Dynamic infrared scene projector
First Claim
1. A dynamic infrared scene projector including first and second infrared light sources, first and second condenser optics, and projection optics for projecting cinematic, two-dimensional spatially distributed scene data to an infrared sensor, the improvement comprising:
- first and second optical modulators, each comprising means for exhibiting hysteretic behavior in an optical property as a function of a stimulus for storing frames of the scene data and for modulating incident infrared light, andan optical framing switch for controlling the storage of said scene data frames on the first and second optical modulators and the presentation of scene data frames to the sensor.
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Accused Products
Abstract
A dynamic infrared scene projector for presenting cinematic, two-dimensional, spatially distributed scene data to an infrared sensor is provided comprising programmable, thermoptic infrared modulators which exploit thermally-induced changes in the infrared optical properties of a thin film of vanadium dioxide. Because of a hysteresis in the vanadium dioxide material, a stored scene can be created in the modulators by scanning a focused modulated visible or near-infrared laser beam across the thin film while it is thermally biased in the hysteresis loop. The scene is projected into the sensor by placing the modulators between an infrared source/condenser system and a system of projection optics. Dynamic scene projection is accomplished by an erase/rebias system and an optical framing switch to yield a flicker-free output. Erasing of the optical modulator is accomplished by momentarily cooling the VO2 film to a temperature below the hysteretic loop. Rebiasing of the optical modulators is accomplished by reheating to increase the temperature of the thin film to a value not exceeding a thermal bias temperature.
30 Citations
26 Claims
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1. A dynamic infrared scene projector including first and second infrared light sources, first and second condenser optics, and projection optics for projecting cinematic, two-dimensional spatially distributed scene data to an infrared sensor, the improvement comprising:
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first and second optical modulators, each comprising means for exhibiting hysteretic behavior in an optical property as a function of a stimulus for storing frames of the scene data and for modulating incident infrared light, and an optical framing switch for controlling the storage of said scene data frames on the first and second optical modulators and the presentation of scene data frames to the sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A dynamic infrared scene projector including infrared light source means, condenser optics means, and projection optics for projecting cinamatic two-dimensional, spatially distributed scene data to an infrared sensor, the improvement comprising:
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first and second optical modulators, each comprising means exhibiting a hysteretic behavior in an optical property as a function of a stimulus for storing frames of the scene data and for modulating incident infrared light, an optical framing switch for controlling the storage of said scene data frames on the first and second optical modulators and the presentation of scene data frames to the sensor, and an erase/rebias means for erasing the frames of scene data from the first and second optical modulators and for rebiasing the first and second optical modulators to receive subsequent frames of the scene data. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for projecting prerecorded cinematic, two-dimensional, spatially distributed scene data from a dynamic infrared scene projector to an infrared sensor, comprising the steps of:
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modulating an infrared light beam as a function of the prerecorded scene data; scanning the beam in a two-dimensional pattern to record (write) the scene data for storage in a frame-by-frame manner on first and second optical modulators capable of modulating incident infrared light; and projecting the stored scene data frames from the first and second optical modulators in an alternating manner to produce a flicker-free image presented to the sensor. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification