Arrangement for and method of regulating laser output power in electro-optical readers
US8733659B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 2010 |
| Grant date | May 27, 2014 |
| Priority date | — |
| Expiry date | Apr 28, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10584
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In an electro-optical reader, an aiming or a scanning laser has a laser chip and a monitor photodiode. Output power of a laser beam emitted by the laser is regulated by a feedback circuit for maintaining substantially constant the laser beam output power during normal operation, a disabling circuit for disabling the feedback circuit, a drive circuit for driving the chip with a drive current when the feedback circuit is disabled, and for concomitantly generating a photodiode output voltage, a current modification circuit for modifying the drive current by a predetermined current with a concomitant change in the photodiode output voltage when the feedback circuit is disabled, and a control circuit for monitoring the change in the photodiode output voltage, for determining whether the change in the photodiode output voltage is sufficient to indicate an over-power condition, and for interrupting power to the chip when the over-power condition is indicated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.