Method and apparatus for extending and confirming the service life of semiconductor laser of bar code reader by detecting current increase corresponding to temperature of semiconductor laser
US5334826A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1992 |
| Grant date | Aug 2, 1994 |
| Priority date | — |
| Expiry date | May 8, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/0683
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A semiconductor laser control method and apparatus includes a semiconductor laser, a semiconductor laser control circuit, a drive current measuring unit, a detection unit, a warning unit, and a memory unit. The memory unit stores initial drive current values and corresponding temperatures. The detection unit performs a step of comparing an actual drive current value measured by the drive current measuring unit with the initial drive current value corresponding to an actual temperature. The warning unit performing a step of generating an alarm predicting the expiration of service life of the semiconductor laser, when the actual drive current value exceeds the corresponding initial drive current value by a specified percentage. Consequently, the near expiration of the service life of the semiconductor laser can be confirmed and therefore render the operational effects such as replacement of the semiconductor laser, without causing any hindrance to the operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.