Patent ID: 7711018

Claim:
An apparatus comprising: a laser diode having a nonlinear current to output luminance characteristic; a look-up table to map desired luminance values to nominal laser diode current values, wherein the look-up table compensates for the nonlinear current to output luminance characteristic in the laser diode by combining a mapping component with the nonlinear current to output luminance characteristic of the laser diode to provide a substantially linear response between the desired luminance values and the nominal laser diode current values, wherein the mapping component is substantially an inverse of the nonlinear current to output luminance characteristic of the laser diode; a multiplier coupled to multiply the nominal laser diode current values by a gain value; and a feedback loop to measure actual output luminance and adjust the gain value, wherein the look-up table is operable to periodically output a desired luminance value corresponding to a periodic calibration pulse, wherein laser diode output for the calibration pulse does not represent brightness of successive pixels to be displayed, and wherein the feedback loop comprises circuitry to measure the actual output luminance of the calibration pulse.