Time-multiplexed multiview backlight, multiview display and method
A time-multiplexed multiview backlight, display, and method of time-multiplexed multiview backlight operation provide one or both of enhanced spatial resolution and enhanced angular resolution using time-multiplexing. The time-multiplexed multiview backlight includes a light guide configured to guide light as time-multiplexed guided light having different directions during different time intervals and an array of multibeam elements configured to scatter the time-multiplexed guided light as directional light beams. A first set of multibeam elements is configured to selectively scatter out the time-multiplexed guided light having the first direction and a second set of multibeam elements of the multibeam element array is configured to selectively scatter out the time-multiplexed guided light having the second direction. The time-multiplexed multiview display further includes an array of light valves configured to modulate the directional light beams as view pixels of a multiview image having different views in the different view directions.
1. A time-multiplexed multiview backlight comprising:
a light guide configured to guide light as time-multiplexed guided light having a first direction during a first time interval and a second direction during a second time interval;
an array of multibeam elements configured to scatter out the time-multiplexed guided light as directional light beams having different directions corresponding to different view directions of a multiview display; and
an array of light valves configured to modulate the directional light beams to provide view pixels of a multiview image having different views in the different view directions, wherein the array of light valves is arranged in sets of light valves representing multiview pixels corresponding to multibeam elements of the array of multibeam elements, a first set of light valves corresponding to a multibeam element of the first set of multibeam elements and a second set of light valves corresponding to a multibeam element of the second set of multibeam elements, and wherein the first set of light valves overlaps the second set of light valves;
wherein a first set of multibeam elements of the multibeam element array is configured to selectively scatter out the time-multiplexed guided light having the first direction and a second set of multibeam elements of the multibeam element array is configured to selectively scatter out the time-multiplexed guided light having the second direction.
2. The time-multiplexed multiview backlight of claim 1 , wherein multibeam elements of the second set of multibeam elements are located between and alternate with multibeam elements of the first set of multibeam elements, and a second set of directional light beams scattered out by the second set of multibeam elements during the second time interval are located between corresponding directional light beams of a first set of directional light beams scattered out by the first set of multibeam elements during the first time interval.
3. The time-multiplexed multiview backlight of claim 1 , wherein multibeam elements of the second set of multibeam elements are collocated with and have a lateral offset relative to multibeam elements of the first set of multibeam elements, and an emanation point of a second set of directional light beams scattered out by the second set of multibeam elements is shifted by the lateral offset from an emanation point of a first set of directional light beams scattered out by the first set of multibeam elements.
4. The time-multiplexed multiview backlight of claim 1 , wherein a size of multibeam elements of the multibeam element array is between twenty-five and two hundred percent of a size of a light valve in an array of light valves of the multiview display.
5. The time-multiplexed multiview backlight of claim 1 , wherein the time-multiplexed guided light having one or both of the first direction and the second direction is collimated according to a collimation factor.
6. The time-multiplexed multiview backlight of claim 1 , wherein a multibeam element of the array of multibeam elements comprises one or more of a diffraction grating configured to diffractively scatter out the time-multiplexed guided light, a micro-reflective element configured to reflectively scatter out the time-multiplexed guided light, and a micro-refractive element configured to refractively scatter out the time-multiplexed guided light.
7. The time-multiplexed multiview backlight of claim 1 , wherein a multibeam element of the array of multibeam elements comprises a reflective island configured to reflect light scattered out by the multibeam element toward an emission surface of the light guide.
8. The time-multiplexed multiview backlight of claim 1 , further comprising a broad-angle backlight adjacent to the light guide of the time-multiplexed multiview backlight, the broad-angle backlight being configured to provide broad-angle emitted light during a two-dimensional (2D) mode and the time-multiplexed multiview backlight being configured to provide the directional light beams during a multiview mode.
9. A time-multiplexed multiview display comprising:
a time-multiplexed multiview backlight comprising a light guide and an array of multibeam elements, multibeam elements of the multibeam element array being configured to scatter out time-multiplexed guided light from the light guide as directional light beams having directions corresponding to different view directions of the time-multiplexed multiview display; and
an array of light valves configured to modulate the directional light beams as view pixels of a multiview image having different views in the different view directions,
wherein a first set of the multibeam elements is configured to selectively scatter out the time-multiplexed guided light having a first direction and a second set of the multibeam elements is configured to selectively scatter out the time-multiplexed guided light having a second direction, and
wherein the array of light valves is arranged in sets of light valves representing multiview pixels corresponding to multibeam elements of the array of multibeam elements, a first set of light valves corresponding to a multibeam element of the first set of multibeam elements and a second set of light valves corresponding to a multibeam element of the second set of multibeam elements, and wherein the first set of light valves overlaps the second set of light valves.
10. The time-multiplexed multiview display of claim 9 , wherein multibeam elements of the second set of the multibeam elements are located between and alternate with multibeam elements of the first set of the multibeam elements, and wherein view pixels provided during a second time interval when the time-multiplexed guided light has the second direction are interspersed between view pixels provided during a first time interval when the time-multiplexed guided light has the first direction.
11. The time-multiplexed multiview display of claim 10 , wherein the time-multiplexed multiview display is configured to provide a first portion of the multiview image using view pixels provided during the first time interval and a second portion of the multiview image using view pixels provided during the second time interval, and sequential time-multiplexing of the first and second portions of the multiview image is configured to provide a multiview image having twice a spatial resolution of either one of the first portion or the second portion.
12. The time-multiplexed multiview display of claim 9 , wherein multibeam elements of the second set of the multibeam elements are collocated with and have a lateral offset relative to multibeam elements of the first set of the multibeam elements, and wherein views of the multiview image during a second time interval when the time-multiplexed guided light has the second direction are interleaved with views of the multiview image during a first time interval when the time-multiplexed guided light has the first direction.
13. The time-multiplexed multiview display of claim 12 , wherein the time-multiplexed multiview display is configured to provide a first portion of the multiview image using view pixels provided during the first time interval and a second portion of the multiview image using view pixels provided during the second time interval, and sequential time-multiplexing of the first and second portions of the multiview image is configured to provide a multiview image having twice an angular resolution of either one of the first portion or the second portion.
14. The time-multiplexed multiview display of claim 9 , wherein a size of multibeam elements of the multibeam element array is between twenty-five and two hundred percent of a size of a light valve in the array of light valves of the time-multiplexed multiview display, and wherein a multibeam element of the array of multibeam elements comprises one or more of a diffraction grating configured to diffractively scatter out the time-multiplexed guided light, a micro-reflective element configured to reflectively scatter out the time-multiplexed guided light, and a micro-refractive element configured to refractively scatter out the time-multiplexed guided light.
15. A method of time-multiplexed multiview backlight operation, the method comprising:
guiding light in a light guide as time-multiplexed guided light having a first direction during a first time interval and a second direction during a second time interval;
scattering out the time-multiplexed guided light as directional light beams using an array of multibeam elements, the directional light beams having different directions corresponding to different view directions of a multiview display; and
modulating the directional light beams using an array of light valves to provide view pixels of a multiview image having different views in the different view directions, wherein modulating the directional light beams using the array of light valves enhances one or both of a spatial resolution and an angular resolution of the multiview image,
wherein a first set of multibeam elements of the array of multibeam elements selectively scatters out the time-multiplexed guided light during the first time interval and a second set of multibeam elements of the multibeam element array selectively scatters out the time-multiplexed guided light during the second time interval; and
wherein the array of light valves is arranged in sets of light valves representing multiview pixels corresponding to multibeam elements of the array of multibeam elements, a first set of light valves corresponding to a multibeam element of the first set of multibeam elements and a second set of light valves corresponding to a multibeam element of the second set of multibeam elements, and wherein the first set of light valves overlaps the second set of light valves.
16. The method of time-multiplexed multiview backlight operation of claim 15 , wherein multibeam elements of the second set of multibeam elements are located between and alternate with multibeam elements of the first set of multibeam elements, and directional light beams selectively scattered out by the second set of multibeam elements during the second time interval are located between corresponding directional light beams selectively scattered out by the first set of multibeam elements during the first time interval.
17. The method of time-multiplexed multiview backlight operation of claim 15 , wherein multibeam elements of the second set of the multibeam elements are collocated with and have a lateral offset relative to multibeam elements of the first set of the multibeam elements, directional light beams scattered out by the first and second sets of the multibeam elements having directions corresponding to different sets of view directions of the multiview display during the first time interval and the second time interval, and wherein sets of view directions during the second time interval are interleaved with sets of view directions during the first time interval.