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US 5,475,534 AGranted
Projection lens systems for projector
AssigneeSony Corporation
InventorsKoji Okajima, Akira Nakamura
Life of this patent
Estimating the term…
Abstract
A projection lens system includes a cathode ray tube which projects the image to be projected on the screen through a set of six projection lens, which include non-spherical surfaces. The projection lens system is obliquely positioned in order to incline the optical axis of the projection lens at a predetermined angle with regard to the optical axis which exits from the projection lens and reaches the screen.
Claims3
A projection lens system comprising a cathode ray tube for projecting images;
- a screen to receive said images projected from said cathode ray tube;
- a series of lenses including, successively from said screen side:
- a first meniscus lens having a convex face on said screen side and at least one face being composed of a non-spherical surface;
- a second meniscus lens having a concave face on said screen side and at least one face being composed of a non-spherical surface;
- a lens having two convex faces;
- a negative lens;
- a positive lens;
- and
- a third meniscus lens having a concave face toward said screen side and said concave face of said third meniscus lens being composed of a non-spherical surface, wherein
- said cathode ray tube and said projection lens system are arranged to satisfy the following equations:
- .theta.L=0.6.multidot..theta.S+2
- .theta.L-0.4.multidot..theta.S-2
- .degree.<.theta. S.ltoreq.30.degree.
- 0.degree..ltoreq..theta.L
- where .theta.S is an angle formed with an axis line from the center point of said screen to the exit pupil of said projection lens system and a line normal to the center of said screen and .theta.L is an angle formed with a line normal to said screen and the optical axis of said projection lens system at the point where the optical axis of said projection lens system intersects said screen;
- and
- said cathode ray tube is arranged to project the center of said images onto the center of said screen through said projection lens system.
14 more elements
Dependencies are inferred from the claim text.