Low cost night vision camera
First Claim
1. A night vision camera comprising:
- a housing having an upper portion, a lower portion and a subhousing disposed therebetween, said subhousing having upper and lower parts, said lower art comprising a cap, and said upper portion having an aperture therethrough;
a window disposed on the housing at the aperture, the window being transmissive to infrared energy;
an array of uncooled detectors disposed within the housing, each detector providing an electrical output signal when illuminated with radiant electromagnetic energy;
a reflective optical arrangement disposed within the subhousing for focusing energy from the aperture onto the array, the optical arrangement including;
a primary mirror mounted in the upper part of the subhousing and having an aspheric surface and a negative power for reflecting energy from the aperture,a secondary mirror mounted on an inner surface of said cap and having an aspheric surface and a positive power for reflecting energy from the primary mirror,a fold mirror for reflecting energy from the secondary mirror, anda tertiary mirror mounted on an inner surface of said cap and having an aspheric surface and a positive power for focusing and redirecting energy from the fold mirror to the array;
a chopper disk disposed within said housing in optical alignment and between said tertiary mirror and said array;
means disposed within said housing for actuating said chopper disk; and
signal processing means disposed within said housing for processing an electrical output signal from the array.
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0 Petitions
Accused Products
Abstract
A low cost infrared camera (1) for night vision. The camera (1) is disposed within a housing (2) having an infrared transmissive window (6) disposed at an input aperture (5) thereof. A compact optical arrangement (10) is disposed within the housing (2) to focus energy from the window (5) onto a focal plane array (20). A chopper disk (19) is positioned between the reflective optical arrangement (10) and the focal plane array (20) to establish a reference level for the array (20) and to facilitate a sequential readout thereof. A signal processing circuit (100) is included for processing the output of the array (20) for display on a standard video screen. Thus, the problems with uncooled detectors are overcome by use of a fast optical system in combination with an uncooled detector. The fast optical system provides a high signal level to the uncooled detector, thereby compensating for losses in collection of thermal radiation. Reflective optical systems can be manufactured inexpensively from plastic or aluminum and reduce the need for expensive infrared materials commonly used in military systems. The combination of the fast optics and uncooled detector provides a truly low cost thermal camera for night vision.
60 Citations
6 Claims
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1. A night vision camera comprising:
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a housing having an upper portion, a lower portion and a subhousing disposed therebetween, said subhousing having upper and lower parts, said lower art comprising a cap, and said upper portion having an aperture therethrough; a window disposed on the housing at the aperture, the window being transmissive to infrared energy; an array of uncooled detectors disposed within the housing, each detector providing an electrical output signal when illuminated with radiant electromagnetic energy; a reflective optical arrangement disposed within the subhousing for focusing energy from the aperture onto the array, the optical arrangement including; a primary mirror mounted in the upper part of the subhousing and having an aspheric surface and a negative power for reflecting energy from the aperture, a secondary mirror mounted on an inner surface of said cap and having an aspheric surface and a positive power for reflecting energy from the primary mirror, a fold mirror for reflecting energy from the secondary mirror, and a tertiary mirror mounted on an inner surface of said cap and having an aspheric surface and a positive power for focusing and redirecting energy from the fold mirror to the array; a chopper disk disposed within said housing in optical alignment and between said tertiary mirror and said array; means disposed within said housing for actuating said chopper disk; and signal processing means disposed within said housing for processing an electrical output signal from the array. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification