Patent ID: 7193762

Claim:
A scanning optical apparatus comprising: light source means; a converting optical system for converting a light beam emitted from the light source means into a light beam of another state; deflecting means for deflecting the light beam and for scanning with the light beam passed through the converting optical system; and an imaging optical system for directing the light beam deflected by the deflecting means onto a surface to be scanned; wherein the light source means is a vertical cavity surface emitting laser having a plurality of light emitting points, and either of the following pairs of conditional expressions 3≦Fnos<Fnom≦15 and dθs/dT<dθm/dT or 3≦Fnom<Fnos≦15 and dθm/dT<dθs/dT is satisfied, where Fnom and Fnos represent the F number of the light source means side of the converting optical system in a main scanning direction and the F number thereof in a sub-scanning direction, respectively, θm and θs represent the half value angle of the far field pattern of the light beam emitted from the light source means in the main scanning direction and the half value angle of the far field pattern thereof in the sub-scanning direction, respectively, and dθm/dT and dθs/dT represent the fluctuations of the half value angles θm and θs of the far field pattern due to change in environmental temperature dT, respectively.