Automatic light intensity controller for CRT lighthouse
Automatic gain control for photosensing devices
Versatile digital controller for light emitting semiconductor devices Patent #: 4592057
ApplicationNo. 06/835557 filed on 03/03/1986
US Classes:372/33, PARTICULAR OPERATING COMPENSATION MEANS250/205, Controlling light source intensity372/26, Modulation372/29.011, Feedback circuitry372/31, Amplitude398/175, Regenerative398/177, Monitoring398/195Including feedback
ExaminersPrimary: LaRoche, Eugene R.
Assistant: Shingleton, Michael B
Attorney, Agent or Firm
International ClassesH01S 5/0683 (20060101)
G06K 15/12 (20060101)
H01S 5/00 (20060101)
H01S 5/068 (20060101)
Foreign Application Priority Data1985-03-15 JP
AbstractA stabilized laser apparatus includes a semiconductor laser, a photodetector for detecting an output laser beam from the semiconductor laser, a differential amplifier for comparing the laser detection signal with a first or second reference signal, a window comparator for comparing a threshold range with an output from the differential amplifier, an up/down counter operated in response to an output from the window comparator, and a driving circuit for supplying a drive current to the semiconductor laser in accordance with a count of the up/down counter. A servo loop from the photodetector to the up/down counter is operated in response to an operation instruction signal or an adjustment instruction signal. The drive current is adjusted to coincide with a reference value before operation, and the adjusted drive current is stored in the up/down counter.