OPTICAL LENS, IMAGING UNIT AND METHOD FOR MANUFACTURING OPTICAL LENS

摘要

PROBLEM TO BE SOLVED: To provide techniques capable of reducing coat cracks or wrinkles generating when an antireflection film is heated in a reflow process and maintaining durability of the antireflection film.SOLUTION: An optical lens includes an antireflection film on a lens surface and is subjected to a reflow process. The antireflection film comprises a porous BaFfilm. A method for manufacturing an optical lens includes: a first film formation step of forming a BaF2 film layer by vapor deposition of BaF2 on a lens surface; a second film formation step of forming a film layer of a high refractive index material by vapor deposition of a high refractive index material having a refractive index higher than that of BaF2 on the BaF2 film layer; and a third film formation step of forming a BaF2 film layer by vapor deposition of BaF2 on the film layer of the high refractive index material. A multilayer antireflection film is formed on the lens surface by alternately carrying out the second film formation step and the third film formation step.