in the present invention is
It refers to a substance that can change from a gel state to a solution state (sol state). The structure of the cross-linking part of the three-dimensional network structure is not limited as long as it is possible to change from the gel state to the solution state, but when the cross-linking structure is generally due to a secondary bonding force other than a covalent bond. In many cases, the secondary binding force here is due to intermolecular force bonding (hydrogen bond, molecular orientation, helix formation, lamella formation, etc.) or ionic bond.
The change of gel into a solution (sol formation) due to intermolecular force bonding is
Generally, it can be caused by raising the temperature (sometimes depending on the environment such as pH). Any material can be used as long as it does not adversely affect the formation of the chemical gel described later. More specifically, natural polymer gels (polysaccharide gels, DNA gels, etc.), low molecular weight gelling agents (alkylamide compounds, etc.) gels, etc. can be used. The change of the gel into a solution (sol formation) due to ionic bonding can be generally caused by changing pH or ionic strength. More specifically,
Natural polymer gel (such as polysaccharide gel containing ionic species),
Synthetic polymer electrolyte gels (polymer electrolytes containing polyvalent ions, polyion complexes, etc.) can be used.
Furthermore, even if the cross-linked portion is covalently bonded, for example, in the case of a gel with an acetal bond or an ester bond, it is possible to cause hydrolysis by pH change and bring it into a solution state,
Such materials can also be used.

The chemical gel used in the case of using a physical gel means that its crosslinked portion is stable and changes against disturbance (environmental change in which the gel is placed such as temperature change, pH change, ionic strength change, etc.). It does not. Of course, it suffices if it is stable in the system used, and it is not always necessary to be stable with respect to all the above-mentioned disturbance factors. Preferably, a synthetic polymer gel can be used. The synthetic polymer gel can be produced by either a method of producing a bond necessary for a crosslinked structure simultaneously with polymerization or a method of crosslinking a linear polymer afterwards. A general method is a method in which a divinyl monomer is allowed to coexist as a crosslinking agent to polymerize the vinyl monomer. Heat, light or radiation can be used to initiate the reaction. The latter method involves adding a reactive species (crosslinking agent: a substance capable of reacting with a functional group) to a polymer solution having a functional group, and causing the two to react with each other by heat and light to form a three-dimensional structure. In the chemical gel in this case, the gel can change its shape in response to environmental changes (external stimulation) in which the gel is placed.
As the gel which is deformed by an external stimulus, a liquid-absorbent polymer which absorbs a liquid, swells, is discharged and contracts, for example, a known acrylic compound or divinylbenzene, N,
Materials such as polyether, polyvinyl alcohol, cellulose, starch, and polyacrylic acid based on graft-polymerization of crosslinkable monomers such as N'-methylenebisacrylamide can be used. In particular, acrylamide derivatives are the main components, and ion dissociation monomers and crosslinks are used. A crosslinkable polymer obtained by polymerizing a volatile monomer, a copolymer of methyl methacrylate and acrylic acid, a polyacrylic acid salt and the like are preferably used. Further, examples of the polymer that is bent by an external stimulus include a polyacrylic acid / polyvinyl alcohol complex.

In the case of producing a chemical gel in a physical gel, as a method therefor, a system capable of producing the above-mentioned physical gel is prepared and brought into a sol state (in a solution state). A liquid before gelation is prepared by adding the above-mentioned compound capable of forming a chemical gel to this. At this time, it is preferable that the system is homogeneous, that is, the physical gel material and the chemical gel material are uniformly dissolved in the solvent, and it is necessary that they do not react with each other in the working environment. Even if there is only one solvent, 2
Mixtures of more than one species can also be used. What is the addition amount of the compound capable of forming a chemical gel to the sol, as long as the sol can be a physical gel and the chemical gel can generate a chemical gel by receiving energy such as heat or light. The amount of addition can be varied, but it should be appropriately determined depending on the material used so that the shape change of the chemical gel due to the external stimulus becomes preferable. In this state, the physical gel is transformed. This allows the system to gel and be treated as an apparent solid. If light is applied in this state (in the case where the polymerization is photoinitiated), the reaction occurs only where the light is applied, and a chemical gel is produced.
That is, the shape of the chemical gel can be controlled by controlling the position where the light is applied. Further, if a light source having a minute spot such as a laser beam is used as light, fine processing is possible. Further, if light is collected using a lens and the temperature is raised locally (in the case where the polymerization is initiated by heat), the chemical gel is produced only at the place where the temperature rises. That is, the shape of the chemical gel can be controlled by controlling the light collecting position. In this way, it is possible to control the shape of the chemical gel by using the physical gel matrix.
Furthermore, if the physical gel thus produced is placed in an environment in which the physical gel undergoes sol transition, the physical gel becomes sol again, that is, it becomes fluid. On the other hand, in the part where the chemical gel is generated, the organic substances are chemically bonded (covalent bond), and therefore, they remain in a gel state, that is, a solid state even when the environment is changed. In this state, the chemical gel whose shape is controlled can be obtained by taking out the chemical gel or pouring off the sol.
When utilizing a temperature change to make the physical gel a sol, the temperature is preferably 40 ° C. or higher because the physical gel maintains a solid (gel) state at room temperature (working environment). More preferably, it is 40 to 80 ° C., and in this range, the energy given to form the sol is small, and the temperature raising device to be used may be a general-purpose one, which is preferable. In consideration of the temperature at which the chemical gel is produced, the solization temperature of the physical gel is preferably equal to or higher than the temperature at which the chemical gel is produced. With this temperature relationship, the physical gel is effectively kept in a solid state at the time when the chemical gel is produced, so that the shape of the chemical gel can be controlled with higher accuracy. The generation of the chemical gel in the physical gel can be performed by heat, light or the like, but it is preferable to use light from the viewpoint of fine processing. Furthermore, when the solization temperature of the physical gel is set to a relatively low temperature of 40 ° C. or higher as described above, it is practically difficult to generate a chemical gel by heat, and thus heat of the chemical gel is less likely to be generated due to light that is less likely to generate heat. It is more preferable to carry out production. Regarding the formation of a chemical gel in a physical gel, even if the chemical gel producing monomer reacts with the physical gel constituent material, the produced chemical gel can cause a volume change due to an external stimulus.

As the gel which can be deformed by an electric field which can be generally used in the present invention, a gel which absorbs a liquid and swells,
There are liquid-absorbent polymers that drain and contract, for example,
Known acrylic compounds, polyethers obtained by graft-polymerizing crosslinkable monomers such as divinylbenzene and N, N-methylenebisacrylamide, polyvinyl alcohol, cellulose, starch, and polyacrylic acid-based materials are mentioned, and especially acrylamide derivatives are mainly used. As the component, a crosslinkable polymer obtained by polymerizing an ion dissociation monomer and a crosslinkable monomer, a copolymer of methyl methacrylate and acrylic acid, a polyacrylic acid salt and the like are preferably used.
Examples of the polymer that bends include a polyacrylic acid / polyvinyl alcohol composite. In order to color the gel, dye particles such as carbon and pigment may be immobilized in the gel or only on the display surface side of the gel by adsorption, bonding or the like. This enables various color displays.

As the solvent which can be used in the present invention, water is preferably used in consideration of easiness of handling, safety and cost, but basically it is used if it can be absorbed in the gel. It is possible. Specifically, water, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, N-methylpyrrolidone,
Aprotic polar solvents such as N, N-dimethylformamide, halogenated hydrocarbons such as carbon tetrachloride and chloroform, ethers such as tetrahydrafuran and diethyl ether, and hydrocarbons such as isopentane and benzene. To be Regardless of water or organic solvent, the temperature at the time of producing the chemical gel is preferably from the freezing point to the boiling point of the solvent used.

When the solvent is colored and used, a dye which does not easily enter the gel is dispersed in the solvent by using a surfactant or the like, if necessary. At this time, the dye used is not particularly limited and may be a usual method such as a dispersion method, and a known hydrophilic ink, lipophilic ink or the like may be used. If necessary, an electrolyte salt such as a chloride salt, a perchlorate salt, a tetrafluoroborate salt, or an ammonium salt may be added to the solvent before use.

As for the substrate, the display-side substrate 1 needs to be transparent, and glass, transparent plastic film, or the like is used. In the case of a transmissive display element, a transparent substrate similar to the display-side substrate 1 is used as the substrate on the side opposite to the display-side substrate 1, that is, the non-display-side substrate 2 (in this case, the gel transmits light). ), In the case of a reflective display element, when the gel itself has a reflection function (in this case, the gel is a light-scattering (white) gel), a transparent substrate similar to the display-side substrate 1 is used. If the gel does not have a reflection function (in this case, the gel transmits light), Al or S
A metal plate of US or the like, a substrate in which a metal film of Al or Cr is formed on a glass or plastic film to enhance the reflection effect, and the like are used.

The electrodes used are the display side substrate.
The transparent electrode is required for the first electrode 5 and₂O₃, S
nO₂, ZnO, CdO, TiO₂, In₂O₃-Sn, S
nO ₂-Sb and other oxide thin films, such as TiN and ZrN
A known material such as a conductive nitride thin film is used. On the other hand, the table
The electrode 6 used on the substrate 2 opposite to the display-side substrate 1 is
In addition to transparent electrodes, metals such as Pt, Au, Cu, Al
A thin film or the like is used.

[0079]

EXAMPLES Examples of the present invention will be described below.

Example 1 In Example 1, glass substrates 1 and 2 on which transparent electrodes were formed were prepared. Next, a solution in which acrylamide / acrylic acid / vinyl alcohol were mixed at a molar ratio of 659/40/1 and ammonium persulfate was added as an initiator and copolymerized to form an ITO different from the above hydrophobized one. It was applied on the glass substrate 2 and crosslinked by heating to form an acrylic acid-acrylamide copolymer white gel. The glass substrate 1 and the glass substrate 2 are sandwiched with a mylar film as a spacer, and the peripheral portion is sealed to form an empty cell, and the cell is filled with the black aqueous ink 3 to swell the gel 4 and the gel 4 is swollen, as shown in FIG. The evaluation cell was as shown in. In the state of FIG. 10A, the gel 4 is the electrode 5 of the display-side substrate 1.
It is in contact with and shows a transparent display. The transmittance at 550 nm was about 1. Substrate 2 for this evaluation cell
When a rectangular wave voltage having a constant peak value is applied for a certain period of time by using + as the electrode 6 on the side and electrode 5 on the side of the substrate as the ground, FIG.
The state becomes 0 (b), the transmittance becomes 0.72, and when a rectangular wave voltage having a doubled peak value is used, the transmittance becomes 0.48, and gradation display is possible.

Example 2 In Example 2, a glass substrate 1 and a substrate 2 on which transparent electrodes were formed were prepared. An aqueous solution in which acrylamide / sodium acrylate / N, N-methylenebisacrylamide was mixed at a molar ratio of 33/2 / 0.33 was applied on the substrate 2, the mask was changed and the light of a low-pressure mercury lamp was irradiated, circular shape. Of sodium acrylate-acrylamide copolymer gel was formed. Next, acrylamide and N, N-methylenebisacrylamide were dissolved in pure water to a molar ratio of 100/1 to prepare a liquid in which titanium oxide fine particles were dispersed. This solution was applied onto the substrate 2 on which a sodium acrylate-acrylamide copolymer gel had been formed, and the gel was irradiated with light through a mask to prepare an acrylamide gel on the sodium acrylate-acrylamide copolymer gel. . Next, the glass substrate 1 and the glass substrate 2 are sandwiched between Mylar films as spacers and sealed to form a cell, and the black water-based ink 3 is filled in the cell.
The evaluation cell as shown in 1 (a) was used. In this state,
The gel 4 is in contact with the electrode 5 of the display side substrate 1 and shows white display. When a voltage is applied after leaving the evaluation cell for a sufficient time, the gel 4 contracts and separates from the display side substrate 1 as shown in FIG.
Was satisfied, and black display was shown from the display side substrate 1 side. Next, when the electric field was cut off, the gel 4 returned to the original swollen state, and the first white display could be confirmed again. In this state, the area of the white portion was measured and compared with the area before driving, the area after driving was 1.05 times the area before driving.

Comparative Example 1 In Comparative Example 1, an evaluation cell was prepared in the same manner as in Example 2 except that the crosslinked gel of acrylamide and N, N-methylenebisacrylamide was not prepared. The area change was 1.21.

Comparative Example 2 Comparative Example 2 is the same as Example 2 except that acrylamide / sodium acrylate / N, N-methylenebisacrylamide is used instead of acrylamide and N, N-methylenebisacrylamide. An evaluation cell was produced. The area change was 1.25.

Example 3 In Example 3, on the glass substrate 1 on which the transparent electrode was formed,
0.5% of γ-aminopropyltrimethoxysilane (Nippon Unicar A1110) as a silane coupling agent
An ethanol solution was applied and heated at 100 ° C. for 10 minutes to subject the surface to a coupling treatment for hydrophobic treatment. When the contact angle (receding contact angle) between the surface subjected to this hydrophobic treatment and the black aqueous ink used in this example was measured,
It was 62 °. Next, acrylamide / acrylic acid /
Vinyl alcohol / titanium oxide (average particle size 0.2μ
m) in a molar ratio of 659/40/1/200 and ammonium persulfate as an initiator was added thereto to copolymerize the solution, and a solution of about 3 μm was formed on the glass substrate 2 formed with ITO, which was different from the above hydrophobicized solution. It was applied and crosslinked by heating to form an acrylic acid-acrylamide copolymer white gel.
The glass substrate 1 and the glass substrate 2 were sandwiched with a 10 μm Mylar film as a spacer, and the peripheral edge was sealed to prepare an empty cell, and the cell was filled with a black aqueous ink containing an electrolyte to swell the gel and evaluated. It was a cell.
In this state, the gel is in contact with the electrode of the display-side substrate 1, and white display is shown. When a voltage of 3 V is applied to the evaluation cell with the electrode on the substrate 2 side as + and the electrode on the substrate 1 side as −, the gel contracts and separates from the display side substrate 1,
Black ink was filled there, and black display was shown from the display substrate side. Next, when the electric field was cut off, the gel returned to the original swollen state, the first white display could be confirmed again, and the contrast of white and black obtained from the reflectance was 9.6. Further, even when the electric field was turned on and off a number of times, the white and black contrasts were firmly maintained.

Comparative Example 3 In Comparative Example 3, in Example 3, the IT on the glass substrate was used.
When the O surface was not subjected to the hydrophobic treatment with the silane coupling agent, the contact angle (receding contact angle) with the liquid used in Example 1 was 14 °. With this substrate,
When the same evaluation cell as in Example 1 was produced and evaluated,
When the black state when the electric field is applied changes to the white state when no voltage is applied, the swollen gel with the black ink adhering to the display-side electrode surface comes into contact with the electrode surface. Therefore, bright white display cannot be obtained and the black and white contrast is 6%. It fell to .5.

Example 4 In Example 4, glass substrates 1 and 2 having transparent electrodes formed thereon were prepared. Next, acrylamide and N, N-methylenebisacrylamide were dissolved in pure water so that the molar ratio was 100/1, and ammonium persulfate was added as an initiator to prepare a polymerization pre-solution. This solution was applied onto the substrate 2 and heated to form a chemical gel film. Next, acrylamide / sodium acrylate / vinyl alcohol were mixed at a molar ratio of 659/40/1, ammonium persulfate and titanium oxide powder were added as an initiator, and a copolymerized solution was coated on the chemical gel film. And crosslinked by heating to form a sodium acrylate-acrylamide copolymer white gel. A glass substrate 1 and a glass substrate 2 were sandwiched between Mylar films as spacers and sealed to form a cell, and a black aqueous ink was filled in the cell to swell the gel to obtain an evaluation cell. In this state, the gel is in contact with the electrode of the display-side substrate 1, and white display is shown. When a voltage of 3 V was applied to this evaluation cell, the gel contracted and separated from the display side substrate 1, filled with black ink, and black display was shown from the display substrate side. Next, when the electric field was cut off, the gel returned to the original swollen state, the first white display could be confirmed again, and the contrast of light and dark obtained from the reflectance was 8.0. The contraction of the gel was extremely slow when a voltage of 1.5 V was applied. The repeated operation by applying 3 V was carried out 50 times, but no change appeared.

Comparative Example 4 In Comparative Example 4, acrylamide and N,
An evaluation cell was prepared in the same manner except that a crosslinked gel of N-methylenebisacrylamide was not prepared. Repeat operation 5
After 0 times, the contrast became 39% of the initial value. When the cell was disassembled, the gel was peeled off from the surface of the substrate 2.

Example 5 In Example 5, glass substrates 1 and 2 having transparent electrodes formed thereon were prepared. Next, acrylamide and N, N-methylenebisacrylamide were dissolved in pure water so that the molar ratio was 100/1, and ammonium persulfate and carbon powder were added as an initiator to prepare a polymerization pre-solution.
This solution was applied onto the substrate 2 and heated to form a conductive chemical gel film. Next, the acrylamide / natoyl acrylate / vinyl alcohol molar ratio of 659/40 /
The solution obtained by mixing in 1 and adding ammonium persulfate and titanium oxide powder as an initiator and copolymerizing is applied on the above chemical gel film and crosslinked by heating to form a sodium acrylate-acrylamide copolymer white gel. did. A glass substrate 1 and a glass substrate 2 were sandwiched between Mylar films as spacers and sealed to form a cell, and a black aqueous ink was filled in the cell to swell the gel to obtain an evaluation cell. In this state, the gel is in contact with the electrode of the display-side substrate 1, and white display is shown. When a voltage of 3 V was applied to this evaluation cell, the gel contracted and separated from the display side substrate 1, filled with black ink, and black display was shown from the display substrate side. Next, when the electric field was cut off, the gel returned to the original swollen state, the first white display could be confirmed again, and the contrast of light and dark obtained from the reflectance was 8.1. Next, a voltage of 1.5 V was applied, but the same movement as that at 3 V was exhibited. Repeated operation by applying 3V is 5
It was carried out 0 times, but no change appeared.

Example 6 In Example 6, 40 mm * 30 mm glass substrates 1 and 2 with transparent electrodes were prepared. The substrate 1 is a side top CTX-80 thermoplastic resin having a perfluor structure on the electrode surface.
A 5% solution of 5A (Asahi Kasei) was added to CT-solv. 100
What was diluted with (Asahi Kasei) to 0.1% was spin-coated and heated at 150 ° C. for 2 hours (the electrode part was left in an area of 10 × 30 mm at the end: for electrode extraction). The substrate 2 was coated with the polymerization pre-solution of Example 4 and heated to form a chemical gel film.

Substrates 2 are superposed on each other with spacers made of polypropylene having a thickness of 500 μm and having a size of 2 mm * 30 mm on both sides of the electrode surface of the substrate 1 (inside the electrode surface; the shape after the two substrates are superposed). Was made L-shaped), and kept warm. The spacers were clamped and fixed on both sides at the position where the spacers were placed in the overlapped state. Separately, a solution prepared by dissolving agar in warm water was prepared. Acrylamide 0.7M, sodium acrylate 0.2
8 mM of M, N, N'-methylenebisacrylamide was dissolved. After introducing this solution between the previous two substrates,
Cooled down to 100 degrees. The liquid gelled and became an apparent solid. A photomask having an opening of 1.5 mm square was set on the surface of the substrate, and 253.7 nm ultraviolet light of a low pressure mercury lamp was irradiated to produce a chemical gel. The physical gel was made into a sol by immersing it in a heated black aqueous ink without removing the clamp and replacing the sol liquid with the black ink. When the clamped substrate was taken out, it was confirmed that only the portion where the chemical gel was produced at room temperature was transparent and the other portions were black. In this state, when the electric field was applied with the electrode substrate on the side top treated as minus and the other as plus, the gel contracted, the black ink was filled, and only the black display was visible from the side top side substrate surface. .

[0091]

As described above, according to the first to ninth aspects of the invention, a light-transmissive display side substrate,
There is a non-display side substrate facing the display side substrate, between the display side substrate and the non-display side substrate, at least a colored liquid and a gel that deforms in response to an electric field are housed, and the gel is an electric field. In a display element that performs display by adjusting incident light by utilizing the deformation by
Incident light passes through the colored liquid by changing the thickness of the gel contained in the thickness direction formed by the display-side substrate and the non-display-side substrate by the electric field when the concentration of the colored liquid in the colored liquid is constant. Since the distance is adjusted, the accuracy of gradation display can be improved.

Particularly, according to the invention described in claim 2, in the display element according to claim 1, a gel which is not deformed by an electric field is arranged at a position inscribed in the display side substrate and is not deformed by an electric field. Since the gel that is deformed by the electric field is arranged on the side of the gel opposite to the display side substrate, gradation display is possible.

According to the invention described in claim 3, in the display element according to claim 1 or 2, the display side substrate for the colored liquid contained between the display side substrate and the non-display side substrate. Since the wettability of the inner surface of the is low, the contrast can be improved.

According to the invention described in claim 4, in the display element according to claim 3, since the surface of the display side substrate which is in contact with the colored liquid is subjected to the liquid-generating treatment, it is rendered hydrophilic or hydrophobic. However, a wide range of liquids can be used.

According to the invention described in claim 5, in the display element according to any one of claims 1 to 4, the display element is not deformed according to an electric field at a position inscribed in the non-display side substrate. Since the gel is arranged, the durability of repeated display can be improved.

According to the sixth aspect of the invention, in the display element according to the fifth aspect, since the gel that is not deformed by the electric field is a conductive gel, the response speed can be improved.

According to the invention described in claim 7, in the display element according to claim 6, since the conductive gel contains a conductive polymer, the stability of the conductive gel can be improved. .

Further, according to the invention of claim 8, in the display element according to any one of claims 1 to 7, since the gel inscribed in the display side substrate is colored, a color display is provided. Is possible.

According to a ninth aspect of the present invention, in the display element according to any one of the first to eighth aspects, the colored liquid is black and the gel inscribed in the display side substrate is white. Since it is colored, it can be used for reflective black and white display.

According to the tenth to fourteenth aspects of the present invention, the display-side substrate and the non-display-side substrate facing the display-side substrate are provided, and the display-side substrate and the non-display-side substrate are provided. At least a colored liquid and a gel that deforms in response to an electric field are accommodated between the substrate and the gel, and the display is performed by adjusting and emitting the incident light by utilizing the deformation of the gel by the electric field. In the method for manufacturing a display element, the gel is a chemical gel, and the chemical gel is produced in a physical gel matrix, so that the shape controllability during gel production can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a display element using gel.

FIG. 2 is a diagram for explaining a problem with gradation display.

FIG. 3 is a diagram showing a configuration example of a display element according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a state in which a gel that is not deformed by an electric field is dragged by a contracting force of a gel (a lower gel) that is deformed by an electric field and is deformed.

FIG. 5 is a diagram for explaining a contact angle.

FIG. 6 is a diagram showing a state during gel contraction.

FIG. 7 is a diagram showing a configuration example of a display element according to a fourth embodiment of the present invention.

FIG. 8 is a diagram for explaining a problem of the display element according to the fourth embodiment of the present invention.

FIG. 9 is a diagram showing a configuration example of a display element of a fifth embodiment.

FIG. 10 is a diagram showing an evaluation cell of Example 1.

11 is a diagram showing an evaluation cell of Example 2. FIG.

[Explanation of symbols]

1 Display side substrate 2 Non-display side substrate 3 colored liquid 4 gel 5, 6 electrodes 14 Gel that does not deform under electric field 24 Gel deformed by electric field 34 Gel that is not deformed by electric field 44 Gel deformed by electric field

Claims (14)

[Claims] 1. A display-side substrate that is light-transmissive and a non-display-side substrate that faces the display-side substrate. At least a colored liquid and an electric field are provided between the display-side substrate and the non-display-side substrate. In the display element that contains a gel that deforms in accordance with, and displays by adjusting and emitting the incident light by utilizing the deformation of the gel by the electric field, the concentration of the coloring matter in the coloring liquid is constant. By adjusting the thickness of the gel contained in the thickness direction formed by the display-side substrate and the non-display-side substrate by the electric field, the distance that incident light passes through the colored liquid is adjusted. A display element characterized by the above. 2. The display element according to claim 1, wherein a gel that does not deform with respect to an electric field is disposed at a position inscribed in the display side substrate, and the gel that does not deform with respect to the electric field is opposite to the display side substrate. A display element, in which a gel that is deformed by an electric field is arranged in the. 3. The display element according to claim 1 or 2, wherein the wettability of the inner surface of the display-side substrate with respect to the colored liquid contained between the display-side substrate and the non-display-side substrate is lowered. A display element characterized by being. 4. The display element according to claim 3, wherein the surface of the display-side substrate that comes into contact with the colored liquid is subjected to a liquid generation process. 5. The display element according to claim 1, wherein a gel that does not deform according to an electric field is arranged at a position inscribed in the non-display side substrate. Display element. 6. The display element according to claim 5, wherein the gel that is not deformed by an electric field is a conductive gel. 7. The display element according to claim 6, wherein the conductive gel contains a conductive polymer. 8. The display element according to claim 1, wherein the gel inscribed in the display-side substrate is colored. 9. The display device according to claim 1, wherein the colored liquid is black and the gel inscribed in the display side substrate is colored white. Display element. 10. A light-transmissive display-side substrate and a non-display-side substrate facing the display-side substrate, wherein at least a colored liquid and an electric field are provided between the display-side substrate and the non-display-side substrate. In the method for manufacturing a display element, which contains a gel that deforms according to, and displays by adjusting the incident light by utilizing the deformation of the gel by an electric field, the gel is a chemical gel. A method for manufacturing a display device, which comprises producing the chemical gel in a physical gel matrix. 11. The method for manufacturing a display element according to claim 10, wherein the temperature at the time of preparing the chemical gel is equal to or lower than the temperature at which the physical gel is converted into a sol. 12. The method of manufacturing a display element according to claim 10 or 11, wherein a chemical gel is produced, and then the physical gel is converted into a sol. 13. The method for producing a display element according to claim 10, wherein the chemical gel is produced by light. 14. The method of manufacturing a display element according to claim 10, wherein the chemical gel is formed in a dot matrix on a substrate. .