LASER UNIT AND ITS FAULT PREVENTING METHOD

PROBLEM TO BE SOLVED: To provide a laser unit which can prevent a fault in a laser diode more reliably and more inexpensively, and also a method of preventing a fault in the laser unit. SOLUTION: The laser unit 1 has a substrate (semiconductor chip 11) having a laser diode 12 and a photodiode 13 for...

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Bibliographic Details
Main Author NAITO HAYATO
Format Patent
LanguageEnglish
Published 08.11.2007
Subjects
BASIC ELECTRIC ELEMENTS
DEVICES USING STIMULATED EMISSION
ELECTRICITY
INFORMATION STORAGE
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER
PHYSICS
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Summary:PROBLEM TO BE SOLVED: To provide a laser unit which can prevent a fault in a laser diode more reliably and more inexpensively, and also a method of preventing a fault in the laser unit. SOLUTION: The laser unit 1 has a substrate (semiconductor chip 11) having a laser diode 12 and a photodiode 13 for detecting the amount of light emitted from the laser diode 12 mounted thereon. The laser unit comprises a detection resistance 14 connected in series with or in parallel with the photodiode 13 for detecting an output current of the photodiode 13, and a current control means (protection circuit 30) connected in series with the laser diode 12 for controlling a drive current flowing through the laser diode 12 on the basis of a detection result of the detection resistance 14. The detection resistance 14 has a resistive value different from a resistive value of the resistance when mounted onto the substrate (semiconductor chip 11). COPYRIGHT: (C)2008,JPO&INPIT
Bibliography:Application Number: JP20060123152