Method of projecting a line image of uniform brightness

摘要

A line image of uniform brightness is obtained from laser beam in spite of its Gaussian distribution of intensity about its optical axis by taking advantage of the fact that the intensity distribution is symmetrical. A laser beam emitted from a laser is diverged into a flat beam by means of a cylindrical lens. The flat beam is divided into two portions along a line passing normal to the flat beam through its optical axis. The two portions are projected onto the surface to be illuminated and superimposed thereon to form a line image cooperatively with each other. The two portions are superimposed so that the maximum intensity area of one portion falls on the minimum intensity area of the other.