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:
Dec. 19, 2006
Filed:
Jul. 15, 2004
Daisuke Ogata, Hyogo, JP;
Daisuke Ogata, Hyogo, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical head includes a laser source () irradiating the laser beam having a wavelength not longer than 500 nm, a collimator lens () for collimating the laser beam to the parallel rays, an optical beam shaping system () that adjusts the cross sectional shape of the beam from the collimator lens, and an objective lens () that converges the beam on an optical information medium. The optical head has a relationship between a focal length fof the collimator lens and a magnification M of beam shaping satisfies the following equation: in which C is a constant in (λ·mm), Ais a maximum astigmatism per displacement of the collimator lens from the focal position, and n is a refractive index of a member of optical beam shaping system.