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:
Aug. 10, 1993
Filed:
Jan. 15, 1991
Shigeru Nakamura, Tachikawa, JP;
Eiichi Seya, Hachioji, JP;
Seiichi Mita, Kanagawa, JP;
Masuo Kasai, Nishinomiya, JP;
Masahiro Ojima, Tokyo, JP;
Hiroshi Yasuoka, Fujisawa, JP;
Motoyasu Terao, Tokyo, JP;
Yoshinori Miyamura, Tokyo, JP;
Takeshi Nakao, Sagamihara, JP;
Kiyoshi Matsumoto, Kokubunji, JP;
Yoshihiro Hamakawa, Koganei, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A separation type optical head according to the present invention includes at least a light source portion for emitting collimated beams, a focusing device (a focusing lens) for focusing the collimated beams onto an information recording surface of an optical disc medium, a focal point control mechanism for the position of the spot on the information recording surface, and a photo-detection portion for receiving beams reflected by the information recording surface. The structure is divided into a fixed portion including the light source portion and the photo-detection portion and a movable portion including the focusing device (focusing lens) and the focal point control mechanism. At least the movable portion of the separation type optical head is movably accommodated n a frame (sealing case) for the optical head so as to prevent irregular vibrations of the movable portion due to high speed air flows or turbulence. Furthermore, a focal point control mechanism of an air float type may be employed in the movable portion of the separation type optical head so as to actively utilize the high speed air flow generated due to the rotation of the disc medium to perform a rough adjustment of the focal point of the focusing device.