Segmented polarization control panel
View Patent ↗This disclosure describes stereoscopic flat panel display systems based on the polarization encoding of sequentially displayed left and right eye images. The systems comprise line-by-line addressed liquid crystal display (LCD) panels, illuminating back light units and polarization control panels (PCPs). Right and left eye images are written sequentially onto the LCD whose polarization is controlled by a substantially synchronously driven PCP. The backlight may be continuously illuminated, or modulated temporally, spatially or both, as can the PCP.
1. A polarization control panel (PCP) for a stereoscopic display, operable to selectively transform the state of polarization of modulated light from an image modulation panel, the PCP having a plurality of polarization control segments, the PCP comprising:
a liquid crystal (LC) layer disposed on a first plane;
a common electrode disposed on a first side of the LC layer, and parallel to the first plane;
a first electrode disposed on a second side of the LC layer, on a second plane that is parallel to the first plane; and
a second electrode disposed on the second side of the LC layer, on a third plane, wherein a portion of the first electrode overlaps with the second electrode and is conductively isolated from the second electrode;
wherein the first electrode is operable to cause the second electrode to be driven to a voltage potential, and
wherein the PCP is operable to transform the state of polarization of the modulated light from the image modulation panel in accordance with the voltage potential of the second electrode being driven by the first electrode.
2. The PCP of claim 1 , further comprising a quarter wave plate in an output optical path.
3. The PCP of claim 1 , wherein the LC layer comprises zero twist nematic liquid crystal material having zero retardation in a first state and a half wave of retardation in a second state.
4. The PCP of claim 1 , wherein applying an input voltage greater than a predetermined bias voltage across the first electrode and the common electrode operates to allow the modulated light from the image modulation panel to pass through without any polarization transformation.
5. The PCP of claim 1 , wherein applying an input voltage less than a predetermined bias voltage across the first electrode and the common electrode operates to transform the state of polarization of the modulated light from the image modulation panel by a half wavelength.
6. The PCP of claim 1 , wherein the first electrode does not touch the second electrode.
7. The PCP of claim 1 , wherein the portion of the first electrode that overlaps the second electrode is capacitively coupled to the second electrode.
8. The PCP of claim 1 , wherein the electrodes comprise a transparent conductive oxide.
9. The PCP of claim 8 , wherein the transparent conductive oxide comprises Indium tin oxide.
10. The PCP of claim 1 , wherein the first and second electrodes are operable to control different polarization control segments on the PCP.
11. A polarization control panel (PCP) for a stereoscopic display, operable to transform the state of polarization of modulated light from an image modulation panel, the PCP having a plurality of polarization control segments, the PCP comprising:
a liquid crystal (LC) layer;
a common electrode disposed on a first side of the LC layer;
a first electrode disposed on a second side of the LC layer;
a second electrode disposed on the second side of the LC layer; and
an intermediate electrode disposed on the second side of the LC layer and overlapping a portion of the first electrode and the second electrode;
wherein the first electrode is operable to cause the intermediate electrode to be driven to a voltage potential, and
wherein the PCP is operable to transform the state of polarization of the modulated light from the image modulation panel in accordance with the voltage potential of the second electrode being driven by the first electrode.
12. The PCP of claim 11 , further comprising a quarter wave plate in an output optical path.
13. The PCP of claim 11 , wherein the LC layer comprises zero twist nematic liquid crystal material having zero retardation in a first state and a half wave of retardation in a second state.
14. The PCP of claim 11 , wherein the LC layer is disposed on a first plane, wherein the common electrode is parallel to the first plane, wherein the first and second electrodes are on a second plane that is parallel to the first plane, and wherein the intermediate electrode is on a third plane that is parallel to the first plane.
15. The PCP of claim 11 , wherein a portion of the second electrode overlaps and is conductively isolated from the intermediate electrode.
16. The PCP of claim 11 , wherein the LC layer comprises zero twist nematic liquid crystal.
17. The PCP of claim 11 , wherein the first electrode does not touch the second electrode.
18. The PCP of claim 11 , wherein the first electrode and the intermediate electrode are electrically coupled and wherein a portion of the intermediate electrode overlaps the second electrode.
19. The PCP of claim 11 , wherein the voltage potential of the intermediate electrode is directly related to drive electrode voltages of the first and second electrodes.
20. The PCP of claim 11 , wherein the electrodes comprise indium tin oxide.
21. A polarization control panel (PCP) for a stereoscopic display, operable to transform the state of polarization of modulated light from an image modulation panel, the PCP having a plurality of polarization control segments, the PCP comprising:
a liquid crystal (LC) layer;
a common electrode disposed on a first side of the LC layer;
a first electrode disposed on a second side of the LC layer;
a second electrode disposed on the second side of the LC layer; and
an intermediate electrode disposed on the second side of the LC layer and overlapping a portion of the first electrode and the second electrode;
wherein the intermediate electrode follows an average of drive electrode voltages between the first and second electrodes.