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Patent Searching and Data


Title:
FAR-INFRARED CAMERA LENS, LENS UNIT, AND IMAGING APPARATUS
Document Type and Number:
Japanese Patent JP2009063942
Kind Code:
A
Abstract:

To provide a far-infrared camera lens which is mounted on a vehicle, is small and inexpensive, and has a wide angle of view of 50 to 70 and to provide a lens unit and an imaging apparatus which use this lens.

Three lenses formed of ZnS are used in combination. A first lens is a meniscus lens having a middle portion which is convex on an object side. A second lens has a middle portion that is a meniscus, which is concave on an object side and has positive refractive power, and a peripheral portion, which is convex on the object side. The first and second lenses have positive refractive power in combination. A third lens is provided adjacent to the second lens with a distance therebetween 1 mm or less and has a middle portion, which is a convex meniscus on an object side, and a peripheral portion which is concave on the object side. A diffraction surface is formed in either surface of the lens. The total focal distance f of the lens system is 6 to 11 mm. The focal distances f12 of the first and second lenses are 5 to 18 mm, and there is a limit of 0.9f12/f1.6.


Inventors:
IZUMI TATSUYA
Application Number:
JP2007233509A
Publication Date:
March 26, 2009
Filing Date:
September 10, 2007
Export Citation:
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Assignee:
SUMITOMO ELECTRIC INDUSTRIES
SEI HYBRID KK
International Classes:
G02B13/14; G02B3/00; G02B9/12; G02B13/18
Attorney, Agent or Firm:
川瀬 茂樹