| 摘要 |
PURPOSE:To make all of laser light parallel and to improve its utilization efficiency by allowing a lens which makes divergent light differing in radiation angle in an X and a Y direction parallel to have two focuses corresponding to equivalent light emission points in the XY direction. CONSTITUTION:The divergent light from a semiconductor laser 2 has different spread angles in the X-axis and Y-axis direction and the Fresnel lens 1 which makes the divergent light parallel has equivalent light emission points PX and PY determined by the radiation phim of the X-axially and Y-axially divergent light components on the lens surface and the thickness distribution dm of the lens 1 form equations based upon two focal lengths fx and fy and the lens 1 is manufactured according to equations I and II. Thus, all of the laser light is made parallel to improve its utilization efficiency. In the equations I and II, (k) is a wave number and (d) is lambda/(n-1) [lambda: wavelength of laser beam, (n): refractive index of lens material]. |
