JPH10133277A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal projector small in size and in which contrast is enhanced by using a reflection type liquid crystal panel. SOLUTION: The light beam 800 radiated from a light source 200 is separated into an S wave and a P wave by a polarization separating surface 310. The P wave is thrown away. The S wave is modulated by a reflection type liquid crystal panel for color 400 to be reflected as a P wave. The P wave is made incident on a polarizing plate 500. The S wave being included in the light beam reflected from the reflection type liquid crystal panel for color 400 is eliminated to enhance the contrast of a picture. The P wave passing through the polarizing plate 500 is projected on a screen 700 by a projection lens 600.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector using a reflection type liquid crystal panel.
In particular, it relates to miniaturization of a liquid crystal projector device.

[0002]

2. Description of the Related Art FIG. 19 shows a "color liquid crystal display".
(Display Technology Series, Shunsuke Kobayashi, Industrial Books, P
FIG. 203 is a diagram showing a side view and a perspective view of a liquid crystal projector device as shown in 203). In a conventional liquid crystal projector, an optical unit 163 is built in a cabinet 162. The light emitted from the optical unit 163 is
The light is reflected by the reflection mirror 161 and projected on the screen 120. FIG. 20 is a diagram showing an internal configuration of the optical unit 163 shown in FIG. The internal configuration shown in FIG. 20 is composed of an S-wave and a P-polarized light whose polarization directions are orthogonal to each other as shown in Japanese Patent Application No. 6-298462 (filed on Dec. 1, 1994).
The case where a wave is used is shown. Light generated by the lamp 101 is reflected by the reflector 102 and illuminates the front surface. The light emitted from the reflector 102 is incident on a separation polarizing beam splitter (separation PBS) 103. The light incident on the splitting polarization beam splitter 103 is split into an S wave and a P wave, which are polarized waves whose polarization directions are orthogonal to each other. The P wave passes through the polarizing beam splitter 103 for separation. The S-wave is reflected by the polarization splitting surface of the splitting polarization beam splitter 103. The S-wave output from the separating polarization beam splitter 103 is reflected by the reflection mirror 106 and enters the color liquid crystal panel 108.
The S-wave incident on the color liquid crystal panel 108 is converted into a P-wave, and the polarization beam splitter for synthesis (PBS for synthesis) 1
It is incident on 10. On the other hand, the polarizing beam splitter 1 for separation
The P-wave passing through 03 is reflected by the reflection mirror 107 and enters the luminance liquid crystal panel 109. The P-wave incident on the liquid crystal panel 109 for luminance is converted into an S-wave, and is incident on the polarization beam splitter 110 for synthesis. In the combining polarizing beam splitter 110, the P wave and the S wave are combined,
Output to the projection lens 111. The projection lens 111
The synthesized image is illuminated on the screen. Further, the signal processing circuit 99 receives the R, G, and B color signals and drives the color liquid crystal panel 108 with the color signals (R signal, G signal,
B signal) and a luminance signal (Y signal) for driving the liquid crystal panel 109 for luminance. In the configuration shown in FIG. 20, since the color liquid crystal panel 108 and the luminance liquid crystal panel 109 are transmissive liquid crystal panels that transmit light, a space is required before and after the liquid crystal panel, and the distances L1 and L2 can be reduced. Can not.

FIG. 21 is a configuration diagram of a conventional liquid crystal projector using a reflective liquid crystal panel as disclosed in Japanese Patent Application No. 6-298462 (filed on December 1, 1994). Light 800 output from the light source 200 is split into a P wave and an S wave by a polarization splitting surface 310 of a polarizing beam splitter (PBS) 300. The S wave reflected by the polarization separation surface 310 is modulated by the color reflective liquid crystal panel 400 and reflected as a P wave. On the other hand, the polarization separation surface 3
The P-wave passing through 10 is reflected by the reflective liquid crystal panel 401 for luminance.
And is output as an S wave. The P-wave and the S-wave output from the color reflective liquid crystal panel 400 and the luminance reflective liquid crystal panel 401 are combined by the polarization splitting surface 310 to become light 801. The light 801 is transmitted through the projection lens 600
Is projected on the screen 700.

[0004]

The conventional liquid crystal projector shown in FIG. 20 has a problem that it is difficult to reduce the size of the device because it uses a transmissive liquid crystal panel.

When the reflective liquid crystal panel shown in FIG. 21 is used, there is an advantage that it is easy to reduce the size, but the S-wave and the P-wave are present at any part of the optical path.
There is a drawback that a polarizing plate for increasing the degree of polarization of the S wave or the P wave cannot be arranged in the middle of the optical path, and the contrast of an image cannot be improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to reduce the size and size of a liquid crystal projector. Another object of the present invention is to provide a liquid crystal projector that can improve the contrast of an image using a polarizing plate in a configuration using a reflective liquid crystal panel.

[0007]

A liquid crystal projector according to the present invention has the following elements. (A) a light source that emits light; (b) a polarizing beam splitter that receives light from the light source and separates the incident light into P-wave and S-wave light having different polarization directions; A reflection-type liquid crystal panel that receives one of the P-wave and S-wave light, changes one of the incident light into the other modulated light, and emits the modulated light to the polarization beam splitter; (d) A polarizing plate arranged to transmit the polarized light of the other modulated light output from the polarizing beam splitter; and (e) a projection lens for projecting the light output from the polarizing plate onto a screen.

[0008] The above-mentioned reflection type liquid crystal panel comprises R light, G light, B light,
The liquid crystal projector includes three reflective liquid crystal panels corresponding to light. The liquid crystal projector further includes an R light and a G light between the polarization beam splitter and the three reflection liquid crystal panels. , B light, output to three reflective liquid crystal panels, and R, G, and B light reflected by the three reflective liquid crystal panels are input and combined with a dichroic surface. Features.

The above polarizing beam splitter comprises an R light, a G light,
The reflective liquid crystal panel includes three reflective liquid crystal panels corresponding to R light, G light, and B light; Further comprises, between the light source and the three polarization beam splitters, a separation dichroic surface that separates light from the light source into R light, G light, and B light and outputs the light to the three polarization beam splitters; A combining dichroic surface for combining R light, G light, and B light output from the three polarizing beam splitters and outputting the combined light to the polarizing plate is provided between the three polarizing beam splitters and the polarizing plate. I do.

The separating dichroic surface and the synthesizing dichroic surface are arranged in the same plane, and the light from the light source and the light to the polarizing plate travel in opposite directions.

The polarizing beam splitter includes a first polarizing beam splitter that outputs one of the P wave and the S wave, and a second polarizing beam splitter that outputs the other light of the P wave and the S wave. Wherein the reflection type liquid crystal panel receives the light output from the first polarization beam splitter, and receives the light output from the second polarization beam splitter. A first polarizer that has a second reflective liquid crystal panel and transmits the polarized light of light output from the first reflective liquid crystal panel;
A second polarizer that transmits polarized light of light output from the second reflective liquid crystal panel; the liquid crystal projector further includes a second polarizer that transmits light output from the first polarizer and a second polarizer. A polarizing beam splitter for combining the lights output from the polarizing plates is provided.

The first polarizing beam splitter has an R
The first reflection type liquid crystal panel includes three polarization beam splitters corresponding to light, G light, and B light.
Equipped with three reflective liquid crystal panels corresponding to G light and B light,
The liquid crystal projector further transmits R light, G light between the light source and the three polarizing beam splitters.
A separating dichroic surface for separating the light into B light and outputting the light to three polarizing beam splitters; R output from the three polarizing beam splitters between the three polarizing beam splitters and the first polarizing plate; The image display device further includes a combining dichroic surface that combines the light, the G light, and the B light and outputs the combined light to the first polarizing plate.

The dichroic surface is composed of R light, G light, B light
A first dichroic surface that reflects one light out of the light, and a second dichroic surface that reflects the other one of the R, G, and B light; A second dichroic surface is crossed.

The dichroic surface is composed of R light, G light, B light
Among the light, a first dichroic surface that transmits one light, a second dichroic surface that transmits another light out of R light, G light, and B light, and the first dichroic surface. It is characterized by comprising a first deformed prism that includes therein, and a second deformable prism that includes the second dichroic surface.

The liquid crystal projector device according to the present invention comprises:
It has the following elements. (A) a light source that emits light; (b) a polarizing beam splitter that receives light from the light source and separates the incident light into P-wave and S-wave light having different polarization directions; Λ / 4 plate for inputting one of the P-wave and S-wave light, and (d) the light output from the λ / 4 plate is incident, and the incident light is modulated to produce the λ / (E) the above-mentioned λ
A projection lens that projects the modulated light output from the polarizing beam splitter through a / 4 plate onto a screen.

The λ / 4 plate is used for inputting an S wave to the first λ
And a second λ / 4 plate for inputting a P-wave, wherein the reflective liquid crystal panel is a first reflective liquid crystal for inputting and outputting light to and from the first λ / 4 plate. And a second reflective liquid crystal panel that inputs and outputs light to and from a second λ / 4 plate.

The above-mentioned reflection type liquid crystal panel includes R light, G light, B light,
The liquid crystal projector includes three reflective liquid crystal panels corresponding to light. The liquid crystal projector further includes an R light and a G light between the polarization beam splitter and the three reflection liquid crystal panels. , B light, output to three reflective liquid crystal panels, and R, G, and B light reflected by the three reflective liquid crystal panels are input and combined with a dichroic surface. Features.

The liquid crystal projector device according to the present invention comprises:
It has the following elements. (A) a light source that emits light, (b) a polarization beam splitter that receives light from the light source and separates the incident light into P-wave and S-wave light having different polarization directions, (c) R light, G light, Three reflective liquid crystal panels corresponding to the B light, (d) one of the P-wave and S-wave lights separated by the polarizing beam splitter is incident, and R light and G light are converted from the incident light. , B light and the combined light of the other two lights are separated, and the separated one light is output to the reflection type liquid crystal panel corresponding to the separated light. A first deformed prism that inputs and combines one of the light and the B light and the combined light of the other two lights and outputs the combined light to the polarization beam splitter; (e) the first deformed prism The combined light separated by the prism is input, the other two lights combined are separated, and the two separated lights are separated. Is output to the reflective liquid crystal panel corresponding to the light, and two lights reflected from the reflective liquid crystal panel are input, combined and output to the first deformed prism, (f) A) a projection lens that inputs the light combined by the first deformed prism via the polarizing beam splitter and projects the light on a screen.

The first and second deformed prisms are each provided with a dichroic surface such that the incident angle of the light is 15 degrees or less.

The first and second deformed prisms are characterized in that the incident light is totally reflected to form an optical path.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a diagram showing an example of the liquid crystal projector device of the present invention. Light 800 emitted from the light source 200 enters the PBS 300. The polarization separation surface 310 of the PBS 300 separates the light 800 into a P wave and an S wave. The P wave that has passed through the polarization separation surface 310 is not used and is discarded as it is. The S wave reflected by the polarization splitting surface 310 enters the reflective liquid crystal panel 400 for color. The S wave incident on the reflective liquid crystal panel 400 for color is modulated,
Reflected as waves. Color reflective LCD panel 400
The P-wave reflected from the light passes through the polarization splitting surface 310. Then, a polarizing plate 500 arranged to pass the P wave
Pass through. The P wave that has passed through the polarizing plate 500 is projected on the screen 700 by the projection lens 600.

In the configuration shown in FIG. 1, the P wave occupying half of the light is discarded and not used. However, when the number of pixels is large, the aperture ratio of the color reflective liquid crystal panel 400 (effective display area with respect to the pixel unit area of the liquid crystal panel) is about twice that of the transmissive liquid crystal panel. I have.
For example, if the aperture ratio of the transmissive liquid crystal panel is 45%, the aperture ratio of the reflective liquid crystal panel is about 90%.
Therefore, even when the P-wave is discarded and only the S-wave is used as in the configuration of FIG. 1, the brightness is not significantly deteriorated as compared with the case of the transmission type liquid crystal panel. The polarizing plate 500 transmits the P wave reflected from the reflective liquid crystal panel 400 for color. In other words, the polarizing plate 50
0 is for blocking the S wave. Polarization separation surface 31
0 is not ideal, the polarization separation surface 31
The S wave separated by 0 is incident on the reflection type liquid crystal panel 400 for color while containing the P wave. Therefore, the P wave reflected by the color reflective liquid crystal panel 400 includes the S wave. If the P wave containing the S wave is projected by the projection lens 600 without passing through the polarizing plate 500, the contrast of the image is deteriorated. By blocking the S-wave included in the P-wave by the polarizing plate 500, only the P-wave can be passed and the contrast of the image can be improved.

As described above, in this embodiment, only one of the P wave and the S wave is used, so that even when a reflective liquid crystal panel is used, a polarizing plate can be arranged. Image contrast can be improved.

Embodiment 2 FIG. FIG. 2 is a diagram showing another configuration of the liquid crystal projector device of the present invention. The difference from FIG. 1 is that the reflective liquid crystal panel modulates light of three colors, a red (R) color reflective liquid crystal panel 400R, a green (G) color reflective liquid crystal panel 400G, and a blue (B). ) Is a reflective liquid crystal panel 400B for color. S separated by the polarization separation surface 310
A dichroic surface 351 and a dichroic surface 352 are provided to further separate the waves into three colors of R, G, and B. The dichroic surface 351 and the dichroic surface 352 are orthogonal to each other, and are dichroic surfaces for separating and synthesizing the S wave into three colors and synthesizing the P wave.

As described above, even in the three-panel type liquid crystal projector as shown in FIG. 2, an image with improved contrast can be generated by using the reflection type liquid crystal panel and the polarizing plate 500.

Embodiment 3 FIG. FIG. 3 is a diagram showing another configuration of the liquid crystal projector device of the present invention. FIG. 3 is FIG.
The difference from the above is the arrangement positions of the dichroic surface 351 and the dichroic surface 352 and the arrangement positions of the reflective liquid crystal panel 400R for color, the reflective liquid crystal panel 400B for color, and the reflective liquid crystal panel 400G for color. The arrangement angles θ1 and θ2 of the dichroic surface 351 and the dichroic surface 352 are each 45 degrees or less.
S wave is vertically incident. Further, the reflected P-waves are vertically incident as much as possible. In this way, by making the P wave and the S wave incident as perpendicularly as possible, the dichroic surface 35
The difference between the characteristics of P-wave and S-wave of 1 and the dichroic surface 352 is suppressed as much as possible. FIG. 4 is a diagram illustrating the red reflection characteristic of the dichroic surface 351. FIG. 5 is a diagram illustrating a blue reflection characteristic of the dichroic surface 352. FIG. 6 shows the dichroic surface 351 and the dichroic surface 35.
2 is a diagram showing green transmission characteristics according to No. 2. FIG. As shown in FIGS. 4 to 6, the dichroic surface 351 and the dichroic surface 352 have different reflection characteristics and different transmission characteristics for the P wave and the S wave, and the wavelengths are shifted by 20 to 30 nm. As shown in FIG. 3, the dichroic surface 351 is used to minimize the shift of 20 to 30 nm.
And the arrangement angles θ1 and θ2 of the dichroic surface 352 are set to 45
The P-wave and the S-wave are made to be perpendicularly incident at a temperature equal to or less than the degree.

Further, in FIG.
The point is that the distance between the three reflective liquid crystal panels and the light source 200 and the distance between the three reflective liquid crystal panels and the projection lens 600 are equal. That is, in FIG. 3, the distances L3 are the same length. The distances L4 are the same length.
By making the optical path lengths equal, the quality of the image to be generated is improved.

Embodiment 4 FIG. 7 is a diagram showing another configuration of the liquid crystal projector device of the present invention. In FIG. 7, a polarizing plate 501 is a polarizing plate that transmits an S wave and blocks a P wave. The feature of the configuration shown in FIG. 7 is that the dichroic surface is divided for separation and synthesis. Dichroic surface 351 and dichroic surface 352
Is a dichroic surface for separation. On the other hand, the dichroic surface 353 and the dichroic surface 354 are dichroic surfaces for synthesis. As shown in FIGS. 4 to 6,
The dichroic surface has different characteristics depending on the P wave and the S wave. Therefore, the dichroic surface 351 and the dichroic surface 352 that are suitable for the characteristics of the P wave are used. Further, the dichroic surface 353 and the dichroic surface 354 that are suitable for the characteristics of the S wave are used.

As described above, by separating the dichroic surface for separation and the dichroic surface for synthesis, separation and synthesis suitable for the characteristics of the P wave and the S wave can be performed. In addition, each PBS3
Polarizers may be placed at the outlets of 01, 302, and 303, respectively.

Embodiment 5 FIG. 8 is a diagram showing another configuration of the liquid crystal projector device of the present invention. 8, the characteristic point is that the light output from the light source 200 travels in the direction of arrow A, and the light projected on the screen 700 travels in the direction of arrow B. Arrows A and B indicate opposite directions. As described above, by making the light emitted from the light source 200 and the light projected on the screen 700 in opposite directions, the configuration of the apparatus can be further downsized.

Embodiment 6 FIG. FIG. 9 is a central sectional view of the liquid crystal projector of the present invention. FIG. 10 is a plan view thereof. FIG. 11 is a partial perspective view thereof. A feature of the configurations shown in FIGS. 9 to 11 is that a three-panel reflective liquid crystal panel is used. Another difference is that a two-story dichroic surface is used. The dichroic surface 351 and the dichroic surface 352 are separation dichroic surfaces adapted to light polarized in the surfaces.
The dichroic surface 353 and the dichroic surface 354 are
This is a dichroic surface for synthesis adapted to light polarized in that plane. In the lower stage, light 800 is divided into R, G, B light by dichroic surface 351 and dichroic surface 352.
Are separated into three colors. The separated light is reflected by a reflecting mirror 901,
The light is reflected upward by 902 and 903. In the upper stage, R, G, and B are separated into P waves and S waves by the polarization separation surfaces 311, 312, and 313 of the PBSs 301, 302, and 303. The separated S wave is discarded. The P wave is modulated by the color reflective liquid crystal panel 400R, the color reflective liquid crystal panel 400G, and the color reflective liquid crystal panel 400B, and is reflected as an S wave. The reflected S wave is further reflected by the polarization splitting surfaces 311, 312, and 313, converted into a P wave by the λ / 2 plate 560, and combined by the dichroic surface 353 and the dichroic surface 354. Dichroic surface 35 by λ / 2 plate 560
Since the light is converted into the in-plane polarized light of 3 and 354, the same condition as that of the polarized light of the incident light to the dichroic surfaces for separation 351 and 352 is obtained, and the color characteristics of the three colors of R, G and B are uniform. Is improved. The synthesized light is a polarizing plate 501.
Is input to The polarizing plate 501 blocks the S wave and passes the P wave. In this way, the contrast of the image is improved, and the image is
Projected on

FIG. 12 is a diagram showing another configuration of the liquid crystal projector of the present invention. FIG. 12 differs from FIG. 11 in that a reflective liquid crystal panel is provided in the lower stage. FIG.
Although not shown, the reflective liquid crystal panel 400R for color and the reflective liquid crystal panel 400B for color as shown in FIG.
03, a reflecting mirror 901, and a reflecting mirror 903,
3 shows a three-panel type liquid crystal projector device.

Embodiment 7 FIG. 13 is a diagram showing another configuration of the liquid crystal projector device of the present invention. In FIG. 13, a characteristic point is that in a configuration using a reflective liquid crystal panel, a polarizing plate is disposed even when both S waves and P waves are used. The S-wave separated by the polarization splitting surface 310 of the PBS 300 enters the color reflective liquid crystal panel 400 and reflects the P-wave. P wave is polarizing plate 5
00 and is reflected by the reflecting mirror 900. on the other hand,
The P wave that has passed through the polarization splitting surface 310 is
And enters the reflective liquid crystal panel 401 for luminance.
The reflective liquid crystal panel 401 for luminance reflects S waves. The polarization splitting surface 311 reflects the S wave and makes the S wave incident on the polarizing plate 501. The S-wave that has passed through the polarizing plate 501 is combined with the P-wave reflected by the reflection mirror 900 by the polarization splitting surface 312. The combined light 801 is projected on the screen 700 by the projection lens 600.

According to the above configuration, since both the P wave and the S wave are used, the brightness is improved. Furthermore, P
Since the polarizing plate is provided for the optical path of the wave and the S wave, an image with improved contrast can be obtained.

FIG. 14 is a diagram showing another configuration of the liquid crystal projector of the present invention. FIG. 14 differs from FIG. 13 in that the reflection type liquid crystal panel for color is of a three-plate type, and the whole is of a four-plate type. Although not shown in FIG. 14, the color reflective liquid crystal panel 400R, the color reflective liquid crystal panels 400B and P as shown in FIG.
BS301, PBS303, reflector 901 and reflector 9
03 is provided. The dichroic surface 351 and the dichroic surface 352 are dichroic surfaces for separation. Dichroic surface 353, dichroic surface 354
Is a dichroic surface for synthesis. The λ / 2 plate (half wavelength plate) 560 changes the S wave to the P wave. Also, λ
The / 2 plate 561 changes the P wave to the S wave. λ / 2 plate 56
The 0 and λ / 2 plates 561 are for making the light projected from the projection lens 600 in the direction of arrow B. If the light projected from the projection lens 600 is in the direction of arrow C, the λ / 2 plate 560 and λ / 2 plate 561 need to be removed.

Also in the case shown in FIG. 14, there are optical paths of only P-waves and only S-waves, and the contrast of an image can be improved by disposing the polarizing plate 500 and the polarizing plate 501 in the respective optical paths.

Embodiment 8 FIG. FIG. 15 is a diagram showing another configuration of the liquid crystal projector device of the present invention. In FIG. 15, the feature is that the first deformed prism 570 and the second deformed prism 571 are used. First
The planar shape of the deformed prism 570 is triangular. Second
The planar shape of the deformed prism 571 is a parallelogram. The dichroic surface 355 is a dichroic surface that transmits red light. The dichroic surface 356 is a dichroic surface that passes green. The S wave reflected by the polarization splitting surface 310 of the PBS 300 is totally reflected by the surface of the first deformed prism 570. The incident angle θ3 of the S wave to the dichroic surface 355 is 15 degrees or less, and the difference in the characteristics of the P wave and the S wave described in FIGS. 4 to 6 is suppressed as much as possible. Dichroic surface 35
The S wave that passed through 5 is a color reflective liquid crystal panel 400R.
Is reflected as a P wave. The incident angle of the P-wave reflected from the color reflective liquid crystal panel 400R is also 15 degrees or less, so that the difference between the S-wave transmission characteristics and the P-wave transmission characteristics is suppressed. It is desirable that the incident angle θ3 be as small as possible. S reflected by dichroic surface 355
The wave is refracted by the surfaces of the first deformed prism 570 and the second deformed prism 571, and the dichroic surface 35
6 at an incident angle θ4. The angle of incidence θ4 is desirably as small as possible at 15 degrees or less. By reducing the incident angle θ4, it is possible to minimize the difference in the pass characteristics of the P wave and the S wave. Dichroic surface 356
Is modulated by the color reflective liquid crystal panel 400G and reflected as a P wave. The S wave reflected by the dichroic surface 356 is totally reflected on the surface of the second deformed prism 571, and is input to the color reflective liquid crystal panel 400B. Reflective LCD panel for color 4
00B reflects the P wave. P wave is the second deformed prism 5
The light is totally reflected on the surface 71 and is combined with the P-wave from the color reflective liquid crystal panel 400G on the dichroic surface 356. Further, the P-wave from the reflective liquid crystal panel 400R for color is combined on the dichroic surface 355 and the PBS 30
Reflected to zero. In the configuration shown in FIG. 15, a first deformed prism 570 having a dichroic surface 355 and a second deformed prism 571 having a dichroic surface 356 are arranged as shown, and three reflective liquid crystal panels are arranged. By doing so, it is possible to provide a compact liquid crystal projector using a reflective liquid crystal panel. Further, by using the polarizing plate 500, an image with improved contrast can be provided.

FIG. 16 is obtained by adding a reflective liquid crystal panel 401 for luminance to FIG. In the case shown in FIG. 16, a bright image can be provided by using both the S wave and the P wave. Note that, in the case shown in FIG. 16, since a P wave and an S wave exist in all of the optical paths, a polarizing plate cannot be provided.

Embodiment 9 FIG. 17 is a diagram showing another configuration of the liquid crystal projector device of the present invention. A feature of the configuration shown in FIG. 17 is that a polymer dispersion type reflective liquid crystal panel (reflective PDLC) 450 is used. Light 800 emitted from the light source 200 is separated into a P wave and an S wave by the polarization splitting surface 310. The S wave reflected by the polarization separation surface 310 is converted into circularly polarized light by a λ / 4 plate (a quarter wavelength plate) 550. The polymer-dispersed reflective liquid crystal panel 450 modulates and reflects this circularly polarized light. The reflected circularly polarized light is polarized into a P wave by the λ / 4 plate 550. The P wave output from the λ / 4 plate 550 passes through the polarization separation surface 310 and is projected on the screen 700 by the projection lens 600. Even in the case of using the polymer dispersion type reflection type liquid crystal panel 450, the polarizing plate 500 can be provided to improve image contrast.

As described above, it is possible to provide a very small liquid crystal projector using the polymer dispersion type reflection liquid crystal panel 450 and the λ / 4 plate 550.

FIG. 18 is a diagram showing an improved example of FIG. A characteristic feature of FIG. 18 is that three polymer-dispersion reflective liquid crystal panels 450R, 450G, and 450B are used as color reflective liquid crystal panels. Another difference is that a polymer-dispersed reflective liquid crystal panel 451 is used as a reflective liquid crystal panel for luminance. The λ / 4 plate 550 is
S-wave is input and circularly polarized light is output to each polymer-dispersed reflective liquid crystal panel. The λ / 4 plate 550 inputs circularly polarized light from each polymer dispersion type reflection type liquid crystal panel and outputs a P wave. The λ / 4 plate 551 receives the P wave and converts the circularly polarized light into a polymer dispersed reflective liquid crystal panel 451.
Output to The λ / 4 plate 551 receives circularly polarized light from the polymer dispersion type reflection type liquid crystal panel 451 and
Output a wave.

According to the configuration shown in FIG. 18, it is possible to provide a small-sized liquid crystal projector using a four-panel polymer-dispersed reflective liquid crystal panel.

[0043]

As described above, according to the present invention, since a reflective liquid crystal panel is used, a small-sized liquid crystal projector can be provided. Further, since the polarizing plate is used, a liquid crystal projector device with improved contrast can be provided.

According to the present invention, in a three-panel type liquid crystal projector, a small-sized liquid crystal projector using a reflection type liquid crystal panel and having improved contrast can be obtained.

Further, according to the present invention, in a liquid crystal projector having a two-stage structure, a small and
A liquid crystal projector device with improved contrast can be obtained.

Further, according to the present invention, a smaller liquid crystal projector can be obtained by causing the light from the light source and the light to the polarizing plate to travel in opposite directions.

Further, according to the present invention, it is possible to obtain a small-sized liquid crystal projector device having improved contrast utilizing both P-waves and S-waves.

According to the present invention, in a four-panel type liquid crystal projector, a small-sized liquid crystal projector with improved contrast can be obtained.

Further, according to the present invention, it is possible to obtain a small-sized liquid crystal projector using crossed dichroic surfaces.

Further, according to the present invention, a small-sized liquid crystal projector using a reflective liquid crystal panel can be obtained by using a deformed prism including a dichroic surface.

Further, according to the present invention, a small-sized liquid crystal projector can be obtained by using a polymer-dispersed reflective liquid crystal panel.

Further, according to the present invention, it is possible to obtain a liquid crystal projector using a polymer dispersion type reflection type liquid crystal panel utilizing S and P waves.

Further, according to the present invention, it is possible to obtain a liquid crystal projector using at least a three-plate type polymer dispersion type reflection type liquid crystal panel.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a liquid crystal projector device of the present invention.

FIG. 2 is a diagram illustrating a configuration of a liquid crystal projector device of the present invention.

FIG. 3 is a diagram illustrating a configuration of a liquid crystal projector device of the present invention.

FIG. 4 is a characteristic diagram of a dichroic surface according to the present invention.

FIG. 5 is a characteristic diagram of a dichroic surface according to the present invention.

FIG. 6 is a characteristic diagram of a dichroic surface according to the present invention.

FIG. 7 is a diagram showing a configuration of a liquid crystal projector device of the present invention.

FIG. 8 is a diagram showing a configuration of a liquid crystal projector device of the present invention.

FIG. 9 is a central sectional view of the liquid crystal projector of the present invention.

FIG. 10 is a plan view of the liquid crystal projector device of the present invention.

FIG. 11 is a partial perspective view of the liquid crystal projector of the present invention.

FIG. 12 is a diagram showing a configuration of a liquid crystal projector device of the present invention.

FIG. 13 is a diagram illustrating a configuration of a liquid crystal projector device of the present invention.

FIG. 14 is a diagram illustrating a configuration of a liquid crystal projector device of the present invention.

FIG. 15 is a diagram showing a configuration of a liquid crystal projector device of the present invention.

FIG. 16 is a diagram showing a configuration of a liquid crystal projector device of the present invention.

FIG. 17 is a diagram showing a configuration of a liquid crystal projector using a polymer dispersion type reflection type liquid crystal panel of the present invention.

FIG. 18 is a diagram showing a configuration of a liquid crystal projector device using a polymer dispersion type reflection type liquid crystal panel of the present invention.

FIG. 19 is a side view and a perspective view of a conventional liquid crystal projector device.

FIG. 20 is a configuration diagram of a conventional optical unit.

FIG. 21 is a configuration diagram using a conventional reflective liquid crystal panel.

[Explanation of symbols]

200 light source, 300-304 polarized light separating surface, 351-
356 dichroic surface, 400 color reflective liquid crystal panel, 401 luminance reflective liquid crystal panel, 450
Polymer-dispersed reflective liquid crystal panel, 500, 501
Polarizing plate, 550,551 λ / 4 plate, 560,561
λ / 2 plate, 570,571 deformed prism, 600 projection lens, 700 screen, 800,801 light,
900-903 reflector.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G02F 1/1335 520 G02F 1/1335 520 G03B 33/12 G03B 33/12 (72) Inventor Teruo Miyamoto 2-chome Marunouchi, Chiyoda-ku, Tokyo 2-3 No.3 Mitsubishi Electric Co., Ltd. (72) Yasuhito Nai 2-3-2 Marunouchi, Chiyoda-ku, Tokyo 2-3-3 Mitsubishi Electric Co., Ltd. (72) Toshimasa Tomoda Marunouchi, Chiyoda-ku, Tokyo 2-3-2, Mitsui Electric Co., Ltd. (72) Inventor Eiichi Tsuide 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Haruhiko Nagai Marunouchi, Chiyoda-ku, Tokyo 2-3-2, Mitsui Electric Co., Ltd. (72) Inventor Tohru Tajime 2-3-2, Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Toshi Ito Akira 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (14)

[Claims] 1. A liquid crystal projector having the following elements: (a) a light source that emits light; and (b) light from a light source is incident and splits the incident light into P-wave and S-wave light having different polarization directions. A polarizing beam splitter, (c) one of the P-wave and S-wave lights separated by the polarizing beam splitter is made incident, and one of the incident light is changed to the other modulated light to produce the polarized light. A reflection-type liquid crystal panel that emits light to a beam splitter; (d) a polarizing plate that is arranged to transmit the polarized light of the other modulated light output from the polarizing beam splitter; and (e) a polarizing plate that is output from the polarizing plate. A projection lens that projects the reflected light onto the screen. 2. The reflection type liquid crystal panel according to claim 1, wherein the reflection type liquid crystal panel includes an R light, a G light,
The liquid crystal projector includes three reflective liquid crystal panels corresponding to the B light, and the liquid crystal projector further includes an R light and a G light between the polarized beam splitter and the three reflective liquid crystal panels. It has a dichroic surface that separates the light into B light, outputs it to three reflective liquid crystal panels, and inputs and combines the R, G, and B light reflected by the three reflective liquid crystal panels. Claim 1 characterized by the following:
The liquid crystal projector device as described in the above. 3. The polarization beam splitter according to claim 1, wherein the R beam, the G beam,
The reflective liquid crystal panel includes three reflective liquid crystal panels corresponding to R light, G light, and B light; Further comprises, between the light source and the three polarization beam splitters, a separation dichroic surface that separates light from the light source into R light, G light, and B light and outputs the light to the three polarization beam splitters; A combining dichroic surface for combining R light, G light, and B light output from the three polarizing beam splitters and outputting the combined light to the polarizing plate is provided between the three polarizing beam splitters and the polarizing plate. The liquid crystal projector device according to claim 1. 4. The dichroic surface for separation and the dichroic surface for synthesis are arranged in the same plane, and allow light from the light source and light to the polarizing plate to travel in opposite directions. 3. The liquid crystal projector device according to 3. 5. The polarization beam splitter according to claim 1, wherein the polarization beam splitter comprises a P wave and an S wave.
A first polarizing beam splitter that outputs one of the waves, and a second polarizing beam splitter that outputs the other of the P and S waves. A first reflection type liquid crystal panel for inputting light output from the first polarization beam splitter, and a second reflection type liquid crystal panel for inputting light output from the second polarization beam splitter; The plate includes a first polarizing plate that transmits polarized light of light output from the first reflective liquid crystal panel, and a second polarized light that transmits polarized light of light output from the second reflective liquid crystal panel. And the liquid crystal projector device further includes a combining polarizing beam splitter that combines light output from the first polarizing plate and light output from the second polarizing plate. The liquid crystal projector device according to claim 1, 6. The first polarization beam splitter according to claim 1, wherein
The first reflection type liquid crystal panel includes three polarization beam splitters corresponding to light, G light, and B light.
Equipped with three reflective liquid crystal panels corresponding to G light and B light,
The liquid crystal projector further transmits R light, G light between the light source and the three polarizing beam splitters.
A separating dichroic surface for separating the light into B light and outputting the light to three polarizing beam splitters; R output from the three polarizing beam splitters between the three polarizing beam splitters and the first polarizing plate; 6. The liquid crystal projector according to claim 5, further comprising a combining dichroic surface for combining light, G light, and B light and outputting the combined light to the first polarizing plate. 7. The dichroic surface according to claim 7, wherein the R light, the G light,
A first dichroic surface that reflects one light of the B light, and a second dichroic surface that reflects another light of the R, G, and B light; a first dichroic surface 7. The liquid crystal projector according to claim 2, wherein the second dichroic surface intersects with the second dichroic surface. 8. The dichroic surface according to claim 1, wherein the dichroic surface has an
Among the B light, a first dichroic surface that transmits one light, among R light, G light, and B light, a second dichroic surface that transmits another light, and the first dichroic surface 7. The liquid crystal projector device according to claim 2, further comprising: a first deformable prism including the first dichroic surface; and a second deformable prism including the second dichroic surface. 9. A liquid crystal projector having the following elements: (a) a light source that emits light; and (b) light from a light source is incident and splits the incident light into P-wave and S-wave light having different polarization directions. A polarizing beam splitter, (c) a λ / 4 plate for inputting one of the P-wave and S-wave lights separated by the polarizing beam splitter, and (d) a light output from the λ / 4 plate. A reflection type liquid crystal panel of a polymer dispersion type which is incident and modulates the incident light and outputs the modulated light to the λ / 4 plate; and (e) modulates the modulated light output from the polarizing beam splitter through the λ / 4 plate. Projection lens that projects on the screen. 10. The λ / 4 plate is a first λ / 4 plate for inputting an S wave.
Λ / 4 plate and a second λ / 4 plate for inputting a P-wave, and the reflection type liquid crystal panel has a first reflection type for inputting and outputting light to and from the first λ / 4 plate. 10. The liquid crystal projector device according to claim 9, further comprising: a liquid crystal panel of a type, and a second reflective liquid crystal panel for inputting and outputting light to and from a second λ / 4 plate. 11. The reflection type liquid crystal panel according to claim 1, wherein the reflection type liquid crystal panel comprises an R light, a G light,
The liquid crystal projector device further comprises three reflective liquid crystal panels corresponding to light and B light, and the liquid crystal projector further transmits R light from the polarizing beam splitter between the polarizing beam splitter and the three reflective liquid crystal panels. , G light, and B light are separated and output to three reflective liquid crystal panels, and R light, G light, and B light reflected by the three reflective liquid crystal panels are input and combined with a dichroic surface. The liquid crystal projector device according to claim 9, wherein: 12. A liquid crystal projector device having the following elements: (a) a light source that emits light; (b) light from a light source is incident and splits the incident light into P-wave and S-wave light having different polarization directions. Polarizing beam splitter, (c) R light, G light, B
(D) one of the P-wave and S-wave lights separated by the polarization beam splitter is incident, and R light, G light, B
Any one of the lights is separated from the combined light of the other two lights, and the separated one light is output to the reflective liquid crystal panel corresponding to the separated light. A first deformed prism that inputs and combines any one of the B light and the combined light of the other two lights, and outputs the combined light to the polarization beam splitter; (e) the first deformed prism The separated combined light is input, the other two combined lights are separated, and the two separated lights are output to the reflection type liquid crystal panels corresponding to the lights, respectively, and reflected from the reflection type liquid crystal panel. A second deformed prism that inputs and combines the two lights and outputs the light to the first deformed prism; and (f) inputs the light combined by the first deformed prism via the polarizing beam splitter. , Projection lens to project on the screen. 13. The liquid crystal projector device according to claim 12, wherein each of the first and second deformed prisms has a dichroic surface such that the incident angle of the light is 15 degrees or less. 14. The liquid crystal projector according to claim 13, wherein the first and second deformed prisms totally reflect incident light to form an optical path.