JP3152041B2 - Liquid crystal panel, method of manufacturing the same, and liquid crystal projection television using the same - Google Patents

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 for forming an optical image as a change in light scattering state, a method for manufacturing the liquid crystal panel, and an image displayed on the liquid crystal panel enlarged on a screen. The present invention relates to a projection television for projecting.

[0002]

2. Description of the Related Art In recent years, home theaters, presentations, and large-screen displays have been attracting attention. Conventionally, many types of projection devices using light valves have been proposed.However, recently, a liquid crystal projection television that obtains a large-screen display image by enlarging and projecting a display image of a small liquid crystal panel with a projection lens or the like has been developed. It has been commercialized.

A liquid crystal panel mainly performs display by electrically changing its optical characteristics, and there are many types of operating principles. A twisted nematic (hereinafter, referred to as TN) liquid crystal panel used in a liquid crystal projector currently commercialized uses a phenomenon in which the optical rotation of liquid crystal is changed by an electric field. However, the TN liquid crystal panel requires polarizing plates on the incident side and the output side for light modulation, and as a result, there is a problem that the amount of light effectively used is reduced and the light use efficiency is reduced. As a method of controlling light without using a polarizing plate, there is a method using a scattering phenomenon. As a liquid crystal panel that forms an optical image by changing a light scattering state, for example, phase change (PC), dynamic scattering (DS)
M) and polymer dispersed liquid crystals. Particularly, in recent years, polymer dispersed liquid crystal panels as disclosed in Japanese Patent Publication No. 3-52843 and the like have been actively studied from the expectation of improvement in brightness.

The polymer-dispersed liquid crystal will be briefly described below. The polymer-dispersed liquid crystal is roughly classified into two types depending on the dispersion state of the liquid crystal and the polymer. One is a type in which a liquid crystal in the form of water droplets is dispersed in a polymer. The liquid crystal exists in a discontinuous state in the polymer. Hereinafter, such a liquid crystal is referred to as PDLC. The other type adopts a structure in which a polymer network is stretched around a liquid crystal layer. It looks just like a sponge with liquid crystal. Liquid crystals exist continuously without being in the form of water droplets.
Hereinafter, such a liquid crystal is referred to as PNLC. In order to display an image on the two types of liquid crystal panels, scattering and transmission of light are controlled. In the present invention, PDLC will be mainly described as an example.

[0005] As a polymer matrix in a polymer dispersed liquid crystal layer to be a liquid crystal layer of such a dispersion type liquid crystal display element, basically a thermoplastic resin or a thermosetting resin may be used as long as it is transparent. Although not available, UV-curable resins are the simplest, have good performance, and are commonly used. The reason is that the conventional method of manufacturing a TN mode liquid crystal panel can be applied as it is. As a conventional method of manufacturing a liquid crystal panel, first, a predetermined electrode pattern is formed on two upper and lower substrates in advance, and the two substrates are overlapped so that the electrodes face each other. At this time, a spacer having a predetermined size and a uniform particle size is sandwiched between the substrates, and the two substrates are fixed with an epoxy resin sealing material in a state where a gap between the two substrates can be maintained.
Next, a manufacturing method of injecting a liquid crystal 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 the material of the polymer matrix is an ultraviolet-curable resin, particularly, for example, an acrylic resin is used as an example, the polymer matrix is used before the injection. Is a monomer or /
And a relatively low-viscosity precursor such as an oligomer, and a blend with a 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 formed by applying a manufacturing method and applying a method of forming a polymer-dispersed liquid crystal layer by irradiating light after injection and promoting a curing reaction.

When the panel is irradiated with ultraviolet rays after the injection, only the resin causes a polymerization reaction to become a polymer, and only the liquid crystal is phase-separated. If the amount of the liquid crystal is smaller than that of the resin, independent particles are formed. Liquid crystal droplets are formed,
On the other hand, when the amount of the liquid crystal is large, the polymer matrix exists in the liquid crystal material in the form of particles or network, and the liquid crystal is formed so as to form a continuous layer. At this time, unless the particle diameter of the liquid crystal droplet 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 is not improved. For this purpose, the material must be a material that can be cured in a relatively short time, and an ultraviolet curable resin is desirable.

The operation of the polymer dispersed liquid crystal (FIG. 9)
This will be briefly described using (a) and (b)). (FIG. 9 (a)
(B) is an explanatory view of the operation of the polymer dispersed liquid crystal panel. 9 (a) and 9 (b), reference numeral 91 denotes an array substrate, 92 denotes a pixel electrode, 93 denotes a counter electrode, 94 denotes a water-drop liquid crystal, 95 denotes a polymer, and 96 denotes a counter electrode substrate. A TFT (not shown) or the like is connected to the pixel electrode 92, and the TFT
A voltage is applied to the pixel electrode by turning on and off the pixel, and the direction of liquid crystal alignment on the pixel electrode is changed to modulate light. As shown in FIG. 9A, when no voltage is applied, the liquid crystal droplets 94 are oriented in an irregular direction. In this state, a difference in refractive index occurs between the polymer 95 and the liquid crystal 94, and the incident light is scattered. Here (FIG. 9
When a voltage is applied to the pixel electrode 92 as shown in (b)), the directions of the liquid crystals are aligned. If the refractive index when the liquid crystal is oriented in a certain direction is adjusted in advance to the refractive index of the polymer, the incident light is emitted from the array substrate 91 without being scattered.
When the liquid crystal is expressed in the form of water droplets like PDLC, the average of the diameters of the liquid crystal in the form of water droplets is called an average particle diameter.

FIG. 10 shows a configuration example of a liquid crystal projection television using a polymer dispersed liquid crystal panel. Light emitted from the lamp 101 is collected by the concave mirror 102 and
03. All the light incident on the liquid crystal panel 103 is incident on the projection lens 104 when no modulation is performed. The liquid crystal panel 103 is a polymer dispersed liquid crystal panel, and a liquid crystal layer 107 is sandwiched between glass substrates 105 and 106. One glass substrate 105, 1
A matrix-shaped pixel electrode is provided on the surface of the liquid crystal layer 06 on the liquid crystal layer 107 side, and an optical image can be formed on the liquid crystal panel 103 as a change in a scattering state in accordance with a video signal. All the light emitted from the pixels to which a sufficient voltage has been applied enters the projection lens 104 and reaches the screen 108, so that bright pixels are displayed at corresponding positions on the screen 108. Scattered light is emitted from a pixel to which no voltage is applied, and deviates from the projection lens 104 so that the screen 10
8 and a dark pixel is displayed at the corresponding position on the screen 108. Thus, the optical image formed as a change in the scattering state on the liquid crystal panel 103 is:
The image is enlarged and projected on the screen 108 by the projection lens.

[0010]

In a conventional TN liquid crystal panel, a light shielding layer called a black matrix is formed in a non-display portion between pixels. In an active matrix liquid crystal panel including a switching element, the black matrix is arranged on a substrate facing the switching element and the signal line. These are for the purpose of improving the contrast, and further, in the active matrix liquid crystal panel, there is also a purpose of preventing photo-conduction of the TFT and blocking light leakage due to the 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 the empty cell where the black matrix is formed by the method described above, the light is blocked by the black matrix when irradiating with ultraviolet light, and the resin in the blocked portion remains uncured. Resulting in.

On the other hand, in a polymer dispersed liquid crystal panel in which a black matrix is not formed, liquid crystal molecules rise due to an electric field between a signal line and an electrode, so that the scattering ability is weakened and light leakage occurs. Blurred image due to light leaking from between pixels,
The display lacks sharpness. Further, when a TFT is used for the switching element, the leaked light enters the semiconductor layer of the TFT, causing a leakage current due to photoconductivity called a photocon, thereby causing display defects such as crosstalk.

The scattered light having 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, the light rays returning to the non-display portion between the pixels cause the photo-conduction of the TFT, and the TFT again scatters in this portion, and the back-scattered light returns to the emission side, thereby reducing the display contrast and the display quality.

Further, the scattering characteristics of the polymer-dispersed liquid crystal panel have a large wavelength dependence. In particular, the scattering characteristics for long-wavelength red light are inferior to those for green and blue light. Therefore, especially in a liquid crystal panel that includes a color filter and modulates red, green, and blue light for each pixel, the contrast of only red deteriorates.

According to the present invention, in a polymer dispersed liquid crystal panel which forms an optical image as a change in scattering state, a black matrix is not formed, and the characteristics of liquid crystal in pixels for modulating red, green and blue light are made equal. It is an object of the present invention to improve the display quality and further improve the contrast of a liquid crystal projection television using the same.

[0016]

Means for Solving the Problems] The liquid crystal panel of the present invention to achieve this purpose, at least one of chromatic optical transparency
A first substrate and a second substrate facing each other,
Pixels formed on the surface with respect to the second substrate of the first substrate
Switch that controls the signal applied to the electrode and its pixel electrode.
A chucking element and the second substrate with respect to the first substrate.
A counter electrode formed on that surface, it at least from the first substrate and the polymer dispersed liquid crystal layer sandwiched between the second substrate
In the liquid crystal panel, the first substrate is provided on the second substrate.
Reflects or absorbs ultraviolet light corresponding to the pixel electrodes on the substrate
Layer is formed.

Further, a polymer dispersed liquid crystal layer is formed by irradiating light from the substrate side on which the ultraviolet reflective layer is formed, and the liquid crystal particle diameter of the polymer dispersed liquid crystal layer on the substrate portion on which the ultraviolet reflective layer is formed is reduced. The configuration is different from the liquid crystal particle diameter of the substrate portion where the ultraviolet reflection layer is not formed.

The UV-reflective layer specifically includes an UV-reflective filter or a UV-reflective film.

The ultraviolet reflecting layer may be an ultraviolet absorbing film or an ultraviolet absorbing filter as long as it reduces the transmittance of ultraviolet light by reflection or absorption.

Further, in the polymer-dispersed liquid crystal panel of the present invention, at least one of the two substrates sandwiching the liquid crystal layer has a center thickness of the transparent substrate of t, a refractive index of n, and an effective display of the liquid crystal panel. The maximum diameter of the region is d, and the following condition is satisfied.

[0021]

(Equation 3)

In another liquid crystal panel according to the present invention, a transparent plate is disposed on the light incident side or the light emitting side or both sides of the liquid crystal panel, and the liquid crystal panel and the transparent plate are optically coupled by a transparent coupler. May be.

Further, a color filter is used to set red,
In a liquid crystal panel that modulates green and blue light, a layer that reflects or absorbs ultraviolet light is formed on a pixel that modulates green and blue light, or the layer is formed on each pixel. The layer may be formed so that the reflectance or absorptivity of ultraviolet rays of the formed layer differs depending on the wavelength of the light beam modulated by each pixel. In particular, the reflectance or absorptivity of ultraviolet rays of a layer formed on a pixel that modulates red is made lower than that of a layer formed on another pixel.

According to the liquid crystal projection television of the present invention, a light generating means, a liquid crystal panel on which light emitted from the light generating means enters to form an optical image as a change in a light scattering state, and the light generating means generate the light. The liquid crystal panel includes a first optical element component that guides light to the liquid crystal panel, and a second optical element component that projects light modulated by the liquid crystal panel, and uses the liquid crystal panel as a liquid crystal panel.

[0025]

According to the present invention, when forming a polymer-dispersed liquid crystal layer in which a polymer matrix is made of a photocurable resin, a layer that reflects or absorbs ultraviolet light so that the amount of ultraviolet light applied to the liquid crystal layer is different. Is formed in a part of the pixel display area on the substrate. The portion where the layer is formed has a low ultraviolet transmittance. On the other hand, the portion where the layer is not formed has a higher ultraviolet transmittance. Therefore, if the polymer-dispersed liquid crystal layer is formed by irradiating light from the substrate side on which the layer is formed, the liquid crystal layer in the portion without the layer has a higher amount of ultraviolet light than the liquid crystal layer below the layer, so that a higher The polymerization rate of the molecular matrix is high, and the phase separation from the liquid crystal is performed quickly. Therefore, the composition of the polymer-dispersed liquid crystal layer is different, and the polymer-dispersed liquid crystal layer in the portion without the layer has a very small liquid crystal particle diameter, extremely high scattering performance,
The driving voltage also increases. Therefore, a layer that reflects or absorbs ultraviolet light is formed only in the portion corresponding to the pixels of the liquid crystal panel, and when light is irradiated from the substrate side on which the layer is formed, the liquid crystal layer in the non-display portion has a scattering performance compared to the liquid crystal layer in the display portion. And the driving voltage both increase. With such a configuration, high-quality black display is always performed in this portion even if there is no black matrix in the non-display portion. Further, it is difficult to drive even with respect to the electric field between the signal line and the electrode.

The light beam scattered and emitted by the polymer dispersed liquid crystal is a secondary light source by so-called diffuse reflection, which is partially reflected at the interface between the substrate and the air layer and scattered again at the polymer dispersed liquid crystal layer. The brightness of the liquid crystal layer that originally displays black is increased.
In particular, it is necessary to prevent reflected light from entering the polymer-dispersed liquid crystal layer in the non-display area between pixels. One is to reduce the brightness of the liquid crystal layer in this part as much as possible because there is no black matrix between pixels, and the other is to prevent the photo-conversion of the TFT by the reflected light.

Assuming that 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.

[0028]

(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 d is the distance of the effective display area.

[0030]

(Equation 5)

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

With the above arrangement, the brightness of the non-display portion between pixels on the liquid crystal panel can be reduced even if there is no black matrix, and a high-quality black display can be maintained. Therefore, a sharp, bright and high-contrast image can be obtained. A liquid crystal panel for displaying can be provided. Also, if this liquid crystal panel is used for a projection television, a bright and high-contrast image can be obtained.

On the other hand, in a liquid crystal panel having a color filter and modulating red, green and blue light for each pixel, the same action is used to reflect or absorb ultraviolet rays on the pixel which modulates green and blue light. When the polymer dispersion liquid crystal layer is formed by simultaneously irradiating the layers and irradiating light, the polymer dispersion liquid crystal layer of the pixel that modulates red light has a larger liquid crystal than the polymer dispersion liquid crystal layer of the pixel that modulates blue and green light. Fine particle size and high scattering performance. In this way, the uniformity of the contrast can be obtained by making the scattering characteristics of the liquid crystal layer at each wavelength of the light beam controlled by each pixel equal. This has the same effect even if the layer is formed on each pixel, and at least the layer formed on the pixel that modulates red light has low UV reflectance or absorptivity.

[0034]

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 FIGS. 1 (a) and 1 (b). (Figure 1
1A is a cross-sectional view of a liquid crystal panel according to a first embodiment of the present invention, and FIG. 1B is a plan view illustrating a counter substrate of the liquid crystal panel of the present embodiment. The liquid crystal panel of the present embodiment has a polymer dispersed liquid crystal layer 13 sandwiched between two transparent substrates 11 and 12. On the liquid crystal layer side of the substrates 11 and 12, a counter electrode 16 and a pixel electrode 17 are formed as transparent electrodes, respectively. The counter electrode 16 and the pixel electrode 17 are made of ITO
An alloy of indium oxide and tin oxide, called a film, is used. The counter electrode 16 is formed entirely solid, and the pixel electrodes 17 are formed in a matrix. In the vicinity of each pixel electrode 17, a TFT 18 is provided as a switching element. Each TFT 18 is connected to a source signal line (not shown) and a gate signal line (not shown), and is connected to a signal supply circuit and a scanning circuit, respectively, to supply 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 the incident light when no electric field is applied. Therefore, the liquid crystal layer of each pixel controls the light scattering state by the applied voltage. Can be.

No light-shielding layer such as a black matrix is formed on the counter electrode 16. In this embodiment, the light-shielding layer 20 is directly disposed only on the TFT 18 in order to prevent the photo-conduction of the TFT. The light-shielding layer 20 used in the present embodiment is made of an acrylic resin mixed with carbon, but a metal such as chromium may be provided via an insulating layer. However, this is provided in order to prevent a photo transistor of the TFT when a strong light beam used as a light valve of a projection television is incident, and may be omitted.

Further, on the surface of the counter substrate 11, an ultraviolet reflection layer 19 is formed only on a portion corresponding to each pixel electrode 17. For further understanding (FIG. 1B), a plan view of the counter substrate 11 is shown. In the present embodiment, a multilayer film in which dielectric thin films of SiO ₂ and TiO ₂ are alternately laminated is used as the ultraviolet reflection layer 19. In addition, for example, Al ₂ O ₃ ,
A multilayer film in which low-refractive-index dielectric thin films such as CeF ₃ , WO ₃ , LaF ₃ and NdF ₃ and high-refractive-index dielectric thin films such as CeO ₂ , HfO ₂ and Nd ₂ O ₅ are alternately laminated. Is also good.

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 liquid crystal compounds or a mixture containing a substance other than the liquid crystal compound. Good. Incidentally, the nematic liquid crystal of relatively large cyanobiphenyl difference extraordinary refractive index n _e and ordinary index n _o of the liquid crystal materials mentioned above are most preferred. As the polymer matrix material, a transparent polymer is preferable. As the polymer, any of a thermoplastic resin, a thermosetting resin, and a photocurable resin may be used. In view of the above, it is preferable to use an ultraviolet curing type resin. As a specific example, an ultraviolet curable acrylic resin is exemplified, and a resin containing an acrylic monomer or acrylic oligomer which is polymerized and cured by irradiation with ultraviolet light 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 promptly. For example, 2-hydroxy-2-
Methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-
ON ("Darocure 1116" manufactured by Merck Ltd.), 1-bidroxycyclohexylphenylketone ("Irgacure 184" manufactured by Ciba-Gaiky), benzyl methyl ketal ("Irgacure 651" manufactured by Ciba-Geigy) and the like are listed. In addition, a chain transfer agent, a photosensitizer, a dye, a cross-linking agent and the like can be appropriately used 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%. 20% not yet
When full , the amount of liquid crystal droplets is small, and the scattering effect is poor.
Also when it comes to 90% stronger tendency to polymer and the liquid crystal is phase-separated into upper and lower layers, scattering properties becomes the proportion of surfactant is small is reduced. The structure of the polymer-dispersed liquid crystal layer changes depending on the liquid crystal fraction. At about 60% or less, liquid crystal droplets are present as independent droplets. At 60% or more, the polymer and liquid crystal become a continuous layer in which the polymer and liquid crystal are intertwined with each other. The thickness of the liquid crystal layer 13 is preferably in the range of 5 to 25 μm. If the film thickness is small, the scattering characteristics are poor and contrast cannot be obtained. Conversely, if the film thickness is large, high voltage driving must be performed, making it difficult to design a drive IC.

Next, a method for manufacturing the liquid crystal panel of the present invention will be described. The two substrates 11 and 12 are overlapped while maintaining a predetermined interval so that the electrode surfaces of the substrates 11 and 12 face each other, and are positioned and sealed to fix the periphery. At this time, only the entrance is left, and the above-mentioned mixed solution of the uncured photocurable resin and the liquid crystal is injected between the substrates. Alternatively, when the upper and lower substrates are overlapped, the periphery may be sealed while maintaining a predetermined interval by dropping the mixed solution. As described above, the liquid crystal panel in which the mixed solution of the uncured photocurable resin and the liquid crystal is filled between the upper and lower substrates is prepared. This is irradiated with ultraviolet light from the counter substrate 11 side, and the mixed solution is cured to form a polymer matrix and perform phase separation of liquid crystal.
The polymer dispersed liquid crystal layer 13 is formed. At this time, the amount of ultraviolet light applied to the liquid crystal layer is different between the portion where the ultraviolet reflection layer 19 is formed and the portion where the ultraviolet reflection layer 19 is not formed.

FIG. 2 is a graph showing the transmittance of the ultraviolet reflecting film used in this example according to the wavelength of light. As is clear from this, the light transmittance at a wavelength of 500 nm or less is very poor. The portion where the ultraviolet reflection layer 19 is not formed has a much larger amount of ultraviolet irradiation than the portion where the ultraviolet reflection layer 19 is formed. Therefore, in the portion where the ultraviolet reflection layer 19 is not formed, the phase separation between the liquid crystal and the polymer is performed very quickly.

Further, the ultraviolet reflecting layer 19 may be another means that does not transmit ultraviolet light, such as an ultraviolet absorbing layer or an ultraviolet absorbing filter. A resin layer mixed with an ultraviolet absorber such as a hydroxybenzophenone-based, benzotriazole-based or salicylic acid ester-based or an inorganic thin film having a high refractive index may be used.

By forming 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 reduced as shown in FIG. The dispersion liquid crystal layer 15 can be formed to be very small in comparison with the liquid crystal particle diameter. In order to perform TFT driving, the driving voltage of the liquid crystal layer must be 5 or 6V. That is, at such an applied voltage, the liquid crystal layer must change from the scattering state to the transparent state. At this time, the liquid crystal particle diameter is about 1-2 μm.
m, and the driving voltage increases as the particle diameter decreases. At the same time, the scattering characteristics are improved. Therefore, even if there is no black matrix on the signal line between the pixels, the liquid crystal layer in this portion performs good black display. Further, since the driving voltage of the liquid crystal layer is high with respect to a horizontal electric field generated between the pixel electrode and the signal line, light leakage does not occur.

Next, FIG. 3 shows a sectional view of a second embodiment of the liquid crystal panel of the present invention. The liquid crystal panel of the present embodiment is configured such that R (red), G (green), and B (blue) color filters are formed corresponding to the respective pixels, and one panel can perform color display. In the conventional liquid crystal panel, a light-shielding layer called a black matrix is also formed between the color filters, but in this embodiment, no light-shielding layer is formed between the color filters. The other configuration is almost the same as that of the first embodiment, and the description is omitted. Color filters 21 and 22 that transmit only R, G, and B light rays on the opposing substrate 11 at positions corresponding to the pixel electrodes 17 respectively.
23 are formed, and an ultraviolet reflective layer 29 is formed on the array substrate 12. Further, the ultraviolet reflective layer 29a formed on the pixel corresponding to G and B and the ultraviolet reflective layer 29b formed on the pixel corresponding to R have different transmittances of ultraviolet light.
UV transmittance is higher than a. In FIG. 3, the ultraviolet reflective layer 29 is formed on the outer surface of the array substrate 12.
Or on the pixel electrode 17 in contact with the liquid crystal layer 13. Further, the ultraviolet reflection layer 29a may not be formed.

In the step of manufacturing the liquid crystal panel of the present invention, the liquid crystal layer 13 is phase-separated by irradiating ultraviolet rays from the side of the array substrate 12 on which the ultraviolet reflective layer 29 is formed. This is because a color filter is formed on the counter substrate 11 side and does not transmit ultraviolet light. At this time, the amount of ultraviolet light applied to the liquid crystal layer differs between the portion where the ultraviolet reflection layer 29 is formed and the portion where the ultraviolet reflection layer 29 is not formed. The polymer dispersed liquid crystal layer 13 formed as described above has G and B
The liquid crystal layer of the pixel electrode displaying R and the liquid crystal layer of the pixel electrode displaying R have different sizes of liquid crystal particles, and the scattering characteristics and the driving voltage are higher in the liquid crystal layer of the pixel electrode displaying R. . On the other hand, the liquid crystal layer 13 has wavelength dependence, and particularly has poor scattering characteristics with respect to R light, and the driving voltage is low. By adjusting the UV transmittance of the UV reflective layer 29 according to the present invention, a liquid crystal layer having the same characteristics in RGB can be formed.

Next, a liquid crystal display device according to a third embodiment of the present invention will be described.
A cross-sectional view of the device is shown in FIG. Of the present inventionLiquid crystal display
Is the liquid crystal panel shown in the first or second embodiment of the present invention.
A transparent panel 43 and a transparent body 44 are provided.
The emission side of the liquid crystal panel 42 is transparent via a transparent body 44.
The plate 43 is connected. Glass substrate 12 and transparent plate 43
Is provided with a spacer around it.
The thickness of the transparent body 44 is regulated by a laser. Transparent plate 4
The black paint 47 is applied to the side surface 46 of the third
The effective area of the exit surface 48 is provided with an anti-reflection film 49.
I have. The glass substrate 12 is a glass plate having a thickness of 1 mm,
The transparent plate 43 is a glass plate having a thickness of 10 mm, and has a refractive index of
Both are 1.52. Transparent body 44 is Shin-Etsu Chemical
It is a transparent silicone resin KE1051 manufactured by
The length is 2 mm and the refractive index is 1.40. This is two types
The two liquids are mixed and left at room temperature or
When heated, it is cured into a gel by an addition polymerization reaction.

As the transparent plate 43, a transparent resin such as an acrylic resin may be used. The transparent body 44 only needs to be transparent, and a liquid such as ethylene glycol, an epoxy-based transparent adhesive, a transparent silicone resin that cures in a gel state by irradiation with ultraviolet rays, or the like can be used. In any case, if there is an air layer between the glass substrate 12 and the transparent plate 43, an abnormal image quality occurs there, so it is necessary to exclude the air layer.

When a liquid crystal panel is manufactured by the method described in the first embodiment and the second embodiment, as shown in FIG. The light is reflected at the interface between the substrate and air and returns to the liquid crystal layer 13 again.
The light further promotes the phase separation of the liquid crystal layer. For this reason, the liquid crystal layer in the portion where the ultraviolet reflective layer 19 is formed is cured by the reflected ultraviolet light, and the difference in the characteristics of the liquid crystal layer depending on the presence or absence of the layer 19 is reduced. However, when the transparent plate 43 is attached to the substrates 11 and 12 and the structure as shown in FIG. 4 is used, the thickness from the polymer dispersed liquid crystal layer 13 to the boundary surface 48 in contact with air becomes thicker. The scattered light emitted from 13 is reflected by the emission surface 48 of the transparent plate 43 and the brightness of the light returning to the liquid crystal layer 13 decreases.

When the liquid crystal panel is used in this configuration, the luminance of the light scattered again by the liquid crystal layer 13 is reduced by the transparent plate 4.
3 is smaller than when there is no 3. This can prevent the floating of black in the non-display portion between pixels. Further, the light incident on the side surface 46 of the transparent plate 43 is absorbed by the black paint 47 applied to the side surface 46 and the reflected 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. Further, since the anti-reflection film 49 is provided on the emission surface 48 of the transparent plate 43, the reflection of the light emitted from the liquid crystal layer 13 at a small emission angle on the emission surface 48 is reduced, which also improves the contrast of the display image. Contribute.

Further, since the scattered light emitted from the liquid crystal layer 13 is reflected on the emission surface 48 of the transparent plate 43 and the amount of light incident on the TFT 18 can be reduced, photo-conduction can be prevented.

In this embodiment, the transparent plate 43 is optically connected to the substrate 12 using the transparent body 44 in order to obtain a predetermined thickness. However, the substrate itself satisfies the predetermined thickness. You may. Further, the surface far from the panel may be concave to reduce the thickness of the transparent plate. Further, these are connected to the incident side of the liquid crystal panel 42, that is, the opposing substrate 11
It is still more preferable to form them also. For the above configuration, the one proposed by the present applicant in Japanese Patent Application No. 4-145277 is adopted. The liquid crystal panel of the present embodiment includes a structure such as a transparent plate or a substrate having a specific thickness, which is the technical idea of the above publication.

FIG. 5 shows the configuration of the first embodiment of the liquid crystal projection television according to the present invention. The liquid crystal projection television of this embodiment includes the liquid crystal panel 42 shown in the first embodiment or the second embodiment, a light source 51, a projection lens 54, and a screen 56.

The light source 51 is composed of a lamp 52 and a concave mirror 53. Light emitted from the lamp 52 is condensed by the concave mirror 53 to emit light having a relatively narrow directivity. The field lens 55 is used to refract light passing through the peripheral portion of the display area of the liquid crystal panel 42 to enter the pupil of the projection lens 54 so that the peripheral portion of the projected image is not darkened.

An optical image is formed on the liquid crystal panel 42 as a change in the scattering state according to the video signal. Projection lens 54
Captures light included in a certain solid angle out of the light emitted from each pixel. When the scattering state of the light emitted 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 42 changes in illuminance on the screen 56. Is converted. Thus, the optical image formed on the liquid crystal panel 42 is enlarged and projected on the screen 56 by the projection lens 54.

In the liquid crystal projection type television of this embodiment, even if the liquid crystal panel 42 has no black matrix,
The liquid crystal layer on the signal line and on the TFT always performs good black display, and a display with good contrast is obtained. When the liquid crystal panel 42 is the liquid crystal panel with a color filter shown in the second embodiment, the contrast is high in both RGB and good white display is obtained. In either case, there is no problem because the ultraviolet light reflecting layers 19 and 29 transmit visible light, but rather remove the ultraviolet light applied to the liquid crystal, so that the liquid crystal is hardly deteriorated and the reliability of the liquid crystal panel is improved.

FIG. 6 shows the configuration of a second embodiment of the liquid crystal projection television according to the present invention. 41 is a liquid crystal display device,
It is composed of a liquid crystal panel 42, a transparent plate 43 and a transparent body 44, 51 is a light source, 54 is a projection lens, and 56 is a screen. The liquid crystal display device 41 is that shown in the third embodiment.

The light emitted from the light source 51 passes through the field lens 55, the liquid crystal panel 42, the transparent body 44, and the transparent plate 43 in this order, and enters the projection lens 54. Projection lens 54
The size of the pupil is such that when a pixel at the center of the screen of the liquid crystal panel 42 is in a transparent state, about 90% of the amount of light out of the light spread and emitted from the pixel is incident. By combining the projection lens 54 with the transparent plate 43, good imaging characteristics can be obtained. The focus adjustment of the projection image is performed by moving the projection lens 54 along the optical axis 57.

In the liquid crystal projection type television of this embodiment, since the light reflected at the interface between the substrate and the air among the light scattered by the liquid crystal panel 42 is prevented from being scattered again by the liquid crystal layer, the secondary scattering is prevented. Good indication can be provided. In addition, since black floating between pixels due to secondary scattering can be prevented, a sharp display can be obtained.

FIG. 7 shows the structure of a third embodiment of the liquid crystal projection television according to the present invention. 42a, 42b, 42c are liquid crystal panels, 51 is a light source, 54 is a projection lens, 70a, 7
0b and 70c are transparent plates, 71a, 71b and 71c are transparent plates, 74, 76, 77 and 79 are dichroic mirrors,
75 and 78 are plane mirrors.

The liquid crystal panels 42a, 42b and 42c are polymer dispersed liquid crystal panels, all of which are the same as those shown in FIG. The transparent plates 70a, 70b, 70c are respectively coupled to the incident side of the liquid crystal panel using a transparent adhesive, and the transparent plates 71a, 71b, 71c are respectively coupled to the exit side of the liquid crystal panel using a transparent adhesive. I have. Transparent plates 70a, 70b, 70c, 71a, 71b, 71c
Black paint 72a, 72b, 72c, 73a,
73b and 73c are applied.

The light source 51 includes a lamp 52, a concave mirror 53, and a filter 57. The lamp 52 is a metal halide lamp, and emits light including three primary color components of red, green, and blue. The concave mirror 53 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 57 is formed by depositing a multilayer film that transmits visible light and reflects infrared light and ultraviolet light on a glass substrate. The visible light included in the light emitted from the lamp 52 is reflected by the reflecting surface of the concave mirror 53, and the reflected light becomes almost parallel light. The reflected light emitted from the concave mirror 53 is emitted after the filter 57 removes infrared light and ultraviolet light.

The light from the light source 51 enters a color separation optical system in which dichroic mirrors 76 and 77 and a plane mirror 78 are combined, and is separated into three primary color lights. Each primary color light is
Each of the light passes through a field lens (not shown) and enters the liquid crystal panels 42a, 42b, and 42c. Light emitted from the liquid crystal panels 42a, 42b, and 42c is combined into one light by a color combining optical system in which dichroic mirrors 74 and 79 and a plane mirror 75 are combined, and then enters the projection lens 54. Liquid crystal panels 42a, 42b, 4
2c, an optical image is formed as a change in the scattering state according to the video signal, and the optical image is enlarged and projected on the screen by the projection lens 54.

The transparent plates 70a, 70b, 7 for suppressing stray light on the incident side and the exit side of the liquid crystal panels 42a, 42b, 42c.
Since 0c, 71a, 71b, and 71c are combined, a decrease in contrast due to stray light is suppressed. In addition, since the three liquid crystal panels 42a, 42b, and 42c are used for red, green, and blue, respectively, a projected image with good brightness and resolution can be obtained. The scattering characteristics of the polymer-dispersed liquid crystal have wavelength dependence, and in particular, the scattering characteristics for red light are inferior. At least one of the three liquid crystal panels 42a, 42b, and 42c has a different thickness from the liquid crystal layer or the liquid crystal particle diameter of the display portion of the liquid crystal panel, so that the respective panels have the same scattering characteristics. Is preferred.

In the present invention, the dichroic mirror used in the color separation and color synthesis optical system may be simply a color filter, or the red, green, and blue light without using the color synthesis optical system. One projection lens system may be provided for each modulation system, and a total of three projection lenses may be used to overlap and project on a screen.

[0068]

As described above, according to the present invention, in a polymer dispersed liquid crystal panel, high-quality black display can always be performed in a non-display portion between pixels even without a black matrix, and sharp A liquid crystal panel for displaying an image can be provided. In a liquid crystal panel that can perform color display with one sheet using a color filter, each pixel of RGB has good contrast,
A bright liquid crystal panel can be provided. Further, by increasing the thickness of the transparent substrate and combining the transparent substrate with the transparent substrate, a liquid crystal panel which displays a high-quality image which is bright, has good contrast, and does not cause crosstalk due to a photocon can be provided.

If a liquid crystal projection television is constructed using this liquid crystal panel, a liquid crystal projection television capable of displaying a bright and high-contrast image can be provided, which has a very great effect.

[Brief description of the drawings]

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

FIG. 2 is a graph showing light transmittance at each wavelength of an ultraviolet reflective film.

FIG. 3 is a schematic view of a liquid crystal panel according to a second embodiment of the present invention.

FIG. 4 is a schematic view of a liquid crystal panel according to a third embodiment of the present invention.

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

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

FIG. 7 is a schematic configuration diagram of a liquid crystal projection television according to a third embodiment of the present invention.

FIG. 8 is a schematic diagram for explaining the operation of the polymer dispersed liquid crystal panel.

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

FIG. 10 is a schematic configuration diagram showing the configuration of a conventional liquid crystal projection television.

[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 19 ultraviolet reflection layer 20 light shielding layer 21, 22, 23 color filter 29a, 29b ultraviolet reflection layer 42 liquid crystal panel 43 Transparent plate 44 Transparent body 47 Black paint 49 Anti-reflection film 51 Light source 54 Projection lens 55 Field lens 56 Screen 70a, 70b, 70c, 71a, 71b, 71c Transparent plate 72a, 72b, 72c, 73a, 73b, 73c Black paint 74, 76, 77, 79 Dichroic mirror 75, 78 Flat mirror

Claims (7)

(57) [Claims] At least one of a first substrate and a second substrate having a light transmitting property and facing each other, a pixel electrode formed on a surface of the first substrate facing the second substrate, and a pixel thereof A switching element for controlling an applied signal to an electrode; a counter electrode formed on a surface of the second substrate facing the first substrate; and a polymer dispersion sandwiched between the first substrate and the second substrate. A liquid crystal panel comprising at least a liquid crystal layer, wherein a layer that reflects or absorbs ultraviolet light is formed on the second substrate corresponding to a pixel electrode of the first substrate. 2. The liquid crystal panel according to claim 1, wherein the liquid crystal particle diameter on the pixel electrode of the polymer dispersed liquid crystal layer is different from the liquid crystal particle diameter in other portions. 3. The liquid crystal panel according to claim 1, wherein a light shielding layer is formed directly on the switching element formed on the first substrate or via an insulating layer. At least one of the first substrate and the second substrate has a center thickness of the light-transmitting substrate as t, a refractive index of n, and a maximum diameter of an effective display area of the liquid crystal panel as d. And the following condition is satisfied.
The liquid crystal panel as described. (Equation 1) 5. A first substrate and a second substrate having at least one which are light-transmissive and face each other, a pixel electrode formed on a surface of the first substrate with respect to the second substrate, and a pixel thereof. A switching element for controlling an applied signal to an electrode; a counter electrode formed on a surface of the second substrate with respect to the first substrate; and a pixel formed on at least one of the first substrate and the second substrate. The color filter is formed in a liquid crystal panel comprising at least three corresponding primary color filters of red, green and blue, and a polymer dispersed liquid crystal layer sandwiched between the first substrate and the second substrate. A liquid crystal panel comprising a substrate that does not have a layer that reflects or absorbs ultraviolet light at least corresponding to pixels that modulate blue and green . 6. A pixel electrode and a pixel electrode on at least one of a first substrate and a second substrate, which are light-transmissive and face each other, on a surface of the first substrate facing the second substrate. Forming a switching element for controlling an applied signal of the second substrate, forming a counter electrode on a surface of the second substrate facing the first substrate, and forming a pixel on the first substrate or the second substrate. A step of forming a layer that reflects or absorbs corresponding ultraviolet light, a step of sandwiching a solution in which liquid crystal and uncured resin are mixed between the first substrate and the second substrate, and a step of reflecting or absorbing the ultraviolet light Irradiating light from the substrate side on which the layer is formed to form a polymer dispersed liquid crystal layer by phase separation of liquid crystal and resin. 7. A liquid crystal panel according to claim 1, light generating means, a first optical element component for guiding the light generated by said light generating means to said liquid crystal panel, and a light modulated by said liquid crystal panel. A liquid crystal projection television, comprising: a second optical element component for projecting light; and wherein light is incident on the liquid crystal panel from a substrate side on which a layer that reflects or absorbs ultraviolet light is formed.