APERTURE MEMBER, OPTICAL SCANNING SYSTEM WITH SAME, AND IMAGE-READING DEVICE AND IMAGE-FORMING APPARATUS WITH THE OPTICAL SCANNING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an aperture member which can suppress unwanted reflection of a laser beam and substantially completely absorb the unwanted laser beam, and to provide an optical scanning system and an image-forming apparatus that use this aperture member.

SOLUTION: The aperture member 10 is disposed on the optical path of the laser beam and has a surface perpendicular to the beam axis and a hole to made the light flux of the laser beam pass through. The member has a anti-reflection structure, which is formed at least at a part on the perpendicular surface the laser beam passes and which is an array of predetermined shape units, arranged periodically with a pitch smaller than the wavelength of the laser beam. At least either of the anti-reflection structure itself or the area of the optical components, where the antireflection structure is formed, is made of a material capable of absorbing the laser beam.

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