| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical scanning device which stably performs optical scan without incurring a high cost and to provide an image forming apparatus. SOLUTION: An optical scanning device includes: a light source 1; a pre-deflector optical system; a polygon mirror 5; and scanning optical systems 7 and 8, wherein the pre-deflector optical system has at least one diffractive optical element. The diffractive optical element is a hybrid lens in which a resin layer is joined to a glass-lens base material, and a diffractive surface is provided in the resin layer. The diffractive surface of the diffractive optical element has a multi-step structure including a plurality of zonal surfaces substantially perpendicular to an optical axis and a plurality of step surfaces which are adjacent to the respective zonal surfaces. Thus, a high quality image is stably formed even when the change in environment or the unexpected change in oscillation wavelength of the light source 1 happens while keeping an easy machining and a low cost. COPYRIGHT: (C)2010,JPO&INPIT
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