Apple Inc.

Adam C Urness

Jonathan B Pfeiffer

Mark R Ayres

Friso Schlottau

Vikrant Bhakta

Se Baek Oh

Francesco Aieta

Jaebum Chung

An electronic device may include a display with an optical combiner. The combiner may include a waveguide and a cross coupler on the waveguide. The combiner may redirect light from a display module to an eye box while passing world light to the eye box within a field of view. The cross coupler may include surface relief gratings or other broadband gratings. The combiner may include an angular filter that at least partially overlaps the cross coupler. The cross coupler may include surface relief grating structures or other broadband gratings. The angular filter may include angled absorbers or diffractive gratings. The angular filter may prevent world light that would otherwise produce distracting flares at the eye box (e.g., world light incident on the waveguide outside the field of view such as high-incident angle light from an overhead light source) from passing to the cross coupler.

Optical systems with flare-mitigating angular filters

An electronic device may provide images to an eye box. The device may include first and second sets of holograms that sequentially diffract light along an optical path. Each hologram in the first set may have a respective grating vector oriented along a common axis. Each of the grating vectors may have a respective magnitude. The magnitudes may be non-uniformly spaced across the first set of volume holograms. Similarly, each hologram in the second set may have a respective additional grating vector oriented along an additional common axis. Each of the additional grating vectors may have a respective additional magnitude. The additional magnitudes may be non-uniformly spaced across the second set of holograms. This may serve to produce diffracted light within filaments of k-space that mitigate angular harmonic sight lines in angle space, thereby preventing formation of non-uniformities in the images at the eye box.

Optical systems with holographic elements for producing uniform images

An electronic device may include a display that generates light for an optical system that redirects the light towards an eye box. The optical system may include a waveguide, a non-diffractive input coupler, a cross coupler, and an output coupler. The cross coupler may expand the light in a first direction. The cross coupler may perform an even number of diffractions on the light and may couple the light back into the waveguide at an angle suitable for total internal reflection. The output coupler may expand the light in a second direction while coupling the light out of the waveguide. The cross coupler may include surface relief gratings or holographic gratings embedded within the waveguide or formed in a separate substrate. The optical system may direct the light towards the eye box without chromatic dispersion and while supporting an expanded field of view and optical bandwidth.

Optical systems with light-expanding couplers

Systems and methods of dispersion compensation in an optical device are disclosed. A holographic optical element may include a set of different holograms in a grating medium. Each hologram in the set may have a corresponding grating vector with a grating frequency and direction. The directions of the grating vectors may vary as a function of the grating frequency. Different holograms in the set may diffract light in a particular direction so that the light emerges from a boundary of the grating medium in a single given direction regardless of wavelength. A prism may be used to couple light into the grating medium. The prism may be formed using materials having dispersion properties that are similar to the dispersion properties of the grating material. The prism may have an input face that receives perpendicular input light. The prism may include multiple portions having different refractive indices.

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Louisville, CO, United States of America

Adam C Urness