| 摘要 |
PURPOSE:To obtain the small-sized, inexpensive device by providing plural laser diodes successively and inspecting a linear area on the surface of a body to be inspected by a linear scan. CONSTITUTION:Laser light radiated from a light source 10 constituted by providing plural laser diodes successively is converged through a cylindrical lens 12 to illuminate uniformly the linear area P' on a wafer 4 on a rack 7. Further, three array photoelectric detecting elements 8-1, 8-2, and 8-3 are arrayed in opposition to a line P'', a cylindrical lens 16 is arranged while the line P'' faces a line P', and the line P'' is set on its optical axis 16a in parallel to the line P'. Reflecting mirrors 17-1 and 17-3 are so provided that the laser light converged by the lens 16 along the optical axis 16a is made incident on the elements 8-1 and 8-3. An element 8-2 is equipped with no reflecting mirror and provided on the optical axis 16a, and those elements are arranged in three dimensions so that their optical path lengths are equal. Thus, plural inexpensive laser diodes are arranged to obtain the surface inspecting device which illuminates the linear area uniformly. |
