JPH0695090A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To provide the novel liquid crystal display element which has all of the advantages of a high-polymer dispersed liquid crystal, can be operated with a low driving voltage, has excellent steepness, enables simple matrix driving and is usable for a reflection type display as well. CONSTITUTION:A solid-state transparent high polymer layer 1 is inserted between a pair of electrodes 4 and 4. The solid-state transparent high polymer layer 1 is provided with a liquid crystal housing part 2 extending longitudinally from one electrode toward the other electrode. A liquid crystal 3 is filled and held in the liquid crystal housing part 2. The liquid crystal 3 orients approximately perpendicularly to the electrode surface in the state that a voltage is not impressed to the electrodes 4, 4 and the liquid crystal orients in the direction approximately non-perpendicular to the electrode surface in the state the voltage is not impressed to the electrodes 4, 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device.
More specifically, the present invention relates to a liquid crystal display element that can be driven at a voltage lower than that of a conventional one and can clearly display information even under direct sunlight.

[0002]

2. Description of the Related Art Liquid crystal display elements, which are widely used for displaying information, have various characteristics such as low voltage driving, high speed display, and thin type. However, since they are non-luminous elements, they are exposed to direct sunlight. There was a weakness in the visibility below.

In order to solve this, recently, a system having a light source on the back side of a liquid crystal element (so-called backlight system)
Is becoming more common. However, this backlight system has a problem that power consumption increases, and it is the current situation that it is not sufficient for use under direct sunlight.

Therefore, as a method capable of solving this problem, for example, as described in Japanese Patent Laid-Open No. 60-252687, research on polymer dispersed liquid crystals has been actively conducted. The polymer dispersed liquid crystal device has superior characteristics in brightness, contrast, viewing angle, and response speed compared to the liquid crystal display device using polarized light, which is currently the mainstream, and it does not require a polarizing plate and has a cell structure. Because of its simplicity, it is expected to have a wide range of applications as well as a replacement for current display elements.

Polymer-dispersed liquid crystals have a structure in which a liquid crystal phase is dispersed inhomogeneously in a polymer serving as a matrix. Polymer-dispersed liquid crystal devices currently being studied have a structure in which liquid crystal particles are dispersed in a polymer matrix, which is commonly called NCAP (Nematic Curvilinear Alligned Phase) structure, and liquid crystals are dispersed in a sponge-like polymer. , Commonly known as PN
-LCD (Polymer Network-Liquid Crystal Display) structure. The polymer-dispersed liquid crystal element performs display by changing the light scattering intensity with a polymer due to liquid crystal alignment brought about by the refractive index anisotropy of liquid crystal molecules. Since the nematic liquid crystal used in the display element has different dielectric constants in the long axis direction of the molecule and in the direction orthogonal thereto, it has a birefringence index different in the linearly polarized light having the wavefront in each direction. The refractive index for polarized light in the principal axis direction is called the extraordinary light refractive index (n _e ), and the other is called the ordinary light refractive index (n ₀ ). By the way, in the case of liquid crystal for display, usually, n _e > n ₀ , and n _e −n ₀ = 0.1.
It is 0.3. TN (T currently used for display
Wisted Nematic) In the case of liquid crystal, a substrate whose surface is pretreated is used to give twist to the liquid crystal layer, and the birefringence change caused by the alignment change of the liquid crystal is performed by two polarizing plates sandwiching the cell. On the other hand, in the polymer dispersed liquid crystal, the refractive index n _s of the polymer matrix is matched with the ordinary refractive index n ₀ of the liquid crystal, and the display is performed by utilizing the refractive index change brought about by the liquid crystal alignment.

Since the electric field is not applied to the liquid crystal when the element is OFF (no voltage is applied), the liquid crystal molecules are aligned along the interface due to the interaction with the matrix polymer. At this time, the refractive index of the liquid crystal phase for vertically incident light from the device surface is between n _e and n ₀ and is larger than that of the polymer matrix, so that the incident light is scattered (FIG. 1).
3 (a)). Further, when the element is ON (voltage is applied), an electric field is applied to the liquid crystal, and the liquid crystal molecules are aligned in the electric field direction. Therefore, the refractive index of the liquid crystal phase with respect to the incident light is n ₀ , which matches the refractive index n _{s of the} matrix, and the light is transmitted to enable display (see FIG. 13B).

Compared with conventional TN liquid crystals, polymer dispersed liquid crystals are
The element changes from a light-scattering state to a transparent state according to the electric field strength, so it is strong against external light, uses scattering, and has a wide viewing angle. Have advantages. The conventional TN liquid crystal can be used only for a small display area such as a television, a clock and a calculator, whereas the polymer dispersed liquid crystal can be used for a large display area such as a large area screen, an optical pulp and an advertising billboard. On the other hand, the polymer-dispersed liquid crystal has a higher permittivity of the transparent polymer than the liquid crystal, so that the drive voltage is higher (about 10 to 100 V) than the general liquid crystal element, and the display-drive voltage characteristic is steep. It cannot be used as a simple matrix element with a simple electrode configuration suitable for low-cost information display because of its lack of properties. Moreover, since the liquid crystal has a small anisotropy of refractive index, backscattering is small and a reflective display has a large film thickness. There are drawbacks of.

[0008]

Therefore, an object of the present invention is to have all the advantages of polymer-dispersed liquid crystal, to be able to operate at a low driving voltage, to have excellent steepness, and to enable simple matrix driving. , A novel liquid crystal display device that can be used for a reflective display.

[0009]

In order to achieve the above object, according to the present invention, a solid transparent polymer layer is interposed between a pair of electrodes, and the solid transparent polymer layer has one of the electrodes. Is provided with a liquid crystal housing that extends in the vertical direction from the other electrode to the other electrode, and the liquid crystal housing is filled with and held by the liquid crystal, and the liquid crystal is in a state in which a voltage is applied to the electrodes. Provided is a liquid crystal display element, which is oriented substantially perpendicular to the electrode surface and is oriented substantially non-perpendicular to the electrode surface when a voltage is not applied to the electrode. The liquid crystal accommodating portion is a through hole or a through groove that extends from the upper surface to the lower surface of the solid transparent polymer layer, or a concave hole or a groove that does not reach the lower surface.

[0010]

[Function] By filling and sealing the liquid crystal in the liquid crystal housing provided in the solid transparent polymer layer and applying a voltage from both ends of the liquid crystal housing, the conventional liquid crystal is randomly distributed in the polymer layer. The effective electric field applied to the liquid crystal molecules existing between both electrodes is much smaller than that of the polymer-dispersed liquid crystals, and low voltage driving can be realized. This drive voltage can be reduced to almost the same level as the drive voltage of the conventional TN liquid crystal. Further, the display-driving voltage characteristic is not affected by the liquid crystal particle distribution, unlike the polymer-dispersed liquid crystal, so that steepness can be achieved. Further, there is an advantage that the driving element can be easily manufactured.

[0011]

The liquid crystal display device of the present invention will be described in more detail below with reference to the drawings.

FIG. 1 is a schematic view of the liquid crystal display element of the present invention in a state where no voltage is applied. The solid transparent polymer layer 1 is provided with a plurality of liquid crystal accommodating portions 2 in the shape of through holes, and liquid crystal molecules 3 are filled in the through holes. Transparent electrodes 4 are provided on both ends of the through hole, that is, on the upper and lower surfaces of the solid transparent polymer layer 1. Both electrodes 4 are in contact with the liquid crystal in the through holes. A conductor 5 is connected to each electrode 4, a power source 6 is connected to one of the conductors, and a switch 7 for applying a voltage to the electrodes is provided between the conductors. The upper part of each electrode is covered with a transparent glass substrate 8, for example. As shown in the drawing, when no voltage is applied, that is, when the switch 7 is open, the liquid crystal molecules must be oriented so as to be orthogonal or intersect with the wall surface of the through hole 2. Thereby, for example, even if light is incident from one transparent glass substrate, the light is scattered by the liquid crystal and information is not displayed.

On the other hand, as shown in FIG. 2, when the switch 7 is closed and an electric field is applied to the liquid crystal, the liquid crystal is in a direction parallel to the wall surface of the through hole (that is, perpendicular to the electrode surface). Direction). As a result, when light is incident from one of the transparent glass substrates, this light is transmitted through the liquid crystal, and necessary information is displayed.

The material for forming the solid transparent polymer layer is not particularly limited. Polycarbonate, Teflon, polyethylene,
A transparent resin such as an acrylic compound can be preferably used. The film thickness itself of the solid transparent polymer layer is not particularly limited. The thickness may be a necessary and sufficient one for a liquid crystal display device. Generally, 1 μm to 200 μm, preferably 1 μm to 50 μm
A polymer layer having a film thickness within the range is preferable.

The liquid crystal accommodating portion provided in the transparent polymer layer may be a through hole or a through groove reaching from the upper surface to the lower surface of the transparent polymer layer, or a concave hole or a groove not reaching the lower surface. Alternatively, the adhesive layer may be in contact with the electrode through a substance such as a color filter. The cross-sectional shapes of the through hole, the through groove, the concave hole and the concave groove are not particularly limited. The through hole and the concave hole can have any shape such as a perfect circle, an ellipse, a rectangle, a triangle, and a polygon, and the through groove and the concave groove have a parallel shape, a mesh shape,
Various configurations such as concentric circles and spirals are possible. Also,
These through holes or recessed holes may be physically separated from each other, or may exist in a checkered pattern.

The size of the liquid crystal housing depends on the thickness of the polymer layer used. Generally, the inner diameter of the hole or the width of the groove is preferably within the range of 1/20 to 2 times the film thickness of the polymer layer. The inner diameter of the hole or the width of the groove is 0.5 μm to 50 μm
It is preferably within the range. If the holes have a square cross-sectional shape, the inner diameter should be understood to mean the length of one side of the square. When the hole has an elliptical or rectangular cross-sectional shape, the minor axis diameter and major axis diameter or the short side and the long side are also preferably within the range of 0.5 μm to 50 μm. The porosity (that is, the ratio of the total value of the opening area of the liquid crystal containing portion to the total area of the upper surface or the lower surface of the polymer layer) is not particularly limited, but is generally 3% to 95%.
%, Preferably 3 to 80%. Porosity is 3
If it is less than%, it is difficult to display sufficient information. On the other hand, if the porosity exceeds 95%, the shape retention of the solid transparent polymer layer is deteriorated, which causes an inconvenient situation such that the liquid crystal housing cannot be stably held.

The method of forming the liquid crystal containing portion itself is not an essential requirement of the present invention. All known and conventional methods can be used. It can also be formed by a method such as photoresist.
Further, the molded pattern can be transferred to a mold or a rubber mold, and based on the pattern, a solid transparent polymer layer having a liquid crystal accommodating portion of a predetermined pattern can be formed by an ultraviolet curable resin or the like.

It is preferable that the wall surface of the liquid crystal accommodating portion is treated to be water repellent or hydrophobic. If the wall surface of the liquid crystal container is not water-repellent or hydrophobically treated, the alignment direction of the liquid crystal cannot be changed when an electric field is applied to the liquid crystal filled in the liquid crystal container. That is, when the wall surface of the liquid crystal containing portion is treated to be water repellent or hydrophobic, the liquid crystal is oriented so as to be orthogonal to the wall surface of the liquid crystal containing portion when the electric field is not applied, and the liquid crystal is aligned when the electric field is applied. Information can be displayed by orienting it so that it is parallel to the wall surface of the accommodating portion. And
When the electric field is not applied, the liquid crystal is realigned so as to be orthogonal to the wall surface of the liquid crystal accommodating portion, and the information display is erased. In other words, when the electric field is applied, the liquid crystal is oriented substantially perpendicular to the electrode surface, and when the electric field is not applied, the liquid crystal is oriented substantially non-perpendicular to the electrode surface.
Information can be displayed and deleted. When a water-repellent or hydrophobic material is used as the material for forming the solid transparent polymer layer, this water-repellent or hydrophobic treatment may not be necessary. In this case, as the hydrophobic polymer material, for example, long-chain aliphatic acrylic monomers such as lauryl acrylate, lauryl methacrylate, tridecyl acrylate, tridecyl methacrylate, stearyl acrylate, stearyl methacrylate, or trifluoroethyl acrylate, trifluoroethyl. Polymers of materials containing a fluorine-based acrylic monomer such as methacrylate, tetrafluoropropyl acrylate, tetrafluoropropyl methacrylate, perfluorooctylethyl acrylate, and perfluorooctylethyl methacrylate can be used.

The water-repellent or hydrophobic treatment of the wall surface of the liquid crystal container must be performed before filling the liquid crystal. The water repellent or hydrophobic treatment method itself is not an essential requirement of the present invention. As an example, a long-chain aliphatic acrylic monomer such as lauryl acrylate, lauryl methacrylate, tridecyl acrylate, tridecyl methacrylate, stearyl acrylate, stearyl methacrylate or trifluoroethyl acrylate, trifluoroethyl methacrylate, tetrafluoropropyl acrylate, tetrafluoropropyl Fluorine-based acrylic monomers such as methacrylate, perfluorooctylethyl acrylate, and perfluorooctylethyl methacrylate,
A transparent polymer layer having a liquid crystal accommodating portion is immersed in a melt of a copolymer with a monomer having reactivity with a polar compound such as glycidyl acrylate and glycidyl methacrylate, and the temperature is within a range of 100 ° C to 150 ° C. At 0.2 ~
By heating for 2 hours, the wall surface of the liquid crystal containing portion can be treated to be water repellent or hydrophobic. Alternatively, for example, long-chain aliphatic acrylic monomers such as lauryl acrylate, lauryl methacrylate, tridecyl acrylate, tridecyl methacrylate, stearyl acrylate, stearyl methacrylate or trifluoroethyl acrylate, trifluoroethyl methacrylate, tetrafluoropropyl acrylate, tetrafluoro In a mixture of a fluorinated acrylic monomer such as propyl methacrylate, perfluorooctylethyl acrylate, and perfluorooctylethyl methacrylate, a monomer reactive with a polar compound such as glycidyl acrylate and glycidyl methacrylate, and a photopolymerization initiator The transparent polymer layer having the liquid crystal containing portion is immersed, and the temperature is within the range of 100 ° C to 150 ° C.
By heating for 2 to 2 hours, the wall surface of the liquid crystal containing portion can be treated to be water repellent or hydrophobic. As another method, the solid transparent polymer layer having a liquid crystal containing portion is dipped in an alcohol solution of a silane coupling agent, and then heated at 80 ° C to
The wall surface of the liquid crystal containing portion can be treated to be water-repellent or hydrophobic by heating at a temperature in the range of 130 ° C. for 0.2 hours to 2 hours. A silane coupling agent suitable for such treatment is, for example, C ₈ F ₁₇ C ₂ H ₄ Si.
(OCH ₃ ) ₃ , C ₁₈ H ₃₇ Si (OCH ₃ ) ₃ , C ₁₈ H
₃₇ Si (OCH ₃ ) ₂ Cl, C ₁₈ H ₃₇ Si (OC ₂ H
₅ ) ₃ , C ₆ F ₁₃ CH ₂ SiCl ₃ , C ₆ F ₁₃ C ₂ H ₄
Si (OCH ₃ ) ₃ and the like. It is preferable to dilute the silane coupling agent with an alcohol such as ethanol within a range of 0.2% to 2% before use. Solvents other than alcohol can also be used.

The liquid crystal material itself filled in the liquid crystal containing portion of the solid transparent polymer layer is not particularly limited. It is possible to use all kinds of liquid crystals that have been conventionally used, for example, nematic liquid crystals, smectic liquid crystals, chiral nematic liquid crystals, cholesteric liquid crystals, and p-type liquid crystals or n-type liquid crystals due to dielectric anisotropy. .
In this case, the ordinary refractive index of the liquid crystal needs to be as close as possible to the refractive index of the solid transparent polymer layer, and the difference between the two is 0.1 or less, preferably 0.05 or less.

Further, a so-called guest-host (GH) mode in which a dichroic dye is added to liquid crystal is effective in obtaining a high display contrast, particularly when used in a reflective element. In this case, it is not necessary to make the ordinary refractive index of the liquid crystal and the refractive index of the transparent polymer layer completely match.
The dichroic dye is a dye having a property that the absorption coefficient of light is significantly different between the direction parallel to the long axis of the molecule and the direction perpendicular thereto. When a dichroic dye having a rod-shaped structure is used, the dye molecules have a property of being aligned parallel to the liquid crystal molecules. Therefore, when an electric field is applied to change the molecular alignment of the liquid crystal, the alignment direction of the dye also changes. Since this dye may or may not be colored depending on the direction, the cell can be colored or colorless by applying a voltage. Such dyes are known to those skilled in the art.

The liquid crystal can be easily filled in the liquid crystal container by, for example, immersing the solid transparent polymer layer in a liquid crystal solution and applying ultrasonic vibration to degas bubbles in the liquid crystal container. Other filling methods can of course be implemented.

The electrode structure itself is not an essential requirement of the present invention. All transparent electrodes commonly used in liquid crystal display devices (LCDs) can be used. Indium tin oxide (ITO) film electrodes are preferred. Also, any LCD such as a matrix LCD or an active matrix LCD can be configured by the electrodes used.

[0024]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 Pores having a pore diameter of 1 μm are formed through the film,
A polycarbonate porous film having a porosity of 10% and a film thickness of 13 μm (for example, “Nuclepore” commercially available from Nuclepore, Inc. in the US) is irradiated with short wavelength ultraviolet rays by a low pressure ultraviolet lamp in air to modify the surface. After that, it is immersed in a silane coupling agent KBP-40 (manufactured by Shin-Etsu Chemical Co., Ltd.) 10% ethanol diluted solution and heated at 115 ° C. for 1 hour, and further, a silane coupling agent TSR8233 (chemical formula: C ₈ F ₁₇ C ₂ H ₄
(OCH ₃ ) ₃ , manufactured by Toshiba Silicone Co., Ltd. was immersed in a 2% ethanol solution and heated at 115 ° C. for 1 hour for water repellent treatment, and then a cyanobiphenyl nematic liquid crystal K-15 (chemical formula: C ₅ H ₁₁ -C ₆ H ₄ -CN, manufactured by Merck Japan Ltd., was impregnated with two pieces of indium tin oxide (IT
The ITO film was sandwiched between O 2) film-attached glasses so that the ITO film was on the side in contact with the film, and an element having a structure as shown in FIG. 3 was produced. In the figure, reference numeral 1 is a polycarbonate porous film serving as a solid transparent polymer layer, 2 is a through hole, 3 is a liquid crystal, 4 is an electrode (ITO film), and 8 is glass.

Example 2 A negative dry resist film, Ryodry DFA-8166 (manufactured by Toyo Ink Co., Ltd.) having a film thickness of 20 μm was attached onto an ITO film of an ITO film-coated glass, and grids of 10 μm in length and width were formed on the surface ( That is, a pattern was formed by irradiating a parallel light beam with an ultraviolet light source for lithography through a photomask formed in a checkered pattern, performing exposure, and then etching with a 1% sodium carbonate aqueous solution. After that, the glass with resist was treated with a silane coupling agent TSR8185 (chemical formula: C ₁₈ H ₃₇ Si (OCH ₃ ) ₃ , manufactured by Toshiba Silicone).
2% ethanol solution was heated at 115 ° C. for 1 hour for water repellent treatment. Then, this film is impregnated with cyanobiphenyl nematic liquid crystal K-15, and this is sandwiched with another glass with an ITO film so that the ITO film is on the side in contact with the film, and the structure shown in FIG. 4 is obtained. A device having the above was manufactured. In the figure, reference numeral 9 indicates a solid transparent polymer layer made of resist. Other reference numerals indicate the same components as those in FIG. 3, respectively.

Example 3 Negative type dry resist film / Riodry DFA-8166 having a film thickness of 20 μm (manufactured by Toyo Ink Co., refractive index n _s =)
1.51) is pasted on the ITO film and the line width is 25μ on the surface.
A parallel light beam was irradiated with an ultraviolet light source for lithography through a photomask having a mesh line formed by m to expose the film, and then, a pattern was formed by etching with a 1% sodium carbonate aqueous solution. Then, stearyl methacrylate and glycidyl methacrylate copolymer (weight ratio 4: 1) was immersed in this resist-coated glass in a liquid heated to 90 ° C., pulled up, and then heated at 130 ° C. for 1 hour for water repellent treatment. Nematic liquid crystal ZLI-441
8 (manufactured by Merck & Co., ordinary refractive index n ₀ = 1.49) was impregnated and sandwiched with another glass with ITO so that the ITO film was on the side in contact with the film, and the liquid crystal element shown in FIG. It was made. Reference numeral 9 in the figure indicates a solid transparent polymer layer made of a resist.

Example 4 A positive type dry resist film AZ4903 (manufactured by Hoechst, refractive index n _s = 1.6) was applied onto an ITO film of an ITO film-coated glass so as to have a dry film thickness of 20 μm,
A parallel light beam is irradiated by an ultraviolet light source for lithography through a photomask having parallel lines with a line width of 7 μm formed in stripes, and after exposure, it is 1: 4 of a developing solution AZ400-K (manufactured by Hoechst). Etching was performed with an aqueous solution to form a pattern. Then, stearyl methacrylate and glycidyl methacrylate copolymer (weight ratio 4: 1) was immersed in this resist-coated glass in a liquid heated to 90 ° C., pulled up, and then heated at 130 ° C. for 1 hour for water repellent treatment. The film thus obtained was impregnated with a guest-host type nematic liquid crystal ZLI-3512 (manufactured by Merck, ordinary light refractive index n ₀ = 1.50) in which a dichroic dye was mixed, and another film I
The ITO film was sandwiched by glass with a TO film so that the ITO film was in contact with the film, and the liquid crystal element shown in FIG. 6 was produced. Reference numeral 9 in the figure indicates a solid transparent polymer layer made of a resist.

Example 5 As shown in FIG. 7A, a silicone rubber SH9555 (manufactured by Shin-Etsu Chemical Co., Ltd.) for molding is dropped on the surface of a photoresist having grooves formed in the same manner as in Example 4 to cure it. Then, as shown in FIG. 7B, the pattern was transferred to the silicone rubber surface. The mold was removed to obtain a silicone mold as shown in FIG. 7 (c). As shown in FIG. 7 (d), 30 parts by weight of dicyclopentadienyl diacrylate and 7 parts of stearyl methacrylate were added to the silicone type.
After pouring an ultraviolet curable resin (refractive index n _s = 1.50) consisting of 0 part by weight and 2 parts by weight of a photopolymerization initiator Irgacure 184 (manufactured by Ciba-Geigy), the glass 8 with the ITO film 4 is covered and irradiated with ultraviolet rays. Then, the resin was cured to form the solid transparent polymer layer 10. Then, it was taken out from the silicone mold to obtain a glass substrate having a patterned transparent polymer layer 10 as shown in FIG. 7 (e). After that, nematic liquid crystal E-7 (manufactured by BDH, ordinary light refractive index n ₀ = 1.50) is impregnated into the pattern groove of the transparent polymer layer 10 on the glass substrate, and this is coated with another ITO film. The ITO film 4 was sandwiched by the glass 8 so as to be on the side in contact with the liquid crystal layer 3, and the liquid crystal element shown in FIG. 8 was produced.

Comparative Example 1 An ultraviolet curable resin NOA-65 (manufactured by Norland) was mixed with a cyanobiphenyl nematic liquid crystal K-15 at a weight ratio of 1: 1. It was sandwiched so as to be in contact with and was irradiated with ultraviolet light from a light source to prepare a polymer dispersed liquid crystal device in which liquid crystal particles were dispersed in a cured resin as shown in FIG. The resin thickness after curing was 20 μm. In the figure, reference numeral 1 indicates a cured resin layer (solid transparent polymer layer), and other reference numerals indicate the same components as those in FIG.

Regarding the liquid crystal elements produced in Examples 1 to 3, Example 5 and Comparative Example 1, 50 Hz was set between two glass plates.
Was applied to measure the change in light transmittance of the device. The results are shown in Fig. 10. Since the thickness of the composite film layer is different between Example 1 and other conditions, the results are normalized by the voltage per 1 μm of the composite film thickness in this figure. Further, in the liquid crystal device manufactured in Example 4, a white alumina plate was attached to the back side of the device and the change in the total amount of reflected light and scattered light was measured by a photometer with an integrating sphere. The results are shown in Fig. 11. As can be understood from these results, the voltage required for driving the device of the example is much smaller than that of the device of the comparative example.

Further, the ratio of the voltages V ₁₀ and V ₉₀ causing the transmittance changes of 10% and 90% of the total transmittance change width, which is an index showing the steepness of the driving characteristics, and V ₉₀ / V ₁₀ (see FIG. 12). ) Is shown in Table 1 below. From the results shown in Table 1, it can be seen that the steepness of the device of the example is higher than that of the device of the comparative example.

[0033]

Table 1 Element V ₉₀ / V ₁₀ Example 1 1.5 Example 2 1.7 Example 3 1.8 Example 4 1.7 Example 5 1.6 Comparative Example 1 3.0

An element having the same structure as that of the embodiment but not having the surface water-repellent treatment on the inner wall surface of the through hole was prepared,
As a result of characteristic evaluation, no clear change in transmittance was observed in these devices, and it was confirmed that the device was not practical. When observing the liquid crystal layer of these devices with a polarization microscope in the absence of applied voltage, liquid crystal molecules are aligned along the polymer layer interface without surface treatment, whereas surface repellency with good display characteristics is observed. It was found that the liquid crystal molecules subjected to the water treatment were oriented almost vertically to the transparent medium layer, which is considered to bring about the display characteristics.

In the embodiment of the present invention, as a method for producing a liquid crystal display element, a pattern formed by photolithography is used, or a pattern formed by an ultraviolet curable resin is used, and the gap is filled with liquid crystal. Although the method was used, the method and material are not particularly limited as long as the liquid crystal layer can be formed so as to penetrate the transparent polymer layer.

Further, the liquid crystal layer does not need to completely penetrate the transparent polymer layer, and the liquid crystal and the electrodes are separated from each other by an adhesive layer or the transparent medium itself within a range that does not cause a problem in device driving characteristics. There is no problem. Even when the liquid crystal and the electrodes are not in contact with each other, when an alternating voltage is applied, the solid transparent polymer is electrostatically polarized, so that the liquid crystal is in a conducting state, and the liquid crystal can be vertically aligned as in the case of FIG. However, in this case, a voltage slightly higher than the applied voltage in the case of FIG. 2 must be applied.

In order to orient the liquid crystal molecules substantially perpendicularly to the transparent medium layer in such a constitution, in the embodiment of the present invention, a method of water-repellently treating the polymer surface before filling the liquid crystal into the transparent polymer layer. However, the means for vertically aligning the liquid crystal molecules is not particularly limited to this, and for example, a method using a fluorine-based compound or a long-chain aliphatic compound as the polymer film, and a transparent polymer in the liquid crystal. It is also possible to use a method in which a water-repellent compound that reacts is added and reacted by heating or the like.

Further, in the embodiment of the present invention, the inner diameter or the width of the liquid crystal accommodating portion is set to 1 μm to 25 μm, but this value is not particularly limited to this range, and the width of the liquid crystal accommodating portion depends on device characteristics and manufacturing. It can be set arbitrarily according to the above requirements.

Further, regarding the shape of the pattern, it is of course possible to form various patterns in a curtain shape for the purpose of increasing the scattering intensity.

Although the nematic liquid crystal having a positive dielectric anisotropy is used as the liquid crystal in the above embodiment, any other liquid crystal such as smectic liquid crystal and cholesteric liquid crystal may be used. Further, it is naturally possible to add a dichroic dye to these liquid crystals as necessary to improve the visibility. Further, although glass is used as the substrate in the embodiments, it is of course possible to use transparent plastics such as polycarbonate, polymethylmethacrylate, and polyethylene terephthalate in addition to this.

[0041]

As described above, in the present invention, the liquid crystal layer is formed so as to penetrate the transparent medium in the direction perpendicular to the electrode surface, so that it can be driven at a lower voltage than the conventional polymer dispersed liquid crystal device. In addition, a steep threshold characteristic desired for simple matrix driving can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of a liquid crystal display element of the present invention in a voltage non-applied state.

FIG. 2 is a schematic diagram of a voltage application state of the liquid crystal display element of the present invention.

FIG. 3 is a partially cutaway cross-sectional perspective view showing the structure of the liquid crystal display element manufactured in Example 1.

FIG. 4 is a partially cutaway cross-sectional perspective view showing the structure of a liquid crystal display element manufactured in Example 2.

5 is a partially cutaway cross-sectional perspective view showing a structure of a liquid crystal display device manufactured in Example 3. FIG.

FIG. 6 is a partially cutaway cross-sectional perspective view showing the structure of a liquid crystal display device manufactured in Example 4.

7A is a schematic cross-sectional view showing one step of the manufacturing process of the liquid crystal display element in Example 5, and FIG. 7B is a schematic cross-sectional view showing one step following the step (a). And (c) is a schematic cross-sectional view of the silicone mold obtained in the step (b), and (d) shows a liquid crystal display device using the silicone mold obtained in the step (b). It is a typical sectional view showing one process of manufacturing, and (e) is I which has the patterned transparent polymer layer obtained at the above-mentioned process (d).
It is a schematic cross section of a glass substrate with a TO film.

8 is a partially cutaway cross-sectional perspective view showing the structure of a liquid crystal display element manufactured in Example 5. FIG.

9 is a cross-sectional perspective view showing a structure of a liquid crystal display element manufactured in Comparative Example 1. FIG.

10 is a characteristic diagram showing changes in transmittance with respect to a drive voltage of each liquid crystal display element obtained in Examples 1 to 3, Example 5 and Comparative Example 1. FIG.

11 is a characteristic diagram showing a change in reflectance with respect to a driving voltage of the liquid crystal display element obtained in Example 2. FIG.

FIG. 12 is a schematic characteristic diagram illustrating steepness of drive characteristics.

FIG. 13 (a) is an electric field OFF of a conventional polymer-dispersed liquid crystal.
FIG. 4B is a schematic diagram for explaining the driving operation in the state of FIG. 4B, and FIG. 6B is a schematic diagram for explaining the driving operation of the conventional polymer dispersed liquid crystal in the state of the electric field ON.

[Explanation of symbols]

 1 Solid Transparent Polymer Layer 2 Through Hole 3 Liquid Crystal 4 Transparent Electrode 5 Conductor 6 Power Supply 7 Switch 8 Glass 9 Solid Transparent Polymer Layer with Resist 10 Solid Transparent Polymer Layer with UV Curing Resin

Claims (14)

[Claims] 1. A solid transparent polymer layer is interposed between a pair of electrodes, and the solid transparent polymer layer is provided with a liquid crystal accommodating portion extending vertically from the one electrode to the other electrode. Liquid crystal is filled and held in the liquid crystal container, and the liquid crystal is oriented substantially perpendicular to the electrode surface when a voltage is applied to the electrode, and a voltage is applied to the electrode. A liquid crystal display device, wherein the liquid crystal display device is oriented in a direction substantially non-perpendicular to the electrode surface when not being formed. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal accommodating portion is a through hole or a through groove that extends from the upper surface to the lower surface of the solid transparent polymer layer, or a concave hole or a groove that does not reach the lower surface. 3. The cross-sectional shape of the holes is a perfect circle, an ellipse, a rectangle, a triangle or a polygon, and the holes are spaced apart from each other or arranged in a staggered pattern. The liquid crystal display device according to claim 1, wherein the grooves are arranged in parallel stripes, meshes, concentric circles or spirals. 4. The liquid crystal display device according to claim 1, wherein a wall surface of the liquid crystal storage portion is water repellent or hydrophobic. 5. The liquid crystal display device according to claim 4, wherein the wall surface of the liquid crystal containing section is coated with a substance having water repellency or hydrophobicity so that the wall surface of the liquid crystal containing section becomes water repellent or hydrophobic. 6. The liquid crystal display element according to claim 4, wherein the solid transparent polymer layer is made of a material having water repellency or hydrophobicity, whereby the wall surface of the liquid crystal storage portion becomes water repellent or hydrophobic. 7. The liquid crystal display device according to claim 1, wherein the inner diameter of the hole or the width of the groove forming the liquid crystal storage portion is within a range of 1/20 to 2 times the film thickness of the solid transparent polymer layer. 8. The liquid crystal display device according to claim 1, wherein the inner diameter of the hole or the width of the groove forming the liquid crystal storage portion is in the range of 0.5 μm to 50 μm. 9. The liquid crystal according to claim 1, wherein the porosity (ratio of the total value of the opening area of the liquid crystal containing portion to the total area of the upper surface or the lower surface of the solid transparent polymer layer) is in the range of 3% to 95%. Display element. 10. The thickness of the solid transparent polymer layer is 1 μm to 2
The liquid crystal display device according to claim 1, wherein the liquid crystal display device has a thickness in the range of 00 μm. 11. The electrode is indium tin oxide (IT).
The liquid crystal display device according to claim 1, which is composed of an O) film. 12. The liquid crystal display device according to claim 1, wherein the difference between the ordinary refractive index of the liquid crystal and the ordinary refractive index of the solid transparent polymer layer is 0.1 or less. 13. The liquid crystal display device according to claim 1, which is a guest-host mode liquid crystal display device in which a mixture of a liquid crystal and a dichroic dye is filled in the liquid crystal container. 14. The liquid crystal display device according to claim 1, wherein the liquid crystal is a p-type or n-type nematic liquid crystal, smectic liquid crystal, chiral nematic liquid crystal, or cholesteric liquid crystal.