The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 06, 2009
Filed:
Jun. 04, 2007
Kouki Hozumi, Shibuya-ku, JP;
Masato Miyata, Shibuya-ku, JP;
Tomoyuki Satori, Shibuya-ku, JP;
Olympus Imaging Corp., Tokyo, JP;
Abstract
The invention relates to a zoom lens favorable for offering a tradeoff between slimming down a lens system upon received in an associated lens mount and making sure a small F-number. There is a zoom lens provided, which comprises, in order from its object side, a first lens group Ghaving negative refracting power, a second lens group Ghaving positive refracting power, and a third lens group Ghaving positive refracting power. Upon zooming from a wide-angle end to a telephoto end, the first second and third lens groups GGand Geach move along an optical axis while a spacing between the first lens group and the second lens group becomes narrow and a spacing between the second lens group and the third lens group becomes wide. The first lens group Gcomprises one single lens that is a double-concave negative lens or two lenses: a double-concave negative lens and a positive lens. The second lens group Gcomprises two positive lenses and one negative lens. At least one of the positive lenses has an aspheric lens surface. The zoom lens satisfies condition (1) that defines the relation between the total length of the lens system and the height of a marginal ray at the entrance surface in the first lens group G