Claims
- 1. An optical system comprising:
a reflective liquid crystal device having a plurality of independently activated liquid crystal elements; and an optical element for directing a plurality of input light beams at said reflective liquid crystal device such that each input light beam impinges upon one of said liquid crystal elements, wherein each liquid crystal element of said reflective liquid crystal device comprises:
a transparent first electrode; a reflective second electrode spaced apart from said first electrode; and a liquid crystal medium disposed between the first and second electrodes, and wherein said liquid crystal elements are independently operable to change between half-wave and zero retardation states in response to an applied voltage.
- 2. The optical system of claim 1 and further comprising a first polarizer for passing an input light beam at a first polarization prior to impinging upon said reflective liquid crystal device.
- 3. The optical system of claim 2 and further comprising a second polarizer for passing a light beam reflected from said reflective liquid crystal device at a second polarization.
- 4. The optical system of claim 3, wherein the second polarization is orthogonal to the first polarization.
- 5. The optical system of claim 3, wherein the second polarization is parallel to the first polarization.
- 6. The optical system of claim 2 and further comprising a compensation plate disposed in front of said reflective liquid crystal device for compensating for residual birefringence of said reflective liquid crystal device when a high voltage is applied.
- 7. The optical system of claim 2 and further comprising a quarter-wave plate disposed in front of said reflective liquid crystal device.
- 8. A reflective liquid crystal device for use in an optical communication system in which a plurality of input light beams are directed at the liquid crystal device, the liquid crystal device comprising:
a transparent first substrate having a first surface upon which the at least one light beam is incident and a second surface opposite the first surface; a transparent first electrode layer supported on the second surface of said first substrate; a second substrate having first and second surfaces, the first surface of said second substrate being opposed to the second surface of said first substrate; a second electrode layer supported on the first surface of said second substrate, wherein said second electrode layer is either reflective or transparent if a reflective layer is otherwise supported by one of the surfaces of said second substrate; a first alignment layer supported on the second surface of the first substrate; a second alignment layer supported on the first surface of the second substrate; and a liquid crystal medium disposed between the first and second electrode layers, wherein at least one of said first and second electrode layers is patterned so as to define a plurality of independently activated liquid crystal elements each sized to receive one of the input light beams, wherein said liquid crystal elements are operable to change between half-wave and zero retardation states in response to an applied voltage.
- 9. The reflective liquid crystal device of claim 8, wherein said second electrode layer is reflective.
- 10. The reflective liquid crystal device of claim 8, wherein the second electrode layer is transparent and the device further comprises a reflective layer supported by either the first or second surface of said second substrate.
- 11. The reflective liquid crystal device of claim 8, wherein said second substrate is transparent.
- 12. The reflective liquid crystal device of claim 8, wherein both said electrode layers are patterned.
- 13. The reflective liquid crystal device of claim 8, wherein the liquid crystal material has a positive dielectric anisotropy.
- 14. The reflective liquid crystal device of claim 13, wherein both said alignment layers provide homogenous alignment of the molecules of said liquid crystal medium when no voltage is applied to the electrodes.
- 15. The reflective liquid crystal device of claim 14, wherein, when a voltage is applied to the electrodes, the molecules align perpendicular to the second surface of said first substrate and to said first surface of said second substrate.
- 16. The reflective liquid crystal device of claim 15, wherein the thicknesses of the layers of the device are selected such that the polarization of an incident light beam is maintained when a voltage is applied to the electrodes and, when no voltage is applied to the electrodes, the polarization of an incident beam is rotated 90 degrees.
- 17. The reflective liquid crystal device of claim 13, wherein, when no voltage is applied to the electrodes, said first alignment layer provides homeotropic alignment of the molecules of said liquid crystal medium that are proximate said first alignment layer, and said second alignment layer provides homogeneous alignment of the molecules of said liquid crystal medium that are proximate said second alignment layer.
- 18. The reflective liquid crystal device of claim 17, wherein, when a voltage is applied to the electrodes, the molecules align perpendicular to the second surface of said first substrate and to said first surface of said second substrate.
- 19. The reflective liquid crystal device of claim 18, wherein the thicknesses of the layers of the device are selected such that the polarization of an incident light beam is maintained when a voltage is applied to the electrodes, and, when no voltage is applied to the electrodes, the polarization of an incident beam is rotated 90 degrees.
- 20. The reflective liquid crystal device of claim 8, wherein the liquid crystal material has a negative dielectric anisotropy.
- 21. The reflective liquid crystal device of claim 20, wherein both said alignment layers provide homeotropic alignment of the molecules of said liquid crystal medium when no voltage is applied to the electrodes.
- 22. The reflective liquid crystal device of claim 21, wherein, when a voltage is applied to the electrodes, the molecules align parallel to the second surface of said first substrate and to said first surface of said second substrate.
- 23. The reflective liquid crystal device of claim 22, wherein the thicknesses of the layers of the device are selected such that the polarization of an incident light beam is maintained when no voltage is applied to the electrodes and, when a voltage is applied to the electrodes, the polarization of an incident beam is rotated 90 degrees.
- 24. The reflective liquid crystal device of claim 8, and further comprising a protective layer supported by one of the second surface of said first substrate and the first surface of said second substrate, said protective layer preventing electrons from flowing between the electrodes and through the liquid crystal medium.
- 25. The reflective liquid crystal device of claim 8, and further including a seal disposed between said first and second substrates to constrain said liquid crystal medium.
- 26. The reflective liquid crystal device of claim 8, wherein said alignment layers are disposed between said electrode layers and said substrates.
- 27. An optical communication system comprising:
a reflective liquid crystal device having a plurality of independently activated liquid crystal elements; and an optical element for directing a plurality of input light beams at said reflective liquid crystal device such that each input light beam impinges upon one of said liquid crystal elements, wherein said reflective liquid crystal device comprises:
a transparent first substrate having a first surface upon which a plurality of light beams are incident and a second surface opposite the first surface; a transparent first electrode layer supported on the second surface of said first substrate; a second substrate having first and second surfaces, the first surface of said second substrate being opposed to the second surface of said first substrate; a second electrode layer supported on the first surface of said second substrate, wherein said second electrode layer either is reflective or is transparent if a reflective layer is otherwise supported by one of the surfaces of said second substrate;
a first alignment layer supported on the second surface of the first substrate; a second alignment layer supported on the first surface of the second substrate; a liquid crystal medium disposed between the first and second electrode layers; and wherein at least one of said first and second electrode layers is patterned so as to define said plurality of independently activated liquid crystal elements, wherein said liquid crystal elements are independently operable to change between half-wave and zero retardation states in response to an applied voltage.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority under 35 U.S.C. §119(e) for U.S. Provisional Patent Application No. 60/283,756 entitled “HIGH CONTRAST REFLECTIVE LCD FOR TELECOM APPLICATIONS,” filed on Apr. 13, 2001, the entire disclosure of which is incorporated herein by reference.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60283756 |
Apr 2001 |
US |