Light source degeradation detecting apparatus for laser device

Abstract

A light source degradation detecting apparatus for a laser device monitors drive currents and output laser beams. The degradation detecting apparatus includes drivers for supplying three drive signals to the laser, a photodiode for detecting laser outputs produced in response to the drive signals, a memory for storing measured values and the drive signals, and a discriminator for calculating ratio P from storage data (laser outputs W.sub.n, W.sub.n+1, and W.sub.n+2 produced in response to drive currents I.sub.n, I.sub.n+1, and I.sub.n+2) as follows: P={(W.sub.n+2 -W.sub.n)/(I.sub.n+2 -I.sub.n)}/{(W.sub.n+1 -W.sub.n)/(I.sub.n+1 -I.sub.n)} and for discriminating that the laser has reached an end of its life when the ratio P falls outside a predetermined range.

Dependencies are inferred from the claim text.