Optical: systems and elements – Polarization without modulation – Polarizarion by dichroism
Reexamination Certificate
1998-02-27
2001-06-19
Spyrou, Cassandra (Department: 2872)
Optical: systems and elements
Polarization without modulation
Polarizarion by dichroism
C359S488010, C359S584000, C353S020000
Reexamination Certificate
active
06249378
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mirror and a projection type display apparatus using a liquid crystal light valve.
2. Related Background Art
There has been known a projection type display apparatus in which light from a light source is chromatically decomposed into R, G, and B light components; these individual color light components are made incident on liquid crystal light valves disposed for the respective color light components and emitted therefrom after being modulated therein; thus emitted light components are analyzed and then are chromatically combined together; and thus chromatically combined light is projected onto a screen by a projection optical system. Such an apparatus is disclosed in U.S. Pat. No. 5,357,370.
SUMMARY OF THE INVENTION
The mirror in accordance with the present invention has a polarizing characteristic (polarization separating characteristic) for causing reflected light to approximate linearly polarized light. Since this mirror has such a characteristic, it attains a reflecting function and a polarizing function at the same time. Accordingly, in a projection type display apparatus, When this mirror is employed as a bending mirror, disposed in an optical path through which light is incident on a light valve, for bending the optical path, the light incident on the light valve yields an enhanced purity in polarization, thus allowing the contrast of projection image to improve.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 4836649 (1989-06-01), Ledebuhr et al.
patent: 5278680 (1994-01-01), Karasawa et al.
patent: 5357370 (1994-10-01), Miyatake et al.
patent: 5559634 (1996-09-01), Weber
Hattori Tetsuo
Okamoto Mikio
Shimamura Naotaka
Curtis Craig
Foley & Lardner
Nikon Corporation
Spyrou Cassandra
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