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Patent Searching and Data


Title:
PROJECTION LENS AND PROJECTION DISPLAY APPARATUS USING THE SAME
Document Type and Number:
Japanese Patent JP2008309990
Kind Code:
A
Abstract:

To obtain a wide-angle projection lens having high projection performance while securing a long back focus, capable of using an inexpensive light reflection mirror as an optical path bending component, and whose manufacturing cost is reduced.

The projection lens is constituted by arraying a first group G1 having negative refractive power and a second group G2 having positive refractive power in order from an enlargement side, and the projection lens is nearly telecentric on a reduction side. The first group G1 comprises at least six lenses in order from the enlargement side, that is, an aspheric lens L1, a negative meniscus lens L2 with a convex surface facing the enlargement side, a negative lens L3 with a concave surface facing the reduction side, a negative lens L4 with a concave surface facing the reduction side, a biconvex lens L5 and a negative lens L6 with a concave surface facing the enlargement side (three-cemented lens composed of lenses L4, L5and L6). Further, the projection lens satisfies three conditional expressions (1) to (3).


Inventors:
YAMAMOTO TSUTOMU
Application Number:
JP2007157250A
Publication Date:
December 25, 2008
Filing Date:
June 14, 2007
Export Citation:
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Assignee:
FUJINON CORP
International Classes:
G02B13/00; G02B9/62; G02B13/18; G02B17/08; G03B21/14
Attorney, Agent or Firm:
Hiroshi Kawano
Yasuto Ogata