JP2884782B2 - Liquid crystal panel 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 liquid crystal display device (hereinafter referred to as a liquid crystal projection television) for enlarging and projecting an image displayed on a small liquid crystal panel onto a screen, and a liquid crystal used in the liquid crystal projection television. It is about panels.

[0002]

2. Description of the Related Art A liquid crystal panel has many features such as light weight and thinness, and thus has been actively researched and developed. However, there are many problems such as difficulty in increasing the screen size. Thus, in recent years, 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 attracting attention. At present, a commercially available liquid crystal projection type television uses a twisted nematic (hereinafter, referred to as TN) liquid crystal panel utilizing the light emission characteristics of liquid crystal.

First, a general liquid crystal panel will be described. FIG. 5 is a plan view of the liquid crystal panel. In FIG. 5, reference numeral 56 denotes a glass substrate (hereinafter, referred to as an array substrate) on which a thin film transistor (hereinafter, referred to as a TFT) as a switching element is formed, and 53, a substrate on which a transparent electrode made of ITO or the like is formed ( A drive IC (hereinafter, referred to as a gate drive IC) 51 for applying a signal for controlling on / off of a TFT connected to a gate signal line of the array substrate 56, and a reference numeral 52 on the array substrate 56 Drive IC for applying a data signal to a source signal line (hereinafter referred to as a source drive IC)
It is.

FIG. 6 is an equivalent circuit diagram of an image display section of an array substrate 56 constituting a liquid crystal panel. (FIG. 6), the gate drive circuit 61, the source drive circuit 62, G ₁ ~G _m gate signal line, S ₁ to S _n denotes a source signal line, 63 is TFT, 64 is additional capacitance, 65 display Liquid crystal as an element. One electrode constituting the additional capacitance 64 is a pixel electrode, and the other electrode is a transparent electrode (additional capacitance electrode) made of ITO maintained at a constant potential.

As an operation of the liquid crystal panel, the gate drive circuit 61 sequentially applies an on-voltage to the gate signal lines G _{1 to} G _m . At the same source drive circuit in synchronization 62 outputs a voltage applied to each pixel in the source signal line S ₁ to S _n. A voltage for causing the liquid crystal to transmit a predetermined amount of transmission is applied to each display element 65 and held. This voltage is held in the next cycle until each TFT is turned on again. Light is modulated by repeating the above operation, and an image is displayed.

Next, a conventional liquid crystal panel will be described.
FIG. 7 is a sectional view of one pixel of a conventional liquid crystal panel.
However, it is drawn as a model, and portions unnecessary for description are omitted. In FIG. 7, reference numeral 71 denotes a counter substrate, reference numeral 72 denotes a counter electrode made of ITO or the like, reference numeral 73 denotes a TN liquid crystal layer, reference numeral 74 denotes a black matrix (hereinafter referred to as BM), reference numeral 75 denotes a source signal line, reference numeral 76 denotes a drain terminal , and reference numeral 77.
Is a gate terminal, 78 is an amorphous silicon film as a semiconductor constituting a TFT, 79 is an array substrate, 80 is one electrode constituting an additional capacitor, 88 is an insulating film, and 89 is a pixel electrode. As is clear from FIG. 7, in the conventional liquid crystal panel, a TFT is formed for controlling a signal applied to the pixel electrode 89 for each pixel, and light is not applied to the TFT on the counter substrate 71. BM74 is formed. Further, the space between the opposing substrate 71 and the array substrate 79 is usually arranged at an interval of 4 to 6 μm, the periphery of the liquid crystal panel is sealed with a sealing resin, and a TN liquid crystal is injected into the interval.

FIG. 8 is a diagram for explaining the operation. In FIG. 8, 81 and 82 are polarizing plates, 83 is a polarization direction,
84 is a transparent electrode (hereinafter referred to as ITO), 85 is a liquid crystal molecule, 86 is a signal source, and 87 is a switch. As shown in FIG. 8, the incident polarized light rotates 90 degrees in the off state, and transmits without rotating in the on state. Therefore, if the polarization directions of the two polarizing plates 81 and 82 are orthogonal, light is transmitted in the off state and cut off in the on state. However, the reverse is true if the polarization directions are parallel to each other. As described above, the TN liquid crystal panel modulates light to display an image.

Hereinafter, a conventional liquid crystal projection television will be described with reference to the drawings. FIG. 9 is a configuration diagram of a conventional liquid crystal projection television. In FIG. 9, reference numeral 91 denotes a condensing optical system, 92 denotes an infrared cut mirror that transmits infrared light, and 93a denotes a blue light reflecting dichroic mirror (hereinafter, referred to as a dichroic mirror).
93b is a green light reflecting dichroic mirror (hereinafter referred to as GDM), 93c is a red light reflecting dichroic mirror (hereinafter referred to as RDM), 94a, 9
4b, 94c, 96a, 96b, 96c are polarizing plates, 95
a, 95b, 95c are transmissive TN liquid crystal panels, 97
Reference numerals a, 97b, and 97c denote projection lens systems. When the projection lens system is not touched, it is generically called a projection lens. In addition, components unnecessary for the description, such as a field lens, are omitted from the drawings.

The operation of the conventional liquid crystal projection television will be described below with reference to FIG. First, the condensing optical system 91
The blue light (hereinafter referred to as B light) reflected by the BDM 93a from the white light emitted from the
Is incident on. The light transmitted through the BDM 93a is GDM9
3b reflects green light (hereinafter referred to as G light) to the polarizing plate 94b, and RDM 93c reflects red light (hereinafter referred to as G light).
R light) is reflected and incident on the polarizing plate 94C. The polarizing plate transmits only one of the longitudinal wave component and the transverse wave component of each color light, and irradiates each liquid crystal panel with the polarization direction of the light aligned. At this time, 50% or more of the light is absorbed by the polarizing plate, and the brightness of the transmitted light is reduced to half or less at the maximum. Each liquid crystal panel modulates the transmitted light with a video signal. The modulated light is applied to each polarizing plate 96 according to the degree of modulation.
a, 96b, 96c, and each projection lens system 97a,
97b and 97c, and are enlarged and projected on a screen by the lens.

[0010]

As is clear from the above description, in a liquid crystal projection television using a TN liquid crystal panel, it is necessary to make linearly polarized light incident on the liquid crystal panel. Must be placed before and after. At this time, since light is lost due to the polarizing plate, there is a problem that only low screen brightness can be obtained when the image is enlarged and projected on a screen. Therefore, a polymer dispersed liquid crystal is used in the liquid crystal panel and the liquid crystal projection television of the present invention. Polymer-dispersed liquid crystals are roughly classified into two types depending on the dispersion state of the liquid crystal and the polymer.

One type is a type in which liquid crystals in the form of water droplets are dispersed in a polymer. The liquid crystal exists in a discontinuous state in the polymer. Hereinafter, such a liquid crystal is referred to as a PDLC, and a liquid crystal panel using the liquid crystal is referred to as a PD liquid crystal panel. 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 P
A liquid crystal panel using the liquid crystal is called NLC.
This is called an N liquid crystal panel. In order to display an image on the two types of liquid crystal panels, scattering and transmission of light are controlled.

[0012] PDLC utilizes the property that the refractive index varies in the direction in which the liquid crystal is oriented. In the state where no voltage is applied, the respective liquid crystal droplets are oriented in an irregular direction. In this state, a difference in refractive index occurs between the polymer and the liquid crystal, and the incident light is scattered. Here, when a voltage is applied, the alignment directions of the liquid crystals are aligned. If the refractive index when the liquid crystal is aligned in a certain direction is adjusted in advance to the refractive index of the polymer, incident light is transmitted without being scattered. In contrast, PNLC uses the irregularity of the alignment of liquid crystal molecules. In an irregular orientation state, that is, in a state where no voltage is applied, incident light is scattered. On the other hand, when a voltage is applied to make the arrangement state regular, light is transmitted. It should be noted that the above-mentioned PDLC and PN
The explanation of the movement of the LC liquid crystal is based on a model. Although the present invention is not limited to one of a PD liquid crystal panel and a PN liquid crystal panel, a PD liquid crystal panel will be described as an example for ease of explanation. Further, PDLC and PNLC are collectively called polymer dispersed liquid crystal, and PD liquid crystal panel and PN liquid crystal panel are collectively called polymer dispersed liquid crystal panel. Further, liquids containing liquid crystal to be injected into the polymer dispersed liquid crystal panel are collectively referred to as a liquid crystal solution or a resin, and a state in which the resin is polymerized and cured is referred to as a polymer.

First, the operation of the polymer-dispersed liquid crystal will be briefly described with reference to FIGS. 10 (a) and 10 (b). (FIG. 10
(A) (b)) is an explanatory view of the operation of the polymer dispersed liquid crystal panel. 10 (a) and 10 (b), 101 is an array substrate, 102 is a pixel electrode, 103 is a counter electrode, 10
Reference numeral 4 denotes a water-drop liquid crystal, 105 denotes a polymer, and 106 denotes a counter substrate. A TFT or the like is connected to the pixel electrode 102, and TF
A voltage is applied to the pixel electrode by turning T on and off, and the direction of liquid crystal alignment on the pixel electrode is changed to modulate light.
As shown in FIG. 10A, when no voltage is applied, each of the liquid crystal droplets 104 is oriented in an irregular direction. In this state, a difference in refractive index occurs between the polymer 105 and the liquid crystal, and the incident light is scattered. Here (Fig. 10
As shown in (b)), when a voltage is applied to the pixel electrode, 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, incident light is emitted from the array substrate 101 without being scattered.

As described above, since the polymer-dispersed liquid crystal panel does not use a polarizing plate, the light use efficiency is high and a display image with extremely high luminance may be obtained. However, (FIG. 1
Since the incident light is scattered in the liquid crystal panel as shown in 1), the following problem occurs.

In FIG. 11, a, b, and c show the trajectories of the incident light. The incident light is modulated according to the degree of application of the voltage to the pixel electrode. There is no particular problem in the case of the incident light A, but there is a problem in the case where the trajectory is rounded by the droplet liquid crystal 26 as in the case of the incident light A and the TFT is irradiated. This is because amorphous silicon is used as a semiconductor film constituting a TFT of a liquid crystal panel. The amorphous silicon has photoexcitation characteristics as used in solar cells. Therefore, when light is irradiated on the amorphous silicon film, the TFT
Will not be completely turned off.

In order to prevent this, in a conventional TN liquid crystal panel, a BM 74 is formed on a counter substrate, and light is transmitted to the BM 74.
To prevent light from being emitted to the TFT. On the other hand, there is a case where light is incident from the array substrate as shown by light locus c. This is the case where the polymer-dispersed liquid crystal panel scatters light, so that light emitted from the array substrate is reflected back by a lens or the like and returned. In this case, too, light excitation occurs, which is a problem. As shown in FIG. 10, the polymer-dispersed liquid crystal displays an image by controlling the scattering and transmission of light.

For this reason, even if the BM has a structure in which light does not directly hit the TFT, the trajectory of the light is scattered by the liquid crystal 26 in a scattering state, and the amorphous silicon of the TFT is irradiated. Since a strong light of tens of thousands of lux or more is normally incident on a liquid crystal panel used in a liquid crystal projection television as shown in FIG. 9, the intensity of the scattered light shown above is also strong. For this reason, in the conventional liquid crystal panel structure, the off-state characteristics of the TFT deteriorate, and the contrast of the displayed image decreases. Therefore, it has not been possible to construct a liquid crystal projection television using a conventional polymer dispersed liquid crystal panel.

[0018]

In order to solve the above-mentioned problems, a liquid crystal panel according to the present invention comprises a switch on a first light-shielding film.
Forming a TFT as a switching element, and insulating the TFT on the TFT
A second light-shielding film is formed by forming a film. Sa
In addition, the first and second light shielding films are electrically connected to a gate signal line and the like.
A pneumatic connection is taken to fix the potential .

The liquid crystal projection television of the present invention uses the liquid crystal panel of the present invention as a light valve.
You. In addition, an anti-reflection film is formed on the light incident surface of the liquid crystal panel
It was done. Preferably, a polymer dispersed liquid crystal is used for the liquid crystal layer.
The condensing angle θ is set to 8 degrees or less using a liquid crystal panel
You.

[0020]

According to the present invention, the light shielding film is formed on the upper and lower surfaces of the TFT of the liquid crystal panel, so that the semiconductor film of the TFT is not irradiated with light, and no light excitation occurs. Further, by fixing the potential of the light-shielding film, the influence of the parasitic capacitance accompanying the formation of the light-shielding film is eliminated, and the occurrence of off-leakage of the TFT is also eliminated. As a result, the off characteristics of the TFT are improved, and the contrast of the displayed image can be significantly improved. Further, the light-shielding film 19 is connected to the gate terminal 20 of the TFT.
A first light-shielding film pattern that is not formed immediately below the center portion and that blocks light incident from one side of the gate terminal 20 of the TFT;
By comprising a second light-shielding film pattern that shields light incident from the other side of the gate terminal 20,
The overlap between the gate terminal 20 and the light shielding film 19 is reduced .
With this configuration, it is possible to minimize the occurrence of parasitic capacitance. Further, by forming an anti-reflection film on the light incident surface of the liquid crystal panel, the occurrence of light excitation can be further reduced, and a good contrast can be realized. Intense light enters the light valve of a liquid crystal projection television. for that reason,
Light excitation is likely to occur in the TFT of the light valve. Also,
If a polymer dispersed liquid crystal panel is used as a light valve,
Since it is not necessary to use a polarizing plate for light modulation, high-luminance display can be realized. However, since the polymer dispersed liquid crystal panel scatters light in the liquid crystal layer to perform light modulation, the conventional black matrix formed on the counter electrode cannot prevent photoexcitation. Since the liquid crystal panel of the present invention has light-shielding films formed on both the upper surface and the lower surface of the TFT, there is no occurrence of light excitation, and it is most suitable for a light valve of a liquid crystal projection television.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid crystal panel according to one embodiment of the present invention will be described. FIG. 1 is a sectional view of one pixel of the liquid crystal panel of the present invention. However, in the drawings, portions that are not necessary for description are omitted for ease of description, and are drawn as models. The above applies to the following drawings.

In FIG. 1, reference numeral 11 denotes a counter substrate on which a counter electrode 12 is formed, 13 denotes a liquid crystal layer made of polymer dispersed liquid crystal, 20 denotes a gate terminal of the TFT, 22 denotes a drain terminal of the TFT, and 23 denotes a TFT terminal. A source terminal, 21 is a semiconductor film made of amorphous silicon, 14, 16, and 24 are insulating films, and 19 is a light shielding film formed on a part of the additional capacitance electrode 17 made of ITO. Part of the gate terminal 20 when viewed from above the TFT
Is formed so as to at least overlap with the formation position of.
Since the light shielding film 19 is formed in a part of the additional capacitance electrode, the potential held by the additional capacitance electrode and the light shielding film 1
9 and the same potential, and the potential is stabilized. As is clear from FIGS. 1 and 2, the light-shielding film 19 includes a first light-shielding film pattern for shielding light incident from one side of the gate terminal 20 of the TFT, and the gate terminal 2.
Second light- shielding for blocking light incident from the other side of 0
It is composed of a film pattern . Since the gate terminal 20 is composed of a metal thin film, it is directly incident on the semiconductor layer of the TFT.
Shields the incident light to be attempted . On the other hand, the first light shielding film
The light-shielding film 19 composed of the turn and the second light-shielding film pattern shields light incident from the periphery of the gate terminal 20. Thus, complete light shielding can be realized by the gate terminal 20 and the light shielding film 19. The light-shielding film 19 is formed closer to the gate terminal 20 than the light-shielding film 25 is. Therefore, the parasitic capacitance using the light-shielding film 19 and the gate terminal 20 as electrodes is likely to increase. In the liquid crystal panel of the present invention, as shown in FIG. 1, a first light-shielding film pattern and a second light-shielding film pattern constitute a light-shielding film 19 . With this configuration , the overlap between the gate terminal 20 and the light-shielding film 19 can be reduced, so that the occurrence of parasitic capacitance can be minimized.

As a constituent material, a metal material such as Al or Cr is applied, and its film thickness is 100 Å to 1000 Å, and especially 50 Å.
0 Å to 800 Å is preferred. The light-shielding film 25 is formed on the insulating film having a thickness of 1000 Å to 8000 Å on the TFT, and the same metal material as the light-shielding film 19 is applied as a constituent material. Further, the film thickness is usually formed to be 500 Å or more, and it is preferable to form the film to be 1000 Å or more in order to completely shield light. Further shielding film 19, 25 are electrically connected is taken as a gate terminal 20 or the gate signal line of the TFT. This is because a parasitic capacitance is generated by the light shielding films 19 and 25.
This is to prevent them from being produced.

Reference numeral 15 denotes a pixel electrode made of ITO, and a drain terminal 22 of the TFT through a contact hole 27.
Is connected to. (Fig. 1)
The TFT of the liquid crystal panel of this embodiment has a shape in which the semiconductor film 21 formed therein is shielded from light by the light shielding films 25 and 19. An array substrate is formed by forming an electrode 17 of an additional capacitance on a glass substrate and then forming a metal material, usually C
The light-shielding film 19 is formed by evaporating r. Hereinafter, it is well known until the TFT is formed.

After the TFT is formed, an insulating film 24 is formed on the substrate by using SiO ₂ or SiNx. Next, a mask is formed on the insulating film 24 so as to have a predetermined pattern, and patterning is performed so as to leave the insulating film on at least the TFT and the gate / source signal lines. At this time, the light shielding film 25
Drilling of a contact hole (not shown) for connection between the gate terminal 20 and the gate terminal 20 is also performed. Next, a metal thin film made of a metal material such as Cr is formed on the insulating film patterned into a predetermined shape. The thickness of the thin film to be formed is the insulating film 24.
And a thickness at which the metal / thin film and the gate terminal 20 can be electrically connected at least. Finally, a mask is formed on the metal thin film and patterning is performed to form a light shielding film 25, thereby completing the process.

As a method of assembling the liquid crystal panel, a sealing resin containing fibers is applied to the periphery of the array substrate 18 as described above while leaving a liquid crystal injection port, while a predetermined liquid crystal is applied to the opposing substrate 11. Spray beads to obtain layer thickness. The bead diameter is preferably 5 μm to 20 μm, and most preferably 10 μm to 15 μm. As the fiber diameter described above, a diameter suitable for the bead diameter is used. Next, the array substrate 21b is positioned on the opposing substrate 21a and bonded. Thereafter, the resin is heated to cure the sealing resin. Next, put the bonded panel in a vacuum chamber,
A vacuum is applied between the substrates 18 and 11. Then, after immersing the injection port in the liquid crystal solution, the vacuum in the vacuum chamber is broken. Then, the liquid crystal solution is injected into the substrate from the injection port. The liquid crystal material of the liquid crystal solution 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 compounds.

Among the liquid crystal materials described above, a nematic liquid crystal of cyan biphenyl type is most preferable. As the resin material, a transparent polymer is preferable, and any of a thermoplastic resin, a thermosetting resin, and a photocurable resin may be used. However, as described above, ease of the manufacturing process, separation from the liquid crystal phase, etc. 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. In addition, when irradiated with ultraviolet rays, only the resin causes a polymerization reaction to become a polymer.At this time, when only the liquid crystal is phase-separated and the amount of liquid crystal is small compared to the resin component, an independent particulate water droplet is formed. Liquid crystals are formed, while
When the amount of the liquid crystal is large, the resin matrix exists in the liquid crystal material in the form of particles or a network, and the liquid crystal is formed so as to form a continuous layer. At this time, unless the particle size of the droplet liquid crystal or the pore size of the polymer network is uniform to some extent and the size is in the range of 0.1 μm to several μm, the dispersibility of incident light is poor and the contrast is not improved.
For this reason, the material must be a material that can be cured in a short time, such as an ultraviolet curable resin. Further, the compounding ratio of the liquid crystal material to the resin material is 9: 1 to 1: 9, in particular, 2: 1 to 1
A range of 1: 2 is preferred.

Hereinafter, a liquid crystal projection television according to the present invention will be described with reference to the drawings. FIG. 4 is a configuration diagram of the liquid crystal projection television of the present embodiment. However, components unnecessary for the description are omitted. In FIG. 3, a condensing optical system 31 has a concave mirror and a 250 W metal halide lamp as light generating means inside. The concave mirror is configured to reflect only visible light. Further, an ultraviolet cut filter is disposed at the emission end of the light collecting optical system 31. Reference numeral 32 denotes an infrared cut mirror that transmits infrared light and reflects only visible light. However, the infrared cut mirror 32 is a condensing optical system 31
Needless to say, it may be arranged inside the.

33a is BDM, 33b is GDM, 33c
Is RDM. In addition, the BDM 33a to the RDM 33c
Is not limited to the above order, and it is needless to say that the last RDM 33c may be replaced with a total reflection mirror. 34a, 34b and 34c are polymer dispersed liquid crystal panels according to the present invention. In this liquid crystal panel, an anti-reflection film is formed at least on the light incident surface in order to prevent halation and reflection of light. Light shielding film 19,
25, and by forming an anti-reflection film,
To prevent switching and reflection,
There is no light incident on the body film 21 and no light excitation occurs
Become. 35a, 35b and 35c are lenses, 37a,
37b and 37c are projection lenses, and 36a, 36b and 36c are apertures as apertures. In addition, 3
5, 36 and 37 constitute a schlieren optical system. 35, 36 and 3 unless otherwise specified.
The set of 7 is called a projection lens system. The aperture is the FNo. Obviously this is not necessary when is large.

The arrangement of the projection lens system is as follows. First, the distance L between the polymer-dispersed liquid crystal panel 34 and the lens 35 and the distance between the lens 35 and the aperture 36 are arranged to be substantially equal. The lens 35 is selected so that the light collection angle θ is about 6 degrees or less. The aperture diameter D of the aperture 46 is set to about 1 cm when the distance L is 10 cm. The above-described projection lens system plays a role of transmitting parallel light rays transmitted through each liquid crystal panel and transmitting light scattered by each liquid crystal panel. As a result, a high-contrast full-color display can be realized on the screen. If the aperture diameter D of the aperture is reduced, the contrast is improved. However, the image brightness on the screen decreases.

The thickness of the liquid crystal layer of the liquid crystal panel of the present invention is 10
In the case of １５15 μm, the condensing angle θ of the lens needs to be at least 8 degrees or less. Especially around 6 degrees is the best,
At that time, the contrast is 200: 1 at the center of the screen.
Compared with the RT projection television, the same or higher screen brightness could be obtained. At this time, the aperture diameter of the aperture was 10 mm, and the distance L was about 100 mm.

More specifically, the configuration diagram of FIG. 3 is shown in the perspective view of FIG. In FIG. 4, 4
Reference numerals 1 and 42 are lenses, 43 is a mirror, and 44a, 44b and 43c are projection lenses or projection lens systems.

The operation of the liquid crystal projection television according to the present embodiment will be described below. The R, G, and B light modulation systems perform almost the same operation. Therefore, the B light modulation system will be described as an example. First, white light is emitted from the condensing optical system 31, and the B light component of the white light is BDM3.
It is reflected by 3a. The B light is incident on the polymer dispersed liquid crystal panel 34a. The polymer-dispersed liquid crystal panel 34 modulates the light by controlling the scattering and transmission of the incident light by a signal applied to the pixel electrode, as shown in FIG.
The scattered light is shielded by the aperture 36a, and conversely, parallel light or light within a predetermined angle passes through the aperture 36a.
The modulated light is enlarged and projected on a screen (not shown) by the projection lens 37a. As described above, the B light component of the image is displayed on the screen. Similarly, the polymer dispersed liquid crystal panel 34b modulates the light of the G light component, and the polymer dispersed liquid crystal panel 34c modulates the light of the R light component.
A color image is displayed on the screen.

In this embodiment, the insulating film 24 is made of T
Although illustrated as if it was formed only on the FT and its vicinity, it is needless to say that the present invention is not limited to this and may be formed in a wide range.

Although the light-shielding film 25 is expressed as if it is electrically connected to the gate terminal 20, the present invention is not limited to this. For example, the gate signal line of a TFT or one electrode 17 of an additional capacitor may be used. Needless to say, the connection may be established.

Although the TFT of the liquid crystal panel of this embodiment is described as using amorphous silicon as the semiconductor film, it may be, for example, one using polysilicon. The configuration of the liquid crystal panel of the present invention is a TFT.
It is apparent that the present invention is not limited to this, and is effective also in a liquid crystal panel using a two-terminal element such as a diode as a switching element.

The substrate 18 is a glass substrate, but is not limited to this, and may be a semiconductor substrate such as silicon. In addition, although the light is described to be incident from the counter substrate 11 side, it goes without saying that the light may be incident from the array substrate 18 side since the liquid crystal panel of the present invention has the light shielding film 19.

In the liquid crystal panel of this embodiment,
Although described as a transmissive liquid crystal panel, the present invention is not limited to this, and it is apparent that a reflective structure may be adopted. In that case, the pixel electrode may be formed of a metal material.

In the embodiment of the liquid crystal projection type television of the present invention, the rear type liquid crystal projection type TV has been described. However, the present invention is not limited to this, and the front type liquid crystal projection type TV for projecting an image on a reflection type screen is provided. Needless to say, this is fine. Further, although the description has been made on the assumption that the color separation is performed by the dichroic mirror, the color separation may be performed using, for example, an absorption type color filter.
In the liquid crystal projection television of the present invention, one projection lens system is provided for each of the R, G, and B light modulation systems. However, the present invention is not limited to this. It goes without saying that the display images modulated by the panel may be combined into one and then incident on one projection lens system.

[0040]

As described above, according to the present invention, a light-shielding film is formed on a part of an additional capacitance electrode, and a light-shielding film is formed on an upper layer of a TFT, as shown in FIG. Light scattered by the dispersed liquid crystal, light incident on the TFT, or light returned as reflected by light locus C is not irradiated to the semiconductor film of the TFT. Therefore, optical excitation does not occur in the semiconductor film. Therefore, the operating characteristics of the TFT when the TFT is off are improved, and an image with high contrast can be displayed. Further, by setting the potential of the light-shielding film to a predetermined potential, the influence of the parasitic capacitance is eliminated, and the occurrence of off-leakage of the TFT is eliminated. In addition, the structure in which the light-shielding film is formed on a part of the additional capacitance electrode has less unevenness and the manufacturing process is easy. The light-shielding film 19 is not formed immediately below the center of the TFT , and the first light-shielding film 19 that shields light incident from one side of the gate terminal 20 of the TFT is provided.
Since the light-shielding film pattern and the second light-shielding film pattern that shields light incident from the other side of the gate terminal 20 are formed, the overlap between the gate terminal 20 and the light-shielding film 19 can be reduced. In addition, generation of parasitic capacitance can be minimized. As a result, the load on the gate signal line can be reduced, and the gate drive IC
51 can be improved. Further, by forming an anti-reflection film on the light incident surface of the liquid crystal panel or the like, halation and reflection can be prevented, and optical excitation of the switching element does not occur. This effect is particularly effective when the liquid crystal panel of the present invention is used in a liquid crystal projection television in which strong light is incident on the liquid crystal panel. Further, by narrowing the condensing angle θ, the spread angle of the incident light incident on the liquid crystal panel is reduced, so that halation and reflection generated in the liquid crystal panel are reduced. When a polymer-dispersed liquid crystal panel is used as the light valve, the light is scattered by the liquid crystal layer to modulate the light, so that halation easily occurs. However, unnecessary halation is reduced by setting the condensing angle θ to 8 degrees or less. Display contrast can be improved. In addition, optical excitation of the switching element hardly occurs.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of an effect of the liquid crystal panel of the present invention.

FIG. 3 is a configuration diagram of a liquid crystal projection television according to an embodiment of the present invention.

FIG. 4 is a partial perspective view of a liquid crystal projection television according to one embodiment of the present invention.

FIG. 5 is a plan view of a conventional liquid crystal panel.

FIG. 6 is an equivalent circuit diagram of a conventional liquid crystal panel.

FIG. 7 is a cross-sectional view of one pixel portion of a conventional liquid crystal panel.

FIG. 8 is an explanatory diagram of an operation of the TN liquid crystal panel.

FIG. 9 is a configuration diagram of a conventional liquid crystal projection television.

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

FIG. 11 is an explanatory diagram of a problem of a conventional liquid crystal panel.

[Explanation of symbols]

 Reference Signs List 11 counter substrate 12 counter electrode 13 polymer dispersed liquid crystal layer 14, 16, 24 insulating film 15 pixel electrode 17 additional capacitance electrode 19, 25 light shielding film 20 gate terminal 21 semiconductor film 22 drain terminal 23 source terminal 26 droplet liquid crystal 27 contact hole 31 Condensing optical system 32 Infrared cut mirror 33 Dichroic mirror 34 Polymer dispersed liquid crystal panel 35, 37, 41, 42 Lens 36 Aperture 43 Mirror 44 Projection lens system

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1/136 G02F 1/1333 G02F 1/13 505 G02F 1/1335

Claims (10)

(57) [Claims] A plurality of pixels arranged in a matrix and a transistor element for applying a signal to the pixels ;
A first substrate on which one of the electrodes has an additional capacitor formed of a transparent electrode ; a second substrate on which a counter electrode is formed; and a liquid crystal sandwiched between the first substrate and the second substrate. And a layer under the transistor element on the first substrate.
Formed and overlap with a part of the transparent electrode of the additional capacitance.
First light shielding film made of a conductor Te is formed, the first light-shielding film, a liquid crystal panel characterized in that it is held in the transparent electrode and the same potential of the additional capacity. 2. A first substrate on which pixels arranged in a matrix, a transistor element for applying a signal to the pixels, and an additional capacitor are formed; a second substrate on which a counter electrode is formed; A liquid crystal layer sandwiched between the first substrate and a second substrate, wherein a first light-shielding film made of a conductor is formed below the transistor element on the first substrate; A second light-shielding film made of a conductor is formed on the first light-shielding film, the first light-shielding film is connected to be at the same potential as one of the electrodes constituting the additional capacitance, and the second light-shielding film is A liquid crystal panel, which is connected so as to have the same potential as a gate terminal of the transistor element. 3. Pixels arranged in a matrix and
A transistor element for applying a signal to the pixel and an additional capacitor
A first substrate having A second substrate on which a counter electrode is formed; A liquid crystal layer sandwiched between the first substrate and the second substrate;
Have, On the first substrate, under the transistor element
A first light-shielding film made of a conductor is formed, The first light-shielding film is connected to one of the electrodes constituting the additional capacitance.
Connected to the same potential as the pole, and the first
The light-shielding film has at least the first light-shielding film pattern and the second light-shielding film pattern. 2 shading
Composed of a membrane pattern, The first light-shielding film pattern is a gate of a transistor element.
G terminal near one side, The second light-shielding film pattern is formed on another side of the gate terminal.
A liquid crystal panel, wherein the liquid crystal panel is disposed near the liquid crystal panel. 4. Pixels arranged in a matrix and
A transistor element for applying a signal to the pixel, and at least
Also one of the electrodes is formed of a transparent electrode and an additional capacitor is formed
A first substrate, A second substrate on which a counter electrode is formed; A liquid crystal layer sandwiched between the first substrate and the second substrate;
Have, On the first substrate, under the transistor element
Formed and overlap with a part of the transparent electrode of the additional capacitance.
Forming a first light-shielding film made of a conductor,
A second light-shielding film made of a conductor is formed on the star element, The second light-shielding film is provided at a gate end of the transistor element.
It is connected so that it has the same potential as the
Liquid crystal panel. 5. A method according to claim 1, wherein the pixels arranged in a matrix form
A transistor element for applying a signal to the pixel and an additional capacitor
A first substrate having A second substrate on which a counter electrode is formed; A liquid crystal layer sandwiched between the first substrate and the second substrate;
Have, On the first substrate, under the transistor element
A first light-shielding film made of a conductor is formed, and
A second light-shielding film made of a conductor is formed on the The first light-shielding film has a potential of one electrode of the additional capacitance.
And the first shielding.
The optical film has at least a first light shielding film pattern and a second light shielding film.
Composed of patterns, The first light-shielding film pattern is a gate of a transistor element.
G terminal near one side, The second light-shielding film pattern is formed on another side of the gate terminal.
Placed near The second light-shielding film is provided at a gate end of the transistor element.
Become the same as the child's potential Characterized by being connected as
LCD panel. 6. The liquid crystal layer according to claim 1, wherein the liquid crystal layer forms an optical image as a change in a light scattering state .
The liquid crystal panel according to claim 5 . 7. At least one of the first substrate and the second substrate
Also, make sure that the anti-reflection film is
A liquid according to any one of claims 1 to 5, characterized in that:
Crystal panel. 8. A liquid crystal panel according to claim 1 , light generating means, optical means for guiding light emitted by said light generating means to said liquid crystal panel, and modulation by said liquid crystal panel. A liquid crystal projection television, comprising: projection means for projecting the reflected light. A first liquid crystal panel according to any one of claims 9] claims 1 to 7 for modulating the red light, the second according to any one of claims 1 to 7 for modulating the green light 8. A liquid crystal panel, a third liquid crystal panel according to claim 1, which modulates blue light, light generating means, and light emitted by the light generating means emits red light, green light, and blue light. 1. A liquid crystal projection television, comprising: a light separating unit that separates light into light beams; and a projection unit that projects light modulated by the first to third liquid crystal panels. 10. The method according to claim 1, wherein :
A liquid crystal panel according to any one of the above, light generating means, optical means for guiding light emitted by the light generating means to the liquid crystal panel, and projection means for projecting light modulated by the liquid crystal panel. The liquid crystal layer of the liquid crystal panel emits light as a change in the light scattering state.
A liquid crystal layer for forming a scientific image, wherein a condensing angle θ of the projection means is 8 degrees or less.