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:
Sep. 05, 2000
Filed:
Jun. 01, 1998
Mitsuya Okada, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
There is provided an apparatus for optical recording, reproducing and erasing data into or from a recording medium, including an optical head for recording, reproducing or erasing data into or from a recording medium by emitting a light to the recording medium, the optical head including at least an objective lens and a laser diode, a sensor for sensing a thickness of the recording medium, and a focal distance compensator for varying a focal distance of the light in accordance with a thickness sensed by the sensor, the focal distance compensator including a convex lens located between the objective lens and the laser diode and designed to be able to located in or out of an optical path. In accordance with the above-mentioned apparatus, a thickness of a recording medium is readily measured by the sensor, and the focal distance compensator adjusts a focal distance of a light emitted from the light source in accordance with the measured thickness of a recording medium. Hence, it is always possible to properly record, reproduce and erase data into or from a recording medium.