Method and controller for operating a variable optical retarder and an array
A method and a controller for operating an array of variable optical retarders are disclosed. Neighboring pixels of the array of variable optical retarders are driven with disordered temporal bit sequences. An optical beam illuminating the pixels tends to integrate time-domain modulation caused by individual pixels driven in a non-coordinated or disordered fashion, which reduces the overall time-domain modulation amplitude of the optical beam.
1. A method comprising:
selecting temporal bit sequences from a group of temporal bit sequences,
wherein the group of temporal bit sequences includes temporal bit sequences having substantially uncorrelated bit patterns; and
applying the selected temporal bit sequences to respective variable optical retarders to generate a pattern for the respective variable optical retarders to receive a beam of light,
wherein the substantially uncorrelated bit patterns applied to the respective variable optical retarders reduce an amplitude and a coherence of fluctuations in the pattern.
2. The method of claim 1 , wherein the substantially uncorrelated bit patterns are bit patterns in which single-period sub-signals are not aligned.
3. The method of claim 1 , wherein one-bits in the selected temporal bit sequences are non-periodic.
4. The method of claim 1 , wherein one-bits in the selected temporal bit sequences are substantially evenly distributed in time.
5. The method of claim 1 , wherein selecting the temporal bit sequences includes:
selecting, using a look-up table having a plurality of rows that each contains a temporal bit sequence for one of a plurality of optical retardation values, the temporal bit sequences.
6. The method of claim 1 , wherein the selected temporal bit sequences are of equal total duration.
7. The method of claim 1 , wherein the selected temporal bit sequences are simultaneously applied to the respective variable optical retarders.
8. The method of claim 7 , wherein simultaneously applying the selected temporal bit sequences generates a spatial profile in the beam of light.
9. The method of claim 1 , further comprising:
determining respective optical retardation values for the respective variable optical retarders,
wherein the selected temporal bit sequences are selected based on the determined respective optical retardation values.
10. The method of claim 1 , further comprising:
adjusting a bit duration of at least one bit in the selected temporal bit sequences to lessen a time-domain modulation.
11. A controller configured to:
select temporal bit sequences from a group of temporal bit sequences,
wherein the group of temporal bit sequences includes temporal bit sequences having substantially uncorrelated bit patterns; and
apply the selected temporal bit sequences to respective variable optical retarders to generate a pattern for the respective variable optical retarders to receive a beam of light,
wherein the substantially uncorrelated bit patterns applied to the respective variable optical retarders reduce an amplitude and a coherence of fluctuations in the pattern.
12. The controller of claim 11 , wherein the substantially uncorrelated bit patterns are bit patterns in which single-period sub-signals are not aligned.
13. The controller of claim 11 , wherein one-bits in the selected temporal bit sequences are non-periodic.
14. The controller of claim 11 , wherein one-bits in the selected temporal bit sequences are substantially evenly distributed in time.
15. The controller of claim 11 , wherein the controller, when selecting the temporal bit sequences, is configured to:
select, using a look-up table having a plurality of rows that each contains a temporal bit sequence for one of a plurality of optical retardation values, the temporal bit sequences.
16. The controller of claim 11 , wherein the selected temporal bit sequences are of equal total duration.
17. The controller of claim 11 , wherein the selected temporal bit sequences are simultaneously applied to the respective variable optical retarders.
18. The controller of claim 17 , wherein simultaneously applying the selected temporal bit sequences generates a spatial profile in the beam of light.
19. The controller of claim 11 , wherein the controller is further configured to:
determine respective optical retardation values for the respective variable optical retarders,
wherein the selected temporal bit sequences are selected based on the determined respective optical retardation values.
20. The controller of claim 11 , wherein the controller is further configured to:
adjust a bit duration of at least one bit in the selected temporal bit sequences to lessen a time-domain modulation.