System and methods for laser beam display
A laser beam display device includes: a dimming setting input unit into which any one of the dimming values of plural dimming steps are input; a first dimming processing unit having plural dimming LUTs that store dimming amounts regarding the respective dimming steps with the corresponding gradation levels as indexes; a second dimming processing unit having one gain LUT that holds gains regarding the respective dimming steps and a multiplier that creates the indexes for the respective dimming LUTs by multiplying a video signal by the gains; and a light source drive unit that drives a laser diode on the basis of reference results obtained by referring to the dimming LUTs of the first dimming processing unit. The luminance of the emission beam of the laser diode, which corresponds to the video signal, is dimmed in accordance with a dimming setting input from the dimming setting input unit.
1. A laser beam display device in which semiconductor laser light emitted from a laser diode is modulated by a video signal to emit an emission beam, and an image corresponding to the video signal is displayed by scanning the emission beam, the laser beam display device comprising:
one or more memories; a dimming processing circuit coupled to the one or more memories and configured to:
receive a dimming setting corresponding to one of a plurality of dimming steps is input;
store a plurality of dimming look-up tables each corresponding to one or more of the plurality of dimming steps, each dimming look-up table storing a dimming amount for each of a plurality of gradation levels of the video signal at indexes of the table;
store a gain look-up table that holds a gain value corresponding to each of the dimming steps and a multiplier that select one of the indexes of the dimming look-up tables by multiplying the video signal by the gain value; and
drive the laser diode using the selected one of the indexes of the dimming look-up tables,
wherein a luminance of the emission beam of the laser diode, which corresponds to the video signal, is dimmed in accordance with the dimming step,
wherein the dimming step comprises two dimming step parts, the first dimming step part comprising one of a plurality of discrete values and the second dimming step part comprising one of a plurality of steps between two adjacent discrete values, and
wherein each of the plurality of dimming look-up tables corresponds to the first dimming step part and the gain value corresponds to the second dimming step part.
2. The device of claim 1 , wherein the dimming setting comprises a luminance detection value from an external luminance sensor.
3. The device of claim 1 , wherein the dimming setting comprises a setting value set by a user.
4. The device of claim 1 , wherein the dimming amounts for each gradation levels of the video signal corresponds to a drive current compared to light output power characteristic of the laser diode.
5. The device of claim 1 , wherein the dimming processing circuit to select one of the plurality of look-up tables corresponding to the dimming step and output the selected one of the indexes corresponding to the selected one of the plurality of look-up tables to drive the laser diode.