Light field projectors and methods for redistributing light dynamically to achieve a light field
Undesirably high energy-consumption in illuminating devices can be caused at least in part by wasted (attenuated) light. Optically efficient illumination systems that may be used to project light, including images, use light redirection. Phase modulating devices may be applied to create desired light fields. Some embodiments provide dual or multiple modulation display or projection systems in which some or all of the modulators not only attenuate amplitude, but also amplify amplitude, or change the phase, frequency and polarization of the light provided by the light source.
1. A method for displaying an image, the image having a luminance that varies from place to place, such that the image has darker areas and lighter areas, the method comprising:
receiving at a controller image data defining the image for display, wherein the image data describes a target light field;
delivering a delivered amount of light based on the image data, wherein the delivered amount of light is comprised of light from each of a plurality of light sources to illuminate a plurality of corresponding areas of a screen wherein each area corresponds to illumination with a selected amount of light for that area, wherein the plurality of light sources are coupled to the controller;
analyzing the image data defining the image for display from the plurality of light sources to the screen,
receiving by a dynamically addressable light re-distributor the light from each of the plurality of light sources, wherein the dynamically addressable light re-distributor is coupled to the controller that is configured with a light distribution scheme, the dynamically addressable light re-distributor comprises receiving optics and a dynamically-addressable focusing element,
wherein the receiving optics receive an incoming light profile formed by the light from the plurality of light sources and transform the incoming light profile into an illumination light field that substantially matches a size, shape and angular acceptance range of the dynamically-addressable focusing element, and wherein the dynamically-addressable focusing element is controlled by distribution data that corresponds to the light distribution scheme, and
in response to the image data defining the image and the light distribution scheme, dynamically redistributing with the dynamically-addressable focusing element the light displayed to the screen in a non-subtractive manner and by altering sizes of the plurality of corresponding areas that receive the selected amount of light for that area such that the corresponding areas located in the lighter areas of the image are smaller and the corresponding areas located in the darker areas of the image are larger, wherein the amount of light delivered from the dynamically addressable light re-distributor to the display after passing through the dynamically-addressable focusing element substantively does not change compared to the amount of light delivered to the receiving optics of the dynamically addressable light re-distributor.
2. The method according to claim 1 wherein the corresponding areas of the screen are rectangular.
3. The method according to claim 1 wherein altering sizes of the plurality of corresponding areas comprises changing lengths of at least some of the corresponding areas and changing widths of at least some of the corresponding areas.
4. The method according to claim 1 wherein the light sources comprise laser light sources.
5. The method according to claim 1 wherein delivering light from the light sources to the corresponding areas comprises relaying light to the corresponding area by way of beam shaping and beam expanding optics.
6. The method according to claim 5 comprising expanding and shaping a beam from one of the light sources to match a size and shape of the corresponding area and steering the expanded shaped beam to a location of the corresponding area.
7. The method according to claim 6 wherein steering the expanded and shaped beam comprises adjusting two-axis scanning mirror optics.
8. The method according to claim 6 wherein expanding the beam comprises expanding the beam by different amounts in each of two perpendicular directions.
9. The method according to claim 6 wherein expanding the beam comprises passing the beam through a pair of cylindrical lenses.
10. A display apparatus comprising:
a plurality of light sources each associated with an optical path arranged to carry light from the plurality of light sources to a plurality of corresponding image areas, wherein each image area corresponds to illumination with a selected amount of light for that image area, wherein the amount of light from the plurality of light sources corresponds to a delivered amount of light based on image data describing a target light field for displaying an image;
a dynamically addressable light re-distributor configured to receive the delivered amount of light from the plurality of light sources to redirect the light to the image area;
a controller operatively coupled to a dynamically-addressable focusing element to alter sizes of the corresponding image areas in response to image data, wherein the controller is configured with a light distribution scheme based on the image data;
wherein the dynamically addressable light re-distributor comprises receiving optics and the dynamically-addressable focusing element, the receiving optics being configured to receive an incoming light profile formed by the delivered amount of light from the plurality of light sources and transform the incoming light profile into an illumination light field that substantially matches a size, shape and angular acceptance range of the dynamically-addressable focusing element;
wherein the dynamically-addressable focusing element is controlled by distribution data that corresponds to the light distribution scheme and is configured to dynamically redistribute a display of the light to the image area in a non-subtractive manner and by altering sizes of the plurality of corresponding areas that receive the selected amount of light for that area to increase the sizes of the corresponding image areas located in darker areas of the image and to decrease the size of the corresponding image areas located in lighter areas of the image, wherein the amount of light delivered from the dynamically addressable light re-distributor to the display after passing through the dynamically-addressable focusing element substantively does not change compared to the amount of light delivered to the receiving optics of the dynamically addressable light re-distributor.
11. The display apparatus according to claim 10 wherein the control circuit is configured to alter sizes of the plurality of corresponding areas by changing lengths of at least some of the corresponding areas and changing widths of at least some of the corresponding areas.
12. The display apparatus according to claim 10 wherein the light sources comprise laser light sources.
13. The display apparatus according to claim 10 wherein the optical paths comprise controllable beam shaping and beam expanding optics arranged to deliver light from the corresponding light sources to the corresponding areas.
14. The display apparatus according to claim 10 , wherein the optical paths comprise two-axis scanning mirror optics.
15. The display apparatus according to claim 10 wherein each of the optical paths comprises a pair of cylindrical lenses.