Title:
ZOOM LENS AND OPTICAL EQUIPMENT HAVING SAME
Document Type and Number:
WIPO Patent Application WO/2013/161197
Kind Code:
A1
Abstract:
In the present invention, the following are provided in order, from the object side: a first lens group (G1) having a positive refractive power; a second lens group (G2) having a negative refractive power; and a third lens group (G3) having a positive refractive power. When zooming from a wide-angle end state to a telescopic end state, the first lens group (G1) and the third lens group (G3) move towards the object side. The first lens group (G1) has a diffraction optical element (DOE) that joins two optical elements comprising an optical material in which the refractive index difference is no more than 0.45 with respect to the d line, and is provided with a diffraction optical surface (corresponding to the optical surface of curvature radius (R8) in fig. 1) on which at the interface of the two optical elements is formed a diffraction grid groove. The present invention satisfies the following conditional formulae, 0.05 <Φ1/ft < 1.00 and 3.0<Φd/y< 10.0, provided that Φ1 is the valid diameter of the surface of the first lens group (G1) that is closest to the object side; ft is the focal length of the overall system of a zoom lens (ZL) in the telescopic end state; Φd is the valid diameter of a diffraction optical surface; and y is the maximum image height of the zoom lens (ZL).
Inventors:
SUZUKI KENZABURO (JP)
Application Number:
PCT/JP2013/002326
Publication Date:
October 31, 2013
Filing Date:
April 03, 2013
Export Citation:
Assignee:
NIKON CORP (JP)
International Classes:
G02B15/20; G02B5/18; G02B13/18
Foreign References:
| JPH11305126A | 1999-11-05 | |||
| JP2004258239A | 2004-09-16 | |||
| JP2006285021A | 2006-10-19 | |||
| JP2012078397A | 2012-04-19 | |||
| JP2003215452A | 2003-07-30 | |||
| JP2004126391A | 2004-04-22 |
Attorney, Agent or Firm:
OHNISHI, Shogo et al. (JP)
Shogo Onishi (JP)
Shogo Onishi (JP)
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