Time-multiplexed backlight and multiview display using same

A multiview display comprising:

• a time-multiplexed light source configured to provide a light beam having a first non-zero propagation angle during a first time interval and a second non-zero propagation angle during a second time interval that is different from the first non-zero propagation angle;
• and
• a multibeam backlight configured to emit a portion of the light beam as a first plurality of coupled-out light beams during the first time interval and as a second plurality of coupled-out light beams during the second time interval, the first plurality of coupled-out light beams having a first set of different principal angular directions, the second plurality of coupled-out light beams having a second set of different principal angular directions, the first set and the second set being different and being determined respectively by the different first and second non-zero propagation angles of the light beam,
• wherein coupled-out light beams of the first plurality of coupled-out light beams are angularly interleaved with coupled-out light beams of the second plurality of coupled-out light beams, each of the first and second sets of different principal angular directions corresponding to view directions of different views of the multiview display, and
• wherein the multibeam backlight comprises:
• a plate light guide configured to guide the light beam at the first non-zero propagation angle during the first time interval and at the second non-zero propagation angle during a second time interval;
• and
• an array of multibeam diffraction gratings optically coupled to and spaced apart across the plate light guide, each multibeam diffraction grating of the multibeam diffraction grating array being configured to diffractively couple out the portion of the light beam as the first plurality of coupled-out light beams during the first time interval and as the second plurality of coupled-out light beams during the second time interval,
• wherein the time-multiplexed light source is optically coupled to an input of the plate light guide, and wherein a multibeam diffraction grating of the array of multibeam diffraction gratings comprises a chirped diffraction grating having curved diffractive features.

A method of time-multiplexed backlight operation, the method comprising:

• providing a time-multiplexed light beam to be guided in a light guide at a first non-zero propagation angle during a first time interval and at a second non-zero propagation angle during a second time interval using a time-multiplexed light source;
• and
• diffractively coupling out a portion of the guided time-multiplexed light beam as coupled-out light beams during the first time interval and the second time interval using a plurality of diffraction gratings, the coupled-out light beams being directed away from a surface of the light guide at time interval-based different predetermined principal angular directions,
• wherein the predetermined principal angular directions of the coupled-out light beams in each of the first time interval and the second time interval are provided by a respective one of the first non-zero propagation angle and the second non-zero propagation angle of the guided time-multiplexed light beam, the coupled-out light beams diffractively coupled-out during the first time interval being interleaved with the coupled-out light beams diffractively coupled-out during the second time interval, and
• wherein the plurality of diffraction gratings comprises a plurality of multibeam diffraction gratings, each multibeam diffraction grating of the plurality of multibeam diffraction gratings being configured to diffractively couple out the portion of the guided light as a plurality of coupled-out light beams having different principal angular directions from one another, wherein each of the multibeam diffraction gratings is configured to diffractively couple out a first plurality of coupled-out light beams having a first set of different principal angular directions in the first time interval and a second plurality of coupled-out light beams having a second set of different principal angular directions in the second time interval, the first set and the second set being different, the coupled-out light beams of the first plurality of coupled-out light beams being interleaved with coupled-out light beams of the second plurality of coupled-out light beams, the multibeam diffraction grating comprising one or both of a chirped diffraction grating and curved diffractive features adjacent to a surface of the light guide and comprising one of grooves and ridges that are spaced apart from one another at the light guide surface.