Verfahren und Vorrichtung zur Bildung eines kristallisierten Films

Since a laser light source emits a bundle of rays having a spread angle, a laser light transmitted through a plurality of level difference parts of an optical path difference generating member impinges on one lens part of an array lens to cause interference inevitably when an image is formed on an article to be illuminated. Means (2, 3) for dividing/contracting a laser light (1) in one side view into a plurality of split light beams (9) and obtaining a contracted split light beam (10) by separating each split light beam (9) to individual contracted bundle of rays, an optical path difference generating member (7) having a block (7a) for transmitting each contracted split light beam (10) individually while reducing reflection off the split surface side and generating an optical path difference mutually so as to adjust coherency, and a lens (5) for condensing the contracted split light beam (10) transmitted through the optical path difference generating member (7) are provided to a laser light source A emitting the laser light (1) as a bundle of rays having a spread angle ?, whereby a plane (6) to be irradiated is illuminated with a laser light superposed after being passed through the condenser lens (5).