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US 7,255,275 B2Granted
Laser power control arrangements in electro-optical readers
AssigneeSymbol Technologies, Inc.
InventorsVladimir Gurevich, Edward Barkan, Igor Vinogradov
Life of this patent
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Abstract
Laser power control arrangements interrupt power to a laser used in electro-optical readers upon detection of an over-power condition not conforming to preestablished standards to meet prevalent safety standards.
Claims11
A laser power control arrangement in a reader for electro-optically reading indicia, comprising:
- a) an energizable laser for emitting a laser beam to the indicia for reflection therefrom;
- b) a photodetector for detecting light reflected by the indicia during a reading mode, and for generating an electrical signal having a reading amplitude indicative of the light detected by the photodetector;
- c) a microcontroller for comparing the reading amplitude with a maximum amplitude, and for generating a control signal when the reading amplitude differs from the maximum amplitude by a predetermined amount;
- and
- d) a circuit for deenergizing the laser upon generation of the control signal.
2 more elements
A laser power control method, comprising the steps of:
- a) energizing a laser to emit a laser beam to a light-reflecting source for reflection therefrom during a calibration mode;
- b) detecting light reflected by the source during the calibration mode, and generating an electrical signal having a maximum amplitude indicative of the light detected during the calibration mode;
- c) energizing the laser to emit the laser beam to indicia to be electro-optically read for reflection therefrom during a reading mode;
- d) detecting light reflected by the indicia during the reading mode, and generating an electrical signal having a reading amplitude indicative of the light detected during the reading mode;
- e) comparing the reading amplitude with the maximum amplitude, and generating a control signal when the reading amplitude differs from the maximum amplitude by a predetermined amount;
- and
- f) deenergizing the laser upon generation of the control signal.
4 more elements
Dependencies are inferred from the claim text.