| 摘要 |
PURPOSE:To satisfactorily reduce a speckle, while securing the uniformity of an illumination, by determining the arrangement and constitution of a lens element constituting a fly-eye lens. CONSTITUTION:As for a laser beam LB from a light source 10, an optimum exposure quantity is taken into consideration and an exposure quantity per one pulse is set, and the light quantity adjustment is executed by a light-reducing filter 24. Subsequently, the light LB is made incident on a vibrating mirror 16 through lenses 12, 14, and the mirror 16 vibrates at a prescribed angle, and vibrates the light LB. Subsequently, the light LB passes through a collimator lens 26 and a fly-eye lens 28, and on a reticle R, the laser beam becomes a uniform light quantity distribution. Also, the number of spots of a secondary light source Q and its distribution width, the number of arranged lens elements of the fly-eye lens 28 and its interval are set to set values. In such a way, it does not occur that the light LB transmitted through each lens element respectively interferes and generates a speckle.
|
