SUPER-WIDE-ANGLE OPTICAL SYSTEM

Japanese Patent JP3938143

B2

PROBLEM TO BE SOLVED: To provide a super-wide-angle optical system which has good optical performance as an image pickup optical system for an image pickup element and a wide viewing angle and has low cost and a compact shape.
SOLUTION: The super-wide-angle optical system is used to form an optical image IM of a subject to be photographed on the image pickup surface of an image pickup element SR and successively includes, from the subject side, a negative first lens L1, which has a convex meniscus shape facing toward the subject side, and a negative second lens L2. At least one surface among four lens surfaces of the first and the second lenses L1 and L2 is made of an aspherical surface *. At least one positive lens is included toward the subject side outside the first and the second lenses L1 and L2 and one among these lenses has an aspherical surface *. The super-wide-angle optical system satisfies following conditional equations: 0.05<(TLxYd)/{fxtan(Ψd)}<3.5 and -1.55<f12/f<-0.7 (where Ψd is a maximum half viewing angle, Yd is a maximum image height, TL is the distance from a lens surface r1, that is closest to the subject side, to an image formation position IM on an optical axis, f is the focal distance of the total system and f12 is a combined focal distance of the first and the second lenses L1 and L2).

Satoshi Osawa
Keiji Matsuzaka

JP2004031694A

June 27, 2007

February 09, 2004

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Konica Minolta Opto Co., Ltd.

G02B13/04; G02B13/06; G02B13/18; H04N5/225; (IPC1-7): G02B13/04; G02B13/18

JP2003177313A
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JP10039206A
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JP9015492A
JP2003066331A
JP2002072085A
JP63017421A
JP4238312A

Shizuo Sano
Shigeki Yamada

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