Patent ID: 11940595
Assignee: HOYA LENS THAILAND LTD.
Field: Machine tools (Mechanical engineering)
Classification: CPC G  B  C | IPC C  G

Claim 6:
7. An optical member comprising:
an optical base member having an optical surface; and
an antireflection film covering the optical surface of the optical base member,
wherein the antireflection film comprises a multilayer structure in which a low refractive index layer and a high refractive index layer are layered on each other, and is formed such that the high refractive index layer is exposed as a result of a portion of the low refractive index layer of the outermost layer in the multilayer structure being removed, and
wherein, in the high refractive index layer that is exposed through removal of the low refractive index layer, a ratio t1/t2 between a thickness t1 of a removed portion of the low refractive index layer and a thickness t2 of a non-removed portion of the low refractive index layer is in a range of 0.90 or more and 1.00 or less.