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:
May. 27, 1997
Filed:
Dec. 27, 1994
Takanori Maeda, Tsurugashima, JP;
Hajime Koyanagi, Tsurugashima, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
An optical pickup device for writing or reading data from an optical information recording medium has a recording layer whose state changes in response to a density of intensity of an irradiated light beam and a track being used for a tracking servo control system. The device includes a first light spot irradiating element for irradiating a writing or reading light beam onto the recording layer to form a writing or reading spot and a second light spot irradiating element for irradiating at least one controlling light beam onto the recording layer to form a controlling spot having a major axis extending along the track and being longer than a transverse axis perpendicular to the major axis within a level of luminous flux density keeping an original state of the recording layer, whereby a tracking servo control signal having a sufficient level is obtained.