Patent ID: 6606179
Filing Date: 2003-08-12
Classification: G02B

Abstract:
A line-image forming optical system of an optical scanning device through which a beam from the light source is transformed into a beam in a predetermined style by a coupling optical system, the beam is caused to form a line image long in main scanning direction by the line-image forming optical system, then, is deflected by a light deflector having a deflection reflective surface on or in the proximity of the imaging position of the line image, the deflected beam is condensed toward a surface to be scanned by a scanning and imaging optical system, a beam spot is formed on the surface to be scanned, and optical scanning of the surface to be scanned is performed,wherein: said line-image forming optical system comprises at least one resin-made imaging mirror and at least one glass-made lens; said at least one resin-made imaging mirror has at least one surface having a negative power in main scanning direction and a larger negative power in sub-scanning direction; and the powers of respective surfaces of said at least one resin-made imaging mirror are set so that shift of image surface occurring due to temperature change of the coupling optical system and/or scanning and imaging optical system is effectively reduced.