Laser driving circuit, laser driving method, and device using laser light

摘要

A laser driving circuit, a laser driving method, and a device using laser light that can reduce speckle noise caused by laser light as coherent light are provided. In the laser driving circuit that generates laser driving current for driving a plurality of laser light sources emitting laser light of different wavelengths on the basis of an input video signal, a high-frequency signal of a frequency exceeding the band of the video signal is superimposed on the laser driving current generated on the basis of the input video signal, whereby speckle noise caused by the laser light as coherent light is reduced.

主权项

1. A laser driving circuit comprising:
a plurality of laser driving video current generating circuits for generating laser driving current for driving a plurality of laser light sources emitting laser light of different wavelengths on a basis of an input video signal; and a high-frequency superimposing section configured to superimpose a high-frequency signal of a frequency exceeding a band of the input video signal on the laser driving current generated by the plurality of laser driving video current generating circuits; and an oscillator configured to output a signal source of the high-frequency signal, the high-frequency superimposing section includes a level change detecting circuit that is configured to supply a pixel period synchronizing signal to the oscillator, wherein the high frequency superimposing section is configured to change the amplitude of the high frequency signal in accordance with the a level of the input video signal, a signal synchronized with a change of the level of the input video signal is the pixel period synchronizing signal.