Laser power control arrangements in electro-optical readers

US7609736B2 · kind B2 · utility

Assignee

• Symbol Technologies, LLC · US

Inventors

• Costanzo Difazio · East Patchogue, US
• Vladimir Gurevich · Stony Brook, US
• James Giebel · Northport, US
• Gary G. Schneider · Stony Brook, US
• Matthew D. Blasczak · Shirley, US
• Mark Weitzner · Union, US
• Edward Barkan · Miller Place, US

Key dates

• Filing date: Sep 30, 2005
• Grant date: Oct 27, 2009
• Expiry date: Jan 21, 2026

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S5/0683
• WIPO field: Optics
• WIPO sector: Instruments

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 regulatory standards. In one embodiment, during an operational mode, a difference between laser drive currents at two operating points is compared to a difference between laser drive currents at the same two operating points during a calibration mode. The over-power condition is recognized when the difference during the operational mode exceeds the difference during the calibration mode by a predetermined amount. In another embodiment, the laser is only energized to emit the beam at a reduced power level well below regulatory standards for staring at even if a motor drive failed.