Apple Inc.

Byron R Cocilovo

Se Baek Oh

Hyungryul J Choi

Francesco Aieta

Vikrant Bhakta

David A Kalinowski

Ligang Wang

Scott M DeLapp

Bradley Charles Steele

Nathanael D Parkhill

Stanley K Melax

Jian Gao

Zhibing Ge

Graham Butler Myhre

Guolin Peng

Eric J Hansotte

Jonathan B Pfeiffer

Jaebum Chung

Seyedeh Mahsa Kamali

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

An electronic device may include an emissive display panel that emits light. The light may propagate along an optical path extending to an eye box. A waveguide with an input coupler and an output coupler may be interposed on the optical path. An angle-selective transmission filter (ASTF) may be interposed on the optical path and may filter the emitted light as a function of angle to remove high-angle light from the optical path before the light is provided to the output coupler. The ASTF may include diffractive grating structures such as thin-film holograms, volume holograms, or surface relief gratings, louvered mirrors, multi-layer coatings, or a pinhole array. This ASTF may serve to minimize stray light within the display, thereby optimizing the contrast and the modulation transfer function (MTF) of the display.

Optical systems having angle-selective transmission filters

An electronic device may include a display module that produces light having an image, a lens that directs the light to a waveguide, and a waveguide that directs the light to an eye box. The lens may produce a foveated image in the light by applying a non-uniform magnification to the image in the light. The non-uniform magnification may vary as a function of angle within a field of view of the lens. This may allow the foveated image to have higher resolution within the central region than in the peripheral region. Performing foveation using the lens maximizes the resolution of images at the eye box without increasing the size of the display module. Control circuitry on the device may apply a pre-distortion to the image that is an inverse of distortion introduced by the lens in producing the foveated image.

Optical systems with lens-based static foveation

A display may include a waveguide. An input coupler may couple image light into the waveguide and an output coupler may couple the image light out of the waveguide. A surface relief grating on the waveguide may couple infrared light into the waveguide and may couple the infrared light out of the waveguide. The surface relief grating may additionally or alternatively couple reflected infrared light into the waveguide and out of the waveguide and towards an infrared sensor. The surface relief grating may also form a cross-coupler for the image light. The infrared sensor may gather infrared sensor data based on the reflected infrared light. Control circuitry may perform gaze tracking operations based on the infrared sensor data. The input and output couplers may also be formed from surface relief gratings or may include other optical components.

Waveguide display with gaze tracking

An electronic device may include a display that produce images. The display may generate light for an optical system that redirects the light towards an eye box. The optical system may include a waveguide that propagates the light in a first direction towards the output coupler. The output coupler may couple the light out of the waveguide towards the eye box while inverting a parity of the light about the first direction. The coupler may include a first element such as a set of partial mirrors or diffractive gratings that redirects a first portion of the light in a second direction. The coupler may include a second element that redirects a second portion of the light in a third direction opposite the second direction. The first element may redirect the second portion and the second element may redirect the first portion towards the eye box.

Optical systems with interleaved light redirectors

An electronic device may have a display system that produces images. The display system may have one or more pixel arrays such as liquid-crystal-on-silicon pixel arrays. Images from the display system may be coupled into a waveguide by an input coupler and may be coupled out of the waveguide using an output coupler. The input and output couplers may be formed from volume phase holographic gratings. An additional grating may be used to shift light that would otherwise pass above or below the user's field of view towards the viewer. Holographic gratings in the waveguide may have fringes with constant pitch and variable period. The period at a given portion of the grating may be Bragg-matched to maximize diffraction efficiency for light of a given incident angle.

Displays with volume phase gratings

An electronic device may have a light source such as a laser light source. The light source may emit light into a waveguide. A phase grating may diffract the light that is emitted into the waveguide to produce diffracted light. The diffracted light may be oriented parallel to a surface normal of an angled edge of the waveguide and parallel to a surface normal of a microelectromechanical systems mirror element in a two-dimensional scanning microelectromechanical systems mirror that is coupled to the edge of the waveguide. A wave plate may be interposed between the mirror and the edge of the waveguide to change the polarization state of light reflected from the mirror element relative to incoming diffracted light from the phase grating. The phase grating may be configured so that the reflected light is not diffracted by the phase grating.

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San Jose, CA, United States of America

Byron R Cocilovo