JPH0457045A - Liquid crystal projector - Google Patents

Abstract

PURPOSE:To fundamentally eliminate the loss of light caused by a front polarizing plate, to set the utilization rate of light to two folds, and to obtain a bright image by separating the light of a light source into red, green and blue, and also, separating each color into an S polarization wave and a P polarization wave, and providing six pieces of light valves corresponding to each color and each polarization wave. CONSTITUTION:Light emitted from a light source 29 is separated into blue, red and green in a blue reflecting dichroic mirror 30 and a red reflecting dichroic mirror 31. As for a blue light, an S polarization component is reflected and a P polarization component transmits through in a blue beam splitter 32, therefore, the S polarization component of the blue light, and the P polarization component reach an S polarization blue light value 42 and a P polarization blue light valve 41, respectively. In the same way, an S polarization component of a red light and a P polarization component, and an S polarization component of a green light and a P polarization component reach the respective light valves 44, 43, 45 and 46. Optical images formed by each light valve are synthesized at every color by synthesizing prisms 47, 48 and 49, and also, synthesized by a red/green synthesizing prism 50 and a red/green/blue synthesizing prism 51, and projected by a projection lens 52. In such a way, since both the S polarization wave and the P polarization wave are utilized effectively, a bright image is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the structure of a liquid crystal projector.

[Conventional technology]

The configuration of a conventional liquid crystal projector separates light from a light source into red, green, and blue light, and guides the light to a light valve corresponding to each color. The optical images of each color after passing through the light bulb are combined and projected by a projection lens.

FIG. 2 is a block diagram of a conventional liquid crystal projector. In FIG. 2, 17 is a light source, 18 is a blue reflecting dichroic mirror, and 19 is a red reflecting dichroic mirror. 20.
21 is a reflecting mirror; 22 and 23 are composite mirrors; 24 is a blue light valve; 25 is a green light valve; 26 is a red light valve; 27 is a projection lens; and 2 is a video signal processing circuit.

The light emitted from the light source 17 is reflected by the blue reflective dichroic mirror 1
8. The light is separated into colors by a red reflective dichroic mirror 19 and reaches a light valve corresponding to each color. In FIG. 2, 24a is a front polarizing plate, 24b is a liquid crystal panel, 24
c is a rear polarizing plate, and the light valves are all 3 above.
It is made up of points. First, install the front polarizing plate 2 of the light bulb.
At 4a, only the S polarized light wave (or the P polarized light wave) is transmitted.

Next, the S-polarized light wave is optically rotated in the liquid crystal panel 24b, and the degree of optical rotation at this time is determined by the voltage applied to the liquid crystal panel 24b. Further, among the light emitted from the liquid crystal panel 24b, only the S-polarized light wave (or the P-polarized light wave) is transmitted through the rear polarizing plate 24c.

In the liquid crystal panel 24b, when no voltage is applied, the light is 90"
When a voltage is applied, the light does not rotate. Therefore, the liquid crystal panel 24b
When no voltage is applied to , the light does not pass through the rear polarizing plate 24C,
Transmits when voltage is applied. A light valve is divided into tiny pixels, and since the voltage applied to each pixel can be changed, the transmittance can be controlled individually. As a result, an optical image can be formed depending on the intensity of light. The video signal processing circuit 28 outputs signals (voltages) corresponding to red, green, and blue from a composite video signal such as the NTSC system, and outputs signals (voltages) corresponding to red, green, and blue, and outputs signals (voltages) corresponding to red, green, and blue, and
added to. The optical image formed by each light valve is
The images are combined by the combining mirrors 22 and 23 and projected by the projection lens 27.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, only one of the P-polarized light wave and the S-polarized light wave can be used.

Therefore, the light utilization rate is less than 50%, resulting in a dark projected image considering the amount of light from the light source, and the unusable light turns into heat in the light valve, so a cooling device is required. have

Furthermore, the conventional technology has a problem in that it is not possible to realize a flat surface.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a IIk crystal projector that can obtain bright images with high light utilization. Still another object is to provide a liquid crystal projector that can obtain stereoscopic images.

[Means to solve the problem]

The liquid crystal projector of the present invention includes a video signal processing circuit that drives a light valve corresponding to S polarized light waves, a video signal processing circuit that drives a light valve compatible with P polarized light waves,
A color separation filter that separates the light from the light source into red, green, and blue;
A beam splitter that separates each color into an S-polarized light wave and a P-polarized light wave, six light valves corresponding to each color and each polarized light, a combining means that combines images, and a projection lens that projects the combined image. It is characterized by having

[Effect]

According to the above configuration of the present invention, the light from the light source is separated into red, green, and blue, and each color is roughly separated into S-polarized light waves and P-polarized light waves, and six lights corresponding to each color and each polarized light are provided. Since it has a light bulb, there is basically no loss of light in the front polarizing plate of each light valve, and the light utilization rate is doubled. Therefore, a bright image can be obtained. By inputting a video signal from a position corresponding to the right eye of the human eye to one side of the video signal processing circuit and a video signal from a position corresponding to the left eye of the human eye to the other side, projection using S-polarized light waves can be performed. An image corresponding to the right eye is obtained, and an image corresponding to the left eye is obtained as an image projected by the P-polarized light wave. A stereoscopic image can be obtained by viewing this projected image with glasses that have a polarizing plate that transmits S-polarized light waves at a position corresponding to the right eye and a polarizing plate that transmits P-polarized light waves at a position corresponding to the left eye.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the liquid crystal projector of the present invention, in which 1 is a light source, 2 is a color separation filter, and 3 is a blue beam splitter 4 that separates blue light into S-polarized light and P-polarized light. is a red beam subsoter that separates red light into S-polarized light and P-polarized light; 5 is a green beam splitter that separates green light into S-polarized light and P-polarized light; 6 is a light bulb; 7 and 10 are red 7. Light valves, 8 and 11 are green light valves, 12 is a combining means for combining optical images of each light valve, 13 is a projection lens for projecting the combined image, 14 is a light valve 6 corresponding to S-polarized light wave, 7.
8 is a first signal processing circuit that outputs each color signal of red, green, and blue; 15 is a light I bulb 9, 1 that corresponds to P-polarized light waves;
0.11 is a second signal processing circuit that outputs red, green, and blue color signals, and 16 is a switch.

In FIG. 1, when projecting a normal planar image, the switch 16 is turned ON, the first signal processing circuit 14 and the second
The same signal is input to the signal processing circuit 15 of. When projecting a stereoscopic image, switch 16 is turned OFF L, the first signal processing circuit 14 receives a video signal from a position corresponding to the right eye of the human eye, and the second signal processing circuit 15 receives a video signal from a position corresponding to the right eye of the human eye. The video signal from the position corresponding to the left eye of the person is manually generated. As a result, the image from the position corresponding to the right eye of the human eye is projected using S-polarized light waves, and the image from the position corresponding to the left eye of the human eye is projected using P-polarized light waves.

FIG. 3 is a specific optical configuration diagram in an embodiment according to the present invention. 29 is a light source, 30 is a blue reflecting dichroic mirror, 31 is a red reflecting dichroic mirror, 32 is a blue beam splitter, 33 is a red beam splitter, 134 is a green beam splitter, 35 to 40 are reflecting mirrors, 41 is a PI light blue light valve, 42 is the S-polarized front light bulb,
43 is a P polarization field light valve, 44 is an S polarization red light valve, 45 is an S polarization edge light valve, 46 is a P polarization edge light valve, 47 is a blue synthesis prism, 48 is a red synthesis prism, 49 is a green synthesis prism, 50 is a red-green composition prism, 51 is a red-green-blue composition prism, and 52 is a projection lens.

The light emitted from the light source 29 is reflected by the blue reflective dichroic mirror 3.
0, and red reflecting dichroic mirror 31, blue,
Separated into red and green. Blue beam splitter 3 for blue light
2, the S-polarized light component is reflected and the P-polarized light component is transmitted, so that the S-polarized light component of the blue light reaches the S-polarized pre-light valve 42 and the P-polarized light component of the blue light reaches the P-polarized pre-light valve 41. .

Similarly, the S-polarized component of red light is transmitted through the S-polarized field light valve 44.
, the P-polarized component of the red light reaches the P-polarized red light valve 43, and the S-polarized component of the green light reaches the S-polarized edge light valve 4.
5, the P-polarized light component of the green light is transmitted through the P-polarized edge light valve 46.
reach.

The optical images formed by each light valve are combined for each color by combining prisms 47, 48, 49, and further combined by a red-green combining prism 50, a red-green-blue combining prism 51,
It is projected by the projection lens 52.

A color separation dichroic mirror, a beam splitter, and a composite prism both have reflection and transmission wavelengths selected by stacking multiple layers of metal evaporated films on the glass surface.

FIG. 4 is a conceptual diagram when a three-dimensional image is obtained from the liquid crystal projector of the present invention. In Fig. 4, 53 is the subject, 5
4.55 is a video camera, 56 is a liquid crystal projector-5
7 is a projected image, and 58 is a pair of glasses.

The video camera 54 images the subject 53 from a position corresponding to the right eye of the human eye, and the video camera 55 similarly images the subject 53 from a position corresponding to the left eye of the human eye. The output of each video camera is input to the liquid crystal projector 56, and as described above, the image from the video camera 54 is projected with the S polarization component, and the image from the video camera 55 is projected with the P polarization component. On the right eye of the glasses 58, there is an S-polarized light transmitting polarizing plate.
A P-polarized light transmitting polarizing plate is attached to the left eye, and as a result,
An image corresponding to the right eye reaches the right eye, and an image corresponding to the left eye reaches the left eye.

A recording device may be inserted between the video camera 54, 55 and the liquid crystal projector 56.

〔Effect of the invention〕

As described above, according to the present invention, since both S-polarized light waves and P-polarized light waves are effectively used,
You can get twice the brightness compared to

Furthermore, since no unnecessary heat is generated, a highly reliable liquid crystal projector can be provided.

Furthermore, since it is possible to simultaneously project an image using S-polarized light and an image using P-polarized light, it was possible to provide a liquid crystal projector that allows you to enjoy stereoscopic images by simply wearing glasses.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the liquid crystal projector of the present invention. FIG. 2 is a block diagram of a conventional liquid crystal projector. FIG. 3 is a specific optical configuration diagram of FIG. 1. FIG. 4 is a conceptual diagram when obtaining a three-dimensional image. 1... Light source 2... Color separation filter 3... Blue beam splitter 4... Red beam splitter 5... Green beam splitter 6, 9... Blue light bulb 7.10...・Red light valve 8.11...Green light valve 12...Composition means 13...Projection lens 14...First signal processing circuit 15...Second signal processing circuit 16...Switch 44...S polarized light light valve 45...S polarized edge light valve 46...P polarized light valve 47...Blue synthesis prism 48...Red synthesis prism 49...Green synthesis prism 50. ... Red-green composition prism 51 ... Red-green-blue composition prism 52 ... Projection lens 53 ... Subject 54.55 ... Video camera 56 ... Liquid crystal projector 57 ... Projection image 58 ... Glasses and above Applicant Seiko Epson Co., Ltd. agent Patent attorney Kizobe Suzuki and 1 other person 17...Light source 1B...Blue reflective dichroic mirror 19...Red reflective dichroic mirror 20.21...Reflecting mirror 22 .23...Synthetic mirror 24...Light bulb 25...Green light bulb 26...Red light bulb 27...Projection lens 28...Video signal processing circuit 29...Light source 30...・Blue reflection dichroic mirror 31...Red reflection dichroic mirror 32...Blue beam splitter 33...Red beam splitter 34...Green beam splitter 35-40...Reflection mirror 41...P Pre-polarized light bulb 42...S pre-polarized light bulb 43...P-polarized red light bulb

Claims (1)

[Claims] (1) a) In a liquid crystal projector that inputs the output of a video signal processing circuit to a light valve, converts the light from the light source into an optical image by the light valve, and projects it with a projection lens, b) A light corresponding to S-polarized waves. c) a video signal processing circuit that drives the light valve corresponding to P-polarized light; d) a color separation filter that separates the light from the light source into red, green, and blue; e) A beam splitter that separates each color into an S-polarized light wave and a P-polarized light wave, f) Six light valves corresponding to each color and each polarized light wave, g) A composition means for combining images, and h) Projecting the combined image. A liquid crystal projector characterized by being equipped with a projection lens.