Optical data processing system with reflective liquid crystal light valve
First Claim
1. A coherent optical data processor comprising:
- a. reflective mode alternating current driven liquid crystal light valve means of the hybrid field effect mode type for modulating the polarization state of coherent projection light responsively to a noncoherent input light signal;
b. means for providing a noncoherent input light image signal to the input side of said light valve;
c. means for providing coherent projection light to the output side of said light valve said means comprising a source of polarized light, said light valve means including analyzer means positioned to block the exit from said light valve of light in a first polarization state and to transmit light from said light valve when its polarization state has been modulated to at least one state different from said first state in said light valve;
d. lens means positioned to receive said modulated polarization state light projected from said analyzer of said light valve for effecting a transform of the modulation image in said beam produced by said input signal; and
e. means for detecting said transformed image.
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Abstract
There is disclosed a high performance coherent optical data processing system using a reflective mode liquid crystal light valve which is particularly suited for application to real-time coherent optical data processing. A preferred example of the system uses a reflective light valve comprising a CdS photoconductor, a CdTe light absorbing layer, a dielectric mirror, and a liquid crystal layer sandwiched between indium-tin-oxide transparent electrodes deposited on optical quality glass flats. The non-coherent light image is directed onto the photoconductor; this reduces the impedance of the photoconductor, thereby switching the AC voltage that is impressed across the electrodes onto the liquid crystal to activate the device. The liquid crystal is operated in a hybrid field effect mode. It utilizes the twisted nematic effect to create a dark off-state (voltage off the liquid crystal) and the optical birefringence effect to create the bright on-state. The liquid crystal thus modulates the polarization of the coherent read-out or projection light responsively to the non-coherent image. An analyzer is used to create an intensity modulated output beam which is projected through a Fourier transform lens onto a screen or other detector means.
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Citations
10 Claims
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1. A coherent optical data processor comprising:
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a. reflective mode alternating current driven liquid crystal light valve means of the hybrid field effect mode type for modulating the polarization state of coherent projection light responsively to a noncoherent input light signal; b. means for providing a noncoherent input light image signal to the input side of said light valve; c. means for providing coherent projection light to the output side of said light valve said means comprising a source of polarized light, said light valve means including analyzer means positioned to block the exit from said light valve of light in a first polarization state and to transmit light from said light valve when its polarization state has been modulated to at least one state different from said first state in said light valve; d. lens means positioned to receive said modulated polarization state light projected from said analyzer of said light valve for effecting a transform of the modulation image in said beam produced by said input signal; and e. means for detecting said transformed image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification