温度変化に伴う3色の相対光軸ずれを抑制する半導体レーザの把持構造

抄録

A laser-scanning projector displays images by combining red, green, and blue laser beams into a single beam and by scanning the beam in a raster pattern by using a two-axis movable mirror. This projector requires opto−mechanical assembly technology that aligns the optical axes of the beams and maintains this condition despite environmental changes. One main reason for the optical axis alignment deviating is the difference in the amount of warps of laser chips between the red laser beam and the others during temperature changes. A set of laser holders is thus proposed whose right-to-left ratios of widths around the laser diode differ in accordance with the lengths of laser chips. The proposed laser holders with asymmetric thickness distributions can compensate for the difference in the amount of thermal warps of laser chips between them. The calculated results show that using the laser holders with asymmetric thickness distributions can reduce relative optical axis deviations below 30% compared with using laser holders with symmetric thickness distributions in the temperature range of 0 to 65 °C.