Light detecting apparatus

摘要

A light detecting apparatus has a two-axis deflector such as a two-axis mirror capable of controlling the deflection of a light beam. The apparatus realizes a sure and speedy light beam search operation without increasing deflecting frequencies of the two-axis deflector. In the light detecting apparatus, a digital signal processor ( 3 ) generates two periodic signals having different frequencies to separately control deflective operations in two axial directions of the two-axis deflection mirror ( 1 ). A light beam from the two-axis deflection mirror ( 1 ) draws a locus on a two-dimensional position sensitive detector ( 2 ). Along the locus, the search operation is carried out to find an orientation of a light emitting element that emits a light beam toward the two-axis deflection mirror ( 1 ).