Title:
ZOOM LENS
Document Type and Number:
WIPO Patent Application WO/2013/183787
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide a compact zoom lens capable of acquiring high imaging performance even with high magnification. The zoom lens comprises, sequentially from an object, a first lens group with positive power, a second lens group with negative power and a third lens group with positive power. When zooming from a wide angle end to a telescopic end, the distance between the first lens group and the second lens group increases and the distance between the second lens group and the third lens group decreases so that all the lens groups constituting the zoom lens move.
The first lens group comprises, sequentially from the object, a single negative lens and three positive lenses. The zoom lens satisfies the following expressions:
(1) Nd1 > 1.84 vd1 < 35.
(2) Nd2 < 1.60 vd2 > 60,
(3) Nd3 < 1.65 vd3 > 60 and
(4) Nd4 - Nd3 >0.02
Nd4 > Nd3 >Nd2.
Where, Ndi is the refractive index of an i-th glass material from the object and Vdi is Abbe's number of an i-th glass material from the object.
Inventors:
ADACHI NOBUYUKI (JP)
Application Number:
PCT/JP2013/066000
Publication Date:
December 12, 2013
Filing Date:
June 10, 2013
Export Citation:
Assignee:
TAMRON KK (JP)
International Classes:
G02B15/20; G02B13/18
Foreign References:
| JP2012048199A | 2012-03-08 | |||
| JP2011085909A | 2011-04-28 | |||
| JP2007156251A | 2007-06-21 | |||
| JP2003066334A | 2003-03-05 | |||
| JPH09189862A | 1997-07-22 | |||
| JP2007212847A | 2007-08-23 | |||
| JP2007178769A | 2007-07-12 | |||
| JP2010237455A | 2010-10-21 | |||
| JP2011048320A | 2011-03-10 |
Attorney, Agent or Firm:
TSUJII Koichi et al. (JP)
辻居 Koichi (JP)
辻居 Koichi (JP)
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