Multibeam element-based backlight with microlens and display using same
A multiview backlight and a multiview display employ a microlens to adjust directional light beams to have directions corresponding to respective different view directions of the multiview display. The multiview backlight includes a light guide configured to guide light as guided light, a multibeam element configured to scatter from the light guide a portion of the guided light as a plurality of directional light beams, and the microlens configured to adjust directions of the directional light beams. The multiview display further includes a multiview pixel configured to modulate the plurality of directional light beams and provide a plurality of different views of the multiview display, the microlens being between the multibeam element and the multiview pixel.
1. A multiview backlight comprising:
a light guide configured to guide light as guided light;
a multibeam element configured to scatter, from the light guide, a portion of the guided light as a plurality of directional light beams, directional light beams of the directional light beam plurality having different principal angular directions from one another; and
a microlens positioned between the light guide and an array of multiview pixels, the microlens configured to adjust the different principal angular directions of the directional light beams to correspond to respective different view directions of a multiview display.
2. The multiview backlight of claim 1 , wherein a size of the multibeam element is between fifty percent and two hundred percent of a size of a light valve of the multiview display.
3. The multiview backlight of claim 1 , wherein the multibeam element comprises one or more of:
a diffraction grating configured to diffractively scatter the portion of the guided light as the plurality of directional light beams;
a micro-reflective element being configured to reflectively scatter the portion of the guided light as the plurality of directional light beams; and
a micro-refractive element configured to refractively scatter the portion of the guided light as the plurality of directional light beams.
4. The multiview backlight of claim 1 , wherein the multibeam element comprises a diffraction grating configured to diffractively scatter the portion of the guided light as the plurality of directional light beams, and wherein the diffraction grating of the multibeam element comprises a plurality of diffraction gratings.
5. The multiview backlight of claim 1 , wherein the multibeam element is located at one of at a first surface and at a second surface of the light guide, the multibeam element being configured to scatter the portion of the guided light through the first surface.
6. The multiview backlight of claim 1 , wherein the microlens comprises a converging lens configured to adjust the different principal angular directions of the directional light beams by decreasing an angular spread of the plurality of directional light beams.
7. The multiview backlight of claim 1 , wherein the microlens comprises a diverging lens configured to adjust the different principal angular directions of the directional light beams by increasing an angular spread of the plurality of directional light beams.
8. The multiview backlight of claim 1 , further comprising a light source optically coupled to an input of the light guide, the light source being configured to provide the guided light, the guided light is defined as one or both of having a non-zero propagation angle and being collimated according to a predetermined collimation factor.
9. A multiview display comprising the multiview backlight of claim 1 , the multiview display further comprising an array of light valves configured to modulate directional light beams of the directional light beam plurality, a set of light valves of the array corresponding to a multiview pixel of the array of multiview pixels.
10. A multiview display comprising:
an array of multiview pixels configured to provide a plurality of different views of the multiview display, a multiview pixel of the array comprising a plurality of light valves configured to modulate a plurality of directional light beams;
a plurality of multibeam elements, a multibeam element of the multibeam element plurality being configured to provide the plurality of directional light beams; and
a plurality of microlenses between the multiview pixel array and the multibeam element plurality, a microlens of the microlens plurality being configured to adjust directions of directional light beams of the directional light beam plurality to correspond to respective view directions the plurality of different views of the multiview display.
11. The multiview display of claim 10 , wherein a size of the multibeam element is greater than one half of a size of a light valve of the light valve plurality and less than twice the light valve size.
12. The multiview display of claim 10 , further comprising a light guide configured to guide light as guided light, the multibeam element of the multibeam element plurality being configured to scatter a portion of the guided light out of a light guide as the plurality of directional light beams.
13. The multiview display of claim 12 , wherein the multibeam element comprises one of a diffraction grating, a micro-reflective element, and a micro-refractive element optically coupled to the light guide to scatter a portion of the guided light.
14. The multiview display of claim 13 , wherein the diffraction grating comprises a plurality of diffraction gratings.
15. The multiview display of claim 10 , wherein the microlens comprises a converging lens configured to adjust the directions of the directional light beams by decreasing an angular spread of the plurality of directional light beams.
16. The multiview display of claim 10 , wherein the microlens comprises a diverging lens configured to adjust the directions of the directional light beams by increasing an angular spread of the plurality of directional light beams.
17. A method of operating a multiview backlight, the method comprising:
guiding light in a propagation direction along a length of a light guide as guided light;
scattering a portion of the guided light out of the light guide using a multibeam element to provide a plurality of directional light beams, directional light beams of the directional light beam plurality having directions that differ from one another; and
adjusting the directions of the directional light beams towards a multiview pixel using a microlens, the adjusted directions corresponding to respective different view directions of a multiview display employing the multiview backlight,
wherein a size of the multibeam element is comparable to a size of a sub-pixel in the multiview pixel of the multiview display.
18. The method of operating a multiview backlight of claim 17 , wherein the multibeam element comprises one or more of an optical diffuser, a diffraction grating, a micro-reflective element, and a micro-refractive element optically coupled to the light guide to scatter the guided light portion.
19. The method of operating a multiview backlight of claim 17 , wherein the microlens is a converging lens, the directions being adjusted to decrease an angular spread of the plurality of directional light beams.
20. The method of operating a multiview backlight of claim 17 , further comprising providing light to the light guide using a light source, the provided light being guided as guided light having one or both of has a non-zero propagation angle within the light guide and is collimated according to a collimation factor to provide a predetermined angular spread of the guided light.
21. The method of operating a multiview backlight of claim 17 , further comprising modulating the directional light beams using a plurality of light valves configured as the multiview pixel.