Title:
VARIABLE MAGNIFICATION OPTICAL SYSTEM, IMAGE PICKING-UP DEVICE AND DIGITAL EQUIPMENT
Document Type and Number:
WIPO Patent Application WO/2008/072466
Kind Code:
A1
Abstract:
The present invention sufficiently corrects various aberrations of color, astigmatism,
and the like while achieving a super compact structure device. For that purpose,
a variable magnification optical system has first through fourth lens groups
provided with negative, positive, negative and positive optical power in turn
from an object side, wherein a distance between the first lens group and the fourth
lens group becomes narrow at the magnification changing from a wide terminal
to a telescopic terminal. The first lens group is comprised of a negative lens
and a positive meniscus, and the second lens group is comprised of a biconvex positive
lens and a biconcave negative lens and includes aspheric surface. In the case
where distances from the apex surface of the lens closest to the object side to
an image surface at the wide terminal and the telescopic terminal are TLw and TLt
at the object at an infinite distance, respectively, a refractive index difference
between the biconvex positive lens and the biconcave negative lens is ΔN2,
and an Abbe number difference between them is Δν2, a distance from
the apex surface of the positive meniscus lens to the image surface is Lb and a resultant
focus distance of the total optical system at the wide angle terminal is fw, the
variable magnification optical system satisfies TLw/TLt<1.2, ΔN2>0.15,
Δν2>20 and Lb/fw≤1.2.
Inventors:
MATSUSAKA, Keiji (Inc. 2970 Ishikawa-machi, Hachioji-sh, Tokyo 05, 1928505, JP)
松坂 慶二 (〒05 東京都八王子市石川町２９７０番地コニカミノルタオプト株式会社内 Tokyo, 1928505, JP)
FUKUTA, Yasunari (Inc. 2970 Ishikawa-machi, Hachioji-sh, Tokyo 05, 1928505, JP)
松坂 慶二 (〒05 東京都八王子市石川町２９７０番地コニカミノルタオプト株式会社内 Tokyo, 1928505, JP)
FUKUTA, Yasunari (Inc. 2970 Ishikawa-machi, Hachioji-sh, Tokyo 05, 1928505, JP)
Application Number:
JP2007/072823
Publication Date:
June 19, 2008
Filing Date:
November 27, 2007
Export Citation:
Assignee:
Konica Minolta Opto, Inc. (2970, Ishikawa-machiHachioji-sh, Tokyo 05, 1928505, JP)
コニカミノルタオプト株式会社 (〒05 東京都八王子市石川町２９７０番地 Tokyo, 1928505, JP)
MATSUSAKA, Keiji (Inc. 2970 Ishikawa-machi, Hachioji-sh, Tokyo 05, 1928505, JP)
松坂 慶二 (〒05 東京都八王子市石川町２９７０番地コニカミノルタオプト株式会社内 Tokyo, 1928505, JP)
コニカミノルタオプト株式会社 (〒05 東京都八王子市石川町２９７０番地 Tokyo, 1928505, JP)
MATSUSAKA, Keiji (Inc. 2970 Ishikawa-machi, Hachioji-sh, Tokyo 05, 1928505, JP)
松坂 慶二 (〒05 東京都八王子市石川町２９７０番地コニカミノルタオプト株式会社内 Tokyo, 1928505, JP)
International Classes:
G02B15/20; G02B13/18; G02B15/16; G02B15/167
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