US 12,411,352 B2
Composite diffraction element, instrument, and image projection system
Kazuhiko Nemoto, Kanagawa (JP)
Assigned to Sony Semiconductor Solutions Corporation, Kanagawa (JP)
Appl. No. 17/435,526
Filed by SONY SEMICONDUCTOR SOLUTIONS CORPORATION, Kanagawa (JP)
PCT Filed Mar. 3, 2020, PCT No. PCT/JP2020/008787
§ 371(c)(1), (2) Date Sep. 1, 2021,
PCT Pub. No. WO2020/184268, PCT Pub. Date Sep. 17, 2020.
Claims priority of application No. 2019-042370 (JP), filed on Mar. 8, 2019.
Prior Publication US 2022/0057548 A1, Feb. 24, 2022
Int. Cl. G02B 27/42 (2006.01); G02B 5/02 (2006.01); G02B 5/18 (2006.01); G02B 5/32 (2006.01); G02B 27/01 (2006.01)
CPC G02B 27/4272 (2013.01) [G02B 5/0252 (2013.01); G02B 5/18 (2013.01); G02B 5/1842 (2013.01); G02B 5/32 (2013.01); G02B 27/0172 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A composite diffraction element, comprising:
a stack structure including a first diffraction element, a second diffraction element, and a third diffraction element in this order,
wherein the first diffraction element transmits light incident on the first diffraction element within at least a first range of angles,
wherein the second diffraction element diffractively reflects light incident on the second diffraction element within at least a second range of angles that has passed through the first diffraction element and reached the second diffraction element, toward the first diffraction element,
wherein an exit angle of the light incident on the second diffraction element within at least the second range of angles and reflected by the second diffraction element is greater than an incident angle of the light incident on the second diffraction element within at least the second range of angles,
wherein the first diffraction element diffractively reflects the light diffractively reflected by the second diffraction element, toward the third diffraction element,
wherein the second diffraction element transmits the light that has been reflected by the first diffraction element toward the third diffraction element,
wherein the third diffraction element transmits the light diffractively reflected by the first diffraction element and transmitted by the second diffraction element, and diffractively reflects zeroth-order light that has passed through the first diffraction element and the second diffraction element, and
wherein an exit angle of the zeroth-order light that has passed through the first diffraction element and the second diffraction element and that is reflected by the third diffraction element is greater than an incident angle of the zeroth-order light that has passed through the first diffraction element and the second diffraction element on the third diffraction element, and
wherein the exit angle of light incident on the third diffraction element is greater than the exit angle of light incident on the second diffraction element.