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Title:
VARIABLE MAGNIFICATION OPTICAL SYSTEM, IMAGE PICKING-UP DEVICE AND DIGITAL EQUIPMENT
Document Type and Number:
WIPO Patent Application WO/2008/075539
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 includes a first lens group provided with negative optical power, a second lens group provided with positive optical power, a third lens group provided with negative optical power and a fourth lens group provided with positive optical power in turn from an object side, wherein a distance between the first lens group and the second lens group becomes narrow at the magnification from a wide terminal to a telescopic terminal. In the case where T1 is a thickness on the optical axis measured from the most front surface of the fist lens group to the last surface of the fist lens group, fw and ft are resultant focus distances of the total optical system at the wide angle terminal and the telescopic terminal, respectively, ΔN2 is a difference in average refractive index between the positive lenses and the negative lenses in the second lens group, Δν2 is a difference in average Abbe number between the positive lenses and the negative lenses in the second lens group, and N1 is the maximum refractive index in a lens of the first lens group, the variable magnification optical system satisfies the following: 0.20.15, Δν2>20 and N1≥1.8.

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)
Application Number:
JP2007/072824
Publication Date:
June 26, 2008
Filing Date:
November 27, 2007
Export Citation:
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Assignee:
Konica Minolta Opto, Inc. (2970, Ishikawa-machi Hachioji-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)
International Classes:
G02B15/20; G02B13/18; G02B15/167
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