JP2000199895A - Polymer dispersed liquid crystal display device, its manufacture and projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a liquid crystal display device which can be driven by a low voltage and has high contrast, excellent brightness and low hysteresis. SOLUTION: Two liquid crystal supporting plates, each constructed by sticking a pair of upper and lower substrates 2, 3 on which are formed transparent electrode layers 10, 11 composed of indium tin oxide respectively, via a spacer and concurrently sealing resin 20 with a specified gap, are stuck together via a mediating material having the same refractive index as the substrates 2, 3. A polymer dispersed liquid crystal which consists of a liquid crystal 15 held and dispersed in a polymer matrix 16 is enclosed in the gap between the respective liquid crystal supporting plates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scattering-mode polymer-dispersed liquid crystal display having a composite layer composed of liquid crystal droplets and a polymer, a method of manufacturing the same, and a projection liquid crystal display.

[0002]

2. Description of the Related Art In recent years, a polymer dispersed liquid crystal (PDLC) in which a nematic liquid crystal is dispersed and held in a polymer having the same refractive index as liquid crystal molecules is sandwiched between a pair of upper and lower substrates having electrodes. A liquid crystal display device that switches between a scattering state and a transmission state by changing the refractive index of liquid crystal depending on the presence or absence of an electric field has attracted many researchers and developers (Japanese Patent Application Laid-Open No. 60-252687).

The display principle of such a polymer-dispersed liquid crystal display device (hereinafter, appropriately referred to as "liquid crystal display device") will be described below.

When no voltage is applied, as shown in FIG. 10A, the molecular axis of the liquid crystal droplet 24 is oriented in a random direction, so that the refractive index of the liquid crystal region is different from that of the surrounding polymer phase 25. The incident light 22 entering the liquid crystal optical element becomes scattered light 23, and as a result, a scattering state is obtained. On the other hand, when an electric field is applied to the transparent electrode 21, the molecular axes of the liquid crystal droplets 24 are arranged in the direction of the electric field as shown in FIG. Is substantially the same as the refractive index of the surrounding polymer phase 25, so that the light is not scattered and becomes the transmitted light 26. As a result, a transmission state is obtained.

A liquid crystal display using this polymer-dispersed liquid crystal display element utilizes light scattering and does not require the use of a polarizing plate.
Compared to a liquid crystal optical element that requires the use of a polarizing plate to obtain linearly polarized light as in the N) type liquid crystal display device, a brighter display with a wider viewing angle can be performed.

However, in a liquid crystal display device using this liquid crystal display element, there is generally a trade-off between the contrast and the drive voltage, and it is difficult to realize a high contrast at a low voltage. Specifically, in order to achieve high contrast, it is necessary to improve the scattering property of the polymer-dispersed liquid crystal. In order to improve the scattering property, it is conceivable to reduce the size of the liquid crystal droplet or increase the cell gap.However, when such a method is applied, the liquid crystal droplet in the polymer dispersed liquid crystal is reduced. It is necessary to increase the electric field torque for driving. In other words, when high contrast is realized, the driving voltage is high and the power consumption is high. On the other hand, when the drive voltage is reduced, the contrast is reduced due to the operation opposite to the above operation.

Therefore, in order to achieve both high contrast and low voltage, a plurality of liquid crystal cells of a normal configuration in which a polymer-dispersed liquid crystal is sandwiched between a pair of upper and lower substrates provided with electrodes are overlapped with an adhesive. A laminated structure has been proposed (Japanese Utility Model Laid-Open No. 6-54031).

[0008]

However, the above-described conventional example has the following problems.

(1) When two liquid crystal cells are overlapped and bonded with an adhesive, even if the adhesive is applied to the entire surface of the substrate with high accuracy and a uniform thickness, the thickness of the adhesive is slightly increased within the substrate surface. Since variation occurs, air is present between the bonded substrates (between the liquid crystal cells that are overlapped). Further, since the substrate surface is not necessarily a flat surface with high accuracy, even when an adhesive is applied to the entire surface of the substrate and bonded together, there may be a slight amount of air. Therefore, in the conventional example in which two liquid crystal cells are overlapped and bonded with an adhesive, an air layer or an adhesive layer is interposed between the overlapping substrates (between the overlapping liquid crystal cells). Therefore, there is a problem that a difference in the refractive index occurs in this portion and the transmittance decreases.

(2) In addition, the thickness of the entire substrate portion is considerably increased (for example, the thickness of the substrate is approximately doubled when two liquid crystal cells are stacked), and the light transmittance is reduced. There is a problem that brightness is significantly impaired. The main reason is that the refractive index does not match between the superposed portion and the substrate. In other words, light that has entered the liquid crystal display device cannot be directed straight because it is refracted at the overlapped portion, and some light cannot be emitted to the front of the substrate. Would. As a result, the light transmittance is reduced, and the brightness of the liquid crystal display device is significantly impaired.

(3) Further, the liquid crystal display device using the polymer dispersed liquid crystal has a problem that the hysteresis is large and the display quality is significantly impaired. The hysteresis characteristic of this liquid crystal display device is based on the fact that the alignment state of the liquid crystal inside the liquid crystal droplet differs between when the voltage rises and when the voltage drops.
As shown in FIG. 11, the voltage from the scattering state to the transmission state −
The transmittance characteristics are different from the voltage-transmittance characteristics from the transmission state to the scattering state. Hysteresis. When the hysteresis is large, the transmittance is different despite the same voltage, so that the display is not uniform, and is perceived by the human eye as deterioration of display quality such as bleeding and out-of-focus.

The present invention has been made in view of the above problems, and realizes a bright display by realizing a high contrast at a low voltage and suppressing a decrease in transmittance.
It is another object of the present invention to provide a polymer-dispersed liquid crystal display device having improved display quality by realizing low hysteresis, a method of manufacturing the same, and a projection display device.

[0013]

According to a first aspect of the present invention, there is provided a liquid crystal display device according to the present invention, wherein electrodes are formed on both surfaces between a pair of substrates each having an electrode formed on an inner surface. One intermediate substrate is disposed, between one of the pair of substrates and the intermediate substrate, and between the other substrate of the pair of substrates and the intermediate substrate A composite layer composed of a polymer and a liquid crystal is interposed therebetween, and the plurality of composite layers are simultaneously driven by the same drive signal.

According to the above configuration, a high-contrast and bright polymer-dispersed liquid crystal display device with a low voltage can be realized. More specifically, the thickness between one substrate and the intermediate substrate and between the other substrate and the intermediate substrate are designed to be thin, and the composite is assumed to be the same cell as the conventional example having a one-layer structure. If the gap is set, the same scattering properties can be obtained, and the driving voltage can be significantly reduced by the thinner composite layer. On the other hand, in the conventional example in which the composite has a one-layer structure, in order to obtain the same scattering at the same driving voltage as in the present invention, it is necessary to increase the cell gap. This means that if the present invention is set to the same cell gap as that of the conventional example in which the composite has a one-layer structure, the present invention has higher scattering properties than the conventional example. Therefore, in the present invention, higher contrast can be obtained at a lower voltage than in the conventional example.

Further, since the present invention has a structure in which electrodes are provided on both surfaces of the intermediate substrate, unlike a conventional example in which two liquid crystal cells are overlapped and bonded with an adhesive, an air layer or an adhesive layer does not exist. Absent. Therefore, it is possible to suppress a decrease in light transmittance caused by an air layer or an adhesive layer existing in a portion where two liquid crystal cells overlap. Further, the thickness of the entire substrate can be significantly reduced. Therefore, according to the present invention, loss of light transmission is suppressed, and bright display is possible.

In the liquid crystal display device according to a second aspect of the present invention, a plurality of intermediate substrates having electrodes formed on both surfaces are spaced apart from each other between a pair of substrates having electrodes formed on the inner surface. Disposed between one of the pair of substrates and the intermediate substrate, between the other of the pair of substrates and the intermediate substrate, and between the plurality of substrates. A composite layer composed of a polymer and a liquid crystal is interposed therebetween, and the plurality of composite layers are simultaneously driven by the same drive signal.

As described above, a plurality of intermediate substrates may be arranged, and in this case, a lower voltage and higher contrast can be realized.

According to a third aspect of the present invention, there is provided a polymer-dispersed liquid crystal display device comprising a composite layer comprising a polymer and a liquid crystal provided between a pair of substrates each having an electrode formed on an inner surface thereof. A plurality of display elements are arranged in an overlapping manner, and a gap between the outer surfaces of the substrates facing the liquid crystal display element is provided with an intermediate adhesive layer having a refractive index substantially equal to that of the substrate. I do.

According to the above configuration, by arranging a plurality of liquid crystal display elements in an overlapping manner, the cell gap is substantially increased, and high contrast can be realized. In addition, since each liquid crystal display element can be formed thin, high contrast can be realized without increasing the driving voltage. Further, since the plurality of liquid crystal display elements are not bonded by the adhesive, no air layer or adhesive layer is interposed between the liquid crystal display elements. An intervening adhesive layer is provided between the plurality of liquid crystal display elements to adhere the outer surfaces of the substrates to each other. The refractive index of the intermediary adhesive layer is substantially the same as the refractive index of the substrate of the liquid crystal display device. Light incident on the liquid crystal display device travels straight, and a bright display can be realized without a decrease in light transmittance.

According to a fourth aspect of the present invention, there is provided the polymer dispersion type liquid crystal display device according to the third aspect, wherein at least one of the plurality of liquid crystal display elements has a voltage-transmission characteristic of a composite layer of the liquid crystal display element. The rate characteristic is different from the voltage-transmittance characteristic of the composite layer of another liquid crystal display element.

By combining the liquid crystal display elements provided with the composite layers having different voltage-transmittance characteristics as described above, the voltage-transmittance characteristics of the polymer dispersed liquid crystal display device are combined. Characteristics, the hysteresis is reduced, and the transmittance gradually changes with respect to the voltage.

According to a fifth aspect of the present invention, in the polymer-dispersed liquid crystal display device according to the fourth aspect, a distance between a pair of substrates of at least one of the plurality of liquid crystal display elements is equal to or smaller than that of the plurality of liquid crystal display elements. It is characterized in that it is different from the distance between a pair of substrates of another liquid crystal display element.

The transmittance of the voltage-transmittance characteristic changes depending on the voltage applied to the composite layer between the substrates. Therefore, assuming that a common voltage is applied to a plurality of liquid crystal display elements, the electric field strength of each composite layer differs by varying the distance between the substrates, and the voltage-transmittance characteristics of each composite layer differ. Can be.

According to a sixth aspect of the present invention, in the polymer dispersed liquid crystal display device according to the fourth or fifth aspect, an insulating film is provided on an electrode of each liquid crystal display element, and at least one liquid crystal is provided. A critical surface tension of an insulating film provided on an electrode of a display element is different from a critical surface tension of an insulating film provided on an electrode of another liquid crystal display element.

By providing an insulating film on the electrode,
The liquid crystal in contact with the insulating film becomes difficult to move. Since the critical surface tension of each insulating film is different, the movement of the liquid crystal is different for each liquid crystal display element, and the voltage-transmittance characteristic can be changed.

According to a seventh aspect of the present invention, in the polymer dispersion type liquid crystal display device according to the sixth aspect, the critical surface tension of the insulating film of one liquid crystal display element is γa, and the insulating film of another liquid crystal display element is Where γb is the critical surface tension of γb and γLC is the surface tension of the liquid crystal material of the composite layer, and γa ≧ γLC and γb <γLC or γa <γLC and γb ≧ γLC.

It is known that when such a relationship is established, the polymer is easily wetted on the insulating film, and the hysteresis becomes extremely small. This is because dome-shaped liquid crystal droplets are formed on the insulating film, and liquid crystal molecules in the dome-shaped liquid crystal droplets are subject to strong alignment regulation from the substrate interface. This regulating force propagates to spherical liquid crystal droplets in the polymer. As a result, when the electric field is turned off from the electric field on state, all the liquid crystal molecules in the liquid crystal droplet including the vicinity of the liquid crystal / polymer resin interface smoothly transition to the original random arrangement state. Therefore, hysteresis can be reduced.

According to the present invention, there is provided a polymer dispersion type liquid crystal display device according to claim 6 or 7, wherein the thickness of the insulating film of at least one liquid crystal display element is:
It is characterized in that the thickness is different from the thickness of the insulating film of another liquid crystal display element.

As described above, of the plurality of liquid crystal display elements,
When the thickness of the insulating film of at least one liquid crystal display element is different, the voltage-transmittance characteristic of one liquid crystal display element is different from the voltage-transmittance characteristic of another liquid crystal display element.

According to a ninth aspect of the present invention, in the polymer dispersion type liquid crystal display device according to any one of the fourth to eighth aspects, the composite layer includes liquid crystal droplets in a polymer matrix. And the size of the liquid crystal droplet constituting the composite layer of at least one liquid crystal display element is different from the size of the liquid crystal droplet constituting the composite layer of another liquid crystal display element. It is characterized by being.

In general, the drive voltage increases when the liquid crystal droplet is small, and decreases when the liquid crystal droplet is large. Therefore, the difference in size of the liquid crystal droplets causes the alignment at the time of voltage application to be different, so that the hysteresis is also averaged for each liquid crystal droplet and the hysteresis is reduced.

According to a tenth aspect of the present invention, in the polymer dispersed liquid crystal display device according to any one of the fourth to ninth aspects, a composite layer of at least one liquid crystal display element is formed. The material of the polymer is different from the material of the polymer constituting the composite layer of another liquid crystal display element.

As described above, the voltage-transmittance characteristics change due to the difference in the polymer material, and liquid crystal display elements having different voltage-transmittance characteristics can be combined.

The present invention according to claim 11 is the polymer dispersion type liquid crystal display device according to any one of claims 3 to 10, wherein the intermediate adhesive layer is made of a single organic material. Alternatively, it is characterized by being formed of a mixture of several kinds of organic materials.

When the intermediate adhesive layer is formed of a single organic material or a mixture of several organic materials, the intermediate adhesive layer having a refractive index substantially equal to that of the substrate can be easily formed.

The present invention according to claim 12 provides the invention according to claim 11
In the polymer-dispersed liquid crystal display device described in (1), the intermediate bonding layer is formed of a material mainly containing a monomer or oligomer of an acrylic material or a methacrylic material.

Since the acrylic material or the methacrylic material has a refractive index close to that of glass, it is possible to prevent the transmittance of light incident on the liquid crystal display device from being reduced.

According to a thirteenth aspect of the present invention, in the polymer dispersion type liquid crystal display device according to any one of the third to twelfth aspects, the refractive index of the intermediate bonding layer is nM, and the refractive index of the substrate is nM. When the rate is nS, the relationship is that | nS-nM | <0.1.

When the refractive index of the intermediate adhesive layer and the refractive index of the substrate have this relationship, the transmittance is generally good.

According to a fourteenth aspect of the present invention, in the polymer dispersion type liquid crystal display device according to any one of the third to twelfth aspects, the refractive index of the intermediate adhesive layer is nM, and the refractive index of the substrate is nM. When the rate is nS, the relationship is that | nS-nM | <0.05.

When the refractive index of the intermediate adhesive layer and the refractive index of the substrate have this relationship, the transmittance is very good, and a bright display can be achieved.

According to a fifteenth aspect of the present invention, in the polymer dispersed liquid crystal display device according to any one of the third to fourteenth aspects, at least one of the substrates is a film substrate. It is characterized by.

By using a film substrate as the substrate, the weight can be reduced.

According to a sixteenth aspect of the present invention, in the polymer dispersed liquid crystal display device according to any one of the third to fifteenth aspects, the plurality of composite layers are provided with the same drive signal. It is characterized by being driven simultaneously.

When a plurality of composite layers are simultaneously driven by the same drive signal, the drive voltage can be greatly reduced.

In the method for manufacturing a dispersion type liquid crystal display device according to the seventeenth aspect, a plurality of sets of substrates having electrodes formed on one side face are arranged so that the electrodes face each other.
A space is provided between the inner surfaces of the substrate where the electrodes face each other,
A step of providing a gap between the outer surfaces of the substrate where the electrodes do not face each other, and in the gap where the outer surfaces of the substrate face each other,
A step of interposing an intermediate material having a refractive index substantially equal to that of the substrate, and by irradiating the intermediate material in the gap with ultraviolet rays, the intermediate material in the gap is cured, and in the gap of the substrate, A step of forming an intermediary adhesive layer that bonds the substrates, and a step of filling a mixed composition in which a polymer material and a liquid crystal are compatible with each other in a space in which the inner surface of the substrate faces, Irradiating the mixed composition in the space with ultraviolet rays, thereby polymerizing the polymer material in the mixed composition in the space to form a composite layer composed of a polymer and a liquid crystal. I do.

According to this method, the intermediate material in the gap between the outer surfaces of the substrate is irradiated with ultraviolet rays, so that the intermediate adhesive layer having a refractive index substantially equal to that of the substrate is formed. While, the substrates are adhered to each other by the mediating adhesive layer, and then, by irradiating the mixed composition in the space where the inner surface of the substrate is facing with ultraviolet rays,
A composite layer is formed between the inner surfaces of the pair of substrates.

In the method for manufacturing a dispersion type liquid crystal display device according to claim 18 of the present invention, a plurality of sets of substrates having electrodes formed on one side thereof are arranged so that the electrodes face each other. Providing a space between the inner surfaces of the substrate where the electrodes face each other, and providing a gap between the outer surfaces of the substrate where the electrodes do not face each other; Filling the mixed composition in which the molecular material and the liquid crystal are compatible with each other, and irradiating the mixed composition in the space with ultraviolet rays, thereby polymerizing the polymer material in the mixed composition, And a step of forming a composite layer made of liquid crystal, and in a gap where the outer surface of the substrate faces,
A step of interposing an intermediate material having a refractive index substantially equal to that of the substrate, and by irradiating the intermediate material in the gap with ultraviolet rays, the intermediate material in the gap is cured, and in the gap of the substrate, Forming an intermediary adhesive layer that bonds the substrates to each other.

According to this method, the composite composition is formed by irradiating the mixed composition filled in the space facing the inner surface of the substrate with ultraviolet rays. By irradiating the intermediate material in the facing gap with ultraviolet rays, the substrates are bonded to each other, and an intermediate adhesive layer having a refractive index substantially equal to that of the substrate is formed.

The present invention described in claim 19 provides the present invention in claim 17
Alternatively, in the method for manufacturing a dispersion-type liquid crystal display device according to claim 18, the intensity of the ultraviolet light applied to the intermediate material and the intensity of the ultraviolet light applied to the mixed composition are different.

By making the intensity of the ultraviolet rays radiated to the medium material and the mixed composition different from each other, the medium material and the mixed composition can be cured in an optimum state to form the medium bonding layer and the composite layer. it can.

The present invention according to claim 20 provides the present invention according to claim 17.
20. The method of manufacturing a dispersion type liquid crystal display device according to claim 19, wherein the material of the mixed composition filled in at least one space is the material of the mixed composition filled in another space. The feature is that it is different.

By making the materials of the mixed composition different, the voltage of the composite layer formed by curing the mixed composition is reduced.
The different transmittance characteristics are combined to reduce the hysteresis, and the transmittance changes gradually with the voltage.

According to a twenty-first aspect of the present invention, there is provided an eighteenth aspect.
Alternatively, in the method for manufacturing a dispersion type liquid crystal display device according to claim 20, the intensity of the ultraviolet light applied to each mixed composition is different.

By varying the intensity of the ultraviolet light applied to the mixed composition portion, different types of mixed compositions are cured in an optimal state, and a composite layer is formed.

According to the method for manufacturing a dispersion type liquid crystal display device of the present invention, a plurality of sets of substrates having electrodes formed on one side are arranged so as to face each other. Providing a space between the inner surfaces of the substrates where the electrodes face each other, providing a gap between the outer surfaces of the substrates where the electrodes do not face each other, and in the gap where the outer surfaces of the substrates face each other, A medium having a refractive index substantially equal to that of the substrate is interposed, and a space in which the inner surface of the substrate faces is filled with a mixed composition in which the polymer material and the liquid crystal are compatible. And an intermediate bonding material for simultaneously irradiating the intermediate material in the gap and the mixed composition in the space with ultraviolet rays to cure the intermediate material in the gap and to bond the substrates to each other in the gap between the substrates. At the same time as forming the polymer material in the mixed composition It is polymerized, characterized in that it comprises a step of forming a composite layer consisting of polymer and liquid crystal.

According to this method, by simultaneously irradiating the medium material with ultraviolet rays and the mixed composition with ultraviolet rays, it becomes possible to manufacture a dispersion type liquid crystal display device in a short time.

According to the twenty-third aspect of the present invention, there is provided the seventeenth aspect.
23. The method of manufacturing a dispersion-type liquid crystal display device according to claim 22, wherein the intermediate material is formed of a single organic material or a mixture of several organic materials. It is characterized by.

The intermediate adhesive layer is formed by irradiating ultraviolet rays to an intermediate material composed of a single organic material or a mixture of several organic materials, and bonds the outer surfaces of the substrates together. .

The present invention according to claim 24 provides the present invention according to claim 23.
In the method for manufacturing a dispersion-type liquid crystal display device according to the above, the intermediate material is mainly composed of a monomer or oligomer of an acrylic material or a methacrylic material, and contains a polymerization initiator.

When the monomer or oligomer is irradiated with ultraviolet rays, the mediating material is cured and a mediating adhesive layer is formed.

The present invention described in claim 25 provides the present invention in claim 17
25. The method of manufacturing a dispersion type liquid crystal display device according to claim 24, further comprising the step of providing an insulating film on an electrode surface of each substrate.

By providing the insulating film on the electrode surface of the substrate, the liquid crystal in contact with the insulating film becomes difficult to move, and the voltage-
The transmittance characteristics can be changed.

According to the projection type liquid crystal display device of the present invention, light is emitted from a light source lamp between an optical component such as a projection lens for projecting an image on a screen and a light source lamp. A plurality of dichroic mirrors are arranged, and a red, green, and blue polymer dispersed liquid crystal display device is interposed between the dichroic mirrors. Type liquid crystal display device
6 is described.

According to the present invention, a bright projection type display device can be realized by interposing a polymer dispersion type liquid crystal display device which displays brightly between dichroic mirrors.

The present invention described in claim 27 provides the present invention according to claim 26.
In the projection type liquid crystal display device according to the above, when the refractive index of the substrate used for the liquid crystal display element is nS, the refractive index of the mediating material is nM, the polymer dispersion type for red light, green light and blue light | NS- for each liquid crystal display device
It is characterized by being adjusted to have a relationship of nM | <0.1.

Each polymer-dispersed liquid crystal device has | nS−nM | <0.
By having the relationship of 1, a relatively bright projection display device can be realized.

The present invention described in claim 28 provides the present invention according to claim 26.
In the projection type liquid crystal display device according to the above, when the refractive index of the substrate of the liquid crystal display element is nS and the refractive index of the intermediate material is nM, the polymer dispersed liquid crystal display for red light, green light and blue light It is characterized in that adjustment is made so as to have a relationship of | nS-nM | <0.05 for each device.

Each polymer-dispersed liquid crystal device has | nS−nM | <0.
By having the relationship of 05, the projection type display device can display a considerably bright display.

[0070]

BEST MODE FOR CARRYING OUT THE INVENTION A high-contrast, high-brightness, high-contrast, polymer-dispersed liquid crystal display device which enables a low-voltage, high-brightness display will be described in the first embodiment of the present invention. A polymer-dispersed liquid crystal display device with improved display quality, a method of manufacturing the same, and a projection display device will be described in (Embodiment 2).

(Embodiment 1) FIG. 1 is a simplified cross-sectional view of a polymer-dispersed liquid crystal display device 1 according to Embodiment 1 of the present invention. This polymer dispersed liquid crystal display device 1
A pair of transparent substrates 2 and 3, an intermediate substrate 4 disposed between the substrates 2 and 3, a composite layer 6 disposed between the substrates 2 and 4, And a composite layer 7 disposed on the substrate. On the inner surface of the substrate 2, a transparent electrode 10 made of indium tin oxide is formed.
A transparent electrode 11 made of indium tin oxide is formed on the inner surface of the substrate. Transparent electrodes 12 and 13 made of indium / tin oxide are provided on both surfaces of the intermediate substrate 4.
Are formed. The composite layers 6 and 7 are polymer dispersed liquid crystal (PDLC) layers having a structure in which liquid crystal droplets 16 are independently dispersed in a polymer matrix 5715, but the liquid crystal is held in a three-dimensional network polymer. Polymer network type liquid crystal layer may be used. The substrates 2 and 3 are, for example, glass substrates, and the intermediate substrate 4 may be a glass substrate or a transparent film. Further, the distance between the substrate 2 and the intermediate substrate 4 and the distance between the substrate 3 and the intermediate substrate 4 may be the same or different.

The substrates 2 and 3 are bonded together by the spacer / seal resin 20, and the composites 6 and 7 are sealed. One terminal of the liquid crystal driving AC power supply 30 is commonly connected to the transparent electrode 10 and the transparent electrode 13, and the other terminal of the liquid crystal driving AC power supply 30 is commonly connected to the transparent electrode 11 and the transparent electrode 12. Have been. With such wiring, the complex 6 and the complex 7 are simultaneously driven by the same drive signal from the power supply 30.

The transmission / scattering operation of each of the composite layers 6 and 7 in the liquid crystal display device 1 having the above configuration is the same as that of the general polymer dispersed liquid crystal display device shown in FIG.

With the above configuration, the liquid crystal display device 1 has the following effects. That is, the liquid crystal display device 1
When compared with a liquid crystal display device having the same cell gap as a whole and a composite having a single-layer structure, both have the same cell gap and thus the same scattering properties. However, the drive voltage is lower in the liquid crystal display device 1. Because
The liquid crystal display device 1 is configured to drive each of the composites 6 and 7 with the same drive voltage, and the cell gap for each of the composites 6 and 7 is smaller than the entire cell gap. This is because the above scattering property can be obtained. On the other hand, a liquid crystal display device in which the composite has a one-layer structure,
When driving at the same drive voltage as the liquid crystal display device 1, unless the cell gap is made larger than that of the liquid crystal display device 1,
The same scattering property as that of the liquid crystal display device 1 cannot be obtained. In other words, the liquid crystal display device 1 can realize both lower voltage and higher contrast than the liquid crystal display device having a single layer structure.

Furthermore, since electrodes are provided on both surfaces of the intermediate substrate 4, there is no air layer or adhesive layer as in the conventional example in which two liquid crystal cells are overlapped and bonded with an adhesive. Therefore, a decrease in light transmittance due to the presence of the air layer and the adhesive layer can be suppressed. Further, the thickness of the entire substrate can be significantly reduced. Therefore, according to the present invention, loss of light transmission is suppressed, and bright display is possible.

(Embodiment 2) FIG. 2 is a simplified diagram of a polymer-dispersed liquid crystal display device (hereinafter, appropriately referred to as "liquid crystal display device") 50 according to Embodiment 2 of the present invention. It is sectional drawing.

The liquid crystal display device 50 has a plurality of, for example, 2
An intervening adhesive layer 52 is interposed between the two liquid crystal display elements 51, 51 arranged in an overlapping manner. In the liquid crystal display element 51, a thin composite layer 55 is provided between a pair of transparent substrates 53 and 54 facing each other in parallel. In addition, the thickness of the liquid crystal display device 50 related to the scattering characteristics
Since the thicknesses of 3, 54 are integrated, the scattering is greatly improved, and high contrast can be achieved. The substrates 53 and 54 are formed of, for example, glass, but can be formed of a film to reduce the weight. Transparent electrodes 56, 56 made of indium tin oxide are formed on the inner surfaces of the substrates 53, 54. The composite layer 55 is a polymer dispersed liquid crystal (PDLC) layer having a structure in which liquid crystal droplets 58 are independently dispersed in a polymer matrix 57, but is not limited thereto.
It may be a polymer network type liquid crystal layer in which a liquid crystal is held in a three-dimensional network polymer. A pair of substrates 53, 5
The periphery of 4 is bonded with a spacer / seal resin 59, and the composite layer 55 is sealed.

The two liquid crystal display elements 51, 51
Are arranged in parallel with a gap therebetween, and are disposed in the gap G between the outer surfaces of the substrates 54 and 54 facing each other.
Is provided. The intermediary adhesive layer 52 includes a substrate 53,
The substrate 54 is bonded, and is formed of a material substantially equal to the refractive index of the substrates 53 and 54. Specifically, assuming that the refractive index of the intermediate adhesive layer 52 is nM and the refractive indexes of the substrates 53 and 54 are nS, | nS−nM | <0.1 (A), preferably | nS−nM | < It is formed of, for example, an organic single material or a mixture of several organic materials mainly containing an acrylic material or a methacrylic material so as to have a relationship of 0.05... (B). As described above, each of the liquid crystal display elements 51 has the refractive index of the intermediate bonding layer 52 for bonding the substrates 53 and 54 substantially equal to the refractive index of the substrates 53 and 54, so that the substrates 53 and 54 and the intermediate adhesive layer are bonded to each other. There is no loss of transmittance due to the refraction of the incident light at the portion where it is joined with 52, and a bright display is possible in the transmission state.

The voltage-transmittance characteristics of the entire liquid crystal display device 50 are different from those of the liquid crystal display element 51 driven by high voltage as shown in FIG. 3A and the liquid crystal display element 51 driven by low voltage as shown in FIG. 3B. 3c, the hysteresis is reduced as shown in FIG. 3c, and the transmittance is changed gradually with respect to the voltage, the non-uniformity of the display is improved, and the blur and the blur of focus are reduced. Is prevented from occurring.

In order to improve the voltage-transmittance characteristic by making the change of the transmittance with respect to the voltage slow as described above, the distance between the pair of substrates 53 and 54 of a certain liquid crystal display element 51 and the other liquid crystal display The distance between the pair of substrates 53 and 54 of the element 51 is made different, or an insulating film (not shown) is provided on the electrode 56. By making the intervals between the substrates 53 and 54 different, the electric field intensity applied to each of the composite layers 55 and 55 is different, and different voltage-transmittance characteristics can be obtained.

Further, by providing the insulating film on the electrode, the alignment regulating force of the liquid crystal in contact with the insulating film is different, and the critical surface tension of each insulating film is different, so that the voltage-transmittance characteristic can be changed. it can. It is preferable that the thickness of each insulating film be different for each electrode 56. The critical surface tension of the insulating film provided on the electrode 56 of at least one liquid crystal display element 51 is different from the critical surface tension of the insulating film provided on the electrode 56 of another liquid crystal display element 51. . The critical surface tension of one insulating film is γa, the critical surface tension of another insulating film is γb, and the surface tension of the composite layer 55 is γLC.
It is preferable that γa ≧ γLC and γb <γLC (C) or γa <γLC and γb ≧ γLC (D).

With such a relationship, as shown in FIG. 4, a dome-shaped liquid crystal droplet 58 is formed on one of the insulating films, and the liquid crystal molecules in the dome-shaped liquid crystal droplet 58 Strong alignment regulation from interface. This regulating force also propagates to the spherical liquid crystal droplet 58 in the polymer. As a result, when the electric field is turned off from the electric field on state, all the liquid crystal molecules in the liquid crystal droplet 58 including the vicinity of the liquid crystal / polymer resin interface smoothly transition to the original random arrangement state. Therefore, the polymer is easily wetted in the form of an insulating film, and the hysteresis becomes extremely small.

As shown in FIG. 5, such a liquid crystal display device 50 is driven simultaneously by the same drive signal of one power supply 60. That is, one terminal 61 of the power supply 60 is connected to one electrode 56 of one liquid crystal display element 51.
And one electrode 56 of the other liquid crystal display element 51, and the other terminal 62 is connected to the other electrode 56 of the one liquid crystal display element 51 and the other electrode 5 of the other liquid crystal display element 51.
6 is connected. By being wired in this manner, both composite layers 55 of the two liquid crystal display elements 51, 51 are formed.
Are simultaneously driven by the same drive signal from one power supply 60. In the liquid crystal display device 50, the driving voltage can be significantly reduced by simultaneously driving the composite layers 55 of the plurality of thin liquid crystal display elements 51.

Next, a method of manufacturing the polymer dispersed liquid crystal display device 50 of the present invention will be described.

First, the substrate 5 having the electrode 56 formed on one side surface
3, 54 are arranged in a plurality. However, the substrate 5
The layers 3 and 54 are arranged so that the side on which the electrodes 56 are formed faces each other as an inner surface. The surroundings of the substrates 53 and 54 are shown in FIG.
As shown in FIG. 7, a space K is provided between the opposing inner surfaces of the two substrates 53 and 54 by bonding with a spacer / seal resin 59. On the other hand, a gap G is provided between the outer surfaces of the substrates 54 and 54 facing each other.

An intermediary material having a refractive index substantially equal to that of the substrates 53 and 54 is interposed in the gap G. This medium material is formed of an organic single material or a mixture of several organic materials such as a material composed of an acrylic or methacrylic monomer or oligomer and a polymerization initiator. Then, the medium or the oligomer is cured by irradiating the medium with ultraviolet rays to form a medium bonding layer 52 for bonding the substrates 54 to each other in the gap G.

Next, a space K in which the inner surfaces of the substrates 53 and 54 face each other is filled with a mixed composition in which the polymer-forming material and the liquid crystal are compatible. Finally, when the mixed composition is irradiated with ultraviolet light, the polymer material in the mixed composition is polymerized, and liquid crystal droplets 58 are precipitated in the polymer.
Is maintained in a state of being independently dispersed in the polymer matrix 57 to form a composite layer 55. In this way, the liquid crystal display device 50 in which the plurality of liquid crystal elements having the thin composite layer 55 interposed between the substrates 53 and 54 are bonded by the mediating adhesive layer 52 having a refractive index substantially equal to that of the substrates 53 and 54 is provided. Complete.

In the method of manufacturing the polymer-dispersed liquid crystal display device 50 according to the present invention, the above-described steps can be slightly modified. That is, the above-described manufacturing method uses the substrates 54 and 5
After forming the intermediary adhesive layer 52 in the gap G of FIG.
The composite layer 55 was formed therein, but this process was reversed,
First, the composite layer 55 is formed in the space K.
The mediation adhesive layer 52 may be formed in the gap G between the third and the 54th. Therefore, in this manufacturing method, first, the substrate 5
A space K in which the inner surfaces of the polymer matrix material 3 and 54 face each other is filled with a mixed composition in which the polymer forming material and the liquid crystal are compatible with each other, and the mixed composition is irradiated with ultraviolet rays to thereby form a polymer matrix 57. A composite layer 55 in which liquid crystal droplets 58 are dispersed and held is formed. Next, an intermediate material composed of an acrylic or methacrylic monomer or oligomer and a polymerization initiator adjusted to have substantially the same refractive index as the substrates 53 and 54 is placed on the outer surface of the substrate 54 so as to face each other. In the gap G. Then, the intermediate material is irradiated with ultraviolet rays to cure the monomer or oligomer, and the intermediate bonding layer 52 for bonding the substrates 54 to each other.
To form

As still another manufacturing method, the mixed composition to be filled in a certain space K and the mixed composition to be filled in another space K can be made different. In this case, it is preferable to make the intensity of the ultraviolet light applied to each mixed composition different. If the mixture to be filled in the space K is the same or the intensity of the ultraviolet light is the same, the intermediate bonding layer 52
And the composite layer 55 are not formed in separate steps, but instead, the irradiation of the intermediate material with ultraviolet light and the irradiation of the mixed composition with ultraviolet light are performed simultaneously, so that the intermediate bonding layer 52 and the composite layer 5
5 can also be formed simultaneously.

The liquid crystal display device 50 manufactured as described above
Can be incorporated in a projection display device 70 as shown in FIG. This projection type display device 70
Is a plurality of dichroic mirrors for dividing light into red light (R), green light (G) and blue light (B) between an optical component 72 such as a projection lens for projecting an image on a screen 71 and a light source lamp 73. Are arranged, and the liquid crystal display device 50 for RGB according to the present invention is interposed between the dichroic mirrors 74, 74. In each liquid crystal display device 50, the refractive index of the medium material is adjusted so that the refractive index of each of the RGB wavelengths becomes equal to the refractive index of the substrates 53 and 54. Assuming that the refractive indexes of the substrates 53 and 54 used for the liquid crystal display element 51 of the liquid crystal display device 50 are nS and the refractive index of the intermediate material is nM, the above formulas (A) and (B) are provided for each liquid crystal display device 50, respectively. | NS−nM | <0.
The index of refraction of the mediator is adjusted to have a relationship of 1, preferably | ns-nM | <0.05.

This projection type liquid crystal display device 70
Excellent quality of high contrast and bright display at low voltage can be realized. The reason why the display becomes brighter is that the loss of transmittance due to refraction of light at the superimposed portion is minimized by optimizing the refractive index of the mediating material for each color of RGB in accordance with the wavelength of each color. The higher contrast is based on the same reason as described above.

[0092]

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

(Example 1 in Embodiment 1 of the Invention)
Liquid crystal display device 1 having configuration according to Embodiment 1 of the present invention
Was produced by the following method.

Glass having a transparent electrode (thickness: 50 nm) made of indium / tin oxide formed only on one side (thickness: 0.1 mm).
7 mm) and two pieces of glass (0.5 mm thick) each having a transparent electrode layer (50 nm thick) made of indium tin oxide on both sides (corresponding to the intermediate substrate 4). )prepare. On one side (electrode side) of each of the substrates 2 and 3, an acid anhydride-curable epoxy resin in which glass fiber having a diameter of 9 μm is dispersed as a spacer / seal resin is left at 3 mm as an opening on only one side of the four sides. After printing in a 2 mm square, pressurizing the electrode surface in a state where the electrode surface is opposed via the intermediate substrate 4, heating at 150 ° C. for 2 hours to cure and bond,
Completed the space.

Next, P is used as a polymer-dispersed liquid crystal forming material.
Using NM201 (trade name: manufactured by Rodeck Co., Ltd.), the space was injected through the opening, the opening was sealed, and then the polymer was polymerized at 18 ° C. using a high-pressure mercury lamp as a light source. Composite layers 6 and 7 were formed. At this time, polymerization was carried out by arranging a light cut filter (manufactured by Toshiba Color Glass Co., Ltd .: UV35) on the light irradiation surface, and the intensity of ultraviolet light was about 40 mW / cm ^2.
And the irradiation time was 60 seconds. Next, the electrode portion 30 was connected as shown in FIG.
The liquid crystal display device 1 thus manufactured was driven in an AC electric field having a frequency of 60 Hz, and the performance was evaluated.

As the evaluation index, the contrast CR, the driving voltage VC, and the brightness L were used.

Here, the contrast CR and the driving voltage V
C, the brightness L, the transmittance when no electric field is applied is T0, the maximum transmittance of the liquid crystal display device is Tmax, and the transmittance of the liquid crystal display device is Tm.
These values are calculated from the first, second, and third equations, respectively, where the voltage at which 90% of ax is V90 is V90.

CR = Tmax / To (1) VC = V90 (2) L = Tmax (%) (3) The larger the value of the first equation, the higher the contrast, and the smaller the value of the second equation, the more the driving. The lower the voltage and the larger the value of the third equation, the brighter the light and the better the performance of the liquid crystal display device.

As a measurement result of the liquid crystal display device 1, CR =
95, VC = 6.5, and L = 82. From this measurement result, a high-contrast, low-voltage, bright liquid crystal display device was realized.

In the present embodiment, the intermediate substrate 4 has a single structure. However, even if a plurality of intermediate substrates 4 are used, a high-contrast and bright display can be realized at a low voltage. Further, in this embodiment, the thickness between the substrates in each layer is the same, but the thickness between the substrates in each layer may be changed.

Although the thickness of the substrate and the thickness of the electrode layer are not limited to those described in the embodiments, the thinner the better, the better in terms of brightness. Further, the polymer-dispersed liquid crystal is not limited to the material (PNM201) described in the embodiment, and any material may be used.

(Comparative Example 1 in Embodiment 1 of the Invention)
As Comparative Example 1 according to Embodiment 1 of the present invention, a liquid crystal display device was manufactured by the following method. Note that Comparative Example 1 corresponds to a conventional example in which the composite has a one-layer structure.

Glass having a transparent electrode layer (thickness: 50 nm) made of indium / tin oxide formed on only one side (thickness: 0.1 mm).
7 mm), and an acid anhydride-curable epoxy resin in which glass fiber having a diameter of 18 μm is dispersed as a spacer / seal resin on one side (electrode side) of one side of the four sides, leaving 3 mm as an opening on only one side. After printing 2mm square on the edge,
Pressure was applied with the electrode surfaces facing each other, and the mixture was heated and bonded at 150 ° C. for 2 hours to complete the space, thereby completing the space.

Next, P is used as a polymer-dispersed liquid crystal forming material.
Using NM201 (made by Rodeck Co., Ltd.), a liquid crystal display device was completed in the same manner as in Example 1.

The liquid crystal display device completed in this way is described in Example 1.
When measured under the same measurement conditions as in the above, CR = 92, VC
= 12.8, L = 84. As is clear from the measurement results, Comparative Example 1 was capable of high-contrast and bright display, but the driving voltage was much higher than that of Example 1.

(Comparative Example 2 in Embodiment 1 of the Invention)
As Comparative Example 2 in Embodiment 1 of the present invention, a liquid crystal display device was manufactured by the following method. Comparative example 2 corresponds to a conventional example in which two liquid crystal spaces are overlapped and bonded with an adhesive.

Glass having a transparent electrode layer (thickness: 50 nm) made of indium / tin oxide formed only on one side (thickness: 0.1 mm).
7 mm), and an acid anhydride-curable epoxy resin in which glass fiber having a diameter of 9 μm is dispersed as a spacer / seal resin on one side (electrode side) of one side of the four sides is left as 3 mm as an opening. After printing on a 2 mm square at the end, pressure was applied in a state where the electrode surfaces were opposed to each other, and the mixture was heated and bonded at 150 ° C. for 2 hours to complete a cell.

Next, P is used as a polymer-dispersed liquid crystal forming material.
Using NM201 (made by Rodeck Co., Ltd.), a liquid crystal display device was completed in the same manner as in Example 1. Further, another liquid crystal display device having the same configuration was prepared, two liquid crystal display devices were superimposed, and measurement was performed under the same measurement conditions as in Example 1 in this state. The performance of the liquid crystal display device is CR = 96, VC =
6.5, L = 70. From this measurement result, Comparative Example 2 was able to achieve high contrast at a low voltage, but was inferior to Example 1 in brightness.

(Example in Second Embodiment of the Invention) In the liquid crystal display device 50 in the second embodiment of the present invention, the liquid crystal display device 50 in the first embodiment (hereinafter, "in the second embodiment of the present invention" is omitted, and The same applies to other examples.), And can be manufactured as in Example 33. Here, matters common to all the embodiments will be described first collectively, and different matters will be individually described for each embodiment.

As a common matter, the substrates 53 and 54
A glass substrate 1737 having a refractive index nS of 1.522 at a wavelength of 485.1 nm (trade name: manufactured by Geomatech Co., Ltd.) was used. On one side of the glass substrate, a transparent electrode 56 layer made of indium / tin oxide was formed. The two substrates 53 and 54 are opposed to each other so that the electrodes 56 face each other, and glass fibers having a diameter of 9 μm are dispersed on four sides around the substrates 53 and 54 except for the following Example 2. An acid anhydride-curable epoxy resin was interposed. However, one side of the epoxy resin is left as 3 mm as an opening for injecting the mixed composition, and after printing on a 2 mm square at the end, while pressing the two substrates 53 and 54 sandwiching the epoxy resin,
Heating was performed at 150 ° C. for 2 hours, and the epoxy resin was used as the spacer / seal resin 59.

In the space K formed by the spacer / seal resin 59 between the two substrates 53 and 54, a mixed composition as shown in the following Examples 1 to 33 is injected from the opening at 18 ° C. After filling and closing the opening, the mixture composition was irradiated with ultraviolet rays to carry out polymerization at 18 ° C. to form a composite layer 55. Also, two substrates 53,
In the gap G between the outer side surfaces of the first through third embodiments,
The intermediate bonding material 52 was formed by filling the intermediate material as shown in FIG. 1 and irradiating the intermediate material with ultraviolet rays.

In order to evaluate the performance of the completed liquid crystal display device 50, as shown in FIG. 5, a power supply 60 was connected and driven by an AC electric field having a frequency of 60 Hz. The performance was evaluated using green light (G) using a LCD 500 manufactured by Otsuka Electronics Co., Ltd., with a green filter installed on a white light source.

The transmittance when no electric field is applied is T0, the maximum transmittance of the liquid crystal display device 50 is Tmax, the voltage when the transmittance of the liquid crystal display element 51 becomes 90% of Tmax is V90, and the voltage of the liquid crystal display device 50 is V90. In the voltage-transmittance characteristics, the transmittance in the scattering state → transmission state and transmission state → scattering state is T
The voltages at which 50% of max are reached are V50 ↑ and V
When 50 ↓ is set, contrast CR, drive voltage VC,
The brightness L and the hysteresis H are the following first, respectively.
It is calculated from the formula, the second formula, the third formula and the fourth formula.

CR = Tmax / To (1) VC = V90 (2) L = Tmax (%) (3) H = (V50 ↑ −V50 ↓) / V50 ↑ × 100 (%) (4) The larger the value of the first equation, the higher the contrast, the smaller the value of the second equation, the lower the driving voltage, the larger the value of the third equation, the brighter, and the smaller the value of the fourth equation, the more the hysteresis. Smaller, the performance of the liquid crystal display device 50 becomes better.

(Examples 1 to 4 in Embodiment 2 of the Invention)
Fifth Embodiment In any of the first to fifth embodiments of the second embodiment of the present invention, the medium filled in the gap G where the outer surfaces of the substrates 53 and 54 face each other is Darocur 4265 (commercially available) as a polymerization initiator. Name: Benzyl methacrylate (Kyoeisha Chemical Industry Co., Ltd.) containing Chibagaiki Co., Ltd.
And The concentration of Darocure 4265 was 2% by weight based on benzyl methacrylate. The intensity of the ultraviolet light radiated from the upper surfaces of the substrates 53 and 54 to the medium material is 100 mW / cm.
^{And 2} . On the other hand, the mixed composition filled in the space K includes:
As shown in Table 1, the mixed compositions of the other examples were the same, with only a slight difference between Example 4 and Example 5.

[Table 1]

The intensity of the ultraviolet light applied to the mixed composition was about 40 mW / cm ² , and the irradiation time was 60 seconds. At this time, a light cut filter (UV35, manufactured by Toshiba Color Glass Co., Ltd.) was arranged on the light irradiation surface to perform polymerization.

Next, differences between the first embodiment and the fifth embodiment will be described with reference to Table 1.

Example 1 is a specific example of a basic liquid crystal display device 50. The mixed composition is BL00 as a liquid crystal material.
2 (trade name: manufactured by Merck Co., Ltd.), 80 parts, 2-ethylhexyl acrylate (trade name: manufactured by Nakarai Tesque Co., Ltd.) 15.8 parts as a polymerization monomer, HX620 (trade name: Nippon Kayaku Co., Ltd.) as an acrylic oligomer 4), Darocur 4265 (trade name, manufactured by Ciba Gaiki Co., Ltd.) as a polymerization initiator for smoothly promoting the polymerization of the polymer material.
Two parts were employed. Hereinafter, this combination is referred to as mixed composition A.
It is described.

The performance of contrast CR, drive voltage VC, and brightness L of the liquid crystal display device 50 in Example 1 in which the composite layer 55 was formed from the mixed composition A was CR = 17.
0, VC = 6.5 and L = 85, which means that the liquid crystal display device 50 with high contrast and brightness at a low voltage can be realized. Hysteresis H was H = 11.2%.

The second embodiment is a specific example in which the interval between the two substrates 53 and 54 is half that of the first embodiment. Therefore, the diameter of the glass fibers dispersed in the acid anhydride-curable epoxy resin was 4.5 μm. Otherwise, the liquid crystal display device 50 is operated in exactly the same manner as described in the first embodiment.
Was completed.

As described above, the liquid crystal display device 5 according to the second embodiment is configured such that the distance between the two substrates 53 and 54 is half that of the first embodiment.
The performance of contrast CR, drive voltage VC, and brightness L of 0 is CR = 121, VC = 6.2, L = 85, and a high-contrast and bright liquid crystal display device 50 can be realized at a low voltage. Further, the hysteresis was H = 1.8%, which was considerably improved as compared with that of Example 1.

The third embodiment is a specific example in which an insulating film is formed on the electrodes 56 of the substrates 53 and 54. Polyimide JALS214 is used as a material of an insulating film formed on the electrode 56 of one liquid crystal display element 51, and the other liquid crystal display element 51
Polyimide AL1051 was used as a material of the insulating film formed on the electrode 56 of FIG. In order to form each insulating film, a 3% solution of a polyimide component was spin-coated. Spinner is 3000 rpm. For 30 seconds. 180 ° C after application
For 60 minutes to complete the formation of the insulating film. Otherwise, the liquid crystal display device 50 was completed by exactly the same operation as described in the first embodiment.

The surface energy of each of the insulating films thus completed was examined using a wettability standard solution (manufactured by Nacalai Tesque Co., Ltd.).
The critical surface tension γa of 214 is γa = 29.2 dyne / cm,
The critical surface tension γb of polyimide AL1051 is γb = 3
The surface tension γLC of the composite layer 55 was 3.1 dyne / cm, and γLC = 30.5 dyne / cm. Therefore, the liquid crystal display device 50 satisfies the condition of Expression (D) that γa <γLC and γb ≧ γLC.

The contrast CR and the drive voltage V of the liquid crystal display device 50 according to the third embodiment in which such an insulating film is formed.
The performance of C and brightness L is CR = 170, VC = 7.5,
L = 85, and a low-voltage, high-contrast, bright liquid crystal display device 50 was realized. The hysteresis is H =
At 2.8%, it was considerably improved as compared with that of Example 1.

In the fourth embodiment, two liquid crystal display elements 51 and 5
This is a specific example in which the materials of the first composite layers 55 and 55 are different. One space K was filled with the mixed composition A, and the other space K was filled with the mixed composition B. The mixed composition B has a liquid crystal material of BL002 (trade name: manufactured by Merck Ltd.) 82
Parts, 15.8 parts of 2-ethylhexyl acrylate (trade name: manufactured by Nacalai Tesque, Inc.) as a polymerizable monomer, 2 parts of HX620 (trade name, manufactured by Nippon Kayaku Co., Ltd.) as an acrylic oligomer, and Darocure 4265 as a polymerization initiator
(Product name: Ciba Gaiki Co., Ltd.) 0.2 parts was employed.
Otherwise, the liquid crystal display device 50 was completed by exactly the same operation as described in the first embodiment.

The contrast C of the liquid crystal display device 50 according to the fourth embodiment having such two types of composite layers 55 is as follows.
The performance of R, drive voltage VC, and brightness L is CR = 142,
VC = 6.4, L = 85, and a low-voltage, high-contrast, bright liquid crystal display device 50 was realized. In addition, the hysteresis was significantly improved as compared with that of Example 1 at H = 1.5%. After the evaluation of the characteristics, the liquid crystal display device 50 was broken, and the size of the liquid crystal droplet 58 was evaluated by SEM. Liquid crystal drop 5
The size of No. 8 is 1.0 μm in the case of using the mixed composition A.
m and 1.8 μm in the case of using the mixed composition B.
It is considered that the hysteresis is reduced due to the difference in the size of the liquid crystal droplet 58 of each composite layer 55 as described above.

Embodiment 5 also has two liquid crystal display elements 51 and 5
This is an example in which the materials of one composite layer 55 are different. One space K was filled with the mixed composition A, and the other space K was filled with the mixed composition C. The intensity of the ultraviolet light applied to the mixed composition A was about 40 mW / cm ² , and the irradiation time was 60 seconds. The mixed composition C was TL2 as a liquid crystal material.
13 (manufactured by Merck Ltd.) 80 parts, 2 as polymerizable monomer
Ethylhexyl acrylate (Nacalai Tesque, Inc.)
15.8 parts, HX62 as an acrylic oligomer
0 (manufactured by Nippon Kayaku Co., Ltd.) and 0.2 parts of Darocure 4265 (manufactured by Ciba Gaiki Co., Ltd.) as a polymerization initiator. The intensity of the ultraviolet light applied to the mixed composition C is about 20.
mW / cm ² , and the irradiation time was 60 seconds. At this time, a light cut filter (Toshiba Color Glass Co., Ltd .: U
V35) and polymerization was carried out. Otherwise, the liquid crystal display device 50 was completed by exactly the same operation as described in the first embodiment.

The contrast C of the liquid crystal display device 50 in the fifth embodiment having such two types of composite layers 55 is as follows.
The performance of R, drive voltage VC and brightness L is CR = 170,
VC = 6.8, L = 85 The voltage was low, and a high contrast and bright liquid crystal display device 50 was realized. Also, the hysteresis was considerably improved at H = 2.5% as compared with that of Example 1.

(Examples 6 to 6 in Embodiment 2 of the Invention)
Embodiment 18 Embodiments 6 to 18 are specific examples in which the intermediate material of the intermediate adhesive layer 52 interposed in the gap G between the two liquid crystal display elements 51 is methacrylic acid, methacryloyloxyethyl, or the like. Example 1 except for the mediator
The liquid crystal display device 50 was completed in the same manner as described above. Table 2 summarizes the performance of the liquid crystal display device 50 when each of the mediators of Examples 6 to 18 was interposed.

[Table 2]

The contrast CR, the driving voltage VC, and the brightness L of the liquid crystal display device 50 in the sixth to eighteenth embodiments.
As shown in Table 2, each of the performances was CR = 170,
VC = 6.5 and L = 78 to 85, and high-contrast and bright display was realized at low voltage. The hysteresis H was H = 11.2%.

FIG. 8 shows the relationship between the brightness L in the transmission state of the liquid crystal display device 50, the refractive index nM1 of the intermediate material used in this experiment, and the refractive index nS of the substrates 53 and 54 of the liquid crystal support plate. Indicated. There is a certain correlation between L and nM1 and nS. When satisfying the relationship of the formula (A) of | nS-nM1 | <0.1, the effect of improving brightness is seen as shown by the symbol △. Further, when the relationship of | nS−nM1 | <0.05 is satisfied, the result becomes extremely bright as indicated by a circle. When nM1 and nS do not satisfy the relationship of the expression (A), a circle is used. It was not bright as shown.

(Example 19 in Embodiment 2 of the Invention)
-Embodiment 31) Embodiments 19 to 31 are specific examples in which the intermediate material of the intermediate adhesive layer 52 interposed between the liquid crystal display elements 51 is ethylene glycol, benzene, or the like. After the mixed compound A was filled into the space K from the opening at 18 ° C. and the opening was sealed, polymerization was performed at 18 ° C. using a high-pressure mercury lamp as an ultraviolet light source. Liquid crystal display device 50 when each of the mediating materials of Examples 19 to 31 intervenes
Are summarized in Table 3.

[Table 3]

As shown in Table 3, each of the performances of the contrast CR, the driving voltage VC, and the brightness L of the liquid crystal display device 50 in Examples 19 to 31 was CR = 17.
0, VC = 6.5, L = 75-85, and high-contrast and bright display was realized at low voltage. The hysteresis H was H = 11.2%.

FIG. 9 shows the relationship between the brightness L in the transmission state of the liquid crystal display device 50, the refractive index nM2 of the intermediate material used in this experiment, and the refractive indexes nS of the substrates 53 and 54 of the liquid crystal support plate. Indicated. There is a certain correlation between L and nM2, nS, and when satisfying the relationship of the formula (A) of | nS-nM2 | <0.1, the effect of improving brightness is seen as shown by the symbol △. Further, when the relationship of the formula (B) of | nS−nM2 | <0.05 is satisfied, the light becomes extremely bright as indicated by a circle, and when nM1 and nS do not satisfy the relationship of the formula (A), a circle is used. It was not bright as shown.

(Example 3 in Embodiment 2 of the Invention)
2) Example 32 is a specific example in which irradiation of the mixed composition with ultraviolet light and irradiation of the medium material with ultraviolet light were performed simultaneously. Otherwise, the liquid crystal display device 50 was completed in exactly the same manner as described in Example 1. The intensity of the ultraviolet light irradiated to the mixed composition and the intermediate material at 18 ° C. was about 40 mW / cm ² , and the irradiation time was 60 seconds. At this time, a light cut filter (UV35, manufactured by Toshiba Color Glass Co., Ltd.) was placed on the light irradiation surface to perform polymerization.

As described above, the liquid crystal display device 50 of the thirty-second embodiment in which the mixed composition and the intermediate material are simultaneously irradiated with ultraviolet rays.
Of the contrast CR, the driving voltage VC, and the brightness L are CR = 170, VC = 6.5, L as in the first embodiment.
= 85, and high-contrast and bright display was possible at low voltage.

(Example 3 in Embodiment 2 of the Invention)
3) Example 33 is a specific example in which two spaces K are filled with the same mixed composition A at 18 ° C., but the intensity of the ultraviolet light applied to each mixed composition A is different. The intensity of the ultraviolet light applied to the mixed composition A in one space K is about 10
At 0 mW / cm ² , the irradiation time was 60 seconds. The intensity of the ultraviolet light applied to the mixed composition A in the other space K is about 30
The irradiation time was 60 seconds at mW / cm ² . Otherwise, the liquid crystal display device 50 is formed in exactly the same manner as described in the first embodiment.
Was completed.

As described above, in the liquid crystal display device 50 of Example 33 in which the intensity of irradiation of the mixed composition A was varied, the performance of the contrast CR, the driving voltage VC, and the brightness L was CR
= 142, VC = 7.9, L = 85, and a low-voltage, high-contrast, bright liquid crystal display device 50 was realized. In addition, the hysteresis H was significantly improved compared to that of Example 1 at H = 2.0%. After the characteristic evaluation, the liquid crystal display device 50 was broken and the size of the liquid crystal droplet 58 was evaluated by SEM. The size of the liquid crystal droplet 58 was 100 mW / cm ^2.
Is 1.0 μm, and 30 mW / cm ²
Was 1.8 μm. Therefore, it is considered that the effect of improving the hysteresis is caused by the difference in the size of the liquid crystal droplet 58.

(Comparative Example 1 in Embodiment 2 of the Invention)
Comparative Example 1 is an example of a liquid crystal display device in which air is interposed as a mediator in a gap G between two liquid crystal display elements manufactured by exactly the same operation as described in Example 1. The performance of the contrast CR and the drive voltage VC of this liquid crystal display device was CR = 170 and VC = 6.5. Although a high contrast was realized at a low voltage, the brightness was L and L = 7.
0, and the hysteresis H is H = 11.2.
It was significantly inferior to those described. This is considered because the refractive index differs between air and the substrate. Therefore, it can be said that it is important to interpose an intermediate bonding layer having a refractive index substantially equal to that of the substrate between the liquid crystal display elements as in the present invention.

(Comparative Example 2 in Embodiment 2 of the Invention)
In Comparative Example 2, an intermediate bonding layer was not provided, one composite layer was provided between two substrates, and the distance between the two substrates was changed to the outside where the two liquid crystal display elements of the above embodiments were bonded. This is an example in which the distance between the substrates is matched. This liquid crystal display device
It was manufactured in the same manner as in Example 1 except that an acid anhydride-curable epoxy resin in which glass fibers having a diameter of 18 μm were dispersed as a spacer and a seal resin was interposed between two substrates.

The contrast CR and the brightness L of this liquid crystal display device were CR = 170 and L = 85, and a high-contrast and bright display could be realized. However, the driving voltage VC was VC =
13.1, the hysteresis H was H = 11.2, which was significantly higher than that described in Example 1. It can be seen that if the distance between the two substrates is large, the drive voltage must be increased.

It should be noted that the present invention is not limited to the above-described embodiments and examples, and various changes can be made within the technical scope described in the claims. For example, in this embodiment, two liquid crystal display elements are used. However, even when a plurality of liquid crystal display elements are used, a high-contrast and bright display can be similarly realized at a low voltage. Further, the mediating material is not limited to those described in the examples, and can be used by appropriately changing it according to the refractive index of the substrate to be used. In the present invention, a monomer material is used for the acrylic or methacrylic material as a mediating material, but the same good results were obtained with an oligomer material or a mixed material of a monomer and an oligomer.

[0143]

According to the first and second aspects of the present invention, an intermediate substrate having electrodes formed between a pair of substrates is disposed, and a composite layer comprising a polymer and a liquid crystal is formed thin. Unlike the conventional example of bonding with an adhesive, no air layer or adhesive layer is interposed. Accordingly, there is no difference in the refractive index, and the transmittance does not decrease, so that a liquid crystal display device with high contrast and bright display at low voltage can be realized.

According to the invention set forth in claims 3 to 25, a plurality of liquid crystal display elements in which a composite layer composed of a polymer and a liquid crystal is sandwiched between a pair of substrates are arranged, and between the liquid crystal display elements. Since the intermediate adhesive layer having the same refractive index as that of the substrate is provided, the light transmittance does not decrease, and thus a bright display with high contrast is possible.
In addition, since a plurality of liquid crystal display elements are arranged one on top of the other and provided with a thin composite layer, they can be driven at a low voltage, so that power consumption can be prevented from increasing.

According to the twenty-sixth to twenty-eighth aspects of the present invention, the liquid crystal display device having the above-described structure is used as a liquid crystal display device, and an intermediate material is used for each of RGB wavelengths so as to be equal to the refractive index of the substrate. By adjusting the refractive index of the liquid crystal display, it is possible to realize a projection type liquid crystal display device capable of performing high contrast and very bright display at a low voltage.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a polymer-dispersed liquid crystal display device according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a polymer-dispersed liquid crystal display device according to Embodiment 2 of the present invention.

FIG. 3 is a diagram showing hysteresis characteristics of a polymer-dispersed liquid crystal display device according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a polymer-dispersed liquid crystal display device according to Embodiment 2 of the present invention, including a dome-shaped liquid crystal.

FIG. 5 is a diagram showing a connection state when driving the liquid crystal display device of the present invention.

FIG. 6 is a cross-sectional view of the liquid crystal display device according to Embodiment 2 of the present invention, which is being manufactured.

FIG. 7 is a schematic diagram showing a configuration of a projection type liquid crystal display device according to Embodiment 2 of the present invention.

FIG. 8 is a diagram showing the relationship between the refractive index and the transmittance of the substrate in Examples 6 to 18 of the present invention.

FIG. 9 is a diagram showing the relationship between the refractive index and the transmittance of the substrate in Examples 19 to 31 of the present invention.

FIG. 10 is a schematic diagram illustrating a display principle of a polymer dispersed liquid crystal display device.

FIG. 11 is a diagram showing hysteresis characteristics of a conventional polymer-dispersed liquid crystal display device.

[Explanation of symbols]

 1: Polymer dispersed liquid crystal display device 2, 3: substrate 4: intermediate substrate 6, 7: composite layer 10, 11, 12, 13: electrode 15: polymer 50: polymer dispersed liquid crystal display device 51: liquid crystal Display element 52: Intermediate adhesive layer 53, 54: Substrate 55: Composite layer 56: Electrode 56: Polymer matrix 70: Display device 71: Screen 72: Optical component 73: Dichroic mirror K: Space G: Gap

Claims (28)

[Claims] 1. An intermediate substrate having electrodes formed on both surfaces thereof is disposed between a pair of substrates having electrodes formed on inner surfaces thereof, and one of the substrates is provided with one of the substrates. A composite layer made of a polymer and a liquid crystal is sandwiched between the intermediate substrate and the other substrate of the pair of substrates and the intermediate substrate; Are simultaneously driven by the same drive signal. 2. A plurality of intermediate substrates having electrodes formed on both surfaces thereof are arranged at intervals between a pair of substrates having electrodes formed on an inner surface thereof, and one of the pair of substrates is provided. Between the substrate and the intermediate substrate, between the other substrate of the pair of substrates and the intermediate substrate, and between the plurality of substrates, a composite layer made of a polymer and a liquid crystal, A polymer-dispersed liquid crystal display device which is sandwiched between the plurality of composite layers and simultaneously drives the plurality of composite layers with the same drive signal. 3. A plurality of liquid crystal display elements provided with a composite layer composed of a polymer and a liquid crystal between a pair of substrates each having an electrode formed on an inner surface thereof, the liquid crystal display elements facing each other. A polymer adhesive type liquid crystal display device, wherein an intermediate adhesive layer having a refractive index substantially equal to that of the substrate is provided in a gap between outer surfaces of the substrates. 4. A voltage-transmittance characteristic of a composite layer of at least one of the plurality of liquid crystal display elements is different from a voltage-transmittance characteristic of a composite layer of another liquid crystal display element. The polymer-dispersed liquid crystal display device according to claim 3, wherein: 5. The distance between a pair of substrates of at least one of the plurality of liquid crystal display elements is different from the distance between a pair of substrates of another liquid crystal display element. 4. The polymer-dispersed liquid crystal display device according to item 1. 6. An insulating film is provided on an electrode of each liquid crystal display element, and a critical surface tension of the insulating film provided on at least one electrode of the liquid crystal display element is provided on an electrode of another liquid crystal display element. The polymer dispersed liquid crystal display device according to claim 4, wherein the critical surface tension of the insulating film is different from the critical surface tension of the insulating film. 7. When the critical surface tension of the insulating film of a certain liquid crystal display element is γa, the critical surface tension of the insulating film of another liquid crystal display element is γb, and the surface tension of the liquid crystal material of the composite layer is γLC, γa 7. The polymer-dispersed liquid crystal display device according to claim 6, wherein a relationship of ≧ γLC and γb <γLC or γa <γLC and γb ≧ γLC is satisfied. 8. The polymer according to claim 6, wherein the thickness of the insulating film of at least one liquid crystal display element is different from the thickness of the insulating film of another liquid crystal display element. Dispersion type liquid crystal display. 9. The composite layer in which liquid crystal droplets are dispersed and held in a polymer matrix, wherein the size of the liquid crystal droplets constituting the composite layer of at least one liquid crystal display element is different from that of another liquid crystal display device. The polymer dispersed liquid crystal display device according to any one of claims 4 to 8, wherein the size of the liquid crystal droplets constituting the composite layer of the liquid crystal display element is different. 10. The method according to claim 1, wherein a polymer material constituting the composite layer of at least one liquid crystal display element is different from a polymer material constituting the composite layer of another liquid crystal display element. The polymer-dispersed liquid crystal display device according to claim 4, wherein the liquid crystal display device is a liquid crystal display device. 11. The method according to claim 3, wherein the intermediate adhesive layer is formed of a single organic material or a mixture of several organic materials.
4. The polymer-dispersed liquid crystal display device according to any one of the above. 12. The polymer-dispersed liquid crystal display according to claim 11, wherein the intervening adhesive layer is formed of a material mainly containing a monomer or oligomer of an acrylic material or a methacrylic material. apparatus. 13. The method according to claim 3, wherein, when the refractive index of said intermediate adhesive layer is nM and the refractive index of said substrate is nS, | nS−nM | <0.1. 13. The polymer-dispersed liquid crystal display device according to any one of 12. 14. The method according to claim 3, wherein, when the refractive index of the intermediate bonding layer is nM and the refractive index of the substrate is nS, | nS−nM | <0.05. 13. The polymer-dispersed liquid crystal display device according to any one of 12. 15. The substrate according to claim 3, wherein at least one of the substrates is a film substrate.
A polymer dispersed liquid crystal display device according to any one of the above. 16. The polymer dispersed liquid crystal according to claim 3, wherein the plurality of composite layers are driven simultaneously by the same drive signal. Display device. 17. A plurality of sets of substrates, each having an electrode formed on one side thereof, are arranged so that the electrodes face each other, and a space is provided between the inner side surfaces of the substrate where the electrodes face each other. Providing a gap between the outer surfaces of the substrates that do not face each other; and interposing a mediating material having a refractive index substantially equal to that of the substrate in the gap where the outer surfaces of the substrates face each other. By irradiating the medium material in the gap with ultraviolet light,
Curing the intermediary material in the gap, and forming an intermediary adhesive layer in the gap between the substrates, for bonding the substrates together; and in a space in which the inner surface of the substrate faces, a polymer material and a liquid crystal. Filling the mixed composition in which the components are compatible with each other, and irradiating the mixed composition in the space with ultraviolet rays, thereby polymerizing the polymer material in the mixed composition in the space, and polymer and liquid crystal. Forming a composite layer comprising: a polymer dispersed liquid crystal display device. 18. A plurality of substrates, each having an electrode formed on one side thereof, are arranged in an overlapping manner so that the electrodes face each other, so that a space is provided between the inner surfaces of the substrate where the electrodes face each other. Providing a gap between the outer surfaces of the substrates that do not face each other; and filling a space in which the inner surfaces of the substrates face each other with a mixed composition in which the polymer material and the liquid crystal are compatible. Irradiating the mixed composition in the space with ultraviolet rays to polymerize the polymer material in the mixed composition to form a composite layer comprising a polymer and a liquid crystal; and an outer surface of the substrate. A step of interposing a mediating material having a refractive index substantially equal to that of the substrate in the gap where the media faces each other, by irradiating the mediating material in the gap with ultraviolet light,
Curing the intermediary material in the gap and forming an intermediary adhesive layer in the gap between the substrates to bond the substrates to each other. 19. The intensity of ultraviolet light applied to the mediator,
19. The method for producing a polymer-dispersed liquid crystal display device according to claim 17, wherein the intensity of the ultraviolet light applied to the mixed composition is different. 20. The material according to claim 17, wherein a material of the mixed composition filled in at least one space is different from a material of the mixed composition filled in another space. A method for manufacturing a polymer-dispersed liquid crystal display device according to one of the above aspects. 21. The method according to claim 18, wherein the intensity of the ultraviolet light applied to each of the mixed compositions is different.
3. The method for producing a polymer-dispersed liquid crystal display device according to item 1. 22. A plurality of sets of substrates each having an electrode formed on one side thereof are arranged so that the electrodes face each other, and a space is provided between the inner side surfaces of the substrates where the electrodes face each other. A step of providing a gap between the outer surfaces of the substrates that do not face each other, and in the gap where the outer surfaces of the substrates face each other, an intermediate material having a refractive index substantially equal to that of the substrate is interposed, A step of filling a mixed composition in which a polymer material and a liquid crystal are compatible with each other in a space in which the inner surface of the substrate faces, a medium material in the gap, and a mixed composition in the space. Simultaneously irradiate ultraviolet rays to cure the intermediary material in the gap, in the interstices of the substrate, at the same time to form an intermediary adhesive layer that bonds the substrates together, and polymerize the polymer material in the mixed composition, Forming a composite layer comprising a polymer and a liquid crystal. The process for producing a polymer-dispersed liquid crystal display device according to claim Mukoto. 23. The polymer dispersion according to claim 17, wherein the mediating material is composed of an organic single material or a mixed material of several kinds thereof. Manufacturing method of a liquid crystal display device. 24. The polymer-dispersed liquid crystal according to claim 23, wherein the mediating material is mainly composed of a monomer or oligomer of an acrylic material or a methacrylic material, and contains a polymerization initiator. A method for manufacturing a display device. 25. The method according to claim 17, further comprising the step of providing an insulating film on the electrode surface of each substrate. 26. A light source, comprising: a light source lamp; and an optical component such as a projection lens for projecting an image on a screen, and a light source lamp.
In a projection type liquid crystal display device, a plurality of dichroic mirrors for dividing into green light and blue light are arranged, and a polymer dispersed liquid crystal display device for red light, green light and blue light is interposed between the dichroic mirrors. 17. A projection type liquid crystal display device, wherein the polymer dispersed type liquid crystal display device is the one described in any one of claims 3 to 16. 27. When the refractive index of a substrate used for a liquid crystal display element is nS and the refractive index of an intermediate material is nM, each of the polymer-dispersed liquid crystal display devices for red light, green light and blue light is used. 27. The projection-type liquid crystal display device according to claim 26, wherein the projection liquid crystal display device is adjusted so as to have a relationship of | nS-nM | <0.1. 28. A substrate of a liquid crystal display device having a refractive index of nS,
Assuming that the refractive index of the mediating material is nM, each of the polymer dispersion liquid crystal display devices for red light, green light and blue light is adjusted so as to have a relationship of | nS-nM | <0.05. 27. The projection type liquid crystal display device according to claim 26, wherein: