| 摘要 |
PURPOSE:To increase the degree of freedom for the arrangement of an optical sensor for synchronous detection for synchronization in optical scan. CONSTITUTION:A lens 4 arranged on an optical path between an optical deflector 3 and a plane to be scanned in an optical scanner which performs the optical scan by deflecting a beam of light from a light source device 1 in unmagnified angular velocity fashion by the optical deflector 3, and converging a deflected beam of light on the plane to be scanned by an image-forming lens as a light spot is formed in simplex structure by unifying an image-forming lens part 41 provided with a linearity correction function and which converges the deflected beam of light on the plane to be scanned with a lens part 42 for synchronous detection which converges the deflected beam of light on the optical sensor 8 for synchronous detection, and different image-forming characteristics are attached on the image-forming lens part 41 and the lens part 42 for synchronous detection, respectively. |
