Apparatus and method for extending laser life by discontinuous operation
US5212370A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1990 |
| Grant date | May 18, 1993 |
| Priority date | — |
| Expiry date | Nov 20, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K2207/1018
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The useful life of a laser, such as a laser diode, is extended by causing the laser to operate only intermittently when continuous operation is not required. When such a laser diode is used in a scanner for scanning coded symbols, such as bar codes, in merchandise check-out operations, continuous operation is required only when a coded symbol is present in a target area. A sensing device is provided for sensing the transitions in light reflected back from the target area, and a counter is provided for counting the number of such transitions. Since a much larger number of transitions are sensed and counted when a coded symbol is being read than when no such symbol is present in the target area, this difference in number of transitions is used to distinguish between the two conditions and to cause the laser diode to be turned on for continuous operation only when a coded symbol is present in the target area to be read.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.