Multiview display and method using effective light sources
A multiview display and method employ an array of lenses to provide effective light sources from semi-collimated light. The multiview display includes a semi-collimated backlight configured to provide the semi-collimated light, an array of light valves arranged as multiview pixels, and an array of lenses disposed between the semi-collimated backlight and the array of lenses. Each lens of the array of lenses is configured to provide an effective light source at a focal plane of the lens to illuminate a corresponding multiview pixel.
1. A multiview display comprising:
a semi-collimated backlight configured to emit semi-collimated light having a predetermined collimation factor;
an array of light valves arranged as multiview pixels; and
an array of lenses disposed between the light valve array and the semi-collimated backlight, each lens of the array of lenses corresponding to a different multiview pixel and being configured to provide from the semi-collimated light an effective light source at a focal plane of the lens and having a size between one quarter and two times a size of a light valve of the light valve array,
wherein the effective light source is configured to illuminate the corresponding different multiview pixel with directional light beams having directions of views of the multiview display.
2. The multiview display of claim 1 , wherein the size of the effective light source provided by each lens is equal to the predetermined collimation factor of the semi-collimated light emitted by the semi-collimated backlight multiplied by a focal length of the lens and divided by a value of a refractive index of a material at the focal plane, the predetermined collimation factor being chosen to determine the size of the effective light source.
3. The multiview display of claim 2 , wherein the predetermined collimation factor of the semi-collimated light emitted by the semi-collimated backlight is chosen to be proportional to a distance between the effective light source and the light valve array.
4. The multiview display of claim 1 , wherein lenses of the array of lenses comprise converging lenses, the effective light sources being provided at the focal plane between the array of lenses and the light valve array.
5. The multiview display of claim 1 , wherein lenses of the array of lenses comprise diverging lens, the effective light sources being provided at the focal plane between the lenses and the semi-collimated backlight.
6. The multiview display of claim 1 , wherein lenses of the array of lenses comprise one or more of refractive lenses, diffractive lenses, and gradient index lenses.
7. The multiview display of claim 6 , wherein the lenses of the array of lenses comprise refractive lenses, a material of the refractive lenses being integral with a material at the focal plane.
8. The multiview display of claim 1 , wherein lenses of the array of lenses comprise varifocal lenses configured to facilitate adjusting a location of the focal plane to change a viewing position of the multiview display.
9. The multiview display of claim 1 , wherein lenses of the array of lenses are cylindrical lenses having an axis extending in first direction, the multiview pixels each comprising a set of light valves arranged in a row that extends in a second direction across the axis of the cylindrical lenses.
10. The multiview display of claim 1 , further comprising optical baffles between lenses of the array of lenses.
11. The multiview display of claim 10 , wherein the optical baffles extend from a vicinity of the semi-collimated backlight though the array of lenses and to a vicinity of the array of light valves.
12. The multiview display of claim 1 , wherein the semi-collimated backlight comprises:
a light guide configured to guide light along a length of the light guide as guided light, the guided light being collimated according to the predetermined collimation factor; and
an angle-preserving scattering element distributed across the light guide length, the angle-preserving scattering element being configured to scatter out a portion of the collimated guided light as the emitted semi-collimated light.
13. The multiview display of claim 1 , wherein the semi-collimated backlight comprises a plurality of active light emitters arranged on a substrate.
14. A multiview display comprising:
a light guide configured to emit semi-collimated light having a predetermined, non-zero collimation factor;
an array of lenses, each lens of the array of lenses being configured to provide an effective light source at a focal plane of the lens using a portion of the semi-collimated light; and
an array of light valves arranged in sets of light valves, each lens corresponding to a different one of the sets of light valves,
wherein effective light sources provided by the array of lenses are configured to provide directional light beams having directions corresponding to view directions of a multiview image, the array of light valves being configured to modulate the directional light beams to provide a multiview image.
15. The multiview display of claim 14 , wherein an effective light source provided by a lens of the array of lenses has a size being between one quarter and two times a size of a light valve of the light valve array.
16. The multiview display of claim 14 , wherein the predetermined, non-zero collimation factor is chosen to control a size of the effective light source provided by each lens, the size being equal to the predetermined, non-zero collimation factor of the semi-collimated light multiplied by a focal length of the lens and divided by a value of a refractive index of a material between the array of lenses and the light valve array.
17. The multiview display of claim 14 , wherein a lens of the array of lenses is a convex lens and the effective light source is provided at the focal plane between the array of lenses and the light valve array.
18. The multiview display of claim 14 , wherein a lens of the array of lenses is a refractive lens comprising a refractive material that extends from the array of lenses to the light valve array.
19. The multiview display of claim 14 , wherein the light guide comprises:
a light source configured to provide light to be guided by the light guide as guided light; and
scattering structure configured to scatter the guide light out of the light guide as the semi-collimated light having the predetermined, non-zero collimation factor.
20. A method of multiview display operation, the method comprising:
emitting semi-collimated light using a semi-collimated backlight; and
providing a plurality of effective light sources from the semi-collimated light using an array of lenses disposed between the semi-collimated backlight and an array of light valves, each effective light source of the effective light source plurality being provided by a different lens of the array of lenses at a focal plane of the different lens,
wherein each effective light source is provided having a size between one quarter and two times a size of a light valve of the light valve array and is configured to illuminate a different set of light valves with directional light beams having directions corresponding to view directions of the multiview display.
21. The method of multiview display operation of claim 20 , wherein lenses of the array of lenses are converging lenses, each effective light source being provided at the focal plane disposed between the array of lenses and the light valve array.
22. The method of multiview display operation of claim 20 , further comprising:
illuminating different sets of light valves of the array of light valves with light provided by corresponding different ones of the effect light sources, the light provided by each effective light source comprising directional light beams; and
modulating the light comprising the directional light beams to provide a multiview image, directions of the directional light beams corresponding to view directions of the multiview image.