Holographic VR display
AssigneeMeta Platforms Technologies, LLC
InventorsChangwon Jang, Afsoon Jamali, Zhimin Shi
Life of this patent
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Abstract
A holographic display includes an illuminator, a spatial light modulator (SLM) coupled to the illuminator, and an ocular lens coupled to the SLM. The illuminator provides a wide-area illuminating light beam to illuminate the SLM with a spatially homogeneous beam of light. The illuminator may include a slab waveguide with an evanescent out-coupler, or a beam expander based on a diffraction grating with an oblique angle of incidence and a near-normal angle of diffraction of the illuminating light. A low-pass spatial filter may be provided to filter out higher diffraction orders of the illuminating light diffracted on the SLM.
Claims19
A holographic display comprising:
- an illuminator comprising a substrate, a slab core layer on the substrate for guiding a light beam therein, a cladding layer on the slab core layer, and a light extractor on the cladding layer,
- the light extractor having a refractive index higher than an effective refractive index of a mode of propagation of light in the slab core layer, for evanescent out-coupling of the light beam from the slab core layer into the light extractor, thereby forming an illuminating light beam, wherein the light extractor further comprises a prism having first and second faces at an acute angle to one another, wherein:
- the first face is coupled to the cladding layer, and
- the second face includes a reflector
- with a curved outer surface defined by a radius of curvature having an optical power for at least one of focusing or defocusing;
- and
- a spatial light modulator (SLM) operably coupled to the illuminator for receiving and spatially modulating the illuminating light beam in amplitude and phase to provide an image light beam.
A holographic display comprising:
- a beam expander comprising a diffractive layer for diffracting a collimated light beam at an angle of incidence exceeding an angle of diffraction, whereby a lateral size of the collimated light beam increases upon diffraction on the diffractive layer;
- a spatial light modulator (SLM) operably coupled to the beam expander for receiving the light beam diffracted by the diffractive layer and spatially modulating the light beam in amplitude and phase to provide an image light beam, wherein in operation, the image light beam propagates through the diffractive layer;
- and
- a light extractor including a prism having first and second faces at an acute angle to one another, wherein
- the first face is coupled to a cladding layer, and
- the second face includes a reflector with a curved outer surface defined by a radius of curvature with an optical power for at least one of focusing or defocusing.
A holographic display comprising:
- a frontlight illuminator for providing an illuminating light beam;
- a spatial light modulator (SLM) operably coupled to the frontlight illuminator for receiving and spatially modulating the illuminating light beam in amplitude and phase to provide an image light beam propagating through the frontlight illuminator;
- a light extractor including a prism having first and second faces at an acute angle to one another, wherein
- the first face is coupled to a cladding layer, and
- the second face includes a reflector with a curved outer surface defined by a radius of curvature with an optical power for at least one of focusing or defocusing;
- an ocular lens operably coupled to the SLM for receiving the image light beam and forming an image at an eyebox of the holographic display for observation by a user's eye;
- and
- a low-pass spatial filter in an optical path of the image light beam between the SLM and the ocular lens, for blocking higher orders of diffraction of the illuminating light beam on the SLM while propagating a zeroth order of diffraction of the illuminating light beam.
Dependencies are inferred from the claim text.