Patent ID: 9425584
Filing Date: 2016-08-23
CPC Classification: H01S

Claim Text:
1. A laser drive device that drives a laser diode, comprising: a detection unit configured to detect a light amount of a laser beam output from the laser diode; a light amount control unit configured to control the light amount of the laser beam output from the laser diode to a plurality of set light amounts by controlling a drive current supplied to the laser diode according to a detection output from said detection unit; a threshold current calculation unit configured to calculate a threshold current according to the detection output from said detection unit and a drive current supplied to the laser diode; and a control unit configured to switch and select the plurality of set light amounts, compare a plurality of threshold currents with each other which are obtained from said threshold current calculation unit with respect to the plurality of set light amounts, respectively, and determine a set light amount among the plurality of set light amounts as a determined set light amount for use in light amount control of the laser diode according to whether a difference in threshold currents corresponding to the determined set light amount and another set light amount among the plurality of set light amounts is not less than a predetermined value.