US 12,092,840 B2
Diffractive optical element, projection device, and measuring device
Toshiya Yonehara, Fukushima (JP); Ryota Murakami, Fukushima (JP); Koichi Tashima, Fukushima (JP); and Kensuke Ono, Tokyo (JP)
Assigned to AGC Inc., Tokyo (JP)
Filed by AGC Inc., Tokyo (JP)
Filed on Jul. 29, 2021, as Appl. No. 17/443,997.
Application 17/443,997 is a continuation of application No. PCT/JP2020/001300, filed on Jan. 16, 2020.
Claims priority of application No. 2019-016124 (JP), filed on Jan. 31, 2019.
Prior Publication US 2021/0356755 A1, Nov. 18, 2021
Int. Cl. G02B 27/42 (2006.01); G03B 21/20 (2006.01)
CPC G02B 27/4205 (2013.01) [G03B 21/2033 (2013.01); G03B 21/2053 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A diffractive optical element, comprising:
a unit structure periodically formed in a first direction and configured to diffract an incident light in the first direction,
wherein the diffractive optical element has a phase pattern formed such that an angular separation between an outermost diffracted light beam and a second-outermost diffracted light beam along the first direction is smaller than a divergence angle of the incident light, and the phase pattern is corrected within a range of 0.4×H(θ)<I(θ)<1.6×H(θ), where H(θ) denotes a correction function for the phase pattern, and I(θ) denotes a normalized intensity of a diffraction spot.