Apple Inc.

Vikrant Bhakta

Hyungryul J Choi

Guolin Peng

Scott M DeLapp

Scott M Delapp

David A Kalinowski

Byron R Cocilovo

Brian S Lau

Cameron A Harder

Kevin A Keilbach

Jonathan B Pfeiffer

Nathanael D Parkhill

Stanley K Melax

Mark R Ayres

Friso Schlottau

Graham Butler Myhre

Se Baek Oh

Eric J Hansotte

Jonathan C Moisant-Thompson

Dominic P Cincione

Michael J Oudenhoven

Depeng Wang

Adam C Urness

Bradley C Steele

Jose A Dominguez-Caballero

A display may include a waveguide for providing light to an eye box. The display may include polarization recycling structures having a polarizing beam splitter and a prism. The polarizing beam splitter may transmit a first portion of unpolarized light as first image light having a first polarization and may reflect a second portion of the unpolarized light as second image light having a second polarization. One or more waveplates may be mounted to the prism for transmitting the second image light. Upon transmission by the waveplate(s), the second image light may have the same polarization as the first image light. An input coupler may couple the first and second image light into the waveguide. Providing polarized light to the waveguide may maximize the optical efficiency of the waveguide. The polarization recycling structures may maximize the amount of the image light that is coupled into the waveguide.

Optical systems for providing polarized light to a waveguide

An electronic device may include a waveguide with an input coupler and an output coupler. The input coupler may receive the image light from imaging optics. The input coupler may be an input coupling prism and the imaging optics may include lens elements. World light may be viewable at an eye box through the output coupler. Biasing, compensation, and/or prescription lenses may overlap the output coupler. The input coupling prism, the lens elements in the imaging optics, and/or one or more of the biasing, compensation, and prescription lenses may be formed from gradient index (GRIN) material. The GRIN material may have a gradient refractive index that varies in one or more gradient directions. Use of GRIN materials may minimize the volume required to form the device without sacrificing optical performance. In addition, the GRIN materials may compensate for dispersion and aberrations in the device.

Optical systems having gradient index optical structures

A display may include illumination optics, a spatial modulator, and a waveguide. The illumination optics may produce illumination that is modulated by the spatial modulator to produce image light. The waveguide may direct the image light towards an eye box. The illumination optics may include light source sets that produce the illumination. Each set may include a low power light source and a high power light source. In a first state, the high and low power light sources may be active. In a second state, the low power light sources may be active. Control circuitry may adjust between the first and second states based on image data. The second state may be used when virtual objects in the image data are confined to a peripheral region of the field of view of the eye box.

Optical systems having light sources with power saving modes

An electronic device may include a display module that generates light and an optical system that redirects the light towards an eye box. The system may include an input coupler on a waveguide and a lens that directs the light towards the input coupler. The input coupler may include a prism having a reflective surface that reflects the light into the waveguide. The reflective surface may be curved to provide the light with an optical power. The prism may be configured to expand a field of view of the light. A birefringent beam displacer may expand the effective pupil size of the light. The lens may include lens elements that converge the light at a location between the lens elements and the waveguide. A switchable panel may be placed at the location and toggled between first and second orientations to increase the effective resolution of the light.

Optical systems with reflective prism input couplers

A head-mounted device may have a projector that emits light. The light may include visible images produced using image data and optionally infrared light. A waveguide may propagate the light and may have a first output coupler that couples the visible images out of the waveguide and towards an eye box. One or more optical sensors may generate optical sensor data based on the light emitted by the projector. Control circuitry may detect an angle between the waveguide and the projector based on the optical sensor data. The control circuitry may adjust the image data to compensate for changes in the angle over time. The optical sensors may include an optical sensor mounted to the projector and facing the waveguide and/or one or more optical sensors mounted to an optical bridge sensor.

Waveguide angle sensing

A display system may include a waveguide and an input coupling prism. The waveguide may have a lateral surface with a deformed region. The prism may couple the light into the waveguide at an angle whereby the light first reflects off the deformed region. The display module may include a display panel that provides the light with planar wavefronts. The display module may include a deformation mitigation structure that distorts the planar wavefronts to produce non-planar wavefronts. The shape of the non-planar wavefronts may be selected to reverse distortion to the wavefronts of the light produced by the first reflection of the light off the deformed region of the lateral surface. This may serve to mitigate distortion in the light produced by the deformed region of the lateral surface and may serve to maximize the sharpness images in the image light provided to an eye box.

Optical systems with waveguide deformation mitigation structures

A head-mounted device may have a housing with a frame that supports lenses. Each lens may have a positive bias lens element and a negative bias lens element. A waveguide may overlap the lens. During operation, images from the waveguide may be provided to an eye box through the negative bias lens element. An eye sensor such as a gaze tracking camera may operate through the negative bias lens element. The negative bias lens element may have a protruding portion through which the sensor operates, may have a surface facing the sensor that has a curved surface to provide a desired lens characteristic, may have a prism for helping to couple light from the eye box to the eye sensor, and/or may have other features to facilitate use of the eye sensor to monitor the eye of a user in the eye box.

Electronic devices with rearward-facing sensors

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 an optical combiner with a waveguide. The waveguide may have an output coupler that directs high resolution light towards an eye box within a field of view. Peripheral light sources may provide low resolution peripheral light to the eye box about a periphery of the field of view. The peripheral light sources may be mounted to a frame for the waveguide, to an additional substrate mounted to the frame and overlapping the waveguide, in a low resolution projector that projects the peripheral light towards reflective structures in the additional substrate, or in a display module that produces the high resolution light. The optical combiner may overlay real world light with the high resolution light and the low resolution peripheral light.

Optical systems with low resolution peripheral displays

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

An electronic device may have a spatial light modulator. Control circuitry in the electronic device may use the spatial light modulator to generate images. A light source may be used to produce illumination for the spatial light modulator. An optical system may direct the illumination onto the spatial light modulator and may direct corresponding reflected image light towards eye boxes for viewing by a user. Head-mounted support structures may be used to support the spatial light modulator, light source, and optical system. The light source may include light-emitting elements such as light-emitting diodes or lasers. Multiple light-emitting elements may be provided in the light source in a one-dimensional or two-dimensional array. During operation, the control circuitry can individually adjust the light-emitting elements.

Electronic device with multi-element display illumination system

A display having a reflective display panel may provide image light to an eye box. The panel may include mirrors rotatable between first and second angles. The mirrors may take a non-zero time period to transition between the first and second angles. During the non-zero time period, the light source may emit pulses of illumination. The mirrors may reflect the pulses of illumination as offset pupils of image light. The mirrors may be at respective intermediate angles while reflecting each of the pulses of illumination. The mirrors may toggle between the first and second angles at a sufficiently fast rate such that the offset pupils form an effective pupil that is expanded in at least one dimension. If desired, the offset pupils may be used to display virtual objects in different focal planes at the eye box.

Optical systems for leveraging the non-zero transition time of display panel mirrors

A head-mounted device may have projector, a first waveguide, a second waveguide, and an optical bridge sensor coupled between the first and second waveguides. An input coupler may couple light with a calibration pattern into the first waveguide. The calibration pattern may be included in visible or infrared light produced by the projector or may be included in infrared light produced by infrared emitters mounted to the first waveguide. An output coupler may couple the light having the calibration pattern out of the first waveguide. An additional output coupler may be used to couple visible light from the projector out of the waveguide and towards an eye box. An image sensor may generate image sensor data based on the light having the calibration pattern. Control circuitry may process the calibration pattern in the image sensor data to detect deformation or warping of the first waveguide.

Waveguide deformation sensing

An electronic device may provide foveated images at an eye box. The device may have a first display module that produces a low resolution portion of the image and a second display module that produces a high resolution portion of the image. A reflective input coupling prism may be mounted to a waveguide. A steering mirror may overlap the prism. The mirror may receive the high resolution portion through the waveguide and the prism. The mirror may reflect the high resolution portion back into the waveguide and may be adjusted to shift a location of the high resolution portion within the image. For example, the steering mirror may adjust the position of the high resolution portion to align with the gaze direction at the eye box. A reflective surface of the prism may reflect the low resolution portion of the image into the waveguide.

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Santa Clara, CA, United States of America

Vikrant Bhakta