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:
Jul. 14, 1998
Filed:
Feb. 06, 1997
So Ishika, Yokohama, JP;
Yuichi Nakamura, Minato-ku, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An optical head apparatus is disclosed, that comprises a first optical system having a first objective lens (20) and a low power output laser device (24) and a second optical system having a second objective lens (30) and a high power output laser device (37). The focal length of the first objective lens (20) is different from the focal length of the second objective lens (30). One of these optical systems is selected corresponding to the type of an optical disc for use. The energy use efficiency of laser beam of the optical head apparatus with the above-described structure is higher than that of an apparatus using a multi-focus lens. Thus, without need to use a light source having a high light intensity, data of various optical discs can be accurately reproduced. In addition, data can be more accurately and rapidly recorded on various optical discs with different record densities.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile