US 11,693,161 B2
Diffractive optical element, method for producing diffractive optical element, optical device, and image pickup apparatus
Mamo Matsumoto, Kanagawa (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Nov. 11, 2020, as Appl. No. 17/95,533.
Claims priority of application No. 2019-213739 (JP), filed on Nov. 26, 2019.
Prior Publication US 2021/0157040 A1, May 27, 2021
Int. Cl. G02B 5/18 (2006.01); C08G 75/045 (2016.01); C08F 220/30 (2006.01)
CPC G02B 5/1842 (2013.01) [C08F 220/303 (2020.02); C08G 75/045 (2013.01); G02B 5/1857 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A diffractive optical element, comprising:
two resin layers,
wherein one of the two resin layers is a first resin layer having a diffraction grating shape and containing a thiol group and a sulfide group,
wherein the other of the two resin layers is a second resin layer having a diffraction grating shape,
wherein when measurement is performed by laser Raman spectroscopy, α<β, where α is a ratio of intensity of a peak corresponding to the sulfide group to intensity of a peak corresponding to the thiol group in a first region of the first resin layer, the first region containing no interface between the first resin layer and the second resin layer, and β is a ratio of intensity of a peak corresponding to the sulfide group to intensity of a peak corresponding to the thiol group in a second region containing an interface between the first resin layer and the second resin layer, the second region being smaller than a total thickness of the two resin layers.