| 摘要 |
PURPOSE:To obtain a semiconductor laser optical system which converges even light in a low output range where natural emitted light is dominant to a small spot diameter and can utilizes it as scanning light, etc., by compensating the chromatic aberration of a collimator lens provided on the optical path of light emitted by a semiconductor laser. CONSTITUTION:The light oscillated by the semiconductor laser 1 is incident on the collimator lens 3 consisting of lenses 3A-3D provided on the optical path and made into parallel light, which impinges on a rotary polygon mirror 5 after passing through a beam shaping optical system 4. The reflected and deflected light 2 is incident on a condenser lens 6 and converged on a scanning surface 7 to make a scan repeatedly. When the light in the low light emission range where natural emitted light is dominant is used as the scanning light, the convergence spot diameter of the light on the scanning surface 7 becomes larger than that of light in a high output range where the laser oscillated light is dominant because of the chromatic aberration of the lenses on the optical path. For the purpose, the collimator lens 3 compensates the chromatic aberration and even the light in the low light emission range is converged to a spot diameter smaller than before.
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