Light beam scanning device generating a stable synchronizing signal

摘要

A light beam scanning device includes a reference grid plate, a resonant light deflector for deflecting a light beam to cause the light beam to scan the reference grid plate through an f theta lens for thereby enabling the reference grid plate to produce a pulse signal, and a PLL circuit for generating a synchronizing signal from the pulse signal to read or record image information. The reference grid plate has slits defined at intervals, the slit intervals in that area of the reference grid plate which produces a pulse signal that is not directly contributed to the recording or reading of the image information being progressively smaller toward an end of the reference grid plate according to the scanning speed of the light beam.