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US 10,948,647 B2Granted
Unidirectional grating-based backlighting employing a reflective island
AssigneeLeia Inc.
InventorDavid A. Fattal
Life of this patent
Estimating the term…
Abstract
Unidirectional grating-based backlighting includes a light guide and a diffraction grating at a surface of the light guide. The light guide is to guide a light beam and the diffraction grating is configured to couple out a portion of the guided light beam using diffractive coupling and to direct the coupled-out portion away from the light guide surface as a primary light beam at a principal angular direction. The unidirectional grating-based backlighting further includes a reflective island in the light guide between the light guide surface and an opposite surface of the light guide to reflectively redirect a diffractively produced, secondary light beam out of the light guide in a direction of the primary light beam.
Claims19
A unidirectional grating-based backlight comprising:
- a light guide configured to guide a light beam at a non-zero propagation angle;
- a grating array including a plurality of spaced-apart diffraction gratings that are located at a surface of the light guide, a diffraction grating of the grating array being configured to diffractively couple out a portion of the guided light beam as a primary light beam and to direct the primary light beam away from the light guide surface at a predetermined principal angular direction, the diffraction grating further being configured to diffractively produce a secondary light beam and to direct the secondary light beam into the light guide;
- and
- an island array including a plurality of spaced-apart reflective islands located within the light guide that are spaced apart from the light guide surface and spaced apart from an opposite surface of the light guide, a reflective island of the island array extending within a plane, the guided light beam configured to propagate from a first side of the plane to a second side of the plane opposite the first side, the reflective island being configured to reflectively redirect the secondary light beam out of the light guide in a direction of the primary light beam.
1 more element
A three-dimensional (3-D) electronic display comprising:
- a plate light guide to guide light as guided light;
- a grating array including a plurality of spaced-apart multibeam diffraction gratings, a multibeam diffraction grating of the grating array being configured to diffractively couple out a portion of the guided light as a plurality of primary light beams directed in a corresponding plurality of different principal angular directions to form a light field, the multibeam diffraction grating further being configured to diffractively produce a plurality of secondary light beams and to direct the secondary light beam plurality into the plate light guide;
- an island array including a plurality of spaced-apart reflective islands within the plate light guide aligned with the multibeam diffraction gratings of the grating array, the reflective islands of the island array being spaced apart from the light guide surface and spaced apart from an opposite surface of the light guide, the reflective islands of the island array extending within a plane, the guided light configured to propagate between adjacent reflective islands of the island array from a first side of the plane to a second side of the plane opposite the first side, a reflective island of the island array being configured to reflectively redirect the secondary light beam plurality from an aligned multibeam diffraction grating of the grating array in a direction of the primary light beam plurality;
- and
- a light valve array configured to modulate the primary light beams and the reflectively redirected, secondary light beams, the modulated light beams representing pixels corresponding to different views of the 3-D electronic display.
2 more elements
A method of electronic display operation, the method comprising:
- guiding a light beam in a light guide at a non-zero propagation angle;
- diffractively coupling out a portion of the guided light beam using a grating array that includes a plurality of spaced-apart multibeam diffraction gratings, a multibeam diffraction grating of the grating array to produce a plurality of primary light beams directed away from a surface of the light guide at different principal angular directions to form a light field;
- diffractively producing a plurality of secondary light beams with the multibeam diffraction grating;
- directing the plurality of secondary light beams toward a reflective island, the reflective island being included in an island array of spaced-apart reflective islands within the light guide that are spaced apart from a front surface of the light guide and spaced apart from a back surface of the light guide, the island array extending within a plane, the guided light beam propagating from a first side of the plane to a second side of the plane opposite the first side;
- and
- reflectively redirecting the secondary light beams out of the light guide in a direction of the primary light beam plurality using the reflective island.
3 more elements
Dependencies are inferred from the claim text.