Thermal imaging system with a monolithic focal plane array and method
First Claim
1. A thermal sensor mounted on an integrated circuit substrate to provide an image representative of the amount of infrared radiation incident to the thermal sensor comprising:
- a film layer of infrared sensitive material disposed adjacent to a first surface of the substrate with a gap formed therebetween, wherein said gap is approximately one-fourth of a wavelength of said infrared radiation;
a plurality of photosensors disposed on the first surface of the substrate adjacent to the film layer; and
a supporting structure for providing thermal and electrical isolation between the film layer and the substrate.
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0 Petitions
Accused Products
Abstract
A thermal imaging system (10) contains a focal plane array (30) including a plurality of thermal sensors (32) mounted on a substrate (62). Each thermal sensor (32) includes a film layer (34) of infrared sensitive material which is both electronically and thermally isolated from the associated integrated circuit substrate (62). An image may be formed on the film layer (34) in response to infrared radiation from a scene (12). Electromagnetic radiation (22) from a source (visible light or near infrared) (20) is used to reproduce or transfer the image from the thermal sensors (32) onto the first surface (68) of the substrate (62). A thermoelectric cooler/heater (66) may be provided to optimally adjust the temperature of the substrate (62) to improve overall image quality.
158 Citations
21 Claims
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1. A thermal sensor mounted on an integrated circuit substrate to provide an image representative of the amount of infrared radiation incident to the thermal sensor comprising:
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a film layer of infrared sensitive material disposed adjacent to a first surface of the substrate with a gap formed therebetween, wherein said gap is approximately one-fourth of a wavelength of said infrared radiation; a plurality of photosensors disposed on the first surface of the substrate adjacent to the film layer; and a supporting structure for providing thermal and electrical isolation between the film layer and the substrate. - View Dependent Claims (2, 3, 4, 5)
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6. A thermal imaging system for producing an image of a scene in response to incident infrared radiation from the scene, comprising:
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optics for focusing incident infrared radiation emitted by the scene onto a focal plane array; a chopper for the incident infrared radiation disposed between the optics and the focal plane array; the focal plane array including a plurality of thermal sensors for detecting the incident infrared radiation mounted on a substrate with each thermal sensor having a film layer formed from infrared sensitive material which changes its light transmission characteristics in response to incident infrared radiation; a plurality of photosensors disposed on the substrate adjacent to each thermal sensor; a light source disposed adjacent to the focal plane array and the substrate to project electromagnetic radiation onto both the focal plane array and the substrate for use in transferring thermal-images formed on the film layer of each thermal sensor to the associated photosensors; the film layer and the photosensors cooperating with the chopper and the light source to produce a biased signal and a reference signal; electronics for receiving the biased signal and the reference signal and for subtracting the reference signal from the biased signal to obtain an unbiased signal representing radiance differences emitted by objects in the scene; and a display for receiving the unbiased signal and for displaying an image generated in response to the unbiased signal. - View Dependent Claims (7, 8, 9)
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10. A focal plane array including a plurality of thermal sensors mounted on an integrated circuit substrate to provide a signal representative of the amount of thermal radiation incident to the focal plane array, each thermal sensor comprising:
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a layer of infrared sensitive film disposed adjacent to a first surface of the integrated circuit substrate with a gap formed therebetween; a plurality of photosensors disposed on the first surface of the integrated circuit substrate adjacent to the respective thermal sensor; and a supporting structure for providing thermal and electrical isolation between the film layer and the integrated circuit substrate. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for producing an image of a scene using a thermal imaging system having a plurality of thermal sensors with infrared sensitive elements mounted on a substrate, comprising the steps of:
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thermally and electrically isolating the infrared sensitive element of each thermal sensor from the integrated circuit substrate; directing incident infrared radiation from the scene onto the infrared sensitive elements of the thermal sensors to form a thermal image; projecting electromagnetic radiation from a light source onto the thermal sensors and the adjacent surface of the substrate; and detecting the electromagnetic radiation with a group of photosensors disposed on the surface of the substrate to form a signal representative of the image formed on the infrared sensitive element of the respective thermal sensor. - View Dependent Claims (17, 18, 19, 20)
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21. A thermal sensor mounted on a substrate to provide an image representative of the mount of thermal radiation incident to the thermal sensor comprising:
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a film layer of infrared sensitive material disposed adjacent to a first surface of the substrate with a gap formed therebetween, wherein said film layer is formed from material selected from the group consisting of barium strontium titanate, barium titanate, antimony sulfoiodide, lead titanate, and lead lanthanum zirconate titanate; a plurality of photosensors disposed on the first surface of the substrate adjacent to the film layer; and a supporting structure for providing thermal and electrical isolation between the film layer and the substrate.
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Specification