METHOD AND APPARATUS FOR CONTROLLING AND MONITORING LASER POWER IN BARCODE READERS

摘要

A method of monitoring the output power of a laser diode in a barcode reader. The method includes sampling a threshold monitoring-current that is related the driving-current passing through the laser diode during a first time period when this current is at the lasing threshold of the laser diode. The method includes generating a threshold-compensated monitoring-current by subtracting the threshold monitoring-current from the above-threshold monitoring-current. The method includes monitoring the output power of the laser diode in the barcode reader at least partially based on the threshold-compensated monitoring-current.