Projection type image display device

• US 5,394,204 A
• Filed: 08/23/1993
• Issued: 02/28/1995
• Est. Priority Date: 08/21/1992
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nishiura, Takeshi, Shigeta, Teruaki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Dowling, William C.
• Application Number:
  US08/110,551
• Time in Patent Office: 554 Days
• Field of Search: 353/31, 353/33, 353/37, 353/94, 359/48, 359/49, 359/40
• US Class Current: 353/31
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/3164 using multiple light sources

Abstract

A projection type image display device comprises plural light sources, optical converging systems, liquid crystal display elements, a color synthesizing system and a optical projection system.

Claims

1. A projection type image display device comprising:

a plurality of light sources including metal halide lamps for projecting a red color light, a green color light, and a blue color light,

optical converging means for converging the light projected by said plurality of light sources,

a liquid crystal display element for red color, a liquid crystal display element for green color, and a liquid crystal display element for blue color, each display element for controlling the transmission of collimated light from the converging means,

a color synthesizing optical system which synthesizes light from each of said liquid crystal display element to form an optical image having a chromaticity level,

an optical projection system which projects the optical image formed by said liquid crystal elements onto a screen, and

means for individually adjusting the strength of each of said green color light, said red color light, and said blue color light to adjust said chromaticity level of the optical image;

wherein each one of said plurality of light sources emits light of a specified spectral band which is different from the specified spectral band of each other one of said plurality of light sources.

2. The projection type image display device of claim 1, wherein said red color light, said green color light, and said blue color light have respective dominant wave lengths in ranges of 600 to 680 nm, 500 to 580 nm, and 400 to 480 nm.

3. The projection type image display device of claim 2, wherein the ratio of power consumption for each of the plurality of light sources corresponds to the ratio of light emission of the red, green, and blue lights.

4. The projection type image display device of claim 2, wherein the red color metal halide lamp comprises mercury, rare gas, and halogenide including lithium halogenide, the green color metal halide lamp comprises mercury, rare gas, and halogenide including thallium halogenide, and the blue color metal halide lamp comprises mercury, rare gas, and halogenide including indium halogenide.

5. The projection type image display device of claim 1, wherein said plurality of light sources includes two light sources, one of which emits light of one of red, green, and blue colors having dominant wave lengths between 600 to 680 nm, 500 to 580 nm, and 400 to 480 nm respectively.

6. The projection type image display device of claim 5, wherein the ratio of power consumption of the two light sources corresponds to the ratio of light intensity of the sources.

7. The projection type image display device of claim 5, wherein the lamp emitting two color light includes in its discharge tube one of (a) halogenide of lithium and thallium for red and green lights, (b) halogenide of lithium and indium for red and blue lights, and (c) halogenide of thallium and indium for green and blue lights.

8. The projection type image display device of claim 1, further including chromaticity measuring means for measuring the chromaticity level of the optical image and wherein the strength of each of the green color light, the red color light, and the blue color light is individually adjusted in response to the measured chromaticity level.