Laser light scanner

TLDR: In this paper, a pair of rotating plates with plural disk elements and different scanning speeds are used to execute plane scanning by a rotating system and the need for a driving system for the plane scanning is eliminated.

Abstract: PURPOSE:To simplify constitution by disposing a pair of hologram rotating plates which are provided with plural disk elements and have different scanning speeds in such a manner that grating directions are different when the disk elements face each other and executing plane scanning by a rotating system. CONSTITUTION:The laser light from a semiconductor laser 1 is circularly polarized through a collimating lens 2 by a quarter wave plate 7. This light is polarized by 1st and 2nd hologram units 4, 5 and a light spot 10 is formed on a scanning surface 6 by an f.theta lens 5. The diffraction gratings of the disk elements 14, 13 of the units 4, 3 are formed respectively in the direction perpendicular to the radius direction of the disks and in the radial direction. The number omega1 of revolutions of the 1st disk rotating plate 14 and the number omega2 of revolutions of the 2nd disk rotating plate 13 are set at omega2>omega1 and while the spot 10 is linearly scanned on the surface 6, the spot is moved successively in the direction Y so that the plane scanning is eventually executed. The need for a driving system for the plane scanning is, therefore, eliminated and the constitution is simplified.