Backlight, multiview display and method having a grating spreader
AssigneeLeia Inc.
InventorsDavid A. Fattal, Joseph D. Lowney
Life of this patent
Estimating the term…
Abstract
A backlight and a multiview display employ a light guide having angle-preserving scattering feature and a grating spreader. The angle-preserving scattering feature is configured to scatter a portion of guided light out of the light guide as emitted light. The grating spreader includes a diffraction grating and is configured to convert light provided by a light source into spatio-angularly homogenous light to be guided as the guided light. The multiview display includes an array of light valves as well as the angle-preserving scattering feature that includes a multibeam element having a size that is comparable to a size of a light valve of the light valve array.
Claims19
A backlight comprising:
- a light guide configured to guide light along a length of the light guide as guided light, the light guide having an angle-preserving scattering feature configured to scatter a portion of the guided light out of the light guide as emitted light;
- and
- a grating spreader between a light source configured to provide light to the light guide and the angle-preserving scattering feature of the light guide, the grating spreader comprising a reflection-mode diffraction grating that includes a reflective layer and a grating layer between the reflective layer and the light guide, the grating layer having diffractive features that extend in a propagation direction of the guided light within the light guide, the grating spreader being configured to convert the light provided by the light source into spatio-angularly homogenous light within the light guide to facilitate uniform illumination of the backlight.
A multiview display comprising:
- a light guide configured to guide light as guided light;
- an angle-preserving scattering feature comprising an array of multibeam elements configured to scatter out a portion of the guided light as directional light beams having principal angular directions corresponding to view directions of different views of a multiview image of the multiview display;
- a grating spreader comprising a reflection-mode diffraction grating that includes a reflective layer and a grating layer between the reflective layer and the light guide, the grating layer having diffractive features extending in a propagation direction of the guided light, the grating spreader being configured to convert light from a light source into the guided light that is spatio-angularly homogenous prior to the guided light being scattered out by the multibeam element array as the directional light beams;
- and
- an array of light valves configured to modulate the directional light beams as the different views of the multiview image.
A method of backlight operation, the method comprising:
- providing light to a light guide using a light source at an input edge of the light guide;
- converting the provided light into spatio-angularly homogenous light within the light guide using a grating spreader to provide guided light within the light guide, the grating spreader comprising a reflection-mode diffraction grating adjacent to the input edge of the light guide, the reflection-mode diffraction grating including a reflective layer and a grating layer between the reflective layer and the light guide, the grating layer having diffractive features extending in a direction corresponding to a propagation direction of the guided light within the light guide;
- and
- scattering a portion of the guided light out of the light guide as emitted light using an angle-preserving scattering feature of the light guide.
Dependencies are inferred from the claim text.