JPH07181460A - Liquid crystal panel and its projection and projection type display device - Google Patents

Abstract

PURPOSE:To eliminate light leakage from the peripheral parts of pixels and to improve a display contrast by preventing transmission of liquid crystals near source signal lines. CONSTITUTION:Dielectric thin films 17 consisting of TiO2 or SiO are formed in correspondence to pixel electrodes 13 on a counter substrate 12. These dielectric thin films 17 absorb UV light. High polymer dispersed liquid crystals 15 are clamped between this counter substrate 14 and the pixel electrodes 13. The liquid crystals on the pixel electrodes 13 are so formed as to attain a transparent state at 6 to 10(V) and the liquid crystals on the source signal lines 16 are so formed as substantially not to attain the transparent state at these voltages. This control is executed by the intensity of the UV light to cure the UV curing resins constituting the liquid crystals 15. Since dielectric thin films 17 are formed on the pixel electrodes 13, the light on the source signal lines 16 is stronger than on the pixel electrodes 13 when the panel is irradiated with the UV light from the substrate 12 side. The liquid crystal drops become small and the rising voltage rises high when the UV light is strong.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel that modulates incident light to form an optical image, a method of manufacturing the liquid crystal panel, and a projection type display device using the liquid crystal panel as a light valve.

[0002]

2. Description of the Related Art A display device using a liquid crystal panel is lightweight,
Since it can be made thinner, research and development is active. In recent years, a pocket television using a twisted nematic (TN) liquid crystal panel that applies the optical rotatory power of a liquid crystal has been put into practical use, and a projection display device using the panel as a light valve has also been put into practical use.

However, in the TN liquid crystal panel, in order to perform light modulation, it is necessary to use a polarizing plate to make incident light linearly polarized. The polarizing plate absorbs or reflects 50% or more of light. Therefore, the liquid crystal display device using the TN liquid crystal panel has low light utilization efficiency and low display brightness.

In order to solve this problem, a liquid crystal panel using polymer dispersed liquid crystal instead of TN liquid crystal has been proposed. Hereinafter, the polymer dispersed liquid crystal will be briefly described.

Polymer-dispersed liquid crystals are roughly classified into two types depending on the dispersion state of the liquid crystals and the polymers. One is
It is a type in which liquid crystals in the form of water droplets are dispersed in a polymer.
The liquid crystal exists in the polymer in a discontinuous state. Hereinafter, such a liquid crystal will be referred to as a PDLC, and a liquid crystal panel using the liquid crystal will be referred to as a PD liquid crystal panel. The other is a type having a structure in which a polymer network is stretched around the liquid crystal layer. It looks like a sponge containing liquid crystal. The liquid crystal does not form a water drop but continuously exists. Hereinafter, such a liquid crystal is referred to as PNLC. In order to display an image with the above-mentioned two kinds of liquid crystal panels, light scattering and transmission are controlled.

PDLC utilizes the property that the refractive index is different in the direction in which the liquid crystal is aligned. When no voltage is applied, each water droplet liquid crystal is oriented in an irregular direction. In this state, a difference in refractive index occurs between the polymer and the liquid crystal, and incident light is scattered. When a voltage is applied, the alignment direction of the liquid crystal is aligned. If the refractive index when the liquid crystal is oriented in a certain direction is matched with the refractive index of the polymer in advance, incident light is transmitted without being scattered.

On the other hand, PNLC uses the irregularity of the alignment of liquid crystal molecules. The incident light is scattered in the irregular alignment state, that is, in the state where no voltage is applied.
On the other hand, when a voltage is applied and the arrangement state is made regular, light is transmitted.

The above description of the movement of the liquid crystal of PDLC and PNLC is merely a model idea.
Although the specification of the present invention is not limited to one of the PD liquid crystal panel and the PN liquid crystal panel, the PD liquid crystal panel will be described as an example for ease of description. Also, P
DLC and PNLC are collectively referred to as polymer dispersed liquid crystal, and PD liquid crystal panel and PN liquid crystal panel are collectively referred to as polymer dispersed liquid crystal panel. The resin component of the liquid crystal layer is called a polymer.

The operation of the polymer dispersed liquid crystal panel will be briefly described with reference to FIGS. 5 (a) and 5 (b). (Fig. 5 (a)
(B) is an explanatory view of the operation of the polymer dispersed liquid crystal panel. A thin film transistor (not shown, hereinafter referred to as a TFT) or the like is connected to the pixel electrode 13, and a voltage is applied to the pixel electrode 13 by turning on / off the TFT. The voltage modulates the liquid crystal by changing the liquid crystal alignment direction of the water droplet liquid crystal 51 on the pixel electrode 13. As shown in FIG. 5A, in the state where no voltage is applied (OFF), each water droplet liquid crystal is oriented in an irregular direction. In this state, a difference in refractive index occurs between the polymer 52 and the liquid crystal, and incident light is scattered. As shown in FIG. 5B, when a voltage is applied to the pixel electrode 13, the liquid crystal is aligned. If the refractive index when the liquid crystal is aligned in a certain direction is matched with the refractive index of the polymer 52 in advance, the incident light is not scattered and the array substrate 11 is not scattered.
Emit from the side. A common voltage is applied to the counter electrode 14.

As an example of a liquid crystal panel using the above polymer-dispersed liquid crystal, Japanese Patent Laid-Open No. 2-824 is exemplified. This publication discloses a technique for performing light modulation by switching a liquid crystal layer between a cloudy state and a transmissive state. Although the pixel structure and the panel structure are not described, it is considered that the liquid crystal is replaced with the polymer dispersed liquid crystal in the pixel structure and the panel structure of the conventional TN liquid crystal panel to achieve high brightness display.

Usually, a TFT 73 is connected to each pixel electrode 13 as shown in the equivalent circuit diagram of FIG. A polymer-dispersed liquid crystal (hereinafter,
15) which is called a PD liquid crystal. Also, TFT
An additional capacitor 74 for holding an electric charge is formed at 73.

A gate drive IC 71 is connected to the gate signal line Gi (i = 1 to m), and the IC 71 has a voltage for turning on the TFT 73 (hereinafter referred to as an ON voltage) and a voltage for turning it off. (Hereafter referred to as off voltage)
To control the on / off state of the TFT. On the other hand, the source drive IC 72 controls the source signal line Sj (j = 1 to 1).
The video signal is output to n). By synchronously controlling the gate drive IC 71 and the source drive IC 72,
A video signal is written in each pixel 75.

A cross-sectional view of a conventional PD liquid crystal panel (FIG. 6)
Shown in. However, each drawing is drawn as a model, and unnecessary portions for explanation are omitted. Further, there is a reduced portion such as a substrate thickness, and there is an enlarged portion such as a thin film.

A counter electrode 14 and a black matrix (hereinafter referred to as BM) 61 are formed on the counter electrode substrate 12. On the other hand, pixel electrodes 13 are formed in a matrix on the array substrate 11, and TFTs (not shown) as switching elements are connected to each pixel electrode 13. In addition, the source signal line 16 is provided on the array substrate 11.
And a gate signal line (not shown) is also formed.

As an example of using a polymer-dispersed liquid crystal panel as a light valve, there is JP-A-3-94225. In this publication, light from one light source is separated by a dichroic mirror into optical paths of three primary colors of red light (R light), green light (G light) and blue light (B light), and a polymer dispersed liquid crystal is provided in each optical path. There is disclosed a projection display device in which a panel is arranged as a light valve, light modulated by the polymer-dispersed liquid crystal panel is combined again by a dichroic mirror, and enlarged and projected by a projection lens.

[0016]

As shown in FIG. 7 (FIG. 7), a PD liquid crystal 15 is sandwiched between the counter electrode 14 and the pixel electrode 13. The resin component and the liquid crystal component of the PD liquid crystal on the pixel electrode 13 A are phase-separated, but the resin component of the PD liquid crystal on the lower B of the BM 61 remains uncured. Normal,
An ultraviolet curable resin (hereinafter referred to as UV resin) is used as the resin of the PD liquid crystal. A solution (hereinafter referred to as a mixed solution) in which an uncured UV resin is mixed is injected between the counter electrode 14 and the pixel electrode 13. After that, ultraviolet light (hereinafter referred to as UV light) is irradiated from the counter substrate 12 side to cure the resin component of the mixed solution and phase-separate the liquid crystal and the resin component.

The BM 61 is formed of a metal material such as chromium (Cr). Therefore, UV light is not transmitted. Therefore, the UV resin under BM61 does not polymerize. Therefore, it remains liquid. Counter electrode 14 and pixel electrode 1
Since 3 is formed of a transparent electrode (ITO), UV light is transmitted.

The presence of the part B where the UV resin is not cured deteriorates the reliability of the liquid crystal panel. For example, the counter substrate 12 is easily peeled off. Liquid crystal layer 1 due to aging
There is also a phenomenon that 5 is changed and the contrast is lowered. In addition, there occurs a phenomenon that the average particle size of the water-drop-shaped liquid crystal around the BM (or the average pore size of the polymer network) becomes large. It is considered that this is because the liquid crystal component under the BM 61 is drawn onto the pixel electrode when the resin on the pixel electrode 13 is cured. If the average particle diameter or the average pore diameter is large, the scattering property becomes low. Therefore, the pixel peripheral portion (near the BM) is in the transmissive state. The contrast is low due to the low scattering properties in the pixel periphery.

[0019]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal panel capable of realizing high brightness and high contrast display, a manufacturing method thereof, and a projection type display device capable of high quality display. .

The liquid crystal panel of the present invention has a pixel electrode and a TF.
A PD liquid crystal is sandwiched between an array substrate in which T and the like are formed in a matrix and an opposing substrate on which an opposing electrode and a dielectric thin film are formed. The dielectric thin film is patterned so as to substantially match the shape of the pixel electrode. More specifically, in the conventional liquid crystal panel, the BM is formed in a region other than the region where the BM is formed. As the shape material, titanium oxide (TiO ₂ ) or silicon monoxide (Si) is used.
O) is exemplified.

According to the method of manufacturing a liquid crystal panel of the present invention, after the mixed solution is sandwiched between the array substrate and the counter substrate having the above-mentioned structure, U is applied from at least one of the array substrate and the counter substrate.
By irradiating V light to cure the UV resin, the liquid crystal component and the resin component are phase-separated.

Further, the projection type display device of the present invention uses a light source that emits white light and R, G, B emitted light from the light source.
A color separation optical system for separating the light into optical paths, and a liquid crystal panel of the present invention arranged as a light valve in each of the three optical paths. Preferably, the thickness of the dielectric thin film of the liquid crystal panel that modulates the R light is thicker than the thickness of the dielectric thin film of the liquid crystal panel that modulates the B light.

[0023]

The thin film made of TiO ₂ or SiO absorbs UV light. The UV light absorption rate can be controlled by the vapor deposition conditions, the film thickness, and the like. On the other hand, when the mixed solution is irradiated with UV light, when the energy per unit time is large, the average particle diameter of the water droplet liquid crystal becomes small, and when the energy is small, the average particle diameter becomes large. In addition, if the average particle size is small, the driving voltage required to make the transparent state high. Conversely, if the average particle size is large, the driving voltage will be low. This is the same even if the average particle size of the water droplet liquid crystal is replaced with the average pore size of the polymer network. In other words, the voltage at which the liquid crystal layer is in a transmissive state can be changed depending on the intensity of UV light applied during manufacturing.

In the structure shown in FIG. 6, when the BM 61 is removed, the UV resin under the BM 61 is also cured, and the same effect as in the liquid crystal layer A section can be obtained. However, since there is a potential difference between the source signal line 16 and the counter electrode 14, the potential difference causes the liquid crystal layer in the portion B to be in a transmissive state. In the transmissive state, light leakage occurs near the source signal line and around the source signal line 16 (pixel electrode 13). The lack of light causes a decrease in contrast.

The liquid crystal layer 15 on the pixel electrode 13 has a driving voltage of 6
The transparent state is reached at about 10 (V). When manufacturing a liquid crystal panel, the average particle diameter of the water droplet liquid crystal on the pixel electrode 13 is set to 6
The size should be such that it can be driven at -10 (V). This can be done by adjusting the UV light to be applied. The UV light has an appropriate energy when passing through the counter substrate 12, the ITO 14, and the dielectric thin film. On the other hand, if the dielectric thin film is not formed on the source signal line 16 or the like, UV light stronger than an appropriate value is emitted. Therefore,
The average particle size of the liquid crystal in the form of water droplets becomes small, 6-10 (V)
At the voltage of, the liquid crystal layer will not be in a transmissive state. For example, it is always in a scattering state. In the case of the PD liquid crystal in the always-scattering state, since the black display is performed, the same effect as that of the pseudo BM can be obtained.

When the light modulated by the liquid crystal panel has a long wavelength (for example, red light), the average particle diameter of the water droplet liquid crystal is preferably large in order to obtain good contrast. When the light has a short wavelength (for example, blue light), the average particle size is preferably small in order to obtain good contrast. The dielectric thin film absorbs UV light, and the absorption ratio can be changed depending on its thickness. Therefore, if the counter substrate 12 on which the dielectric thin film having a different thickness is formed is used according to the wavelength of the light modulated by the liquid crystal panel and the UV light is irradiated at a constant intensity, the P of the desired characteristic is obtained.
A D liquid crystal panel can be obtained.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The liquid crystal panel of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of the liquid crystal panel of the present invention. A dielectric thin film 17 is formed on the counter substrate 12.
Are patterned and formed. The formation of the thin film 17 substantially matches the shape of the pixel electrode 13.

A more specific design shape is the shape of the opening of the BM 61 of the conventional liquid crystal panel. Therefore, the formation area of the thin film 17 is smaller than the area of the pixel electrode 13. This is the pixel electrode 13 as shown in FIG.
This is because the average particle diameter of the water-drop-like liquid crystal in the peripheral portion of is smaller than the optimum value so that the liquid crystal layer 15 does not enter the transmissive state at a normal driving voltage.

TiO _{2 is} used as a material for the dielectric thin film 17.
Alternatively, SiO is exemplified. The refractive index n of TiO ₂ is 2.3, and the refractive index n of SiO is 1.7. Both materials absorb light with wavelengths in the ultraviolet range and transmit visible light. However, since the absorption wavelength band and the absorption rate change depending on the vapor deposition conditions, it is necessary to repeat the experiment and set the settings. As an example, according to the experiment, in the case of TiO ₂ , when the physical film thickness of the film is 0.075 μm, the light absorption rate is 350.
40% for light with a wavelength of nm, 37 for 360 nm
% At 370 nm and 16% at 380 nm, there was almost no absorption in visible light. Since SiO absorbs visible light to some extent, TiO ₂ is preferable in this sense. The patterning may be performed by etching the TiO ₂ with sulfuric acid and the SiO with hydrofluoric acid (hydrofluoric acid).

The counter electrode 14 is formed on the dielectric thin film 17. The counter electrode 14 is ITO. In addition,
A counter electrode 14 is formed on the counter substrate 12, and the electrode 14
You may form the dielectric thin film 17 on it. Particularly in the case of SiO, it is better to form it on the ITO 14 from the viewpoint of etching. This is because the glass substrate 12 is also melted by the etching liquid.

Although not shown in FIG. 1, a TFT 73 as a switching element is connected to each pixel electrode 13. A light shielding film is formed on the TFT so that light is not incident on the semiconductor layer of the TFT and a photoconductor phenomenon does not occur. Examples of the method of forming the light-shielding film include a method of coating a TFT with an acrylic resin in which carbon is dispersed, a method of forming an insulating thin film, and a method of forming a light-shielding film made of a metal thin film on the insulating thin film.

In the present invention, the pixel electrode 13 has a TFT.
Although an active matrix type liquid crystal panel in which the above are arranged is described as an example, the technical idea of the present invention of forming the dielectric thin film 17 can be applied to a simple matrix type liquid crystal panel. Therefore, the technical scope and technical idea of the present invention includes a simple matrix type liquid crystal panel.

Polymer dispersed liquid crystal is sandwiched between the pixel electrode 51 and the counter signal line 41. The liquid crystal material used in the liquid crystal panel of the present invention is preferably a nematic liquid crystal, a smectic liquid crystal or a cholesteric liquid crystal, and a single or two
A mixture containing more than one kind of liquid crystal compound or a substance other than the liquid crystal compound may be used. Among the above-mentioned liquid crystal materials, a cyanobiphenyl-based nematic liquid crystal or a chloro-based nematic liquid crystal is preferable. Among them, the chloro nematic liquid crystal is stable because it is not easily decomposed by light. In addition, the charge retention ratio of the liquid crystal layer can be made as high as 90% or more, and the heat resistance is good, which is preferable. A transparent polymer is preferable as the resin material, which facilitates the manufacturing process.
It is preferable to use a UV curing type resin from the viewpoint of separation from the liquid crystal. As a specific example, a UV-curable acrylic resin is exemplified, and a resin containing an acrylic monomer or an acrylic oligomer that is polymerized and cured by ultraviolet irradiation is particularly preferable. When these are irradiated with UV light, only the resin undergoes a polymerization reaction to become a polymer, and only the liquid crystal undergoes phase separation.

As such a polymer-forming monomer,
2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, neopentyl glycol acrylate, hexanediol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylate,
Examples include trimethylolpropane triacrylate, pentaerythritol acrylate and the like.

Examples of the oligomer or prepolymer include polyester acrylate, epoxy acrylate and polyurethane acrylate.

A polymerization initiator may be used in order to carry out the polymerization rapidly, and as an example thereof, 2-hydroxy-2-
Methyl-1-phenylpropan-1-one-(“Darocur 1173” manufactured by Merck & Co., Inc.), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1.
-On ("Darocur 1116" manufactured by Merck & Co., Inc.), 1-vidroxycyclohexyl phenyl ketone (Ciba gaiki-
For example, "Irgacure 651" manufactured by the company is applicable. In addition, a chain transfer agent, a photosensitizer, a dye, a cross-linking agent and the like may be appropriately used as an optional component.

At this time, when the amount of the liquid crystal is smaller than that of the polymer resin, the independent liquid crystal in the form of water drops is formed. On the other hand, when the amount of the liquid crystal is large, the resin matrix is formed. It exists in a liquid crystal material in the form of particles or a network, and the liquid crystal is formed so as to form a continuous layer. At this time, the particle size of the water-drop liquid crystal or the pore size of the polymer network is uniform to some extent, and the size is 0.5 μm.
Unless it is in the range of m to several μm, the scattering performance of incident light is poor and the contrast cannot be improved. The average particle size of the water-drop liquid crystal or the average pore size of the polymer network is preferably in the range of 0.8 μm to 3.0 μm. Because of this, U
It must be a material that can be cured in a short time, such as V resin. Further, the orientation ratio of the liquid crystal material and the polymer material is 9
0:10 to 30:70, and especially 50:50 to 9
The range of 0:10 is preferable.

The matters such as the average particle diameter of the liquid crystal droplets described above are the liquid crystals on the pixel electrodes 13. It is formed smaller than that on the source signal line 13 or the like. This is to prevent the transmission state from occurring at a normal drive voltage (6 to 10 (V)).

Next, the manufacturing method of the liquid crystal panel of the present invention will be described mainly with reference to FIG. First, the method of forming the pixel electrodes 13 and the like on the array substrate 11 is the same as the conventional method, and therefore will be omitted.

First, an ITO thin film as the counter electrode 14 is formed on the counter substrate 12. The refractive index of ITO is 2.0.
Before and after. The film thickness is preferably around 1300 angstroms when the wavelength of light modulated by the liquid crystal panel is green light (hereinafter referred to as G light). Red light (hereafter called R light)
At the time of, it is thicker than the above-mentioned film thickness, and blue light (hereinafter referred to as B light)
If, make thin.

Next, a thin film made of TiO ₂ is formed on the ITO 14. The film thickness must be determined experimentally by the radiated ultraviolet wavelength of a high pressure mercury lamp used for curing the UV resin, the spectral distribution, and the like. Also, Si
The same applies to the case of O, but the ultraviolet absorption rate of TiO ₂ or the like changes depending on the vapor deposition conditions. From that point of view, it is necessary to experimentally confirm by constant deposition. What is important is that the intensity of the UV light 21a reaching the area A of the liquid crystal layer 15 is set to 30 to 70% of that of the UV light 21b of the area B.
As an example, TiO has a film thickness of 0.1 μm and absorbs about 50% of UV light having a wavelength of 350 nm. A TiO ₂ film or the like has almost no absorption in the visible light wavelength band. Therefore, the intensity of UV light incident on the liquid crystal layer 15 when the UV resin is cured can be controlled, and the TiO ₂ 17 film does not affect the transmission of visible light during light modulation.

Next, the array substrate 11 and the counter substrate 12 are
The counter electrode 14 and the pixel electrode 13 are attached so as to face each other. As the spacer, a UV curable sealing resin in which glass fibers having a diameter of 13 μm are dispersed is used. next,
The resin is cured by UV light irradiation to complete an empty cell.

Next, as a PD liquid crystal material, a mixed solution having the materials shown in (Table 1) and a weight ratio was prepared.

[0044]

[Table 1]

The nematic-isotropic phase transition temperature of the mixed solution shown in (Table 1) is METTLER FP900.
As a result of measurement using a thermal analysis system, it was 30.5 ° C.

Subsequently, the mixed solution is injected into the empty cell by a pressure injection method. After that, the panel is heated to a temperature of 50 ° C., and in that state, an ultraviolet ray (irradiation intensity on the substrate surface: 30 mW / cm ₂ ) is irradiated to the mixed solution from the counter substrate 12 side for 150 seconds by using an ultrahigh pressure mercury lamp as a light source. Then, the PD liquid crystal panel was completed. The liquid crystal panel thus completed showed a uniform opaque state over the entire display area in the absence of an electric field, and a uniform transmission state without unevenness was obtained by a voltage of 6 (V). Further, the liquid crystal on the source signal line was hardly in the transmissive state at the above voltage. The average pore size of the polymer network is 1.
2 to 2.0 μm, which is approximately 1.0 μm in the B region.
It was formed below m.

The average pore size of the polymer network or the average particle size of the water droplet liquid crystal is 1.5 to 2.0 μm when the light modulated by the liquid crystal panel is R light, and 1.3 to 1 when it is G light. 0.7 μm, 1.0 to 1.5 μm for B light
When set to 1, the contrast becomes good.

The transmittance of UV light of the dielectric thin film 17 is 20%.
Below, U from both the array substrate 11 and the counter substrate 12
There is also a method of irradiating V light to cure the UV resin. The resin on the pixel electrodes 13 is mainly cured by UV light from the array substrate 11 side. The UV light emitted from the array substrate 13 side is not attenuated so much and falls on the region A because the dielectric thin film 17 is not formed. Therefore,
The intensity of the UV light is set such that the liquid crystal in the A region is in a transmissive state at 6 to 10 (V). On the other hand, strong UV light is emitted from the counter substrate 12 side. Since the dielectric thin film 17 is formed in the area A, the UV light is attenuated and is strongly incident on the area B. Therefore, the average particle diameter or average pore diameter of the water droplet liquid crystal in the B region becomes very small, and the liquid crystal does not pass through at a normal driving voltage, and is in a scattering state. The UV light may be simultaneously irradiated from the array substrate 11 and the counter substrate 12 side, or may be first irradiated from the array substrate 11 side and then from the counter substrate 12 side.

The projection display device of the present invention will be described below with reference to the drawings. FIG. 3 is a configuration diagram of the projection display device of the present invention. However, components that are unnecessary for the description are omitted. In FIG. 3, reference numeral 31 is a condensing optical system in which a concave mirror and a metal halide lamp or a xenon lamp as a light generating means are arranged. It is desirable to use a lamp having an arc length as short as possible. Generally, the arc length of a xenon lamp is 2 mm or less, which is sufficient for the application of the projection display device of the present invention. However, it has a short life. Metal halide lamp is of 250W class,
The arc length is about 6 mm. This is not preferable because the arc length is too long. The arc length is preferably 5 mm or less.
Short arc arc metal halide lamps are sold as long as they have low power consumption. As an example, there is one having 120 W and an arc length of 3 mm or more from Iwasaki Electric Co., Ltd.

The concave mirror is designed to have an appropriate value according to the arc length of the lamp. The same applies to the F value of the projection lens.
As an example, if the arc length is 4 mm, the F value of the projection lens is set to about F8, and if it is 3 mm, the F value is set to about F10. The lamp used in the present invention has an arc length of 3.5 mm
In this case, the concave mirror uses a spherical mirror, and the F value of the projection lens is F9.

A UVIR cut filter 32 reflects infrared rays and ultraviolet rays and transmits only visible light.
Further, 33a is a dichroic mirror that reflects B light (hereinafter referred to as BDM), 33a is a dichroic mirror that reflects G light (hereinafter referred to as GDM), and 33c is a dichroic mirror that reflects R light (hereinafter referred to as RDM).
Is called). In addition, from BDM33a to RDM33c
The arrangement of is not limited to the order shown in FIG. It goes without saying that the final RDM 33c may be replaced with a total reflection mirror.

Reference numerals 34a, 34b and 34c are liquid crystal panels of the present invention. In the projection display device of the present invention, the liquid crystal panel of the present invention is used as a light valve. It should be noted that the liquid crystal panel that modulates the R light is configured such that the average particle diameter of the water droplet liquid crystal is larger or the liquid crystal film thickness is thicker than other liquid crystal panels. This is because the longer the wavelength of light is, the lower the scattering characteristic is, and the lower the contrast is. The average particle diameter of the liquid crystal in the form of water droplets can be controlled by ultraviolet light depending on the film thickness of the dielectric thin film 17. That is, when a PD liquid crystal panel that modulates R light is manufactured, the intensity of UV light with which a liquid crystal layer on a pixel is irradiated is set to be 10 to 30% lower than that of a G liquid PD liquid crystal panel. Further, when a PD liquid crystal panel that modulates B light is manufactured, the intensity of UV light with which a liquid crystal layer on a pixel is irradiated is set to be 10 to 30% higher than that of a G liquid crystal PD liquid crystal panel. This can be done by changing the thickness of the barrier-to-thin film 17. The above items regarding the control of the UV light are the same for the projection display device (FIG. 4). The liquid crystal film thickness can be adjusted by changing the bead diameter of the liquid crystal layer. 35a,
Reference numerals 35b and 35c are lenses, 37a, 37b and 37c are projection lenses, and 36a, 36b and 36c are apertures as diaphragms. Note that 35, 36 and 37 form a projection optical system. The aperture is illustrated for the purpose of explaining the operation of the projection display device. Since the aperture defines the converging angle of the projection lens, it may be considered as included in the function of the projection lens. That is, if the F value is large, it can be considered that the hole diameter of the aperture is small. In order to obtain a high contrast display, the larger the F value of the projection lens, the better. However, the larger the brightness, the lower the brightness of white display.

The operation of the projection display device of the present invention will be described below. Since the R, G, and B light modulation systems have almost the same operation, the B light modulation system will be described as an example. First, white light is emitted from the condensing optical system 31, and the B light component of this white light is BDM 33a.
Is reflected by. This B light enters the liquid crystal panel 34a. As shown in FIGS. 5A and 5B, the liquid crystal panel 34a controls the scattering and transmission states of the incident light according to the signal applied to the pixel electrode to modulate the light.

The scattered light is blocked by the aperture 36a, and conversely, the parallel light or the light within a predetermined angle is opened by the aperture 36a.
Pass a. The modulated light is enlarged and projected on a screen (not shown) by the projection lens 37a. As described above, the B light component of the image is displayed on the screen.
Similarly, the liquid crystal display device 34b modulates the G light component light, and the liquid crystal display device 34c modulates the R light component light so that a color image is displayed on the screen.

Although (FIG. 3) is a system for enlarging and projecting onto the screen by three projection lenses 37, there is also a system for enlarging and projecting with one projection lens. The block diagram is shown in FIG. A liquid crystal panel similar to that used in (FIG. 3) is used.

Here, for ease of explanation, it is assumed that 47G is a liquid crystal panel that displays a G light image, 37R is a liquid crystal panel that displays an R light image, and 37B is a liquid crystal panel that displays a B light image. Therefore, regarding the wavelengths that are transmitted and reflected by each dichroic mirror, the dichroic mirror 35a reflects R light and transmits G light and B light. Also,
The dichroic mirror 35b reflects G light and transmits R light. The dichroic mirror 35d reflects B light and transmits G light and R light.

The light emitted from the metal halide lamp is reflected by the total reflection mirror 43a, and the direction of the light is changed. Next, the UVIR cut filter 44 cuts the light having wavelengths in the ultraviolet region and the infrared region. The light from which the ultraviolet rays and the infrared rays are cut is separated into three wavelength regions of R, G, and B lights by the dichroic mirrors 45a and 45b, and the R light is the field lens 46R.
Then, the G light enters the field lens 46G and the B light enters the field lens 46B. Each field lens 46 collects each light, and the liquid crystal panel 47 changes the orientation of the liquid crystal corresponding to the video signal to modulate the light. The R, G, B lights modulated in this way are transmitted to the dichroic mirror 4
The images are combined by 5c and 45d and enlarged and projected on the screen by the projection lens 48.

[0058]

As described above, the liquid crystal panel of the present invention is
Since the black matrix is not formed, the UV resin that does not include the heavy resin does not remain in the liquid crystal layer, the first substrate, the second substrate, etc. do not peel off due to heat shock, etc. It is stable and does not easily change over time.

When the UV resin is cured, the dielectric thin film can be used to set the optimum UV light intensity, and the liquid crystal layer on the signal line can be prevented from being in a transmissive state at a normal driving voltage. Light leakage can be prevented and display contrast can be improved.

The projection type display device of the present invention can realize high contrast and high brightness display by using the liquid crystal panel of the present invention as a light valve. Further, since the average pore diameter of the polymer network is changed according to the wavelength of the modulated light, good pixel display can be performed without wavelength dependence.

[Brief description of drawings]

FIG. 1 is a sectional view of a liquid crystal panel according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a method for manufacturing a liquid crystal panel of the present invention.

FIG. 3 is a configuration diagram of a projection display device according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of a projection display device according to another embodiment of the present invention.

FIG. 5 is an explanatory diagram of the operation of the polymer-dispersed liquid crystal.

FIG. 6 is a sectional view of a conventional liquid crystal panel.

FIG. 7 is an equivalent circuit diagram of a liquid crystal panel.

[Explanation of symbols]

11 Array Substrate 12 Counter Substrate 13 Pixel Electrode 14 Counter Electrode 15 Liquid Crystal Layer 16 Source Signal Line 21 Ultraviolet Rays 31, 42 Condensing Optical System 32, 44 UVIR Cut Filter 33a, 33b, 33c, 45a, 45b, 45c, 4
5d Dichroic mirror 34a, 34b, 34c, 47R, 47G, 47B Liquid crystal panel 35a, 35b, 35c, 37a, 37b, 37c Lens 36a, 36b, 36c Aperture 41 Frame 43a, 43b, 43c Mirror 46R, 46G, 46B Field lens 48 Projection Lens 51 Water Drop Liquid Crystal 52 Polymer 61 Black Matrix 71 Gate Drive IC 72 Source Drive IC 73 TFT 74 Additional Capacitor 75 Pixel

Claims (16)

[Claims] 1. A first substrate on which pixel electrodes are arranged in a matrix, a second substrate on which a dielectric thin film and a transparent electrode are formed, and between the first substrate and the second substrate. A liquid crystal panel, comprising: a light modulation layer which is sandwiched and forms an optical image as a change of a light scattering state, wherein the dielectric thin film is patterned corresponding to a pixel electrode. 2. A first substrate on which pixel electrodes are arranged in a matrix, a second substrate on which a dielectric thin film that absorbs ultraviolet rays and transmits visible light, and a transparent electrode are formed; And a polymer dispersed liquid crystal sandwiched between the second substrate and the second substrate, wherein the dielectric thin film is patterned corresponding to a pixel electrode, and the thin film is patterned corresponding to a pixel electrode, The thin film is formed on the transparent electrode or below the transparent electrode, and the average particle diameter of the liquid crystal of the polymer dispersed liquid crystal or the average pore diameter of the polymer network sandwiched between the pixel electrode and the dielectric thin film is other than the above. A liquid crystal panel characterized by having a larger average particle diameter of the liquid crystal of the polymer-dispersed liquid crystal of any part of the above or the average pore diameter of the polymer network. 3. The liquid crystal panel according to claim 1, wherein the dielectric thin film is titanium oxide (TiO ₂ ) or silicon monoxide (SiO). 4. A liquid crystal panel according to claim 1, wherein the area of the dielectric thin film corresponding to one pixel electrode is smaller than that of the pixel electrode. 5. The liquid crystal panel according to claim 1, wherein each pixel electrode is provided with a switching element for writing a signal to the pixel electrode. 6. The liquid crystal panel according to claim 1, wherein the polymer-dispersed liquid crystal is composed of a resin component that is cured by ultraviolet rays and a nematic liquid crystal component. 7. A first step of preparing first and second glass substrates and forming pixel electrodes in a matrix on the first glass substrate; a counter electrode on the second substrate; and the pixel. A second step of forming a dielectric thin film pattern corresponding to the electrode shape, and a solution prepared by mixing the first substrate and the second substrate with a predetermined interval and mixing the photocurable resin and the liquid crystal in the interval. A liquid crystal panel comprising: a third step of holding the liquid crystal panel; and a fourth step of irradiating light from the second substrate side to cure the photocurable resin and phase-separate the liquid crystal and the resin. Manufacturing method. 8. A first step of preparing first and second glass substrates and forming pixel electrodes in a matrix on the first glass substrate; a counter electrode on the second substrate; and the pixel. A second step of forming a dielectric thin film pattern corresponding to the electrode shape, and a solution prepared by mixing the first substrate and the second substrate with a predetermined interval and mixing the photocurable resin and the liquid crystal in the interval. A third step of sandwiching is performed, and a fourth step of irradiating light from both the first substrate and the second substrate to cure the photocurable resin and phase-separate the liquid crystal and the resin is performed. A method for manufacturing a liquid crystal panel, which is characterized by the above. 9. The method of manufacturing a liquid crystal panel according to claim 8, wherein the intensity of light emitted from the first substrate side is different from the intensity of light emitted from the second substrate side. 10. The method for producing a liquid crystal panel according to claim 7, wherein the photocurable resin is an ultraviolet curable resin. 11. The method for manufacturing a liquid crystal panel according to claim 7, wherein the dielectric thin film is titanium oxide (TiO ₂ ) or silicon monoxide (SiO). 12. A light source, a liquid crystal panel, first optical means for guiding light from the light source to the liquid crystal panel, and projection means for enlarging and projecting light modulated by the liquid crystal panel, A projection type display device using the liquid crystal panel according to claim 1 or 2 as a liquid crystal panel. 13. A light source, a color separation optical system for separating light emitted from the light source into optical paths of a plurality of colors, a liquid crystal panel arranged for each optical path separated by the color separation optical system, and the liquid crystal panel. A projection lens for magnifying and projecting the light modulated by the light source, and the liquid crystal panel as the liquid crystal panel.
A projection display device characterized by using the liquid crystal panel described. 14. The projection display device according to claim 13, wherein a color combining optical system for combining optical paths of a plurality of colors into the same optical path is arranged on the light output side of the liquid crystal panel. 15. The projection display device according to claim 11, wherein the color separation optical system has a function of separating the light paths into three primary color paths of red light, blue light and green light. 16. The projection display device according to claim 13, wherein the thickness of the dielectric thin film of at least one liquid crystal panel is different from the thickness of the dielectric thin film of another liquid crystal panel.