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.

Date of Patent:
Sep. 05, 2000

Filed:

Apr. 29, 1998
Applicant:
Inventors:

Takashi Masaki, Kawasaki, JP;

Shigenori Yanagi, Kawasaki, JP;

Assignee:

Fujitsu Limited, Kawasaki, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 54 ; 369116 ; 369 58 ;
Abstract

A light emission adjustment processing unit of a laser diode sequentially instructs a D/A converter for light emission of a light emission by test powers at predetermined two points, allows the laser diode to emit the light, instructs a D/A converter for subtraction of subtraction currents corresponding to the test powers at two points, and measures each power by an A/D converter for monitoring. From the measurement results, a relation of the instruction values to an arbitrary power in each D/A converter is obtained by a linear approximation and registered into a power table. When deciding an optimum writing power by a test write, a limit power on the lower limit side is detected while gradually decreasing the writing power from a starting power and a predetermined offset is added to the detected limit power, thereby obtaining the optimum writing power.


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