JPH06308468A - Liquid crystal panel and its production and liquid crystal projection type television using the same - Google Patents

Abstract

PURPOSE:To display sharp images and to improve a contrast by constituting the liquid crystal display panel in such a manner that a high-grade black display is always obtd. in non-display parts even if there is no black matrix in these parts and that the liquid crystal panel is hardly driven by the electric fields between signal lines and electrodes. CONSTITUTION:A high polymer dispersed liquid crystal layer 13 is held by two sheets of substrates 11 and 12 and a counter electrode 16 and pixel electrodes 17 are respectively formed as electrodes on the liquid crystal layer side of these substrates 11, 12. The counter electrode 16 is formed only in the parts facing pixel electrodes 17 and the liquid crystal crystal particle size of the high polymer dispersed liquid crystal layer of the non-display parts where the counter electrode 16 is not formed vary from the liquid crystal particle size of the high-polymer dispersed liq. crystal layer of the display part where the counter electrode 16 is formed. As a result, the liquid crystal particle size of the high polymer dispersed liquid crystal layer 13 under the non-display parts is extremely small and the scattering performance is extremely high. The liquid crystal layer in these parts is not driven even by the somewhat high voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer-dispersed liquid crystal panel which forms an optical image as a change in a light scattering state, and a projection type television which magnifies and projects an image displayed on the liquid crystal panel on a screen. .

[0002]

2. Description of the Related Art In recent years, home theaters, presentations and large screen displays have been attracting attention. Many methods have been proposed for a projection device using a light valve, but recently, a liquid crystal projection television is a commercial product that obtains a large-screen display image by enlarging and projecting the display image on a small liquid crystal panel with a projection lens or the like. Has been converted.

A liquid crystal panel is mainly for electrically changing its optical characteristics for display, and there are many kinds of operating principles. A twisted nematic (hereinafter referred to as TN) liquid crystal panel used in a liquid crystal projection device that is currently commercialized utilizes a phenomenon in which the optical activity of liquid crystal changes due to an electric field. However, the TN liquid crystal panel needs a polarizing plate on the incident side and the emitting side for light modulation, and thus has a problem of low light utilization efficiency.

As a method of controlling light without using a polarizing plate, there is a method of using a scattering phenomenon. As a liquid crystal panel that forms an optical image by changing the light scattering state, for example, a phase change (P
C), dynamic scattering (DSM), polymer dispersed liquid crystal and the like. In particular, in recent years, from the sense of expectation for improved brightness, the fairness 3
Polymer-dispersed liquid crystal panels such as those disclosed in Japanese Patent No. 52843 are being actively studied.

When a liquid crystal panel is constructed by using polymer dispersed liquid crystal, there is an advantage that a polarizing plate is unnecessary and an alignment treatment is also unnecessary. Most of the light lost in the polarizing plate is absorbed by the polarizing plate and converted into heat. Therefore, it is difficult to increase the output of the light source and obtain a high brightness display. The heat heats the liquid crystal panel by the polarizing plate itself and radiant heat. Therefore, the polarizing plate, the panel, and the like are in a high temperature state, which causes remarkable performance deterioration in a short period of time. Further, the TN liquid crystal panel needs to be coated with an alignment film and subjected to rubbing treatment. The rubbing process not only increases the number of steps, but also damages the TFT by static electricity and causes a decrease in yield, which causes an increase in manufacturing cost. In recent years,
The liquid crystal panel used in a liquid crystal projection television has a large number of pixels of 300,000 or more, and the pixel size tends to be miniaturized accordingly. The miniaturization of pixels results in the formation of a large number of projections and depressions of signal lines and TFTs, and it is becoming difficult to perform a good rubbing process due to the projections and depressions.

The polymer-dispersed liquid crystal will be briefly described below. The polymer-dispersed liquid crystal is roughly classified into two types depending on the dispersed state of the liquid crystal and the polymer. One 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 is referred to as PDLC. The other is a type that has 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 types of liquid crystal panels, light scattering and transmission are controlled. In the present invention, the PDLC will be mainly described as an example.

The polymer matrix in the polymer-dispersed liquid crystal layer which becomes the liquid crystal layer of such a dispersion type liquid crystal display device may be either thermoplastic resin or thermosetting resin as long as it is basically transparent. However, UV curable resins are the most convenient and have good performance and are often used in general. The reason is that the conventional manufacturing method of the TN mode liquid crystal panel can be applied as it is. As a conventional liquid crystal panel manufacturing method, first, a predetermined electrode pattern is formed in advance on the upper and lower substrates, and the two substrates are stacked so that the electrodes face each other. At this time, two substrates are fixed with an epoxy resin sealing material in such a manner that a spacer having a predetermined size and a uniform grain size is sandwiched between the substrates so that the gap between the two substrates can be maintained. Next, a manufacturing method in which a liquid crystal is injected into the empty cell thus obtained is often used.

In order to manufacture a dispersion type liquid crystal panel by applying this manufacturing method, if a polymer matrix material is an ultraviolet curable resin, particularly an acrylic resin as an example thereof, before injection. Is monomer or
It exists as a relatively low-viscosity precursor such as an oligomer and an oligomer, and a blend with liquid crystal (referred to as a liquid crystal solution) has sufficient fluidity to be injected at room temperature. A dispersion type liquid crystal panel can be easily prepared by applying the manufacturing method and using a method of forming a polymer dispersed liquid crystal layer by irradiating light after injection and proceeding a curing reaction.

Further, by irradiating the panel with ultraviolet rays after the injection, only the resin undergoes a polymerization reaction to become a polymer, and only the liquid crystal is phase-separated, and when the amount of the liquid crystal is smaller than that of the resin component, it becomes an independent particle form. Liquid crystal drops are formed,
On the other hand, when the amount of the liquid crystal is large, the polymer matrix is present in the liquid crystal material in the form of particles or networks, and the liquid crystal is formed to form a continuous layer. At this time, unless the particle diameter of the liquid crystal droplets or the pore diameter of the polymer network is uniform to some extent and the size is in the range of 0.1 μm to several μm, the light scattering performance is poor and the contrast cannot be improved. For this purpose, the material must be one that can be cured in a relatively short time, and an ultraviolet curable resin is desirable.

Operation of polymer dispersed liquid crystal (see FIG. 10)
A brief description will be given using (a) and (b). (Fig. 10 (a)
(B) is an explanatory view of the operation of the polymer dispersed liquid crystal panel. In FIGS. 10A and 10B, reference numeral 91 is an array substrate, 92 is a pixel electrode, 93 is a counter electrode, 94 is a liquid crystal droplet, 95 is a polymer, and 96 is a counter electrode substrate. A TFT (not shown) or the like is connected to the pixel electrode 92.
A voltage is applied to the pixel electrode by turning on and off, and the liquid crystal alignment direction on the pixel electrode is changed to modulate light. As shown in FIG. 10A, in the state in which no voltage is applied, each water droplet liquid crystal 94 is oriented in an irregular direction. In this state, a difference in refractive index occurs between the polymer 95 and the water droplet liquid crystal 94, and incident light is scattered. Here (Fig. 10
As shown in (b), when a voltage is applied to the pixel electrode 92, the directions of the liquid crystal are aligned. If the refractive index when the liquid crystal is aligned in a certain direction is matched with the refractive index of the polymer in advance, the incident light is emitted from the array substrate 91 without being scattered.
When the liquid crystal is represented in the form of water droplets like PDLC, the average diameter of the water droplets of liquid crystal is called the average particle diameter.

A configuration example of a liquid crystal projection type television using a polymer dispersed liquid crystal panel is shown in FIG. The light emitted from the lamp 81 is condensed by the concave mirror 82 and enters the liquid crystal panel 83. All the light that has entered the liquid crystal panel 83 enters the projection lens 84 when it is not modulated at all. The liquid crystal panel 83 is a polymer dispersed liquid crystal panel,
The liquid crystal layer 93 is sandwiched between the glass substrates 91 and 92. Matrix pixel electrodes are provided on the surface of one of the glass substrates 91 and 92 on the liquid crystal layer 93 side, and an optical image can be formed on the liquid crystal panel 83 as a change in the scattering state according to a video signal. All the light emitted from the pixels to which a sufficient voltage is applied enters the projection lens 84 and reaches the screen 88, so that bright pixels are displayed at the corresponding positions on the screen 88. Scattered light is emitted from the pixel to which no voltage is applied, does not reach the screen 88 by leaving the projection lens 84, and a dark pixel is displayed at a corresponding position on the screen 88. In this way
The optical image formed as a change in the scattering state on the liquid crystal panel 83 is enlarged and projected on the screen 88 by the projection lens.

[0012]

In the conventional TN liquid crystal panel, a shield called a black matrix is formed in the non-display area between pixels in order to increase the contrast. In an active matrix liquid crystal panel having a switching element, the black matrix is arranged on the substrate facing the switching element and the signal line. Further, in the active matrix liquid crystal panel, there is also a purpose of blocking light leakage due to reverse tilt of the liquid crystal caused by a horizontal electric field between the signal line and the electrode.

However, in the case of a polymer-dispersed liquid crystal using an ultraviolet curable resin as a polymer matrix, this black matrix cannot be formed. This is because when a polymer-dispersed liquid crystal panel is created in an empty cell having a black matrix formed by the method described above, light is blocked by the black matrix during ultraviolet irradiation, and the blocked polymer remains uncured. It will remain.

On the other hand, in a polymer-dispersed liquid crystal panel that does not form a black matrix, liquid crystal molecules rise due to the electric field between the signal line and the electrode, the scattering function is weakened, and light leakage occurs. The light leaking from between the pixels causes the image to appear blurred and lacking in sharpness. Further, when a TFT is used as the switching element, the leaked light is spilled into the semiconductor layer of the TFT, and a leak current due to photoconduction called photocon occurs, which causes display failure such as crosstalk.

The scattered light with a large emission angle is totally reflected at the interface between the substrate and air and returns to the liquid crystal layer again. In particular, light rays returning to the non-display area between the pixels cause scattering again in this area and return to the emission side, which lowers the display contrast and the display quality.

The present invention improves the display quality without forming a black matrix in a polymer-dispersed liquid crystal panel which forms an optical image as a change in the scattering state, and further improves the contrast of a liquid crystal projection type television using the same. The purpose is to do.

[0017]

In order to achieve this object, a liquid crystal panel of the present invention has a first substrate and a second substrate facing each other, at least one of which has a light transmitting property, and the first and second substrates. And a polymer dispersed liquid crystal layer sandwiched between the first and second substrates, and a pixel electrode on the first electrode substrate and a pixel electrode on the pixel electrode. This is an active matrix liquid crystal panel in which a switching element for controlling an applied signal is formed, and a counter electrode formed on a second electrode substrate is patterned into a display portion and a non-display portion.

Further, the polymer-dispersed liquid crystal layer is formed by irradiating light of 400 nm or less from the counter substrate side, and the liquid crystal particle diameter of the polymer-dispersed liquid crystal layer in the portion where the electrode layer of the counter substrate is formed is the electrode layer. The liquid crystal particle diameter is different from that of the portion where the is not formed.

In the polymer dispersed liquid crystal panel of the present invention, at least one of the two substrates holding the liquid crystal layer has a transparent substrate having a central thickness t, a refractive index n, and an effective display of the liquid crystal panel. The maximum diameter of the region is d, and the following conditions are satisfied.

[0020]

[Equation 3]

Further, another liquid crystal panel of the present invention comprises a transparent plate and a transparent coupling member, the transparent plate is disposed on an incident side, an emitting side or both sides of the liquid crystal panel, and a space between the liquid crystal panel and the transparent plate is provided. It may be optically coupled by the transparent coupling body.

Further, in the above structure, if the transparent substrate, the transparent plate, and the transparent body are provided with the light reflecting means on the surface in contact with the light valve layer, a reflection type light valve device can be realized.

The liquid crystal projection television of the present invention includes a light generating means, a liquid crystal panel on which light emitted from the light generating means is incident and forms an optical image as a change of a light scattering state, and the light generating means. A first optical element part for guiding light to the liquid crystal panel and a second optical element part for projecting light modulated by the liquid crystal panel are provided, and the above liquid crystal panel is used as the liquid crystal panel.

[0024]

In the present invention, when the polymer dispersed liquid crystal layer is formed,
One electrode is patterned so that the display portion and the non-display portion have different amounts of ultraviolet light applied to the liquid crystal layer. In particular, when a transparent conductive film made of a metal oxide is used for this electrode, the ultraviolet ray transmittance of the display section on which the electrode is formed becomes extremely low. On the other hand, in the non-display area, the electrodes are not formed, and thus the ultraviolet transmittance is high. Therefore, since the liquid crystal layer under the non-display portion has a larger amount of ultraviolet light than the liquid crystal phase under the display portion, the polymerization rate of the polymer matrix is high and the phase separation from the liquid crystal is fast. Therefore, the composition of the polymer dispersed liquid crystal layer is different. The polymer-dispersed liquid crystal layer under the non-display area has a very fine liquid crystal particle size, has an extremely high scattering performance, and cannot be driven by a small voltage. With such a configuration, even if there is no black matrix in the non-display portion, high-quality black display is always provided in this portion. Further, it is difficult to drive even for an electric field between the signal line and the electrode.

The light rays scattered and emitted by the polymer-dispersed liquid crystal are partially reflected at the interface between the substrate and the air layer and scattered again by the polymer-dispersed liquid crystal layer. It is a secondary light source by so-called diffuse reflection, which raises the brightness of the pixel that originally displays black. In particular, it is necessary to prevent reflected light from entering the polymer dispersed liquid crystal layer in the non-display area between pixels. When the refractive index of the substrate is n, the critical angle of total reflection obtained from the refractive indices of the substrate and air is given as follows.

[0026]

[Equation 4]

All scattered light emitted at an angle larger than this angle reaches the polymer dispersed liquid crystal layer again and is scattered. The thickness of the substrate may be set so that the light totally reflected at the critical angle does not reach the liquid crystal layer again. It is given as follows, where t is the thickness of the substrate and r is the distance of the effective display area.

[0028]

[Equation 5]

Next, when the light is reflected by the ineffective surface, the light returns to the liquid crystal layer and causes an increase in the brightness of the non-display area between the pixels. The problem is that light-absorbing means is applied to the ineffective surface of the transparent substrate on the output side.
The problem can be solved by absorbing unnecessary light. further,
If an antireflection film is attached to the effective area of the exit surface of the exit-side transparent substrate, the reflectance of the exit surface of the light emitted from the liquid crystal layer at a small angle decreases, so the brightness of the non-display area and the black display area between pixels is reduced. The rise can be reduced.

With the above arrangement, the brightness of the non-display area between the pixels on the liquid crystal panel can be reduced and a high-quality black display can be maintained even without the black matrix, so that a sharp, bright and high-contrast image can be obtained. A liquid crystal panel for displaying can be provided. Further, if this liquid crystal panel is used in a projection television, a bright image with good contrast can be obtained.

[0031]

Embodiments of the present invention will be described with reference to the drawings.

The structure of the first embodiment of the liquid crystal panel of the present invention is shown in (FIG. 1), (FIG. 2 (a)), (FIG. 2 (b)) and (FIG. 2 (c)). FIG. 1) is a cross-sectional view of the liquid crystal panel of the present invention, and (FIG. 2 (a)), (FIG. 2 ((b)) and (FIG. 2 (c)) are electrodes of a counter substrate of the liquid crystal panel of the present invention. It is a top view which shows an example of a pattern.

The liquid crystal panel of the present invention comprises two transparent substrates 1
The polymer-dispersed liquid crystal layer 13 is sandwiched between 1 and 12.
Opposite electrodes 16 and pixel electrodes 17 are formed as transparent electrodes on the liquid crystal layer sides of the substrates 11 and 12, respectively. The pixel electrodes 17 are formed in a matrix, and TFTs 18 are provided as switching elements near each pixel electrode 17. Each TFT 18 is connected to a source signal line (not shown) and a gate signal line (not shown), is connected to a signal supply circuit and a scanning circuit, respectively, and supplies a signal voltage to each pixel. The polymer dispersed liquid crystal 13 makes incident light go straight when a sufficient electric field is applied, and scatters incident light when no electric field is applied. Therefore, the liquid crystal layer of each pixel controls the light scattering state by an applied voltage. You can

In the present invention, an alloy of indium oxide and tin oxide, which is called an ITO film, is used for the counter electrode, and is patterned in the display portion and the non-display portion. For example (Fig. 2
As shown in (a), the counter electrode 16 may be formed only in a portion facing the pixel electrode 17.
In a normal TN liquid crystal, the counter electrode is often formed of a solid ITO film over the entire display area. Also (Fig. 2
As shown in (b), the counter electrode 16 is formed in a strip shape, and the gate signal line of the non-display portion and the TFT 18 are formed.
The portion opposite to may have no electrode. Further, as shown in FIG. 2C, the source signal line of the non-display portion and the portion facing the TFT 18 may have no electrodes. Even if the configuration is not shown in the above example, it is sufficient if it is a counter electrode in which some electrodes of the non-display portion are not formed.

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 may be a single or two or more kinds of liquid crystal compounds or a mixture containing a substance other than the liquid crystal compounds. Good. Among the above-mentioned liquid crystal materials, a cyanobiphenyl nematic liquid crystal having a relatively large difference between the extraordinary light refractive index n _e and the ordinary light refractive index n _o is most preferable. A transparent polymer is preferable as the polymer matrix material, and the polymer may be any of a thermoplastic resin, a thermosetting resin, and a photocurable resin, but the ease of the manufacturing process, the separation from the liquid crystal phase, etc. From this point, it is preferable to use an ultraviolet curable resin. As a specific example, an ultraviolet curable acrylic resin is exemplified, and a resin containing an acrylic monomer or an acrylic oligomer which is polymerized and cured by ultraviolet irradiation is particularly preferable.

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, 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 an example thereof is 2-hydroxy-2-
Methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-
On (Merck's "Darocur 1116"), 1-vidroxycyclohexyl phenyl ketone (Ciba-Gaiki "Irgacure 184"), benzyl methyl ketal (Ciba-Geigy "Irgacure 651"), etc. are mentioned. In addition, a chain transfer agent, a photosensitizer, a dye, a cross-linking agent and the like can be appropriately used in combination as optional components.

Although the proportion of the liquid crystal material in the polymer dispersed liquid crystal layer is not specified here, it is generally about 20% to 90%, preferably about 50% to 85%. When it is 20% or less, the amount of liquid crystal droplets is small and the scattering effect is poor.
On the other hand, when it is 90% or less, the polymer and the liquid crystal tend to be phase-separated into upper and lower two layers, the ratio of the interface becomes small, and the scattering property deteriorates. The structure of the polymer-dispersed liquid crystal layer changes depending on the liquid crystal fraction. When the content is about 60% or less, the liquid crystal droplets exist as independent droplets, and when the content is 60% or more, the polymer and the liquid crystal form a continuous layer. Liquid crystal layer 13
The film thickness is preferably in the range of 5 to 25 μm. If the film thickness is thin, the scattering characteristics are poor and the contrast cannot be obtained. On the contrary, if the film thickness is high, high voltage driving must be performed, which makes it difficult to design a drive IC.

Next, a method of manufacturing the liquid crystal panel of the present invention will be described. The two substrates 11 and 12 are overlapped with each other while keeping a predetermined gap so that their electrode surfaces face each other,
Align and seal the perimeter to secure. At that time, leaving only the inlet, the above-mentioned uncured liquid crystal solution is injected between the substrates. Alternatively, when the upper and lower two substrates are stacked, the liquid crystal solution may be dropped to seal the periphery while maintaining a predetermined interval. As described above, a liquid crystal panel filled with the uncured liquid crystal solution is formed between the upper and lower substrates. This is irradiated with ultraviolet rays having a wavelength of 400 nm or less from the counter substrate 11 side to cure the liquid crystal solution to form a polymer matrix and phase-separate the liquid crystal to form a polymer dispersed liquid crystal layer 13. At this time, the amount of light applied to the liquid crystal layer is different between the portion where the counter electrode 16 is formed and the portion where the counter electrode 16 is not formed.

FIG. 3 shows a graph of the transmittance of the ITO film depending on the light wavelength. As you can see from this, 40
The light transmittance of the wavelength of 0 nm or less is very poor. This is also the case with a film of a metal oxide other than ITO, and for the counter electrode 16, for example, CTO, ZnO or the like may be used.

By producing the liquid crystal panel as described above, the liquid crystal particle diameter of the polymer dispersed liquid crystal layer 14 in the non-display area between pixels is changed to the polymer dispersed liquid crystal layer in the display area as shown in FIG. It can be formed to be much smaller than the liquid crystal particle diameter of 15.

Next, FIG. 4 shows a sectional view of the liquid crystal panel of the second embodiment of the present invention. The liquid crystal panel 31 of the present invention is
It is composed of the liquid crystal panel 32, the transparent plate 33, and the transparent body 34 shown in the first embodiment of the present invention. A transparent plate 33 is coupled to the emission side of the liquid crystal panel 32 via a transparent body 34. A spacer is provided around the glass substrate 12 and the transparent plate 33, and the spacer regulates the thickness of the transparent body 34. A black paint 37 is applied to the side surface 36 of the transparent plate 33, and an antireflection film 39 is applied to the effective area of the emitting surface 38 of the transparent plate 33. The glass substrate 12 is a glass plate having a thickness of 1 mm, the transparent plate 33 is a glass plate having a thickness of 10 mm, and each has a refractive index of 1.52.
Is. The transparent body 34 is a transparent silicone resin KE1051 manufactured by Shin-Etsu Chemical Co., Ltd., and has a thickness of 2 mm and a refractive index of 1.40. This is supplied as two types of liquids, and when the two liquids are mixed and left at room temperature or heated, they cure into a gel by an addition polymerization reaction.

As the transparent plate 33, a transparent resin such as an acrylic resin may be used. The transparent body 34 may be transparent, and a liquid such as ethylene glycol, an epoxy-based transparent adhesive, a transparent silicone resin that is hardened into a gel by ultraviolet irradiation, or the like can be used. In either case, if there is an air layer between the glass substrate 12 and the transparent plate 33, an image quality abnormality will occur there, so it is necessary to exclude the air layer.

With the structure shown in FIG. 4, the thickness from the polymer dispersed liquid crystal layer 13 to the boundary surface 38 in contact with the air becomes thicker. Therefore, when no voltage is applied to the liquid crystal layer 13, the liquid crystal layer 13 is separated from the liquid crystal layer 13. The scattered light emitted is the emission surface 68 of the transparent plate 63.
The brightness of the light reflected by and returned to the liquid crystal layer 13 and scattered again by the liquid crystal layer 13 becomes smaller than that in the case without the transparent plate 33. Then, it is possible to prevent black floating in the non-display area between the pixels. Further, the light incident on the side surface 36 of the transparent plate 33 is absorbed by the black paint 37 applied to the side surface 36, and unnecessary light returning to the liquid crystal layer 13 is reduced, so that the contrast of the display image on the liquid crystal layer 13 is reduced. improves. In addition, the transparent plate 33
Since the antireflection film 39 is provided on the exit surface 38, the reflection of the light exiting from the liquid crystal layer 13 at a small exit angle on the exit surface 38 is reduced, which also contributes to the improvement of the contrast of the display image.

Further, in the present invention, the transparent plate 33 is optically coupled to the substrate 11 using the transparent body 34 in order to obtain a predetermined thickness, but the substrate itself satisfies the predetermined thickness. Good. Further, in order to reduce the thickness of the transparent plate, the surface far from the panel may be concave. Moreover,
It is more preferable to form these on the incident side of the panel.

The configuration of the first embodiment of the liquid crystal projection type television of the present invention is shown in FIG. 32 is a liquid crystal panel, 33 is a transparent plate, 34 is a transparent body, 40 is a light source, 44 is a projection lens,
46 is a screen. The liquid crystal panel 32 is the one shown in the first embodiment.

The light source 40 is composed of a lamp 41 and a concave mirror 42, and the light emitted from the lamp 41 is condensed by the concave mirror 42 to emit light having a relatively narrow directivity. The light emitted from the light source 40 is emitted from the field lens 43, the liquid crystal panel 32,
The transparent body 34 and the transparent plate 33 are transmitted in this order, and the projection lens 44
Incident on. The size of the pupil of the projection lens 44 is set such that when the pixel at the center of the screen of the liquid crystal panel 42 is in a transparent state, about 90% of the light quantity that spreads out from the pixel and enters is incident. The field lens 43 is used for refracting the light passing through the peripheral portion of the display area of the liquid crystal panel 32 inward so as to be incident on the pupil of the projection lens 44 so that the peripheral portion of the projected image does not become dark. By combining the projection lens 44 with the transparent body 33, good imaging characteristics can be obtained. Focus adjustment of the projected image is performed by moving the projection lens 44 along the optical axis 45.

An optical image is formed on the liquid crystal panel 32 as a change in the scattering state according to the video signal. Projection lens 44
Captures light included in a certain solid angle of light emitted from each pixel. If the scattering state of the emitted light from each pixel changes, the amount of light included in the solid angle changes, so that the optical image formed as a change in the scattering state on the liquid crystal panel 32 changes in illuminance on the screen 46. To be converted. Thus, the optical image formed on the liquid crystal panel 32 is enlarged and projected on the screen 46 by the projection lens 44.

The structure of the second embodiment of the liquid crystal projection television of the present invention is shown in FIG. 32a, 32b and 32c are liquid crystal panels, 40 is a light source, 44 is a projection lens, 50a, 5
0b and 50c are transparent plates, 51a, 51b and 51c are transparent plates, 54, 56, 57 and 59 are dichroic mirrors,
55 and 58 are plane mirrors.

The liquid crystal panels 32a, 32b and 32c are polymer dispersed liquid crystal panels, and all are the same as those shown in (FIG. 1). The transparent plates 50a, 50b and 50c are respectively bonded to the incident side of the liquid crystal panel with a transparent adhesive, and the transparent plates 51a, 51b and 51c are respectively bonded to the exit side of the liquid crystal panel with a transparent adhesive. There is. Transparent plates 50a, 50b, 50c, 51a, 51b, 51c
On the side of the black paint 52a, 52b, 52c, 53a,
53b and 53c are applied.

The light source 40 comprises a lamp 41, a concave mirror 42 and a filter 47. The lamp 41 is a metal halide lamp and emits light containing color components of three primary colors of red, green, and blue. The concave mirror 42 is made of glass, and has a reflective surface on which a multilayer film that reflects visible light and transmits infrared light is deposited. The filter 47 is formed by depositing a multilayer film that transmits visible light and reflects infrared light and ultraviolet light on a glass substrate. Visible light included in the emitted light from the lamp 41 is reflected by the reflecting surface of the concave mirror 42, and the reflected light becomes light that is nearly parallel. The reflected light emitted from the concave mirror 42 is emitted after the infrared light and the ultraviolet light are removed by the filter 47.

The light from the light source 40 enters a color separation optical system which is a combination of dichroic mirrors 56 and 57 and a plane mirror 58, and is separated into three primary color lights. Each primary color light is
The light passes through a field lens (not shown) and enters the liquid crystal panels 32a, 32b, 32c. The lights emitted from the liquid crystal panels 32a, 32b, 32c are combined into one light by a color combining optical system in which the dichroic mirrors 54, 59 and the plane mirror 55 are combined, and then enter the projection lens 44. Liquid crystal panels 32a, 32b, 3
2c, an optical image is formed as a change in the diffraction state according to the video signal, and the optical image is enlarged and projected on the screen by the projection lens 44.

Transparent plates 50a, 50b, 5 for suppressing stray light on the incident side and the outgoing side of the liquid crystal panels 32a, 32b, 32c.
Since 0c, 51a, 51b, and 51c are combined, the reduction in contrast due to stray light is suppressed. Further, since the three liquid crystal panels 32a, 32b, and 32c are used for red, green, and blue, respectively, a projected image with good brightness and resolution can be obtained. The scattering characteristics of polymer-dispersed liquid crystals have wavelength dependence. In particular, the scattering property for red light is inferior. Among the three liquid crystal panels 32a, 32b, and 32c, at least one of the liquid crystal layers has a thickness different from that of the other liquid crystal layer or the liquid crystal particle diameter of the display section has a different scattering property. Is preferred.

The dichroic filter used for the color separation and color combining optical system in the present invention may be a simple color filter, or for a red, green and blue light modulating system without using the color combining optical system. Alternatively, one projection lens system may be provided, and a total of three projection lenses may be used to superimpose and project on the screen.

The construction of the third embodiment of the liquid crystal projection television of the present invention is shown in FIG. 40 is a light source, 44 is a projection lens, and 61 is a liquid crystal panel. The light source 40 is the same as that shown in (FIG. 5).

The liquid crystal panel of the present invention comprises a reflective liquid crystal panel 61, a plano-concave lens 62, and a positive lens 63. The liquid crystal panel 61 forms a closed space by the first glass substrate 72, the second glass substrate 71 and the seal member,
A liquid crystal 73 is sealed inside. As shown in FIG. 8, TFTs 74 are formed in a matrix on the first glass substrate 72, and pixel electrodes 76 made of aluminum are formed on the TFTs 74 with an insulating layer 77 interposed therebetween. Each pixel electrode 76 is a drain electrode 79 of each TFT 74.
It is connected to the. A common electrode 75 made of a transparent conductive film is formed on the second glass substrate 71.

The projection lens 64 is the first on the liquid crystal panel 61 side.
It is composed of a lens group 67 and a second lens group 68 on the screen side, and a plane mirror 66 is arranged between the first lens group 67 and the second lens group 68. The scattered light emitted from the pixel at the center of the screen of the liquid crystal panel 61 is transmitted through the first lens group 67, and then about half of the light is incident on the plane mirror 66 and the rest is not incident on the plane mirror 66, and the second lens group is not incident. 6
It is incident on 8. The normal line of the reflecting surface of the plane mirror 66 is inclined 45 ° with respect to the optical axis 65 of the projection lens 64. Light source 4
The light from 0 is reflected by the plane mirror 66, transmitted through the first lens group 67, transmitted through the positive lens 63 and the plano-concave lens 62 in this order, and enters the liquid crystal panel 61. The reflected light from the liquid crystal panel 61 passes through the plano-concave lens 62, the positive lens 63, the first lens group 67, and the second lens group 68 in this order and reaches the screen. The projection lens 64 combines a plano-concave lens 63 and a positive lens so that the optical image on the liquid crystal layer 73 is formed on the screen. In addition, a light beam that exits from the center of the diaphragm of the projection lens 64 and goes toward the liquid crystal panel 61 is incident on the liquid crystal layer 73 substantially vertically.
In other words, it is telecentric.

[0059]

As described above, according to the present invention, in a polymer-dispersed liquid crystal panel, it is possible to always perform high-quality black display in a non-display portion between pixels even without a black matrix, and to obtain a sharp image. It is possible to provide a liquid crystal panel for displaying. Also, by thickening the transparent substrate or combining a transparent plate with a transparent substrate, it is bright and has good contrast.
It is possible to provide a liquid crystal panel that displays a high-quality image in which crosstalk due to a photo controller does not occur. Also,
If this liquid crystal panel is applied to a liquid crystal projection television, it is possible to provide a liquid crystal projection television capable of displaying a bright and high-contrast image, which is extremely effective.

[Brief description of drawings]

FIG. 1 is a sectional view and a plan view of a first embodiment of a liquid crystal panel of the present invention.

FIG. 2 is a graph showing the light transmittance of the ITO film at each wavelength.

FIG. 3 is a configuration diagram of a second embodiment of a liquid crystal panel of the present invention.

FIG. 4 is a schematic configuration diagram of a liquid crystal projection television according to a first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a liquid crystal projection television according to a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a liquid crystal projection television according to a third embodiment of the present invention.

FIG. 7 is an enlarged cross-sectional view of a main part of the liquid crystal panel shown in (FIG. 6).

FIG. 8 is a schematic configuration diagram showing a configuration of a conventional liquid crystal projection television.

FIG. 9 is a schematic diagram for explaining the action of a polymer-dispersed liquid crystal panel.

FIG. 10 is an explanatory diagram of the operation of the polymer dispersed liquid crystal panel.

[Explanation of symbols]

 11, 12 glass substrate 13 polymer dispersed liquid crystal layer 14, 15 polymer dispersed liquid crystal 16 counter electrode 17 pixel electrode 18 TFT 32 liquid crystal panel 33, 50, 51 transparent plate 34 transparent body 37, 52, 53 black paint 39 antireflection film 40 light source 44, 64 projection lens 43 field lens 46 screen 62 plano-concave lens 63 positive lens 54, 56, 57, 59 dichroic mirror 55, 58 plane mirror 61 reflective liquid crystal panel 67, 68 lens 66 plane mirror

Claims (14)

[Claims] 1. A first substrate and a second substrate, at least one of which is light-transmissive and opposed to each other, and the first and second substrates.
An electrode layer formed on opposite surfaces of the substrate, and a polymer dispersed liquid crystal layer sandwiched between the first and second substrates,
A pixel electrode and a switching element for controlling a signal applied to the pixel electrode are formed on the first electrode substrate, and a counter electrode formed on the second electrode substrate is patterned into a display portion and a non-display portion. Characteristic liquid crystal panel. 2. The liquid crystal particle diameter of the polymer-dispersed liquid crystal layer in the portion where the electrode layer of the counter substrate is formed is different from the liquid crystal particle diameter in the portion where the electrode layer is not formed. The described liquid crystal panel. 3. The liquid crystal panel according to claim 1, wherein the electrode layer of the counter substrate is a film made of a metal oxide having transparent conductivity. 4. A first substrate and a second substrate, at least one of which has a light-transmitting property, facing each other, an electrode layer formed on opposite surfaces of the first and second substrates, and the first and second substrates. Second
And a polymer-dispersed liquid crystal layer sandwiched between the substrates, wherein at least one of the electrodes formed on the first and second substrates is patterned into a display portion and a non-display portion. At least one of the first substrate and the second substrate satisfies the following conditions, where t is the central thickness of the optically transparent substrate, n is the refractive index, and d is the maximum diameter of the effective display area of the liquid crystal panel. A liquid crystal panel characterized by: [Equation 1] 5. A first substrate and a second substrate, at least one of which has a light-transmitting property, facing each other, an electrode layer formed on the surfaces of the first and second substrates facing each other, and the first and second substrates. Second
A liquid crystal panel in which at least one of the electrodes formed on the first and second substrates is patterned into a display part and a non-display part. And a transparent combination, wherein the transparent plate is disposed on at least one of an incident side and an emission side of the liquid crystal panel, and the liquid crystal panel and the transparent plate are optically coupled by the transparent combination. Characteristic liquid crystal panel. 6. The following conditions are satisfied, where t is the central thickness from the surface of the transparent plate that contacts the air to the liquid crystal layer, n is the refractive index, and d is the maximum diameter of the effective display area of the liquid crystal layer. The liquid crystal panel according to claim 5. [Equation 2] 7. The liquid crystal panel according to claim 4, wherein a light absorbing means is provided on the ineffective surface of the transparent substrate. 8. A liquid crystal panel according to claim 4, wherein antireflection means is provided in an effective area of a surface of the transparent substrate which is in contact with air. 9. A first substrate and a second substrate facing each other, at least one of which has a light-transmitting property, an electrode layer formed on the surfaces of the first and second substrates facing each other, and the first and second substrates. Second
A liquid crystal solution sandwiched between the substrates, and at least one of the electrodes formed on the first and second substrates is a liquid crystal panel patterned into a display portion and a non-display portion, and the thickness is 400 nm or less from the substrate side. A method for manufacturing a liquid crystal panel, which comprises irradiating the polymer with a light to form a polymer dispersed liquid crystal layer. 10. A liquid crystal panel according to claim 1, a light generating means, and a first optical element for guiding the light generated by the light generating means to the liquid crystal panel. A part and a second part for projecting light modulated by the liquid crystal panel
And a liquid crystal projection television. 11. The light generated by the light generating means is separated by a color filter into light having three wavelengths of blue light, green light and red light, and the liquid crystal panel emits light having wavelengths of the three predetermined ranges. 11. The liquid crystal projection television according to claim 10, wherein the liquid crystal projection television is arranged for at least one of the above. 12. The liquid crystal projection television according to claim 11, wherein the color filter is a dichroic mirror. 13. An optical image of a liquid crystal panel that modulates blue light, an optical image of a liquid crystal panel that modulates green light, and an optical image of a liquid crystal panel that modulates red light are projected at the same position on a screen in a superimposed manner. The liquid crystal projection television according to claim 11, characterized in that: 14. A liquid crystal panel arranged for each wavelength of light, wherein at least one of the thickness of the liquid crystal layer of one or more of the liquid crystal panels or the liquid crystal average particle diameter of the liquid crystal layer is 12. The liquid crystal projection television according to claim 11, which is different from the liquid crystal panel according to claim 11.