Projection-type display apparatus

• US 20030025845A1
• Filed: 08/14/2002
• Published: 02/06/2003
• Est. Priority Date: 05/22/1997
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Murakami, Osamu, Yajima, Akitaka, Itoh, Yoshitaka
• Granted Patent: US 6,778,228 B2
• Time in Patent Office: Days
• US Class Current: 349/5
• CPC Class Codes: G02B 27/1046 for use with transmissive spatial light modulators
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 27/149 using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence

Abstract

A projection-type display apparatus of the invention aiming at solving the problem of heat generation caused by absorption of light by a polarizing means of a liquid crystal light valve. To overcome this problem, the projection-type display apparatus of the invention includes a light source, a light valve for modulating the light from the light source, and a projection optical means for projecting the light modulated by the light valve, with the light valve including a liquid crystal panel and a polarizing means, provided on the light source side of the liquid crystal panel, and the polarizing means being formed of a multi-layered film which primarily transmits one of two types of polarization axis component light beams and primarily reflects the other of the two types of polarization axis component light beams.

Claims

1. A projector, comprising:

a light source;

a light valve that modulates light beam from the light source, the light valve including a liquid crystal panel having a plurality of pixels, a first polarizer provided on a light-incident side of the liquid crystal panel and a second reflective polarizer provided on a light-emitting side of the liquid crystal panel, the second reflective polarizer transmitting one of a first polarized light and a second polarized light among incident light beam and reflecting the other of the first polarized light and the second polarized light among the incident light beam, the liquid crystal panel being formed by sandwiching a liquid crystal between a first substrate provided on a light-incident side and a second substrate provided on a light-emitting side, and the liquid crystal panel including a plurality of switching elements formed on an inner side of the second substrate, and a light-shielding layer formed between the switching element and a surface of the second substrate; and

a projection optical system that projects the light beam modulated by the light valve,

the first polarizer transmitting the first polarized light among incident light beam,

the liquid crystal panel modulating the first polarized light transmitted through the first polarizer by the pixels and transmitting the modulated light toward the second reflective polarizer,

the second reflective polarizer transmitting a part of the incident light beam modulated by the pixels of the liquid crystal panel and reflecting the other part of the incident light beam modulated by the pixels of the liquid crystal panel as a reflected light, and

the reflected light reflected by the second reflective polarizer being transmitted through the pixels of the liquid crystal panel toward the light source.

2. The projector according to claim 1, the first polarizer transmitting the first polarized light and reflecting the second polarized light.

3. The projector according to claim 1, the reflected light reflected by the second reflective polarizer being re-reflected so as to be included in the incident light beam on the first polarizer.

4. The projector according to claim 3, the reflected light reflected by the second reflective polarizer being reflected by a reflector of the light source.

5. The projector according to claim 3, further comprising a polarization converter that aligns the light beam from the light source with light beam having one of the polarized lights, the reflected light reflected by the second reflective polarizer being reflected by a reflector of the light source or by the polarization converter.

6. A projector, comprising:

a light source;

a light valve that modulates light from the light source, the light valve including a liquid crystal panel and a reflective polarizer provided at least on a light-emitting side of the liquid crystal panel, the liquid crystal panel being formed by sandwiching a liquid crystal between a first substrate provided on a light-incident side and a second substrate provided on a light-emitting side; and

a projection optical system that projects the light modulated by the light valve,

the reflective polarizer transmitting one of a first polarized light and a second polarized light among incident light, and reflecting the other of the first polarized light and the second polarized light among the incident light so as to return toward the second substrate and the liquid crystal panel, and

the liquid crystal panel comprising a plurality of pixels having a switching element formed on an inner side of the second substrate, and a light-shielding layer formed between the switching element and a surface of the second substrate.

7. The projector according to claim 6, the reflective polarizer being either adhered to or bonded to the substrate of the liquid crystal panel.

8. A projector, comprising:

a light source;

a colored-light separator that separates light beam from the light source into a plurality of colored light beams different from each other;

a plurality of light valves that modulate the colored light beams separated by the colored-light separator, each of the light valves including a liquid crystal panel and a reflective polarizer provided on at least one side of the liquid crystal panel associated thereto, the reflective polarizer being formed of a multi-layered film that transmits one of a first polarized light and a second polarized light among incident colored light beam and reflects the other of the first polarized light and the second polarized light among the incident colored light beam;

a synthesizing optical element that synthesizes the colored light beams modulated by the plurality of light valves; and

a projection optical system that projects the light beam synthesized by the synthesizing optical element,

at least one of the reflective polarizers having wavelength selective transmission characteristic different from the other of the reflective polarizers so as to selectively transmit the incident colored light beam separated by the colored-light separator and modulated by an associated light valve.

9. The projector according to claim 8, the light valves further comprising a second reflective polarizer provided on the other side of the liquid crystal panel associated thereto,

the second reflective polarizer being formed of a multi-layered film that transmits one of the first polarized light and the second polarized light and reflects the other of the first polarized light and the second polarized light.

10. The projector according to claim 8, the multi-layered film, provided on at least one side of a corresponding liquid crystal panel, being formed of alternately laminated layers of first films and second films,

the first films having a refractive index in a first axial direction of a film surface which differs from a refractive index in a second axial direction perpendicular thereto, and the second films having a refractive index in the first axial direction and the second axial direction which are substantially equal to the refractive index of the first films in the second axial direction, and the first and second films having thickness set to allow selective transmission of the colored light beam which enters the first films and the second films, and

a plurality of the multi-layered films of the light valves having different thickness from each other.

11. The projector according to claim 8, a light reflected by the reflective polarizer being re-reflected so as to be included in the incident colored light beam on the reflective polarizer.

12. The projector according to claim 11, a light reflected by the reflective polarizer being reflected by a reflector of the light source.

13. The projector according to claim 11, further comprising a polarization converter that aligns the light beam from the light source with light beam having one of the polarized lights, a light reflected by the reflective polarizer being reflected by a reflector of the light source or by the polarization converter.