JP2001100154A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use an optical modulating device for a long time by preventing or reducing its deterioration due to light. SOLUTION: The projection type display device is equipped with a light source 30, an optical modulation device 5, and a projection lens 26 and the optical modulation device is composed of two liquid crystal light valves using liquid crystal and has a 1st polarization beam splitter 47 which splits the light from the light source 30 into a P-polarized light beam and an S-polarized light beam, a 1st liquid crystal light valve 5a which modulates and converts the P-polarized light beam separated by the 1st polarization beam splitter into an S-polarized light beam, a 2nd liquid crystal light valve 5b which modulates and converts the S-polarized light beam split by the 1st polarization beam splitter into a P-polarized light beam, and a 2nd polarization beam splitter 48 which puts together the S-polarized light beam exited by the 1st liquid crystal light valve and the P-polarized light beam exited by the 2nd liquid crystal light valve 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device, and more particularly to a projection type display device capable of preventing or alleviating deterioration of a light modulation device due to light and enabling long-term use.

[0002]

2. Description of the Related Art FIG. 8 is a schematic diagram showing a main part of an example of a conventional projection display device.

This projection type display device is of a three-plate type using three light modulation devices.

In FIG. 8, reference numeral 30 denotes a light source, and reference numeral 3 denotes a light source.
Reference numerals 3 and 34 denote dichroic mirrors and reference numerals 35, 36 and 3
7 is a reflection mirror, 38 is an entrance lens, 39 is a relay lens, 20 is an exit lens, 22 and 23,
24 is a liquid crystal light modulator, 25 is a cross dichroic prism, and 26 is a projection lens.

The light source 30 comprises a lamp 31 such as a metal Harald and a reflector 32 for reflecting the light of the lamp 31. Dichroic mirror 33 reflecting blue light and green light
Transmits the red light of the light flux from the light source 30 and reflects the blue light and the green light. The transmitted red light is reflected by the reflection mirror 37 and enters the liquid crystal light modulation device 22 for red light. On the other hand, the green light of the color light reflected by the dichroic mirror 33 is reflected by the dichroic mirror 34 that reflects green light, and is incident on the liquid crystal light modulation device 23 for green light. On the other hand, the blue light also passes through the second dichroic mirror 34. For blue light, in order to prevent light loss due to a long optical path, a light guide means 21 composed of a relay lens system including an incident lens 38, a relay lens 39, and an exit lens 20 is provided. The light enters the liquid crystal light modulation device 24.

The three color lights modulated by the respective light modulators enter a cross dichroic prism 25. In this prism, four rectangular prisms are laminated, and a dielectric multilayer film that reflects red and a dielectric multilayer film that reflects blue are formed in a cross shape on the inner surface. These dielectric multilayer films combine the three color lights to form light representing a color image. The combined light is projected on a screen by a projection lens 26 which is a projection optical system, and an image is enlarged and displayed.

[0007]

However, in such a projection type display device, the luminous flux density applied to the liquid crystal light modulation devices 22, 23 and 24 increases with the increase in the brightness of the light source 30, and There is a problem that the life of the projection display device is shortened due to an increase in damage to the liquid crystal, the alignment film, the polarizing plate, and the like of the liquid crystal panels constituting the liquid crystal light modulation devices 22, 23, and 24.

In particular, a liquid crystal light modulation device 24 for blue light, into which blue light having the shortest wavelength among the separated color lights is incident.
Are susceptible to degradation by light.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a projection type display device capable of preventing or reducing the deterioration of the light modulation device due to light as described above and enabling long-term use. It is an issue.

[0010]

A projection display device according to the present invention comprises a light source, a light modulator for modulating light from the light source, and a projection lens for projecting light modulated by the light modulator. In a projection display device, the light modulation device includes two liquid crystal light valves using liquid crystal,
A first polarizing beam splitter for separating light from the light source into a P-polarized beam and an S-polarized beam; and a first for converting the P-polarized beam separated by the first polarizing beam splitter into an S-polarized beam. A liquid crystal light valve, a second liquid crystal light valve that modulates the S-polarized beam split by the first polarization beam splitter and converts the P-polarized beam, and an S-polarized beam emitted from the first liquid crystal light valve. A second polarizing beam splitter for combining the P-polarized beam emitted from the second liquid crystal light valve.

In such a projection display device, the light from the light source is split into two beams, a P-polarized beam and an S-polarized beam, by the first polarizing beam splitter. Irradiated to the liquid crystal light valve, S
The polarized beam is applied to the second liquid crystal light valve. First
By using, for example, a twisted nematic liquid crystal light valve as the liquid crystal light valve and the second liquid crystal light valve, the P-polarized light beam is converted into the S-polarized light beam, and the S-polarized light beam is converted into the P-polarized light beam. And an image similar to the conventional image can be obtained.

Therefore, the luminous flux density of the light applied to the first liquid crystal light valve and the second liquid crystal light valve is half that of the light from the light source, and it is possible to prevent or reduce the light deterioration of the liquid crystal light valve. it can. Therefore, it is possible to prolong the life of the projection display device.

Further, the projection display device of the present invention comprises a light source, a color separation means for separating the light from the light source into a plurality of color lights, and a plurality of color light means for modulating the plurality of color lights separated by the color separation means. A light modulating device, a color synthesizing means for synthesizing the color lights modulated by the plurality of light modulating devices, and a projection display device including a projection lens for projecting the light synthesized by the color synthesizing means, At least one of the plurality of light modulators includes two liquid crystal light valves using liquid crystal, and separates light incident on the light modulator including the two liquid crystal light valves into a P-polarized beam and an S-polarized beam. A first polarization beam splitter, a first liquid crystal light valve that modulates a P-polarization beam split by the first polarization beam splitter, and converts the P-polarization beam into an S-polarization beam; A second liquid crystal light valve that modulates the s-polarized beam split by the light beam splitter and converts the s-polarized beam into a p-polarized beam; and an s-polarized beam emitted from the first liquid crystal light valve and an emitted light from the second liquid crystal light valve. And a second polarization beam splitter that combines the P-polarized beam.

In such a projection type display device, at least one of the plurality of light modulation devices uses a liquid crystal device.
The light incident on the light modulator including the two liquid crystal light valves is split into a P-polarized beam and an S-polarized beam by the first polarizing beam splitter. The P-polarized beam of the separated light is applied to the first liquid crystal light valve, and the S-polarized beam is applied to the second liquid crystal light valve. For this reason, the luminous flux density of the light applied to the first liquid crystal light valve and the second liquid crystal light valve is half that of a light modulator including one liquid crystal light valve. Can be eased. Therefore, it is possible to prolong the life of the projection display device.

Further, in the above-mentioned projection type display device,
A light modulator that modulates at least the shortest wavelength color light of the plurality of color lights separated by the color separation means includes two liquid crystal light valves using liquid crystals.

In such a projection display device, since the light modulator for modulating the color light on the shortest wavelength side is composed of two liquid crystal light valves using liquid crystals, the color light having a short wavelength is incident. Therefore, it is possible to prevent or reduce the light deterioration of the liquid crystal light valve of the light modulation device that modulates the shortest wavelength side color light, which is particularly easily deteriorated among the plurality of light modulation devices. Thus, the life of the projection display device can be effectively extended.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples.

[Basic Configuration of Liquid Crystal Light Valve] First, the basic configuration of the liquid crystal light valve used in the projection display device of the present invention will be described. FIG. 4 is an equivalent circuit of various elements, wiring, and the like in a plurality of pixels formed in a matrix forming an image display area of a liquid crystal light valve.

As shown in FIG. 4, in the liquid crystal light valve according to the present embodiment, a plurality of pixels formed in a matrix forming an image display area are used to control a pixel electrode 109a and the pixel electrode 109a. Thin film transistor (hereinafter referred to as T)
FT) 130 are formed in a matrix, and a data line 106a for supplying an image signal is connected to the TFT.
130 is electrically connected to the source region. Image signals S1, S2,..., Sn to be written to the data lines 106a
May be supplied line-sequentially in this order, or may be supplied to a plurality of adjacent data lines 106a for each group. A scanning line 103a is electrically connected to the gate of the TFT 130, and the scanning signal G is pulsed to the scanning line 103a at a predetermined timing.
, Gm are applied line-sequentially in this order. The pixel electrode 109a is electrically connected to a drain region of the pixel switching TFT 130, and a pixel switching TFT
By closing the switch of the FT 130 for a certain period, the image signals S1 and S1 supplied from the data line 106a are
.., Sn are written at a predetermined timing.

The image signals S1, S2,..., Sn of a predetermined level written in the liquid crystal via the pixel electrodes 109a are supplied to counter electrodes (described later) formed on a counter substrate (described later).
Is maintained for a certain period of time. Here, in order to prevent the held image signal from leaking, a storage capacitor 170 is added in parallel with a liquid crystal capacitor formed between the pixel electrode 109a and the counter electrode. For example, the voltage of the pixel electrode 109a is
The storage capacitor 170 holds the data for a time three orders of magnitude longer than the time when the source voltage is applied. Thereby, the holding characteristics are further improved, and a liquid crystal device having a high contrast ratio can be realized. In this embodiment, as a method for forming the storage capacitor 170, the capacitor line 103b which is a wiring for forming a capacitor between the semiconductor layer and the semiconductor layer is provided. Instead of providing the capacitor line 103b, a capacitor may be formed between the pixel electrode 109a and the preceding scanning line 103a.

Next, the overall structure of the liquid crystal light valve is shown in FIG.
This will be described with reference to FIG.

FIG. 5 shows the TFT array substrate 110 together with the components formed thereon as well as the counter substrate 120.
6 is a cross-sectional view taken along the line HH ′ of FIG. 5 including the counter substrate 120.

In FIG. 5, on the TFT array substrate 110, a sealing material 152 is provided along the edge thereof, and in parallel with the inside thereof, for example, from the same or different material as the first light shielding film 123. A second light-shielding film 153 is provided as a frame. In a region outside the sealing material 152, a data line driving circuit 201 and an external circuit connection terminal 202 are provided along one side of the TFT array substrate 110, and a scanning line driving circuit 204 is provided on two sides adjacent to this one side. It is provided along. If the delay of the scanning signal supplied to the scanning line 103a does not matter, it goes without saying that the scanning line driving circuit 204 may be provided on only one side. Further, the data line driving circuits 201 may be arranged on both sides along the sides of the image display area. For example, the odd-numbered data lines 106a supply an image signal from a data line driving circuit disposed along one side of the image display area, and the even-numbered data lines 106a are connected to the opposite side of the image display area. The image signal may be supplied from a data line driving circuit disposed along the line. By driving the data lines 106a in a comb-tooth shape in this manner, the area occupied by the data line driving circuit can be expanded, so that a complicated circuit can be formed. Further, the TFT array substrate 110
A plurality of wirings 205 for connecting the scanning line driving circuits 204 provided on both sides of the image display area are provided on the remaining side. Further, at least one of the corners of the counter substrate 120, the TFT array substrate 110
A conductive material 206 for providing electrical continuity between the conductive member 206 and the counter substrate 120 is provided. Then, as shown in FIG. 6, a counter substrate 120 having substantially the same contour as the sealing material 152 shown in FIG. 5 is fixed to the TFT array substrate 110 by the sealing material 152.

FIG. 7 shows the sectional structure of the liquid crystal light valve in more detail.

The liquid crystal light valve, as shown in FIG.
A liquid crystal is sealed between two transparent substrates such as a glass substrate and a quartz substrate, and a TFT array substrate 110 serving as one substrate and an opposing substrate 120 serving as the other substrate disposed opposite to the TFT array substrate 110 are provided. It has. TFT array substrate 11
The whole 0 has a plurality of pixels formed in a matrix forming an image display area of the liquid crystal light valve. T
The FT array substrate 110 includes a pixel electrode 109a and a pixel switching T for controlling the pixel electrode 109a.
A plurality of FTs 130 are formed in a matrix, and a data line 106a for supplying an image signal is
05, it is electrically connected to the source region 101d of the TFT 130. The scanning line 103a is electrically connected to the gate of the TFT 130, and is configured to sequentially apply a scanning signal in a pulsed manner to the scanning line 103a at a predetermined timing. Pixel electrode 109a
Is electrically connected to the drain region 101e of the pixel switching TFT 130 through the contact hole 108, and by closing the pixel switching TFT 130, which is a switching element, for a certain period of time, an image supplied from the data line 106a. A signal is written at a predetermined timing.

An image signal of a predetermined level written in the liquid crystal via the pixel electrode 109a is held for a certain period between the counter electrode 121 formed on the counter substrate 120. Usually, the held image signal is To prevent leaks,
A storage capacitor is added in parallel with a liquid crystal capacitor formed between the pixel electrode 109a and the counter electrode 121. here,
As a method for forming a storage capacitor, a capacitor line 103b which is a wiring for forming a capacitor is provided. Also, the pixel electrode 1
An alignment film 116 that has been subjected to a predetermined alignment process such as a rubbing process is provided on 09a. Pixel electrode 109a
Is formed from a transparent conductive thin film such as an ITO (Indium Tin Oxide) film. The orientation film 116 is generally formed from an organic thin film such as a polyimide thin film.

On the other hand, a counter electrode (common electrode) 121 is provided on the entire surface of the counter substrate 120.
On the lower side, an alignment film 122 on which a predetermined alignment process such as a rubbing process is performed is provided. Similarly to the pixel electrode 109a, the counter electrode 121 is formed of a transparent conductive thin film such as an ITO film. Also, the alignment film 122 is made of TF
Like the alignment film 116 on the T array substrate 110 side, it is formed from an organic thin film such as a polyimide thin film. Further, the opposing substrate 120 has a light shielding film 1 in an area other than the display area of each pixel.
23 are provided. The light shielding film 123 is provided so that incident light from the opposite substrate 120 side is
The channel region 101a ′, the source regions 101b and 101d, the drain region 101c,
This is for preventing intrusion into 101e and the like.
Further, the light-shielding film 123 has functions of improving contrast, preventing color mixture of color materials, and the like, and is also called a so-called black matrix.

Each substrate has such a structure, and liquid crystal is sealed between the TFT array substrate 110 and the opposing substrate 120 in which the pixel electrode 109a and the opposing electrode 121 face each other. Is formed. The liquid crystal layer 150 assumes a predetermined alignment state by the action of the alignment film when no electric field is applied from the pixel electrode 109a.
In this example, the alignment films 116 and 122 have been rubbed, and the liquid crystal molecules assume a horizontal alignment state having a slight pretilt angle when no electric field is applied.

[First Embodiment] FIG. 1 is a schematic configuration diagram showing a main part of an example of a projection type display device of the present invention.

This projection type display device is of a three-plate type using three sets of light modulation devices.

In FIG. 1, reference numeral 30 denotes a light source, and reference numeral 3 denotes a light source.
Reference numerals 3 and 34 denote dichroic mirrors and reference numerals 11, 12, and 1
Reference numerals 3, 14, 15, 16, 17, 18, and 19 indicate reflection mirrors, and reference numerals 2, 3, and 4 indicate light modulation devices. Each of the light modulators 2, 3, and 4 includes, for example, two liquid crystal light valves using twisted nematic liquid crystals. This liquid crystal light valve has, for example, the configuration described above. Reference numerals 41, 43 and 45 denote first polarization beam splitters, and reference numerals 42, 44 and 46 denote second polarization beam splitters.
A polarizing beam splitter, reference numeral 25 indicates a cross dichroic prism, and reference numeral 26 indicates a projection lens.

The light source 30 comprises a lamp 31 such as a metal Harald and a reflector 32 for reflecting light from the lamp 31.

The dichroic mirror 33 for reflecting blue light and green light is set so as to transmit red light of the light beam from the light source 30 and reflect blue light and green light. The transmitted red light is split by the first polarizing beam splitter 41 into a P-polarized beam and an S-polarized beam. The P-polarized beam of the separated light is rotated and modulated by 90 degrees by the first liquid crystal light valve 2a, converted into an S-polarized beam, reflected by the reflection mirror 13, and transmitted to the second polarization beam splitter 42. Incident. On the other hand, the S-polarized beam split by the first polarizing beam splitter 41 is reflected by the reflecting mirror 12 and is incident on the second liquid crystal light valve 2b.
The light is rotated by 90 degrees by the liquid crystal light valve 2b and modulated, converted into a P-polarized beam, and incident on the second polarized beam splitter 42. The S-polarized beam emitted from the first liquid crystal light valve 2a and the P-polarized beam emitted from the second liquid crystal light valve 2b are
The light is synthesized by the polarization beam splitter 42, reflected by the reflection mirror 18, and enters the cross dichroic prism 25.

On the other hand, the green light of the color light reflected by the dichroic mirror 33 is reflected by the dichroic mirror 34 set for reflecting the green light, and is converted by the first polarizing beam splitter 43 into a P-polarized beam and an S-polarized beam. Separated. The separated P-polarized light beam is modulated by the first liquid crystal light valve 3a, converted into an S-polarized light beam, reflected by the reflection mirror 15, and made incident on the second polarized light beam splitter 44. On the other hand, the S-polarized beam split by the first polarizing beam splitter 43 is reflected by the reflecting mirror 14,
The light is incident on the second liquid crystal light valve 3b, is modulated by the second liquid crystal light valve 3b, is converted into a P-polarized beam, and is incident on the second polarized beam splitter 44. The S-polarized beam emitted from the first liquid crystal light valve 3a and the P-polarized beam emitted from the second liquid crystal light valve 3b are combined with the second polarized beam splitter 44.
And enters the cross dichroic prism 25.

The blue light transmitted through the green light reflecting dichroic mirror 34 is reflected by the reflecting mirror 11 and is separated by the first polarizing beam splitter 45 into a P-polarized beam and an S-polarized beam. P isolated
The polarized light beam is modulated by the first liquid crystal light valve 4a, converted into an S-polarized light beam, reflected by the reflection mirror 17, and is reflected by the second polarizing beam splitter 4a.
6 is incident. On the other hand, the first polarization beam splitter 45
The S-polarized beam separated by is reflected by the reflection mirror 16, is incident on the second liquid crystal light valve 4b, is modulated by the second liquid crystal light valve 4b, is converted into a P-polarized beam, and is converted into a P-polarized beam. The light enters the splitter 46. Then, the S-polarized beam emitted from the first liquid crystal light valve 4a and the P-polarized beam emitted from the second liquid crystal light valve 4b are combined by the second polarizing beam splitter 46, reflected by the reflection mirror 19, and crossed. Dichroic prism 25
Incident on.

The cross dichroic prism 25 on which the three color lights modulated by the respective light modulators are incident,
Two right angle prisms are laminated, and a dielectric multilayer film that reflects red and a dielectric multilayer film that reflects blue are formed in a cross shape on the inner surface. These dielectric multilayer films combine the three color lights to form light representing a color image. The combined light is projected on a screen by a projection lens 26 which is a projection optical system, and an image is enlarged and displayed.

In such a projection display device, each of the light modulators 2, 3, and 4 is composed of two liquid crystal light valves using liquid crystal, and the light incident on the light modulators 2, 3, and 4 is reflected by P light. A first polarization beam splitter 41, 43, 45 for separating the polarization beam into an S polarization beam, and a second polarization beam splitter 41, 43, 45 for modulating the P polarization beam separated by the first polarization beam splitter 41, 43, 45 and converting the P polarization beam into an S polarization beam. 1 liquid crystal light valve 2a, 3a, 4a and first polarization beam splitter 4
A second liquid crystal light valve 2 for modulating the S-polarized beam separated by 1, 43, 45 and converting it to a P-polarized beam
b, 3b, 4b and the first liquid crystal light valves 2a, 3a,
Second polarizing beam splitters 42 and 44 for combining the S-polarized beam emitted from 4a and the P-polarized beams emitted from the second liquid crystal light valves 2b, 3b and 4b, respectively.
46, the first liquid crystal light valves 2a, 3a
a, 4a or the second liquid crystal light valves 2b, 3b, 4
The luminous flux density of the light applied to b is half that of a light modulator including one liquid crystal light valve, and light deterioration of the liquid crystal light valve of the light modulator can be prevented or reduced. Therefore, it is possible to prolong the life of the projection display device.

In this projection display device, the light modulator 4 that modulates blue light, which is the shortest wavelength side color light among the plurality of color lights separated by the color separation means, uses two liquid crystals using liquid crystals. The light valves 4a and 4b prevent or mitigate light deterioration of the liquid crystal light valve of the liquid crystal light modulation device 4 which is particularly likely to deteriorate among a plurality of light modulation devices because blue light having a short wavelength is incident thereon. can do. Thus, the life of the projection display device can be effectively extended.

In the above-mentioned projection display device, in order to prevent light loss due to a long optical path with respect to blue light, the distance between the dichroic mirror 34 and the reflection mirror 11 and the distance between the reflection mirror 11 and the first polarization beam splitter 45 are reduced. A light guide means such as a relay lens may be provided in between.

If the first polarized beam splitter alone cannot sufficiently separate polarized light, a polarizing plate having a high polarization separating ability may be provided by a liquid crystal light valve as necessary. By providing such a polarizing plate, the separation of light can be improved and the contrast can be ensured. As an example of the method of providing the polarizing plate, one configuration is considered to be directly attached to the liquid crystal light valve.However, if the configuration is such that the polarizing plate is attached to the polarizing beam splitter, the heat dissipation effect is enhanced, and the heat storage of the liquid crystal light valve or the polarizing plate is performed. Image deterioration can be prevented.

In the projection type display device of the present invention, as shown in the above-described example, all the light modulation devices 2, 3, 4
May be composed of two liquid crystal light valves, but any one or more light modulators may be composed of two liquid crystal light valves, and there is no particular limitation. In the case where the light modulator includes one liquid crystal light valve, the first polarization beam splitter, the second polarization beam splitter, and the reflection mirror interposed therebetween are unnecessary.

[Second Embodiment] FIG. 2 is a schematic diagram showing a main part of another example of the projection type display device of the present invention.

This projection type display device is of a color sequential single plate type (field sequential type) which is a kind of a single plate type in which the light modulator is one set.

In FIG. 2, reference numeral 30 denotes a light source, and reference numeral 5 denotes a light source.
Reference numerals 1 and 52 denote reflection mirrors, and reference numeral 5 denotes an optical modulation device. The light modulation device 5 includes two liquid crystal light valves using, for example, twisted nematic liquid crystals. Reference numeral 47 denotes a first polarization beam splitter, reference numeral 48 denotes a second polarization beam splitter, and reference numeral 26 denotes a projection lens.

The light source 30 comprises a lamp 31 such as a metal Harald and a reflector 32 for reflecting the light of the lamp 31. The light beam from the light source 30 sequentially passes through the condenser lens 55, the color wheel 57, and the condenser lens 56, and is incident on the first polarization beam splitter 47. At this time, by rotating the color wheel 57 at a high speed, the red light, the blue light, and the green light
The light enters the polarization beam splitter 47.

The light incident on the first polarization beam splitter 47 is split by the first polarization beam splitter 47 into a P-polarized beam and an S-polarized beam. The P-polarized beam of the separated light is rotated by 90 degrees by the first liquid crystal light valve 5a and modulated, converted into an S-polarized beam, reflected by the reflection mirror 52, and transmitted to the second polarization beam splitter 48. Incident. On the other hand, the S-polarized beam split by the first polarizing beam splitter 47 is reflected by the reflection mirror 51, enters the second liquid crystal light valve 5b, and is rotated and modulated by 90 degrees by the second liquid crystal light valve 5b. At the same time, the beam is converted into a P-polarized beam, and is incident on the second polarized beam splitter 48. The S-polarized beam emitted from the first liquid crystal light valve 5a and the P-polarized beam emitted from the second liquid crystal light valve 5b are combined with the second polarized beam splitter 4
8 are synthesized.

The synthesized light is projected on a screen by a projection lens 26 as a projection optical system, and an image is displayed in an enlarged scale.

In such a projection display device, the light from the light source is split into two beams, a P-polarized beam and an S-polarized beam, by the first polarizing beam splitter 47. The first liquid crystal light valve 5a is irradiated, and the S-polarized beam is irradiated to the second liquid crystal light valve 5b. Therefore, the luminous flux density of the light applied to the first liquid crystal light valve 5a and the second liquid crystal light valve 5b is:
This is half of the light from the light source, and light degradation of the liquid crystal light valve can be prevented or reduced. Therefore, it is possible to prolong the life of the projection display device.

[Third Embodiment] FIG. 3 is a schematic diagram showing a main part of another example of the projection type display device of the present invention.

This projection type display device is also a kind of single-panel type in which the light modulation device is one set, similarly to the projection type display device shown in FIG. 2, and is a space division single-panel type.

In FIG. 2, reference numeral 30 denotes a light source, and reference numeral 5 denotes a light source.
Reference numerals 3 and 54 denote reflection mirrors, and reference numeral 6 denotes an optical modulation device. The light modulation device 6 is composed of two liquid crystal light valves made of, for example, twisted nematic liquid crystals spatially divided by RGB color filters. Reference numeral 49 denotes a first polarization beam splitter, reference numeral 50 denotes a second polarization beam splitter, and reference numeral 26 denotes a projection lens.

The light source 30 comprises a lamp 31 such as a metal Harald and a reflector 32 for reflecting the light of the lamp 31. The light beam from the light source 30 sequentially passes through the two integrators 58 and 59, and the first polarizing beam splitter 4
9 separates the beam into a P-polarized beam and an S-polarized beam. The P-polarized beam of the separated light is rotated and modulated by 90 degrees by the first liquid crystal light valve 6a, converted into an S-polarized beam, reflected by the reflection mirror 54, and transmitted to the second polarization beam splitter 50. Incident. On the other hand, the S-polarized beam split by the first polarizing beam splitter 49 is reflected by the reflection mirror 53, enters the second liquid crystal light valve 6b, and is rotated by 90 degrees by the second liquid crystal light valve 6b and modulated. At the same time, the beam is converted into a P-polarized beam, and is incident on the second polarized beam splitter 50. The S-polarized beam emitted from the first liquid crystal light valve 6a and the P-polarized beam emitted from the second liquid crystal light valve 6b are combined by the second polarizing beam splitter 50.

The synthesized light is projected on a screen by a projection lens 26, which is a projection optical system, and an image is enlarged and displayed.

In such a projection display device as well, the first liquid crystal light valve 6a and the second liquid crystal light valve 6
The luminous flux density of the light applied to b becomes half that of the light from the light source, which can prevent or mitigate the light deterioration of the liquid crystal light valve, and can prolong the life of the projection display device.

[0055]

As described above, the projection type display device of the present invention has the light modulation device including the two liquid crystal light valves, the first liquid crystal light valve and the second liquid crystal light valve. The luminous flux density of the light applied to the bulb and the second liquid crystal light valve is half that of a light modulator having one liquid crystal light valve, thereby preventing or reducing light deterioration of the liquid crystal light valve of the light modulator. Can be. Therefore, it is possible to prolong the life of the projection display device.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a main part of an example of a projection display device of the present invention.

FIG. 2 is a schematic configuration diagram showing a main part of another example of the projection display device of the present invention.

FIG. 3 is a schematic configuration diagram showing a main part of another example of the projection display device of the present invention.

FIG. 4 is a diagram showing an equivalent circuit such as various elements and wiring provided in a plurality of pixels in a matrix forming an image display area of a liquid crystal light valve used in the projection display device of the present invention.

FIG. 5 is a plan view of the TFT array substrate of the liquid crystal light valve together with the components formed thereon viewed from a counter substrate side.

FIG. 6 is a sectional view taken along line H-H ′ of FIG. 5;

FIG. 7 is a sectional view showing a main part of the liquid crystal light valve.

FIG. 8 is a schematic configuration diagram showing a main part of an example of a conventional projection display device.

[Explanation of symbols]

2, 3, 4, 5, 6 light modulator 2a, 3a, 4a, 5a, 6a first liquid crystal light valve 2b, 3b, 4b, 5b, 6b second liquid crystal light valve 11, 12, 13, 14, 15, 16, 17, 18, 1
9, 35, 36, 37, 51, 52, 53, 54 Reflecting mirror 20 Outgoing lens 21 Light guide means 22, 23, 24 Liquid crystal light modulator 25 Cross dichroic prism 26 Projection lens 30 Light source 31 Lamp 32 Reflector 33, 34 Dichroic Mirror 38 Incident lens 39 Relay lens 41, 43, 45, 47, 49 First polarizing beam splitter 42, 44, 46, 48, 50 Second polarizing beam splitter 55, 56 Condensing lens 57 Color wheel 58, 59 Integrator 103a Scanning Line 106a Data line 109a Pixel electrode 110 TFT array substrate 116, 122 Alignment film 120 Counter substrate 121 Counter electrode 130 Pixel switching TFT 150 Liquid crystal layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G03B 33/12 G03B 33/12 H04N 9/31 H04N 9/31 CF term (Reference) 2H088 EA14 EA15 EA18 HA08 HA13 HA20 HA21 HA24 HA28 MA20 2H089 QA16 TA09 TA12 TA15 TA16 TA18 UA05 2H091 FA05X FA05Z FA10X FA10Z FA14X FA14Z FA26X FA41Z GA13 LA30 MA07 2H099 AA12 BA09 BA17 CA02 DA05 5C060 BA04 BA08 BC07 EA00 HC02 GB02

Claims (3)

[Claims] 1. A projection display device comprising: a light source; a light modulation device that modulates light from the light source; and a projection lens that projects light modulated by the light modulation device, wherein the light modulation device is A first polarizing beam splitter, which comprises two liquid crystal light valves using liquid crystal, and separates light from the light source into a P-polarized beam and an S-polarized beam; and a P-polarized beam separated by the first polarizing beam splitter. A first liquid crystal light valve that modulates the light into an S-polarized light beam, a second liquid crystal light valve that modulates the S-polarized light beam separated by the first polarization beam splitter and converts the light into a P-polarized light beam, A second polarization beam splitter that combines an S-polarized beam emitted from the first liquid crystal light valve with a P-polarized beam emitted from the second liquid crystal light valve. Projection display device characterized by having a motor. 2. A light source, a color separation means for separating light from the light source into a plurality of color lights, a plurality of light modulators for modulating the plurality of color lights separated by the color separation means, and the plurality of lights A projection type display device comprising: a color synthesizing unit that synthesizes the color light modulated by the modulation device; and a projection lens that projects the light synthesized by the color synthesis unit, wherein at least one of the plurality of light modulation devices is provided. The first polarization beam splitter includes two liquid crystal light valves using liquid crystal, and separates light incident on a light modulator including the two liquid crystal light valves into a P polarization beam and an S polarization beam. A first liquid crystal light valve that modulates the p-polarized beam split by the first polarizing beam splitter and converts the p-polarized beam into an s-polarized beam, and splits by the first polarizing beam splitter A second liquid crystal light valve that modulates the obtained S-polarized beam and converts it into a P-polarized beam; and an S-polarized beam emitted from the first liquid crystal light valve and a P-polarized beam emitted from the second liquid crystal light valve. And a second polarizing beam splitter for combining the two. 3. A light modulator for modulating at least the shortest-wavelength color light of the plurality of color lights separated by the color separation means, comprising two liquid crystal light valves using liquid crystals. 3. The projection display device according to 2.