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. 03, 2010
Filed:
Jun. 30, 2008
Laser diode control method, laser diode control device, and information recording/playback apparatus
Kenichi Nagashima, Yokohama, JP;
Kenichi Nagashima, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Even though a laser diode is within the operation guarantee temperature range, the rise time characteristics required to protect and maintain the writing quality right away may not be present at a lower temperature. By sufficiently increasing the rise time, a laser diode control method of the present invention makes it possible to write readily. A laser diode control device includes a temperature sensor for detecting temperature of a laser diode. When a detected temperature by the temperature sensor is equal to or below a predetermined value within the operation guarantee temperature range, a seek motor controls the position of a pickup to move the pickup to a region outside a recording region of a recording medium. In this way, a current exceeding a threshold current value is supplied to the laser diode, and the writing operation starts after the laser diode temperature is increased up to a level where the rise time characteristics required to protect and maintain the writing quality is present.