Patent ID: 7723659

Claim:
A method of screening a semiconductor laser comprising: (a) operating the laser at a first of a number (D) of discrete drive currents in a range of drive currents; (b) acquiring a number (N) of frames of data from a sensor in an optical navigation system (ONS) receiving speckle pattern in light from the laser reflected from a surface proximal to the ONS, the sensor data including differential signal values; (c) calculating an average differential signal value (AVG value) for the N frames of data; (d) sorting the N frames of data across a plurality of bins, the plurality of bins including at least a Bin — 0 for frames of data having a differential signal value within a predetermined amount of the AVG value; and (e) determining if a number of frames of data in any of the plurality of bins other than Bin — 0 exceed a predetermined threshold, and if the number of frames of data in any of the plurality of bins exceed the predetermined threshold, recording the drive current.