Patch correction for light steering projector
Example embodiments provide systems and methods for correcting non-uniformities of a light beam generated by a multi-emitter light source. In some embodiments a phase modulator displays patch lenses to correct for the non-uniformities. In some embodiments each region of the phase modulator is illuminated by a beam generated by one emitter of the multi-emitter light source. Such region of the phase modulator may display a patch lens for correcting non-uniformities in the corresponding beam which illuminates the region.
1 . A projection system comprising:
one or more light sources operable to emit a plurality of light beams;
a phase modulator comprising a two-dimensional array of pixels, the pixels controllable to retard phase of light incident on the pixels by variable amounts, the phase modulator having an active area in an optical path of the plurality of light beams, each of the plurality of light beams incident on the active area of the phase modulator in a corresponding one of a plurality of distinct regions of the active area of the phase modulator;
a controller configured to set the pixels of each of the distinct regions of the phase modulator to display an optical form for a patch lens corresponding to the distinct region, the patch lens is configured to correct for non-uniformities present in the plurality of light beams emitted by the one or more light sources.
2 . The projector according to claim 1 wherein the controller is configured to set the pixels of each of the distinct regions of the phase modulator to display a light steering phase pattern combined with the optical form for the corresponding patch lens.
3 . The projector according to claim 1 wherein the optical form for the patch lens corresponding to the distinct region is at least partially based on measured deviations from ideal of the corresponding light beam.
4 . The projector according to claim 1 wherein the optical form for the patch lens corresponding to the distinct region is at least partially based on measured deviations from ideal of a light field produced at an image plane after the corresponding light beam has interacted with the phase modulator.
5 . The projector according to claim 1 wherein the corrected non-uniformities comprise at least one of pointing parallelism, collimation and intensity distribution.
6 . The projector according to claim 1 wherein adjacent patch lenses abut one another.
7 . The projector according to claim 1 wherein an entire active area of the two-dimensional array of pixels of the phase modulator is covered by patch lenses.
8 . The projector according to claim 1 wherein the optical form of each patch lens is generated independently.
9 . The projector according to claim 1 wherein the optical form of each patch lens is generated by the controller configured to execute an optimization process.
10 . The projector according to claim 9 wherein the optimization process comprises iteratively varying phase shifts of the pixels of the corresponding patch lens until one or more observed characteristics of a corresponding output beam indicate that the patch lens is flight steered suitably correcting for deviations from ideal of the light beam.
11 . The projector according to claim 1 wherein the optical form for each of the patch lenses specifies at least one of focal length, optical centre shift, parameterized astigmatism and tilt of the corresponding patch lens.
12 . The projector according to claim 1 wherein at least one of the distinct regions is divided into a plurality of sub regions and the controller is configured to set the pixels of each of the sub regions to display an optical form corresponding to the sub region.
13 . The projector according to claim 1 wherein different parts of a single light beam illuminate two or more sub regions of a corresponding distinct region of the phase modulator.
14 . The projector according to claim 1 wherein one or more of the optical forms is respectively varied in real time to account for varying characteristics of a corresponding one of the light beams.
15 . The projector according to claim 1 wherein the optical form applied to each of the light beams further comprises a light steering component to steer light.
16 . The projector according to claim 15 wherein the light steering components applied to different light beams are different.
17 . The projector according to claim 15 wherein the light steering components are configured to steer the light beams to converge at a plurality of different points.
18 . The projector according to claim 15 wherein the controller controls each of the distinct regions of the phase modulator individually to display a pattern of phase shifts which steers light from the corresponding light beam.
19 . The projector according to claim 15 wherein the optical forms of each of the patch lenses and the corresponding light steering component are calculated independently of each other.
20 . The projector according to claim 15 wherein the optical forms of each of the patch lenses and the corresponding light steering component are calculated together.
21 . The projector of claim 1 comprising a camera configured to capture images of light steered images and connected to provide the captured images to the controller.
22 . The projector of claim 21 wherein the controller is configured to process the captured images of the light steered images to determine characteristics of light used to generate the light steered images and to vary one or more optical forms of the patch lenses to be displayed by the phase modulator.