Multi-pixel liquid crystal cell array

• US 20040183988A1
• Filed: 03/17/2003
• Published: 09/23/2004
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Xtellus Inc.
• Inventors: Cavanaugh, Shanti A., Young, Mark E., Molinari, Louis J., Austin, Lindsay W.
• Granted Patent: US 7,046,326 B2
• Time in Patent Office: Days
• US Class Current: 349/155
• CPC Class Codes: G02F 1/093 used as non-reciprocal devices, e.g. optical isolators, circulators G02F1/0955 takes precedence
• CPC Class Codes: G02F 1/1326 Liquid crystal optical waveguides or liquid crystal cells specially adapted for gating or modulating between optical waveguides
• CPC Class Codes: G02F 1/133382 Heating or cooling of liquid crystal cells other than for activation, e.g. circuits or arrangements for temperature control, stabilisation or uniform distribution over the cell
• CPC Class Codes: G02F 1/133521 Interference filters
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/13355 Polarising beam splitters [PBS]
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G02F 1/31 Digital deflection, i.e. optical switchingG02F1/33 takes precedence
• CPC Class Codes: G02F 2201/305 diffraction grating
• CPC Class Codes: G02F 2203/055 wavelength filtering
• CPC Class Codes: G02F 2203/06 Polarisation independent
• CPC Class Codes: G02F 2203/12 spatial light modulator

Abstract

A multi-pixel optical processing system includes a multi-pixel liquid crystal cell platform having a deposited metal gasket moisture barrier bonding two opposing substrates each having a spacer layer to accurately control cell gap thickness. A library of specialized pixel constructs is included that can be configured to yield predetermined optical functions at referential locations in the platform. A control system is provided utilizing a time division scheme that multiplexes temperature sensing and heating functions across an optional integrated active thermal element that may be integrated inside the liquid crystal platform. A calibration process characterizes the profile of the cell and generates a polynomial regression formula that provides the voltage drive output for all pixels in the platform based on the platform temperature and state of each pixel.

Claims

1. A multi-pixel liquid crystal cell platform, comprising:

A first substrate having a first electrode layer patterned with multiple pixels, and a first alignment layer,

a second substrate placed in opposition to the first substrate and having a second electrode and second alignment layer,

liquid crystals coupled between the first and second substrates,

a spacer element coupled between the first and second substrates,

A metal gasket element bonded to the first and second substrates.

2. The multi-pixel liquid crystal cell platform of claim 1, wherein the first or second substrate further includes a sub wavelength optical element or nanostructed grating.

3. The multi-pixel liquid crystal cell platform of claim 1, further including an active thermal element disposed between the first and second substrates.

4. The liquid crystal cell platform of claim 1, wherein the spacer element contains one or more materials selected from the group consisting of silicon dioxide, aluminum oxide, silicon nitride, silicon monoxide.

5. The multi-pixel liquid crystal cell platform of claim 1, wherein the metal gasket includes one or more materials selected from the group consisting of indium, gold, nickel, tin, chromium, platinum, tungsten, silver, bismuth, germanium and lead.

6. The multi-pixel liquid crystal cell platform of claim 1, further including an integrated optical element.

7. The multi-pixel liquid crystal cell platform of claim 1, wherein the spacer element and metal gasket is deposited thin film.

8. The multi-pixel liquid crystal cell platform of claim 1, wherein at least one pixel is a NULL.

9. The multi-pixel liquid crystal cell platform of claim 1, wherein at least one pixel is a mirror pixel.

10. The multi-pixel liquid crystal cell platform of claim 1, wherein at least one pixel is a partially transparent mirror pixel.

11. The multi-pixel liquid crystal cell platform of claim 1, wherein at least one pixel is a photovoltaic tap pixel.

12. The multi-pixel liquid crystal cell platform of claim 1, wherein at least one pixel is a fixed rotator pixel.

13. The liquid crystal cell platform of claim 1, wherein at least one pixel is a polarizer pixel.

14. The multi-pixel liquid crystal cell platform of claim 1, wherein at least one pixel is a polarization beam splitter/combiner pixel capable of functioning as a polarization independent variable optical attenuator.

15. The multi-pixel liquid crystal cell platform of claim 1, wherein at least one pixel is a filter pixel.

16. The multi-pixel liquid crystal cell platform of claim 1, wherein at least one pixel is a Faraday rotator pixel capable of functioning as a polarization dependent variable optical attenuator with integrated isolator.

17. The multi-pixel liquid crystal cell platform of claim 2, wherein the sub wavelength optical element is configured to operate in a capacity selected from the group consisting of polarization rotation, polarization filtration, beam splitting, polarization beam splitting, polarization beam combining, and waveguide.

18. The multi-pixel liquid crystal cell platform of claim 3, wherein the active thermal element is disposed substantially around the perimeter of the liquid crystal cell.

19. The liquid crystal cell platform of claim 3, further including a microcontroller that reads the temperature value of the cell and computes the temperature compensated voltage drive based on a stored regression profile of the cell operating characteristics across voltage.

20. The multi-pixel liquid crystal cell platform of claim 3, wherein the active thermal element provides both heating and temperature sensing capability.

21. The multi-pixel liquid crystal cell platform of claim 3, wherein the active thermal element is comprised of chrome-platinum.

22. The multi-pixel liquid crystal cell platform of claim 3, further including at least one VIA formed between the metal spacer element and first or second electrode.

23. The multi-pixel liquid crystal cell platform of claim 3, further including at least one VIA formed between the active thermal element and the metal spacer element.

24. The multi-pixel liquid crystal cell platform of claim 6, wherein the optical element is a mirror and pixels in the cell are reflective.

25. A multi-pixel liquid crystal cell platform, comprising:

A first substrate having an inner surface electrode layer masked to form multiple pixel locations and a liquid crystal alignment layer disposed over the electrode layer, and an outer surface having an integrated optical element that provides a single optical function across multiple pixels,

a second substrate having an inner surface comprising a second electrode and second alignment layers, said substrate placed in opposition to first substrate such that the inside electrode and alignment layers are opposing each other,

liquid crystals coupled between the first and second substrates,

a spacer element coupled between the first and second substrates,

A metal gasket element bonded to the first and second substrates.

26. The multi-pixel liquid crystal cell platform of claim 25, further comprising on the second substrate, an integrated optical element that provides a single optical function across multiple pixels.

27. The multi-pixel liquid crystal cell platform of claim 25, further including an active thermal element having electrodes that may either be supplied with a voltage to heat the thermal element or whose resistance may be read and measured to determine temperature at any instance.

28. The multi-pixel liquid crystal cell platform of claim 25, further including a microcontroller and switch coupled to the active thermal element such that the state of the switch controls routing of resistance values from the active thermal element to the microcontroller and voltage signals from the microcontroller to the active thermal element.

29. A multi-pixel liquid crystal cell platform, comprising:

A first substrate having an inner surface electrode layer masked to form multiple pixel locations and a liquid crystal alignment layer disposed over the electrode layer and an outer surface having at least one integrated optical element that provides a single optical function across a single pixel,

a second substrate having an inner surface comprising a second electrode and second alignment layers, said substrate placed in opposition to first substrate such that the inside electrode and alignment layers are opposing each other,

liquid crystals coupled between the first and second substrates,

a spacer element coupled between the first and second substrates,

A metal gasket element bonded to the first and second substrates.

30. The multi-pixel liquid crystal cell platform of claim 29, further comprising on the second substrate, an integrated optical element that provides a single optical function across multiple pixels.

31. The multi-pixel liquid crystal cell platform of claim 29, further comprising on the second substrate, an integrated optical element that provides a single optical function across a single pixel.

32. The multi-pixel liquid crystal cell platform of claim 31, wherein the optical element on the first and second substrate are aligned over the same pixel location.