US 12,228,734 B2
Optical systems with flare-mitigating angular filters
Jonathan B. Pfeiffer, Lafayette, CO (US); and Adam C. Urness, Boulder, CO (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Sep. 16, 2021, as Appl. No. 17/476,642.
Application 17/476,642 is a continuation of application No. PCT/US2020/050852, filed on Sep. 15, 2020.
Claims priority of provisional application 62/902,613, filed on Sep. 19, 2019.
Prior Publication US 2022/0004006 A1, Jan. 6, 2022
Int. Cl. G02B 27/01 (2006.01); G02B 6/34 (2006.01)
CPC G02B 27/0172 (2013.01) [G02B 6/34 (2013.01); G02B 2027/0118 (2013.01); G02B 2027/0174 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An optical combiner configured to redirect display light produced by a display module and configured to transmit world light, the optical combiner comprising:
a waveguide having a grating medium interposed between waveguide substrates, wherein the waveguide is configured to propagate the display light via total internal reflection;
an input coupler configured to couple the display light into the waveguide;
an output coupler in the grating medium and configured to couple the display light out of the waveguide, wherein the grating medium has a first index of refraction;
a cross coupler on the waveguide and configured to diffract the display light towards the output coupler, wherein the cross coupler comprises a surface relief grating embedded in an additional substrate and wherein the additional substrate has a second index of refraction greater than the first index of refraction; and
an angular filter on the waveguide and at least partially overlapping the cross coupler, wherein the angular filter is configured to transmit the world light while preventing flare-inducing world light from passing to the cross coupler.