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US 11,537,031 B2Granted
Optical system, projector, and imaging apparatus
AssigneeSeiko Epson Corporation
InventorHirotaka Yanagisawa
Life of this patent
Estimating the term…
Abstract
An optical system includes a lens having a first transmission surface, a reflection surface disposed on an enlargement side of the first transmission surface, and a second transmission surface disposed on the enlargement side of the reflection surface. The lens is made of resin. The reflection surface has a concave shape. A conditional expression below is satisfied, 10≤q×Fno/f2≤2989 where Fno is an F-number of the optical system, f is a focal length of the optical system, and q is an amount of light in an enlargement-side conjugate plane.
Claims10
An optical system comprising
- a lens having a first transmission surface, a reflection surface disposed on an enlargement side of the first transmission surface, and a second transmission surface disposed on the enlargement side of the reflection surface,
- wherein the lens is made of resin,
- the reflection surface has a concave shape, and
- 10≤q×Fno/f2≤2989
- where Fno is an F-number of the optical system, f is a focal length of the optical system, and q is an amount of light in an enlargement-side conjugate plane.
2 more elements
Dependencies are inferred from the claim text.