Loading patent…
AssigneesCopal Company Limited, Fujitsu Limited
InventorsYukio Yoshikawa, Takeshi Ishii, Yoshihiro Oyama, Tatsuo Sasaki, Tamotsu Takahashi, Shinichi Sato, Kazumasa Moriya, Ichiro Shinoda, Motohiko Itoh, Tomoyuki Kashiwazaki, Hiroaki Kawai, Mitsuo Watanabe
Estimating the term…
A semiconductor laser driving circuit has a semiconductor laser for emitting a laser beam according to a drive power. A photodetector is provided for effecting photo-electric conversion of the laser beam to output a corresponding electric signal. A monitoring circuit is connected for monitoring the electric signal to output a monitor signal indicative of variation in intensity of the laser beam. A controlling circuit is connected for comparing the monitor signal with a given reference signal to output a control signal according to difference therebetween. A powering circuit is operative according to the control signal to apply to the semiconductor laser a drive power effective to eliminate the difference. An abnormality detecting circuit is provided for comparing the monitor signal with a given limit signal which is set different from the reference signal to detect abnormality to output an abnormality signal.
A semiconductor laser driving circuit comprising:
A semiconductor laser driving circuit comprising:
A semiconductor laser driving circuit for use in a bar code reader, comprising:
Dependencies are inferred from the claim text.