Drive scheme for stereoscopic display polarization modulator and apparatus for same
View Patent ↗An improved drive scheme for a segmented polarizing modulator (or Polarization Control Panel) for use in an electronic stereoscopic display. The segmented polarization modulator segments are arranged contiguously in a direction of the sequential scan. The liquid crystal material used in each segment is driven in a manner to reduce the visibility of segment boundaries, by applying a positive or negative transition voltage (+T or −T volts) for a short period of time prior to applying +H and −H drive voltages. Optionally, the transition voltage may also be applied in transitioning from +H and −H drive voltages.
1. A polarizing modulator for an electronic stereoscopic display system having a sequentially scanning display, the polarizing modulator comprising:
a plurality of segments each containing liquid crystal material and arranged contiguously in a direction of the sequential scan;
driving circuitry coupled to each segment and configured to individually drive liquid crystal in each segment to a desired polarization modulating state by:
providing a positive low drive voltage to a first segment for a first time period, the positive low drive voltage insufficient to switch the first segment to a first polarization modulating state;
increasing the positive low drive voltage to provide a first positive transition voltage to the first segment for a first transition time period, the first positive transition voltage sufficient to drive liquid crystal in the first segment towards the first polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in a second segment immediately adjacent to the first segment; and
increasing the first positive transition voltage to provide a positive high drive voltage to the first segment for a second time period, the positive high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the first polarization modulating state.
2. A polarizing modulator in accordance with claim 1 , further comprising decreasing the positive high drive voltage to provide a second positive transition voltage to the first segment for a second transition time period, the second positive transition voltage substantially equal to the first positive transition voltage.
3. A polarizing modulator in accordance with claim 2 wherein the driving circuitry is further configured to provide a zero voltage to the first segment immediately after providing the second positive transition voltage.
4. A polarizing modulator in accordance with claim 1 , wherein the positive low drive voltage is about +3.5 volts, and wherein the first time period is about 8 milliseconds.
5. A polarizing modulator in accordance with claim 1 , wherein the first positive transition voltage is about +6 to +10 volts, and wherein the first transition time period is about 1 millisecond.
6. A polarizing modulator in accordance with claim 1 , wherein the positive high drive voltage is about +28 volts, and wherein the second time period is about 6 milliseconds.
7. A polarizing modulator in accordance with claim 1 , wherein the driving circuitry is further configured to provide a zero voltage to the first segment immediately prior to providing the positive low drive voltage.
8. A polarizing modulator in accordance with claim 7 , wherein the zero voltage is provided for about 2 milliseconds.
9. A polarizing modulator in accordance with claim 1 , wherein the driving circuitry is further configured to:
provide a negative low drive voltage to the first segment, after providing the positive high drive voltage, for a third time period, the negative low drive voltage insufficient to switch the first segment to a second polarization modulating state;
increase the negative low drive voltage to provide a first negative transition voltage to the first segment for a third transition time period, the first negative transition voltage sufficient to drive liquid crystal in the first segment towards a second polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in the adjacent second segment; and
increase the first negative transition voltage to provide a negative high drive voltage to the first segment for a fourth time period, the negative high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the second polarization modulating state.
10. A polarizing modulator in accordance with claim 9 , wherein the driving circuitry is further configured to decrease the negative high drive voltage to provide a second negative transition voltage to the first segment for a fourth transition time period, the second negative transition substantially equal to the first negative transition voltage.
11. A polarizing modulator in accordance with claim 10 , wherein the driving circuitry is further configured to provide a zero voltage to the first segment immediately after providing the second transition voltage.
12. A polarizing modulator in accordance with claim 9 , wherein the first segment is driven to positive and negative high states by the positive and negative high drive voltages in synchrony with an image for a selected eye, and driven to positive and negative low states by the positive and negative low drive voltages in synchrony with an image for a non-selected eye.
13. A polarizing modulator in accordance with claim 9 , wherein the driving circuitry is further configured to provide a zero voltage to the first segment immediately prior to providing the negative low drive voltage.
14. A polarizing modulator in accordance with claim 9 , wherein the driving circuitry is further configured to drive a second segment in substantially the same manner as the first segment with a 1 millisecond lag behind the first segment to create a scrolling polarization modulator in synchronization with a scrolling liquid crystal modulation panel.
15. A method for driving a polarizing modulator for an electronic stereoscopic display system having a sequentially scanning display comprising a plurality of segments each containing liquid crystal material and arranged contiguously in a direction of the sequential scan, the method comprising:
providing a positive low drive voltage to a first segment for a first time period, the positive low drive voltage insufficient to switch the first segment to a first polarization modulating state;
increasing the positive low drive voltage to provide a first positive transition voltage to the first segment for a first transition time period, the first positive transition voltage sufficient to drive liquid crystal in the first segment towards the first polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in a second segment immediately adjacent to the first segment; and
increasing the first positive transition voltage to provide a positive high drive voltage to the first segment for a second time period, the positive high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the first polarization modulating state.
16. A method in accordance with claim 15 , further comprising decreasing the positive high drive voltage to provide a second positive transition voltage to the first segment for a second transition time period, the second positive transition voltage substantially equal to the first positive transition voltage.
17. A method in accordance with claim 16 , the method further comprising providing a zero voltage to the first segment immediately after providing the second positive transition voltage.
18. A method in accordance with claim 15 , wherein the positive low drive voltage is about +3.5 volts, and wherein the first time period is about 8 milliseconds.
19. A method in accordance with claim 15 , wherein the first positive transition voltage is about +6 to +10 volts, and wherein the first transition time period is about 1 millisecond.
20. A method in accordance with claim 15 , wherein the positive high drive voltage is about +28 volts, and wherein the second time period is about 6 milliseconds.
21. A method in accordance with claim 15 , the method further comprising providing a zero voltage to the first segment immediately prior to providing the positive low drive voltage.
22. A method in accordance with claim 21 , wherein the zero voltage is provided for about 2 milliseconds.
23. A method in accordance with claim 15 , further comprising:
providing a negative low drive voltage to the first segment for a third time period, the negative low drive voltage insufficient to switch the first segment to a second polarization modulating state;
increasing the negative low drive voltage to provide a first negative transition voltage to the first segment for a third transition time period, the first negative transition voltage sufficient to drive liquid crystal in the first segment towards a second polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in the adjacent second segment; and
increasing the first negative transition voltage to provide a negative high drive voltage to the first segment for a fourth time period, the negative high drive voltage sufficient to decisively switch the first segment of the polarization modulator to the second polarizing modulator state.
24. A method in accordance with claim 23 , further comprising decreasing the negative high drive voltage to provide a second negative transition voltage to the first segment for a fourth transition time period, the second negative transition substantially equal to the first negative transition voltage.
25. A method in accordance with claim 24 , the method further comprising providing a zero voltage to the first segment immediately after providing the second negative transition voltage.
26. A method in accordance with claim 23 , wherein the first segment is driven to positive and negative high states by the positive and negative high drive voltages in synchrony with an image for a selected eye, and driven to positive and negative low states by the positive and negative low drive voltages in synchrony with an image for a non-selected eye.
27. A method in accordance with claim 23 , the method further comprising providing a zero voltage to the first segment immediately prior to providing the negative low drive voltage.
28. A method in accordance with claim 23 , further comprising driving the second segment in substantially the same manner as the first segment with a 1 millisecond lag behind the first segment to create a scrolling polarization modulator in synchronization with a scrolling liquid crystal modulation panel.
29. A polarizing modulator for an electronic stereoscopic display system having a sequentially scanning display, the polarizing modulator comprising:
a plurality of segments each containing liquid crystal material and arranged contiguously in a direction of the sequential scan;
driving circuitry coupled to each segment and configured to individually drive liquid crystal in each segment to a desired polarization modulating state by:
providing a positive low drive voltage to a first segment for a first time period, the positive low drive voltage insufficient to switch the first segment to a first polarization modulating state;
increasing the positive low drive voltage to provide a first positive transition voltage to the first segment for a first transition time period, the first positive transition voltage sufficient to drive liquid crystal in the first segment towards the first polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in a second segment immediately adjacent to the first segment;
increasing the first positive transition voltage to provide a positive high drive voltage to the first segment for a second time period, the positive high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the first polarization modulating state;
providing a negative low drive voltage to the first segment for a third time period, the negative low drive voltage insufficient to switch the first segment to a second polarization modulating state;
increasing the negative low drive voltage to provide a first negative transition voltage to the first segment for a third transition time period, the first negative transition voltage sufficient to drive liquid crystal in the first segment towards a second polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in the adjacent second segment; and
increasing the first negative transition voltage to provide a negative high drive voltage to the first segment for a fourth time period, the negative high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the second polarization modulating state.
30. A polarizing modulator in accordance with claim 29 , wherein the driving circuitry is further configured to:
decrease the positive high drive voltage to provide a second positive transition voltage to the first segment for a second transition time period, prior to providing the low negative drive voltage, the second positive transition voltage substantially equal to the first positive transition voltage; and
decrease the negative high drive voltage to provide a second negative transition voltage to the first segment for a fourth transition time period, the second negative transition substantially equal to the first negative transition voltage.
31. A polarizing modulator in accordance with claim 29 , wherein the positive low drive voltage is about +3.5 volts and the first time period is about 8 milliseconds, and wherein the positive high drive voltage is about +28 volts, and wherein the second time period is about 6 milliseconds.
32. A polarizing modulator in accordance with claim 29 , wherein the first and second positive transition voltages are each about +6 to +10 volts, and wherein the first and second transition time periods are each about 1 millisecond.
33. A polarizing modulator in accordance with claim 29 , wherein the driving circuitry is further configured to:
provide a zero voltage to the first segment immediately prior to providing the positive low drive voltage;
provide a zero voltage to the first segment immediately after providing the second positive transition voltage and prior to providing the negative low drive voltage; and
provide a zero voltage to the first segment immediately after providing the second negative transition voltage.
34. A polarizing modulator in accordance with claim 33 , wherein the zero voltages are each provided for about 2 milliseconds.
35. A polarizing modulator in accordance with claim 29 , wherein the first segment is driven to positive and negative high states by the positive and negative high drive voltages in synchrony with an image for a selected eye, and driven to positive and negative low states by the positive and negative low drive voltages in synchrony with an image for a non-selected eye.
36. A polarizing modulator in accordance with claim 29 , wherein the driving circuitry is further configured to drive a second segment in substantially the same manner as the first segment with a 1 millisecond lag behind the first segment to create a scrolling polarization modulator in synchronization with a scrolling liquid crystal modulation panel.
37. A method for driving a polarizing modulator for an electronic stereoscopic display system having a sequentially scanning display comprising a plurality of segments each containing liquid crystal material and arranged contiguously in a direction of the sequential scan, the method comprising:
providing a positive low drive voltage to a first segment for a first time period, the positive low drive voltage insufficient to switch the first segment to a first polarization modulating state;
increasing the positive low drive voltage to provide a first positive transition voltage to the first segment for a first transition time period, the first positive transition voltage sufficient to drive liquid crystal in the first segment towards the first polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in a second segment immediately adjacent to the first segment;
increasing the first positive transition voltage to provide a positive high drive voltage to the first segment for a second time period, the positive high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the first polarization modulating state;
providing a negative low drive voltage to the first segment for a third time period, the negative low drive voltage insufficient to switch the first segment to a second polarization modulating state;
increasing the negative low drive voltage to provide a first negative transition voltage to the first segment for a third transition time period, the first negative transition voltage sufficient to drive liquid crystal in the first segment towards a second polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in the adjacent second segment; and
increasing the first negative transition voltage to provide a negative high drive voltage to the first segment for a fourth time period, the negative high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the second polarization modulating state.
38. A method in accordance with claim 37 , further comprising:
decreasing the positive high drive voltage to provide a second positive transition voltage to the first segment for a second transition time period, prior to providing the negative low drive voltage, the second positive transition voltage substantially equal to the first positive transition voltage; and
decreasing the negative high drive voltage to provide a second negative transition voltage to the first segment for a fourth transition time period, the second negative transition substantially equal to the first negative transition voltage.
39. A method in accordance with claim 37 , wherein the positive low drive voltage is about +3.5 volts and the first time period is about 8 milliseconds, and wherein the positive high drive voltage is about +28 volts, and wherein the second time period is about 6 milliseconds.
40. A method in accordance with claim 37 , wherein the first and second positive transition voltages are each about +6 to +10 volts, and wherein the first and second transition time periods are each about 1 millisecond.
41. A method in accordance with claim 37 , further comprising:
providing a zero voltage to the first segment immediately prior to providing the positive low drive voltage;
providing a zero voltage to the first segment immediately after providing the second positive transition voltage and prior to providing the negative low drive voltage; and
providing a zero voltage to the first segment immediately after providing the second negative transition voltage.
42. A method in accordance with claim 41 , wherein the zero voltages are each provided for about 2 milliseconds.
43. A method in accordance with claim 37 , wherein the first segment is driven to positive and negative high states by the positive and negative high drive voltages in synchrony with an image for a selected eye, and driven to positive and negative low states by the positive and negative low drive voltages in synchrony with an image for a non-selected eye.
44. A method in accordance with claim 37 , wherein the method further comprises driving a second segment in substantially the same manner as the first segment with a 1 millisecond lag behind the first segment to create a scrolling polarization modulator in synchronization with a scrolling liquid crystal modulation panel.
45. A polarizing modulator for an electronic stereoscopic display system having a sequentially scanning display, the polarizing modulator comprising:
a plurality of segments each containing liquid crystal material and arranged contiguously in a direction of the sequential scan;
driving circuitry coupled to each segment and configured to individually drive liquid crystal in each segment to a desired polarization modulating state by:
providing a positive high drive voltage to the first segment for a first time period, the positive high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the first polarization modulating state;
decreasing the positive high drive voltage to provide a positive transition voltage to the first segment for a first transition time period, the positive transition voltage insufficient to drive liquid crystal in the first segment towards the second polarization modulating state and insufficient to create a lateral electric field of significant magnitude to significantly affect liquid crystal in a second segment immediately adjacent to the first segment; and
decreasing the positive transition voltage toward zero voltage after the first transition time period;
wherein the drive circuitry is further configured to provide a negative low drive voltage to the first segment for a second time period, the positive low drive voltage insufficient to switch the first segment to the second polarization modulating state;
increase the negative low drive voltage to provide a first negative transition voltage to the first segment for a second transition time period, the first negative transition voltage insufficient to drive liquid crystal in the first segment towards the second polarization modulating state and insufficient to create a lateral electric field of significant magnitude to significantly affect liquid crystal in a second segment immediately adjacent to the first segment; and
increase the first negative transition voltage to provide a negative high drive voltage to the first segment for a third time period, the negative high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the second polarization modulating state.
46. A polarizing modulator in accordance with claim 45 , the driving circuitry further configured to decrease the negative high drive voltage to provide a second negative transition voltage to the first segment for a third transition time period, the second negative transition voltage substantially equal to the first negative transition voltage.
47. A polarizing modulator in accordance with claim 46 , wherein the driving circuitry is further configured to:
provide a positive low drive voltage to the first segment, after providing the second negative transition voltage, for a fourth time period, the positive low drive voltage insufficient to switch the first segment to the first polarization modulating state;
increase the positive low drive voltage to provide a second positive transition voltage to the first segment for a third transition time period, the second positive transition voltage sufficient to drive liquid crystal in the first segment towards the first polarization modulating state without creating a lateral electric field of significant magnitude to significantly affect liquid crystal in the adjacent second segment; and
increase the second positive transition voltage to provide the positive high drive voltage to the first segment for a fourth time period, the negative high drive voltage sufficient to decisively switch the first segment of the polarizing modulator to the first polarization modulating state.
48. A polarizing modulator in accordance with claim 47 , wherein the driving circuitry is further configured to provide a zero voltage to the first segment immediately prior to providing the positive low drive voltage.
49. A polarizing modulator in accordance with claim 46 , wherein the first segment is driven to positive and negative high states by the positive and negative high drive voltages in synchrony with an image for a selected eye, and driven to positive and negative low states by the positive and negative low drive voltages in synchrony with an image for a non-selected eye.
50. A polarizing modulator in accordance with claim 46 , wherein the driving circuitry is further configured to drive a second segment in substantially the same manner as the first segment with a 1 millisecond lag behind the first segment to create a scrolling polarization modulator in synchronization with a scrolling liquid crystal modulation panel.
51. A polarizing modulator in accordance with claim 45 , wherein the positive high drive voltage is about +28 volts, and wherein the second time period is about 6 milliseconds.
52. A polarizing modulator in accordance with claim 45 , wherein the positive transition voltage is about +6 to +10 volts, and wherein the first transition time period is about 1 millisecond.
53. A polarizing modulator in accordance with claim 45 , wherein the driving circuitry is further configured to provide a zero voltage to the first segment immediately after providing the positive transition voltage; wherein the zero voltage is provided for about 2 milliseconds.