Acoustically formed diffractive optical elements
AssigneeMeta Platforms Technologies, LLC
InventorSundeep Kumar Jolly
Life of this patent
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Abstract
A diffractive optical element may include a slab of transparent photoelastic material and a set of acoustic transducers spread over the perimeter of the slab. The acoustic transducers generate surface and/or volume acoustic waves that induce a diffractive pattern in the slab due to photoelasticity. The diffractive patterns a dynamic, i.e. they may be changed by changing phases and frequencies of oscillation of the acoustic transducers. Focusing and redirection patterns may be used to refocus and/or redirect image light in a near-eye display.
Claims20
A diffractive optical element for at least one of redirecting or refocusing a light beam, the diffractive optical element comprising:
- a slab of transparent material having opposed first and second surfaces for:
- receiving the light beam at the first surface,
- propagating the light beam unidirectionally from the first surface to the second surface, and
- outputting the light beam at the second surface;
- and
- a set of acoustic transducers, wherein the set of traducers are:
- positioned along a plurality of locations on an outer boundary of the slab, the outer boundary extending between the first and second surfaces of the slab, and
- configured to produce acoustic waves propagating towards a center of the slab.
A near-eye display (NED) comprising:
- a display panel for providing an image in linear domain;
- an ocular lens downstream of the display panel for converting the image in linear domain into an image in angular domain for observation by a user's eye, the image in angular domain being carried by image light;
- and
- a diffractive optical element downstream of the display panel for at least one of redirecting or refocusing the image light, the diffractive optical element comprising:
- a slab of transparent material having opposed first and second surfaces for:
- receiving the image light at the first surface,
- propagating the image light unidirectionally from the first surface to the second surface, and
- outputting the image light at the second surface;
- and
- a set of acoustic transducers, wherein the set of transducers are:
- positioned along a plurality of locations on an outer boundary of the slab, the outer boundary extending between the first and second surfaces of the slab, and
- configured to produce acoustic waves propagating towards a center of the slab.
A near-eye display (NED) comprising:
- an image projector for providing a light beam carrying an image in angular domain;
- a pupil-replicating lightguide optically coupled to the image projector and configured to expand the light beam over an eyebox of the NED;
- a diffractive optical element coupled to the pupil-replicating lightguide for at least one of redirecting or refocusing the light beam expanded by the pupil-replicating lightguide, the diffractive optical element comprising:
- a slab of transparent material having opposed first and second surfaces for:
- receiving the light beam at the first surface,
- propagating the light beam unidirectionally from the first surface to the second surface, and
- outputting the light beam at the second surface;
- and
- a set of acoustic transducers, wherein the set of transducers are:
- positioned along a plurality of locations on an outer boundary of the slab, the outer boundary extending between the first and second surfaces of the slab, and
- configured to produce acoustic waves propagating towards a center of the slab.
Dependencies are inferred from the claim text.