Patent ID: 8624951

Claim:
An optical scanning device that scans a scanning surface with a light beam, the optical scanning device comprising: a light source that emits the light beam; and a pre-deflector optical system that includes at least one diffractive optical element including a diffraction surface, wherein the at least one diffractive optical element includes an edge portion around an outer circumference thereof, the edge portion being perpendicular to an optical axis and bonded to a holding member with UV curable resin, and the transmittance of light at the edge portion is at least 30%, wherein the diffraction surface has a multi-step shape having a plurality of zone surfaces, all of the zone surfaces are perpendicular to the optical axis, each of the plurality of zone surfaces includes a first end and a second end such that each of the plurality of zone surfaces is oriented perpendicular to the optical axis along an entire length of the zone surface from the first end to the second end, and the multi-step shape includes a plurality of step surfaces, a step surface of the plurality of step surfaces is provided respectively between each zone surface and a subsequent zone surface, and wherein the light source includes a plurality of light-emitting units and a plurality of light beams from the respective light-emitting units enter a same diffractive optical element.