US 2006/0140635 A1Published application

Reflection optical system and projection display apparatus using the same

AssigneeFujinon Corporation

InventorChikara Yamamoto

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Abstract

A reflection optical system placed between a light valve 5 and a screen 4, wherein curved surfaces are only three reflection surfaces of first to third mirrors 1 to 3, and satisfies the following: (1) θL<20 degrees, (2) 25 degrees<θUL<55 degrees, (3) 20 degrees<θM1<55 degrees, (4) 15 degrees<θM2<50 degrees, (5) 8 degrees<θM3<30 degrees, (6) θL<15 degrees, (7) 30 degrees<θUL and (8) 7.5 degrees<|θF|, where θL: minimum angle which a light beam of pupil center forms with respect to the enlargement side image surface; θUL: difference between maximum and minimum angles which a light beam of pupil center forms with respect to the enlargement side image surface; θM1, θM2 and θM3: deviation angles of the light beam of pupil center passing the center of the reduction-side image surface in first to third mirrors 1 to 3; and θF: reduction-side pupil divergent angle.

Claims17

Dependent claims

A reflection optical system placed between two image surfaces one of which is an enlargement side image surface and the other of which is a reduction side image surface, and forming no intermediate image between the two image surfaces, said reflection optical system comprising:

a first mirror;
a second mirror;
and
a third mirror;
wherein among optical surfaces of the reflection optical system, curved surfaces are only three reflection surfaces of the first mirror, the second mirror and the third mirror in the order from the side of said enlargement side image surface, and
the following conditional expressions (1) and (2) are met:
θL<20 degrees (1)
25 degrees<θUL<55 degrees (2)
where
θL:
minimum angle which a light beam of pupil center forms with respect to the enlargement side image surface;
and
θUL:
difference between maximum and minimum angles which a light beam of pupil center forms with respect to the enlargement side image surface.

11 more elements

Dependencies are inferred from the claim text.