JPH043041A - Liquid crystal projector - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal projector which has a high resolution and can project bright images by providing plural pieces of green-liquid crystal light valves. CONSTITUTION:At least plural pieces of the green-liquid crystal light valves 1, 2 are provided. Namely, the 1st green-liquid crystal light valve 1, the 2nd green-liquid crystal light valve 2 and the red and blue-liquid crystal light valve 3 are provided. Of the light emitted by a light source 4, the red and blue are reflected by a red and blue reflecting dichroic mirror 5 and are further reflected by a reflecting mirror 7a so as to arrive at the red and blue-liquid crystal light valve 3. On the other hand, the green light transmitted through the red and blue reflecting dichroic mirror 5 enters a green beam splitter 6. The S polarized light of the green light is reflected by the green beam splitter 6 and the P polarized light is transmitted. The S polarized light component of the green light, therefore, arrives at the 1st green-liquid crystal light valve and the P polarized light component is reflected by the reflecting mirrors 7b, 7c and arrives at the 2nd green liquid crystal light valve. The liquid crystal projector which has the high resolution of the projected images and forms the bright projected images is obtd. in this way.

Description

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

[Conventional technology] The basic configuration of a conventional liquid crystal projector is shown in FIG.

In FIG. 2, 4 is a light source, 15 is a blue reflective dichroic mirror (hereinafter referred to as BD*M), 16 is a green reflective dichroic mirror (hereinafter referred to as GD, M), and 7α
, 7b, 7c are reflective mirrors. 12 is a green liquid crystal light valve (hereinafter referred to as a-r, v), 15 is a blue liquid crystal light valve (hereinafter referred to as BL, V), and 14 is a red liquid crystal light valve (hereinafter referred to as BL, V).
9 is a synthesis prism, 10 is a projection lens, and 11 is a screen. A liquid crystal light valve is an element in which a liquid crystal material is sandwiched between two glass substrates, and the light transmitted therethrough can be controlled by applying a voltage. In recent years, active matrix type liquid crystal light valves have been put into practical use, in which thin film transistors are formed on glass substrates and the light transmittance can be controlled individually for each pixel.

The light emitted from the light source 4 is BD, M14 and GD, M2.
At S, the colors are separated into the three primary colors of blue, green, and red, and the liquid crystal light valve corresponding to each color reaches "*12y14." In each liquid crystal light valve, the transmittance of each color is controlled for each pixel. , to form an optical image.The optical images of each color are combined by the combining prism 9 and then projected onto the screen 11 by the projection lens 10.9c of the combining prism 9
The surface has a reflective film that reflects blue and transmits green, and the surface 9b has a red reflective film.
A green-transmissive reflective film is formed respectively.

FIG. 5 is a pixel arrangement diagram of a projected image of a conventional liquid crystal projector. In FIG. 5, 17 indicates a pixel. Areas other than pixels are areas through which no light is transmitted. In an active matrix type liquid crystal light valve, a thin portion is formed that does not transmit light in order to protect the transistor. Each pixel is adjusted to be in the same position for red, green, and blue. The size and number of pixels of each color liquid crystal light valve are the same.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the resolution of the image is determined by the number of pixels possessed by the liquid crystal light valve of each color. Therefore, in order to improve resolution, it is necessary to have as many pixels as possible.However, increasing the number of pixels requires advanced microfabrication, reduces yield, and increases cost. In addition, there are problems such as a decrease in the area @ (aperture ratio) of the pixel portion that covers the entire screen, and a decrease in the brightness of the screen.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and it is an object of the present invention to provide a liquid crystal projector that provides a dramatically high resolution of a projected image and a bright projected image.

[Means for Solving the Problems] The liquid crystal projector of the present invention has a light source, a liquid crystal light valve, and a projection lens to project an image, and has at least a plurality of green liquid crystal light valves. It is characterized by

[Example 1] Fig. 1 is a configuration diagram of an embodiment of the liquid crystal projector of the present invention, in which 1 indicates a first green liquid crystal light valve;
2 is a second green liquid crystal light valve, 5 is a red and blue liquid crystal light valve, 4 is a light source, 5 is a red-blue reflective dichroic mirror, 6 is a green beam splitter, 7α, 7b, 7c are reflective mirrors, 9 is a synthesis prism , 10 is a projection lens, 11
is a screen.

Among the lights emitted from the light source 4, red and blue are reflected by a red-blue reflective dichroic mirror 5, further reflected by a reflective mirror 7α, and reach a red-blue liquid crystal light valve 6. On the other hand, the green light transmitted through the red-blue reflective dichroic mirror 5 enters the green beam splitter 6. In the green beam splitter 6, the S-polarized light of the green light is reflected and the P-polarized light is transmitted. Therefore, the S-polarized component of the green light is the first green-
The P-polarized light component reaches the liquid crystal light valve and passes through the reflection mirror 7.
b, 7c and reaches the second green liquid crystal light valve. The light whose transmission amount is controlled by each liquid crystal light valve, that is, an optical image, is combined by a combining prism 9 and projected onto a screen 11 through a projection lens 1o. The surface 9c of the combining prism 9 is formed with a reflective film that reflects red and blue and transmits green, and the surface 9b is formed with a reflective film that reflects green P-polarized light and transmits green S-polarized light.

FIG. 4 is a pixel layout diagram of a green projected image of the liquid crystal projector according to the present invention. 18 is a pixel of the first green liquid crystal light valve, and 19 is a pixel of the second green liquid crystal light valve. In the pixel array in Figure 4, the number of green pixels is 2.
The horizontal resolution is also doubled. Normally, the human eye has a high resolution for green and a low resolution for red and blue, so simply increasing the number of pixels for green makes it appear as if the resolution of the entire screen has increased.

FIG. 5 is a pixel arrangement diagram of a projected image of the liquid crystal projector according to the present invention. 18 is a pixel of the first green liquid crystal light valve, 19 is a pixel of the second green liquid crystal light valve, 20 and 21 are pixels of the red and blue liquid crystal light valve, 20 is a red pixel, and 21 is a pixel of the first green liquid crystal light valve. It is a blue pixel.

FIG. 6 is a sectional view of a red and blue liquid crystal light valve. A thin film transistor 25 is formed on a glass substrate 22, and a pixel electrode 24 is further formed.

On the other hand, red filters 26 and blue filters 27 are alternately arranged on the opposing glass substrate 25. A light shielding film 28 for protecting the thin film transistor from light is formed between the filters corresponding to each pixel, and a counter electrode 29 is further formed. A liquid crystal material 30 is sealed between the glass substrate 22 and the counter glass substrate 25.

From Figures 5 and 6, the number of pixels corresponding to red and blue is reduced by half, but as mentioned above, the resolution of the human eye is low for red and blue, so this does not have a major effect on the image. .

FIG. 7 is a layout diagram of a green projected image of another embodiment of the liquid crystal projector according to the present invention. 18 is the first green-
Pixel 19 of the liquid crystal light valve is a second green-liquid crystal light valve pixel. With this arrangement, scanning in the odd field of the TV double signal can be performed at the nth column and (tL+1) column t(
rL+2) row and (yL-1-5) row t(yL+4)
Scanning is performed in combinations such as column 1 and (rL+S) column, and scanning in even fields is performed by scanning column 1 (n+1), column 2 (n+2), column 3 (n+3), and (7L+4). Scanning is performed in combinations of columns. 7th
The layout of the figures improves not only the horizontal resolution but also the degree of vertical disassembly.

FIG. 8 is a configuration diagram showing another embodiment of the liquid crystal projector according to the present invention. Green - 2 LCD light bulbs,
This is an example in which one red liquid crystal light valve and one blue liquid crystal light valve are used. In Figure 8, 51
52 is a light source, 52 is a red-blue reflecting dichroic mirror, 56 is a green beam fritter, 54 is a red-reflecting dichroic mirror, 35, 56, 57 is a reflecting mirror, 68 is a blue-liquid crystal light valve, 69 is a red-liquid crystal light valve, and 40 is a red-liquid crystal light valve. 1 green liquid crystal light valve, 41 a second green liquid crystal light valve, a2. as and aa are synthetic prisms, and 45 is a projection lens.

In the configuration shown in FIG. 8, the resolution for green is twice that of the conventional configuration, while the resolution for red and blue remains the same. Additionally, the usage rate of green light is doubled, resulting in a brighter image.

FIG. 9 is a configuration diagram showing still another embodiment of the liquid crystal projector according to the present invention. 46 is a blue reflective dichroic mirror 47 is a red reflective dichroic mirror 48
．． 49.50 is the beam splitter-51, 52, 55,
54 is a reflective mirror 55.56 is a blue liquid crystal light valve,
57 and 58 are red - liquid crystal light bulbs, 59.60 are green -
The liquid crystal light valves 61 to 65 are synthetic prisms.

The configuration shown in Figure 9 consists of two red, blue, and green liquid crystal light valves.
Since each color is used one by one, compared to the conventional configuration, each color is
The resolution is doubled and the brightness is also doubled.

[Effects of the Invention] As described above, according to the present invention, while using a liquid crystal light valve with a conventional number of pixels, the resolution of the projected image is dramatically improved, and bright images with increased light utilization efficiency can be produced. This has the effect of providing a liquid crystal projector that can project images.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the liquid crystal projector of the present invention. FIG. 2 is a basic configuration diagram of a conventional multi-product projector. FIG. 6 is a pixel arrangement diagram of a conventional liquid crystal projector. FIG. 4 is a pixel arrangement diagram of a green projected image of the liquid crystal projector according to the present invention. FIG. 5 is a pixel arrangement diagram of a projected image of the liquid crystal projector according to the present invention. Figure 6 is a cross-sectional view of a red and blue liquid crystal light valve. FIG. 7 is a layout diagram of a green projected image in another embodiment of the liquid crystal projector according to the present invention. FIG. 8 is a configuration diagram showing another embodiment of the liquid crystal projector according to the present invention. FIG. 9 is a configuration diagram showing still another embodiment of the liquid crystal projector according to the present invention. 1...First green-LCD light bulb 2...
...Second green liquid crystal light bulb 6...Red and blue liquid crystal light bulb 4...Light source 5...Red and blue reflective dichroic mirror 6°°°
...Green beam splitter 7α, 7b, 7c...Reflection mirror 9...
・Synthesizing prism 10...Projection lens 11...Screen 12...Green-LCD light valve 13...
・Blue-LCD light valve 14...Red-LCD light valve 15°°゛°°°Blue reflective dichroic mirror 16...Green reflective dichroic mirror 17...
...Pixel 18...First green - pixel 1 of the liquid crystal light valve
9... Second green - pixel 20 of the liquid crystal light valve
... Red pixel 21 ... Blue pixel 22 ... Glass substrate 25 ... Thin film transistor 4 ... Pixel electrode 5 ...・Counter glass substrate 6... Red filter 7... Blue filter 8... Light shielding film 9... Counter electrode 0... Liquid crystal Material Applicant Seiko Epson Co., Ltd. Agent Patent Attorney Kizobe Suzuki (and 1 other person) Rodashi 1koku
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Claims (1)

[Claims] (1) A liquid crystal projector that projects an image and includes a) a light source, a liquid crystal light valve, and a projection lens, and b) a liquid crystal projector that includes at least a plurality of green liquid crystal light valves.