JPS6424219A - Hologram scanner - Google Patents

Abstract

PURPOSE:To obtain a function as an image scanner without using an additional optical system for an image-reformation function by setting only a part of a surface relief type hologram as a laser beam zone where a laser beam is made incident thereon and setting the part except the above-mentioned part as a reflection type hologram zone. CONSTITUTION:In a hologram disk 15, a band part where the laser beam from a semiconductor laser 11 is transmitted, that means, the laser beam zone 31 is removed and a reflecting film 33 is vapor-deposited all over the surface so as to form a transmissive type grading area 34 and a reflecting type grading area 35 surrounding both sides of the area 34. Namely, in case of working as a usual hologram scanner, the laser beam from a light source through the laser beam zone 31 is scanned in a specified direction as usual. Meanwhile, in case of working as the image scanner, most of the reflected light from a medium, as for the wave surface in plane symmetry, is reflected and diffracted in the specified direction by the reflecting type hologram to be converged into a detector 50. Thus, the image scanner can be easily obtained without substantially adding the additional optical system.