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:
Jun. 30, 1998
Filed:
Dec. 20, 1996
Motomichi Shibano, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
An optical head for an optical disk drive which can reduce the light power loss due to the beam characteristics of a laser beam to improve the efficiency of use of laser power. The optical head includes a laser diode, an objective lens for focusing a laser beam emitted from the laser diode onto an optical disk, an optical signal detector for detecting an optical signal from a reflected beam reflected on the optical disk, an error signal detector for detecting a focusing error and a tracking error of the laser beam focused on the optical disk from the reflected beam, and a collimator lens for collimating the laser beam emitted from the laser diode. Further, a hologram-lens unit is located between the laser diode and the collimator lens. The hologram-lens unit includes a gradient index microlens formed on one surface of a transparent substrate and a hologram formed on the other surface of the transparent substrate. The hologram transmits the laser beam emitted from the laser diode, and diffracts the reflected beam toward the error signal detector.