| 摘要 |
PROBLEM TO BE SOLVED: To increase the stray light suppressing capability of the optical component used for light reflection, refraction, etc. SOLUTION: The absorption surface 24 of a microprism 20 is formed in a curved surface shape having a center point P0 and a radius R of curvature. Namely, the absorption surface 24 is in the same shape with part of a columnar flank having a radius R. The center point P0 is determined on the prolongation of a main light beam which is made incident on the absorption surface. The radius R of curvature is set equal to the optical path length r1+r2+r3 from the output of the main light beam of laser beam L3 by a laser diode to the incidence on the absorption surface 24. The microprism 20 having such an arrangement makes the main light beam of the laser beam L3, entering the microprism 20, incident on the absorption surface 24 at right angles. Further, divergent components of the laser beam L3 are also made incident on the absorption surface 24 at right angles as well as the main light beam. Consequently, even when an absorption film 25 has single-angle absorption characteristics, high stray light suppressing capability can be obtained. |
