| 摘要 |
PURPOSE:To increase the lateral width of projection light and to uniform the light quantity distribution in an area to be detected by providing a spatial filter in a specific shape which passes only sheet-shaped beam light and a reflecting mirror which has a specific reflection factor. CONSTITUTION:The quantity I(x,y) of laser beam light l2 emitted by a projection optical system 12 is shown by an equation I [where K is a proportional constant and Wx and Wy are the 1/e<2> width (e: natural number) of the beam light l2] and the light quantity distribution of laser beam light l3 passed through the spatial filter 19 in the specific shape is shown by expressions II wherein diffraction is ignored. Then when the laser beam l3 is reflected by the reflecting mirror 18 whose reflection factor R(X) is distributed as shown by an equation III, the deficiency of the light quantity distribution of laser beam light l4 is corrected and the quantity of light per unit area in the area 16 to be detected is made uniform. |
