Title:
OBJECTIVE LENS
Document Type and Number:
Japanese Patent JP2010281847
Kind Code:
A
Abstract:
To provide an objective lens the image height characteristic of which is good, and the lens thickness of which is made thin as far as possible while taking an operation distance and an edge thickness to a certain extent.
The objective lens is used for recording/reproducing to/from an optical recording medium. At least one of first and second surfaces provided facing each other is formed to be an aspheric surface. The objective lens satisfies following expressions: t<1.1×f and t>1.52×f-0.79, wherein t is an objective lens thickness on the axis, and f is an objective lens focal distance.
Inventors:
SONODA KATSUMORI
NAKAYAMA TAKASHI
KAMEDA HIROSHI
NAKAYAMA TAKASHI
KAMEDA HIROSHI
Application Number:
JP2007257201A
Publication Date:
December 16, 2010
Filing Date:
October 01, 2007
Export Citation:
Assignee:
ALPS ELECTRIC CO LTD
International Classes:
G02B13/00; G02B13/18; G11B7/135
Attorney, Agent or Firm:
Koji Hirokawa
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