Patent Number: 6,295,079

Title: Scanning optical unit

Abstract: A scanning optical unit is provided which can prevent flare reflection of alaser beam at an end portion of a reflecting mirror which is providedoutside an exposure region and which is for detecting a time of startingof exposure by the laser beam. In the scanning optical unit, given that apropagation distance from a transducer of an acousto-optic modulator (AOM)to a diffracted position of the laser beam passing through anacousto-optic modulating medium is L, a propagation speed of ultrasonicwaves within the acousto-optic modulating medium is V, a main scanningspeed of the laser beam is v, a distance from a position on a reflectingmirror at which the laser beam is reflected onto an SOS sensor to arecording medium side end portion of the reflecting mirror is l, and afocal length of an f.theta. lens is f, a relationshipL<l.multidot.V/{v.multidot.(f-t)/f} is established so as to prevent flarereflection of the laser beam.

Inventors: Saito; Kenichi (Kanagawa, JP)


International Classification:

Expiration Date: 09/25/2013