Laser scanner having improved frequency characteristics

Abstract

A laser scanner is disclosed, in which M, the lateral magnification obtained from the first and the second optical members, V.sub.1, the scanning velocity of the scanning beam on the beam receiving surface and V.sub.s, the velocity of the acoustic wave inside the acoustic beam modulator are substantially related by M=-V.sub.1 /V.sub.s, comprising a laser beam emitter, an acoustic optical modulator which generates an acoustic wave having a specified direction of progression to modulate a laser beam emitted from the laser beam emitter and obtain a primary diffracted beam, a first optical member to make the primary diffracted beam a collimated beam, a beam deflecting means to deflect the collimated beam to make it a scanning beam, a second optical member to focus the scanning beam, a receiving surface positioned so that it is in a conjugate position with the acoustic optical modulator with respect to the first and the second optical members, and an aperture means positioned between the first optical member and the beam deflecting means and which restricts the beam in the direction of progression of the acoustic wave across the collimated beam, having a condenser lens which collects the laser beam emitted from the laser beam emitter in the acoustic optical modulator and in which an f.theta. lens is the second optical member.