| 摘要 |
PURPOSE: To prevent a diffracted light from being scattered, by arranging an optical element in an optical path and making the surrounding part of a diffraction grating a protruded state. CONSTITUTION: A laser diode 20 is mounted on an optical system support 21 and a light beam is projected to a diffraction grating 22. The diffraction grating 22 is configured by integrally forming a grating part 22a and a torus lens barrel 22b in the surrounding thereof. The torus lens barrel 22b in the surrounding of the grating part 22a is arranged higher than the grating part 22a. Thus, the grating part 22a is protected by the torus lens barrel 22b, the number of components is reduced, the assembling man-hours is decreased and error in the assembling is decreased. |
