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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Main Author | |
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Format | Patent |
Language | English |
Published |
08.11.2007
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Subjects | |
Online Access | Get full text |
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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 |
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Bibliography: | Application Number: JP20060123152 |