US 12,265,216 B2
Device for augmented reality or virtual reality display
Mohmed Salim Valera, Abingdon (GB)
Assigned to Snap Inc., Santa Monica, CA (US)
Appl. No. 17/279,016
Filed by Snap Inc., Santa Monica, CA (US)
PCT Filed Aug. 7, 2019, PCT No. PCT/GB2019/052210
§ 371(c)(1), (2) Date Mar. 23, 2021,
PCT Pub. No. WO2020/065251, PCT Pub. Date Apr. 2, 2020.
Claims priority of application No. 1815516 (GB), filed on Sep. 24, 2018.
Prior Publication US 2022/0075185 A1, Mar. 10, 2022
Int. Cl. G02B 27/00 (2006.01); G02B 1/02 (2006.01); G02B 6/34 (2006.01); G02B 27/01 (2006.01); G02B 27/09 (2006.01); G02B 27/42 (2006.01)
CPC G02B 27/0081 (2013.01) [G02B 6/34 (2013.01); G02B 27/0172 (2013.01); G02B 27/0944 (2013.01); G02B 27/4272 (2013.01); G02B 1/02 (2013.01); G02B 2027/0123 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A device for use in an augmented reality or virtual reality display, the device comprising:
a waveguide;
an input diffractive optical structure configured to receive light from a projector and couple the received light into the waveguide;
an output diffractive optical structure; and
an intermediate diffractive optical structure configured to receive light from the input diffractive optical structure, provide a one-dimensional expansion of the received light, and couple the expanded light towards the output diffractive optical structure, wherein the output diffractive optical structure is configured to receive light from the intermediate diffractive optical structure and couple it towards a viewer;
wherein the intermediate diffractive optical structure comprises first and second linear gratings, wherein the first grating comprises diffractive features that are oriented at a first angle to light received from the input diffractive optical structure to provide a first diffraction and a second diffraction within the first grating in order to couple light towards the output diffractive optical structure, wherein the first diffraction couples light from the input diffractive optical structure, still captured within the waveguide by total internal reflection, towards the first grating's diffractive features at a second angle so that the second diffraction is provided at a plurality of spaced positions in the first grating thereby providing the one-dimensional expansion of light, wherein the second diffraction couples light towards a first side of the output diffractive optical structure;
wherein the second grating comprises diffractive features that are oriented at a third angle to light received from the input diffractive optical structure to provide a third diffraction and a fourth diffraction within the second grating in order to couple light towards the output diffractive optical structure, wherein the third diffraction couples light from the input diffractive optical structure, still captured within the waveguide by total internal reflection, towards the second grating's diffractive features at a fourth angle so that the fourth diffraction is provided at a plurality of spaced positions in the second grating thereby providing the one-dimensional expansion of light, wherein the fourth diffraction couples light towards a second side of the output diffractive optical structure; and
wherein the first angle is +(45+Δ°) and the third angle is −(45+Δ°), so that a first angular field of view is provided for light emanating from the first side of the output diffractive optical structure and a second angular field of view is provided for light emanating from the second side of the output diffractive optical structure, wherein the first and second angular fields of view overlap partially, but each includes angles that the other does not;
wherein Δ is less than 10°.