Angular subpixel rendering multiview display using shifted multibeam elements
Multiview displays include a backlight and a screen used to form a plurality of multiview pixels. Each multiview pixel includes a plurality of sets of light valves. The backlight includes a light source optically coupled to a plate light guide configured with a plurality of multibeam elements. Each multibeam element corresponds to a set of light valves and is spatially offset with respect to a center of the set of light valves toward a center of the multiview pixel. The plurality of multibeam elements are also configured to couple out light from the plate light guide with different angles and angular offsets such that at least a portion of the coupled-out light beams interleave and propagate in different view directions of the multiview display.
1. A multiview display comprising:
a multiview pixel having a plurality of sets of light valves; and
a backlight comprising a plate light guide configured to guide light as guided light and a plurality of multibeam elements configured to couple out a portion of the guided light as coupled-out light having different angles, each multibeam element of the plurality of multibeam elements corresponding to a different set of light valves of the multiview pixel and each multibeam element having a spatial offset with respect to a center of the set of light valves toward a center of the multiview pixel,
wherein a size of the multibeam element is comparable to a size of a light valve in the sets of light valves of the multiview pixel, and wherein an angular offset of the coupled-out light is provided by the spatial offset of each multibeam pixel, the sets of light valves being configured to provide modulated light beams that interleave to produce directional views of a multiview image within a viewing distance of the multiview display as a result of the angular offset of the coupled-out light.
2. The multiview display of claim 1 , wherein a multibeam element of the plurality of multibeam elements comprises a diffraction grating at a surface of the plate light guide, the diffraction grating being configured to diffractively couple out the portion of the guided light as the coupled-out light having different diffraction angles.
3. The multiview display of claim 2 , wherein the diffraction grating comprises a linearly chirped diffraction grating.
4. The multiview display of claim 2 , wherein the diffraction grating comprises a plurality of diffraction gratings.
5. The multiview display of claim 1 , wherein a multibeam element of the plurality of multibeam elements comprises one or both of a micro-reflective element and a micro-refractive element, the micro-reflective element being configured to reflectively couple out the portion of the guided light as the coupled-out light, and the micro-refractive element being configured to refractively couple out the portion of the guided light as the coupled-out light.
6. The multiview display of claim 1 , wherein the size of the multibeam element is between twenty-five percent and one hundred percent of the size of a light valve of the sets of light valves.
7. The multiview display of claim 1 , wherein a shape of the multibeam element is analogous to a shape of the multiview pixel.
8. The multiview display of claim 1 , wherein the multibeam element is located one of at a first surface and at a second surface of the plate light guide, the multibeam element being configured to couple out the guided light portion through the first surface.
9. The multiview display of claim 1 , further comprising a light source optically coupled to an input of the plate light guide, the light source being configured to provide the guided light one or both of having a non-zero propagation angle and being collimated according to a predetermined collimation factor.
10. The multiview display of claim 1 , wherein the spatial offset with respect to the center of the set of light valves comprises a distance equal to a fraction of the size of the light valve.
11. A multiview display comprising:
a screen having a plurality of multiview pixels, each multiview pixel having a plurality of sets of light valves; and
a backlight having a plurality of multibeam elements, each multibeam element corresponding to a set of light valves and having a spatially offset with respect to a center of the corresponding set of light valves toward a center of the multiview pixel, a size of the multibeam element being comparable to a size of a light valve of the sets of light valves in the multiview pixel,
wherein the plurality of multibeam elements are configured to couple out light from the backlight as coupled-out light having different angles, and wherein the spatial offsets of the multibeam elements are configured to provide angular offsets of the coupled-out light such that the sets of light valves provide modulated light beams that interleave as directional views of a multiview image within a viewing distance of the multiview display.
12. The multiview display of claim 11 , wherein the backlight comprises:
a plate light guide configured to guide light as guided light, the plurality of multibeam elements being located at a surface of the plate light guide; and
a light source coupled to an edge of the plate light guide, the light source to generate light coupled into the plate light guide as the guided light,
wherein a portion of the coupled-in light is coupled out of the plate light guide by the multibeam elements as the coupled-out light.
13. The multiview display of claim 12 , wherein the backlight further comprises a light source optically coupled to an input of the plate light guide, the light source being configured to provide the guided light one or both of having a non-zero propagation angle and being collimated according to a predetermined collimation factor.
14. The multiview display of claim 11 , wherein a multibeam element of the plurality of multibeam elements comprises a diffraction grating configured to diffractively couple out the light from the backlight as the coupled-out light.
15. The multiview display of claim 14 , wherein the diffraction grating comprises a plurality of diffraction gratings.
16. The multiview display of claim 11 , wherein a multibeam element of the plurality of multibeam elements comprises one or both of a micro-reflective element and a micro-refractive element, the micro-reflective element being configured to reflectively couple out the light from the backlight as the coupled-out light, and the micro-refractive element being configured to refractively couple out the light from the backlight as the coupled-out light.
17. The multiview display of claim 11 , wherein the spatial offset of the multibeam element with respect to the center of the set of light valves comprises a distance equal to a fraction of the size of a light valve of the sets of light valves.
18. A method to display a multiview image, the method comprising:
optically coupling light generated by a light source into a plate light guide;
assigning pixel intensities of a series of two-dimensional (2D) images of the multiview image to light valves of a plurality of sets of light valves of a multiview pixel;
coupling out a portion of the light from a plurality of multibeam elements of the plate light guide, each multibeam element corresponding to a set of light valves and having a spatial offset with respect to a center of the set of light valves toward a center of a multiview pixel; and
modulating the coupled-out light portion using light valves of the plurality of sets of light valves of the multiview pixel according to the assigned pixel intensities,
wherein modulated light beams emerging from the light valves interleave according to spatial offsets of the multibeam elements to produce directional views of the multiview image at a viewing distance from sets of light valves, and wherein a size of a multibeam element is comparable to a size of a light valve of the plurality of set of light valves.
19. The method of claim 18 , wherein assigning pixel intensities of the series of 2D images of the multiview image comprises:
assigning pixels of the 2D images with a same pixel coordinate to the multiview pixel; and
assigning pixel intensities of the pixels with the same pixel coordinates in consecutive 2D images in alternating order to light valves of the plurality of sets of light valves of the multiview pixel.
20. The method of claim 18 , wherein each 2D image of the series of 2D images is of a different view of one or more three-dimensional (3D) objects or a 3D scene.