Apple Inc.

Jian Gao

Zhibing Ge

Hyungryul J Choi

Ligang Wang

Byron R Cocilovo

Jaebum Chung

Brandon Born

Di Hu

A display may include a waveguide, an input coupler having a first surface relief grating (SRG) in a substrate on the waveguide, a cross-coupler having a second SRG in the substrate, and an output coupler having a third SRG in the substrate. The display may direct light to an eye box. A capping layer may be disposed over the substrate. An anti-reflective coating may be disposed over the capping layer. Microstructures may be disposed in non-SRG regions of the substrate and may be non-diffractive at visible wavelengths. The microstructures may include grooves and may have a similar filling factor to the SRGs. This may cause portions of the capping layer over the microstructures to sink into the grooves, thereby providing the capping layer with a relatively uniform thickness across a lateral area of the waveguide, without the microstructures producing visible artifacts or interacting with the light.

Display devices having grating substrates with sub-wavelength patterns

An electronic device may include a display with a waveguide and a surface relief grating (SRG) on the waveguide. The SRG may direct image light towards an eye box. An optical blocker may at least partially overlap the SRG. The blocker may include a first optical wedge having a curved surface and a second optical wedge separated from the curved surface by an air gap or a low refractive index material. The curved surface may have a freeform shape that configures the first optical wedge to propagate world light incident upon the blocker within a selected range of incident angles away from the SRG via total internal reflection. The blocker may transmit world light at other incident angles to the eye box through the waveguide. This may allow the blocker to block high incident angle world light from reaching the SRG and producing unsightly rainbow artifacts at the eye box.

Optical systems with artifact blocking structures

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Fremont, CA, United States of America

Jian Gao