Liquid crystal cells – elements and systems – Liquid crystal system – Projector including liquid crystal cell
Reexamination Certificate
2002-08-06
2004-09-21
Hess, Daniel A. (Department: 2876)
Liquid crystal cells, elements and systems
Liquid crystal system
Projector including liquid crystal cell
C349S006000, C349S007000, C349S008000
Reexamination Certificate
active
06795132
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority of Taiwan patent Application No. 090213589, filed on Aug. 9, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a liquid crystal projection display, more particularly to a liquid crystal projection display that can provide an output light beam to a projection lens group with a propagation direction that is parallel to an optical axis of the latter.
2. Description of the Related Art
A conventional projection system is disclosed in U.S. Pat. No. 6,076,931. In the conventional projection system, an illumination beam generated by an illumination source is processed in sequence by a polarizer, a field lens, a reflective LCD, an analyzer and a decentered collimating lens group so as to generate a collimated image beam to a projection lens group. It is noted that the decentered collimating lens group is needed for avoiding the unacceptable displacement of the projected image, thereby resulting in increased costs.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a liquid crystal projection display that can provide an output light beam to a projection lens with a propagation direction that is parallel to an optical axis of the latter.
According to the present invention, a liquid crystal projection display is adapted to process an input light beam and to provide an output light beam to a projection lens group that has an optical axis. The input light beam includes first, second and third color components. The liquid crystal projection display comprises:
a splitter unit adapted to receive and separate the input light beam into the first, second and third color components;
first, second and third polarizers, each of which is disposed adjacent to the splitter unit so as to receive and process a respective one of the first, second and third color components, each of the first, second and third polarizers being disposed perpendicular to a propagation direction of the respective one of the first, second and third color components;
first, second and third liquid crystal modulators, each of which is disposed adjacent to a respective one of the first, second and third polarizers so as to receive and be capable of modulating a respective one of the first, second and third color components;
first, second and third analyzers, each of which is disposed adjacent to a respective one of the first, second and third liquid crystal modulators so as to receive and process a respective one of the first, second and third color components, each of the first, second and third analyzers being disposed perpendicular to the propagation direction of the respective one of the first, second and third color components; and
a recombiner unit disposed above the splitter unit and disposed adjacent to the first, second and third analyzers so as to receive and recombine the first, second and third color components in order to generate the output light beam;
each of the first, second and third liquid crystal modulators being disposed at an angle relative to the recombiner unit such that the output light beam can be provided by the recombiner unit to the projection lens group with a propagation direction that is parallel to the optical axis.
REFERENCES:
patent: 4687301 (1987-08-01), Ledebuhr
patent: 5689321 (1997-11-01), Kochi
patent: 6076931 (2000-06-01), Bone et al.
patent: 6565211 (2003-05-01), Sekine et al.
patent: 6588906 (2003-07-01), Hwang
Hess Daniel A.
Townsend and Townsend / and Crew LLP
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