Liquid crystal projector

• US 5,493,351 A
• Filed: 11/30/1993
• Issued: 02/20/1996
• Est. Priority Date: 11/30/1992
• Status: Expired due to Term

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Kanatani, Keiichi, Kosaka, Haruhisa, Sakata, Masahiro, Hamagishi, Goro, Terada, Katsumi, Kishimoto, Shunichi
• Primary Examiner(s): Will, Thomas B.
• Assistant Examiner(s): Dowling, William C.
• Application Number:
  US08/160,024
• Time in Patent Office: 812 Days
• Field of Search: 353/20, 353/30, 353/31, 353/38, 353/84, 353/102, 353/54, 353/55, 353/52, 359/40, 359/64, 359/63
• US Class Current: 353/84
• CPC Class Codes: G02F 1/133385 with cooling means, e.g. fans
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: H04N 9/3144 Cooling systems cooling of liquid crystal cells in general G02F1/133382; cooling of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/16

Abstract

A liquid crystal projector includes a light source, a color filter for adding color projection image, a liquid crystal panel for forming a projection image on it, a projection lens and an optical unit located between the color filter and the liquid crystal panel for optically coupling the color filter and the liquid crystal panel. The color filter is separately located from the liquid crystal, and therefore the increase in temperature on the color filter because of absorbing the light from the light source has less effect on the liquid crystal panel.

Claims

1. A liquid crystal projector comprising:

a light source for radiating light, said light source having a reflector and a light emitting element;

a color filter for adding color components to the light to form a pattern having the color components, said color filter having a filter portion transparent to the light from said light source and a black matrix for reflecting the light from said light source, said color filter being located adjacent said light source;

.

a projector lens for projecting an image;

a liquid crystal panel separated from said color filter for forming the image having the color components, said liquid crystal panel being located adjacent said projection lens; and

an optical unit located between and removed from said color filter and said liquid crystal panel for optically coupling the image of said liquid crystal panel and the pattern of said color filter in a same orientation,

wherein said optical unit superposes the light passed through said color filter on the image formed by said liquid crystal panel.

2. A liquid crystal projector as defined in claim 1, wherein the black matrix reflects the light substantially toward said light source.

3. A liquid crystal projector comprising:

a light source for radiating light;

a color filter for adding color components to the light, said color filter being located adjacent said light source;

a liquid crystal panel separated from said color filter for forming an image having the color components;

a projector lens for projecting said image, said projector lens being located adjacent said liquid crystal panel; and

an optical unit, having an array of lenses, for optically coupling said liquid crystal panel and said color filter, said optical unit being located between said color filter and said liquid crystal panel and superposing the light passed through said color filter on the image formed by said liquid crystal panel.

4. A liquid crystal projector as defined in claim 3, wherein said array of lenses comprises an array of graded index lenses, and said light source emits diverging light.

5. A liquid crystal projector comprising:

a light source for radiating light;

a color filter for adding color components to the light;

a liquid crystal panel separated from said color filter for forming an image having the color components, said liquid crystal panel being located adjacent said light source;

a projector lens for projecting said image, said projector lens being located adjacent said color filter; and

an optical unit, having an array of lenses, for optically coupling said liquid crystal panel and said color filter, said optical unit being located between said color filter and said liquid crystal panel and imaging the image of said liquid crystal panel on said color filter.

6. A liquid crystal projector as defined in claim 5, wherein said array of lenses comprises an array of graded index lenses, and said light source emits diverging light.

7. A liquid crystal projector comprising:

a light source for radiating light;

a color filter located adjacent said light source and having a filter portion for adding color components to the light and a black matrix for substantially reflecting the light;

a liquid crystal panel for forming an image with the light having the color components, said liquid crystal panel and said color filter being physically separated from each other to substantially eliminate thermal conduction between said liquid crystal panel and said color filter; and

a projector lens for projecting the image, the liquid crystal panel being located between the light source and the projector lens.

8. A liquid crystal panel assembly for a liquid crystal projector, the liquid crystal projector having a light source and a projector lens, the liquid crystal panel assembly comprising:

.

a color filter for forming a pattern having color components;

a liquid crystal panel spaced a distance from said color filter for forming an image; and

an optical unit located between and spaced from said color filter and said liquid crystal panel for optically coupling said pattern and said image in a same orientation,

wherein the color filter includes a filter portion transparent to light from the light source and a black matrix for reflecting light from the light source.

9. A liquid crystal panel assembly for a liquid crystal projector, the liquid crystal projector having a light source and a projector lens, the liquid crystal panel assembly comprising:

a color filter for forming a pattern having color components;

a liquid crystal panel spaced a distance from said color filter for forming an image; and

an optical unit located between and spaced from said color filter and said liquid crystal panel for optically coupling said pattern and said image in a same orientation,

wherein said color filter is located adjacent said light source and said liquid crystal panel is located adjacent said projector lens, and wherein said optical unit has an array of lenses for superposing the pattern of said color filter on the image formed by said liquid crystal panel.