Unilateral backlight, multiview display, and method employing slanted diffraction gratings
AssigneeLeia Inc.
InventorsDavid A. Fattal, Francesco Aieta
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Abstract
A unilateral backlight and a unilateral multiview display employ an array of unilateral diffractive elements configured to provide directional light beams having a unilateral direction. A unilateral diffractive element of the unilateral diffractive element array comprises a slanted diffraction grating configured to provide a directional light beam by diffractive scattering of light guided in a light guide. The unilateral multiview display further includes light valves configured to modulate a plurality of directional light beams as multiview image having the unilateral direction.
Claims18
A unilateral backlight comprising:
- a light guide configured to guide light in a propagation direction along a length of the light guide;
- and
- an array of unilateral diffractive elements spaced apart from one another along the light guide length, a unilateral diffractive element of the array of unilateral diffractive elements comprising a slanted diffraction grating configured to scatter out from the light guide a portion of the guided light as a directional light beam having a unilateral direction,
- wherein the unilateral diffractive element is configured to scatter out the portion of the guided light as a plurality of directional light beams having different principal angular directions in the unilateral direction corresponding to respective different view directions of a unilateral multiview display, a size of the unilateral diffractive element being between fifty percent and two hundred percent of a pixel size of a pixel in a multiview pixel of the unilateral multiview display.
A unilateral multiview display comprising:
- a light guide configured to guide light along a length of the light guide as guided light;
- an array of unilateral multibeam elements spaced apart from one another along the light guide length, a unilateral multibeam element of the array of multibeam elements comprising a slanted diffraction grating configured to scatter out a portion of the guided light in a unilateral direction as a plurality of directional light beams having principal angular directions corresponding to respective view directions of a multiview image;
- an array of light valves configured to modulate the plurality of directional light beams as the multiview;
- and
- a broad-angle backlight configured to provide broad-angle light during a second mode, the light guide and array of unilateral multibeam elements being between the broad-angle backlight and the array of light valves, wherein the array of light valves is configured to modulate the plurality of directional light beams as the multiview image during a first mode and the array of light valves is configured to modulate the broad-angle light during the second mode to provide a displayed image having a single view.
A method of unilateral backlight operation, the method comprising:
- guiding light in a propagation direction along a length of a light guide;
- and
- diffractively scattering a portion of the guided light out of the light guide using an array of unilateral diffractive elements spaced apart from one another along the light guide length to provide a plurality of directional light beams having a unilateral direction,
- wherein a unilateral diffractive element of the array of unilateral diffractive elements comprises a slanted diffraction grating, and
- wherein a unilateral diffractive element of the array of unilateral diffractive elements provides a plurality of directional light beams having different principal angular directions in the unilateral direction, the different principal angular directions corresponding to respective view directions of a multiview display, a size of the unilateral diffractive element being between fifty percent and two hundred percent of a pixel size of a pixel in a multiview pixel of a unilateral multiview display.
Dependencies are inferred from the claim text.