WO2006063177A2

WO2006063177A2 - Method and system for enhanced radiation detection

Info

Publication number: WO2006063177A2
Application number: PCT/US2005/044499
Authority: WO
Inventors: Jorge Roman; Mary Jean Schmidt; William Schmidt; Robert Fryer; Henri Sasmor
Original assignee: Thermophotonics, Inc.
Priority date: 2004-12-06
Filing date: 2005-12-06
Publication date: 2006-06-15
Also published as: US20060226364A1; US7432506B2; US20060118720A1; US20070080292A1; WO2006063177A3; US7135679B2

Abstract

A radiation detection sensor includes a radiation detector that is segmented into an array of mapping elelments, or detectors. The mapping elements may be micro-disposed, such that individual mapping elements are substantially themally isolated from each other comprise pixels of a visual thermal energy map. The mapping elements of the radiation detector may be minimally connected to adjacent radiation detectors, or the mapping elements may be substantially physically isolated from each other.

Description

METHOD AND SYSTEM FOR ENHANCED RADIATION DETECTION

BACKGROUND Field The present invention relates generally to radiation detection systems and in particular to enhanced resolution radiation detection.

Description of the Related Art

Detection of radiation that is emitted from objects and is outside of the visible spectrum can provide useful information. For example, detection systems have been developed for sensing infrared radiation (IR) from an object or source in a target space. Infrared imagers, also called thermal imagers, are instruments that create images of heat instead of light, by converting radiated IR energy to a corresponding map of temperatures or radiance. IR sensing applications including temperature measurement and mapping, forest fire sensing and suppression, and surveillance.

Thermal imaging systems are generally constructed from a variety of different types of infrared detectors. Infrared detectors can be classified as cooled or uncooled. Uncooled detectors include thermal sensors that generate a change in a physical parameter of the detector, such as resistance, due to a change in detector temperature resulting from incident infrared radiation. Cooled detectors include infrared sensors where the change in the physical parameter of the sensor is due to a photoelectron interaction within the material of the sensor.

To detect thermal variation across a target space, thermal imaging systems often use two-dimensional arrays of infrared detectors. In a typical thermal imaging system, the radiation from a target space object will be focused onto a detector array. Electronic or mechanical scanners are generally employed to measure the radiation detected by each detector in the array and thereby produce a two-dimensional display corresponding to a thermal map of the object being imaged. The size and active area of each sensor in the array limits the spatial resolution of the imaging system. Likewise, the need to make electrical connection to the individual detectors, for example to measure a resistance change, can increase system complexity as well as impose constraints on the minimum size for the detectors.

Liquid crystal materials can change color in response to received thermal energy. Typically, liquid crystal materials are used for indicating thermal change and are supplied in film form, or as a coating. In a typical application, a liquid crystal film or coating may be applied to a radiating surface of an object for direct sensing of surface temperature by observing variations in color across the liquid crystal material as a result of the object's surface temperature profile.

Because liquid crystal films are not made up of individual detectors, they do not have the drawback of being limited by a minimum detector size. Also, because liquid crystal films are directly viewed, there is not the need for electrical connections to detect changes in physical parameters. However, liquid crystal films suffer from poor resolution because the thermal energy "bleeds" across the film or coating.

Thus, a need exists for improved methods and apparatus for the detection of radiation emitted from objects. Other problems with the prior art not described above can also be overcome using the teachings of the present invention, as would be readily apparent to one of ordinary skill in the art after reading this disclosure.

SUMMARY Embodiments disclosed herein address the above stated need of improving detection of radiation emitted from an object. In accordance with the invention, a radiation detection sensor includes a radiation detector that is segmented into an array of mapping elements, or detectors. The mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map. The mapping elements of the radiation detector may be minimally connected to adjacent radiation detectors, or the mapping elements may be substantially physically isolated from each other. The mapping elements may be micro-disposed, such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map, or material may be removed to provide the segmentation and isolation.

In one exemplary embodiment of a sensor, a focal plane array comprising a radiation detector with mapping elements formed by a substrate with thermal detection material disposed upon it. In this embodiment, the radiation detector is segmented into an array of mapping elements by voids in the substrate and the corresponding thermal detection material. The voids can be formed by removing portions of the substrate and detection material to create "perforations" between adjacent detectors to minimize thermal conduction between detectors within the array. The voids can also be formed by removing portions of the detection material and leaving the underlying substrate substantially unchanged. Alternatively, the voids can be formed using deposition or lithographic techniques so that detection material is disposed or deposited on the substrate only in areas of interest, thereby forming the array of mapping elements, also referred to herein as detectors. The voids between adjacent detectors serves to minimizes thermal conduction between detectors within the array.

Various techniques may be used to remove the thermal material and the substrate. For example, a laser may be used to remove the thermal material after it has been deposited on the substrate. Alternatively, a mask may be placed on the substrate and thermal detection material can be disposed onto the substrate and mask in a deposition or plating operation. The mask is then removed, thereby removing the thermal material in the mask area and leaving behind the voids that define the mapping elements. In addition, various techniques, such as photolithographic techniques and techniques as used in semiconductor fabrication, may also be utilized to form the mapping elements. In still another exemplary embodiment of a focal plane array sensor, detectors are located in different planes of the sensor. For example, one array of detectors may be located in one plane and another array of detectors may be located in another plane across the array. The two planes may be substantially parallel to each other. Thermal isolation between adjacent detectors may be achieved if adjacent detectors are in different planes. The focal plane arrays do not need to include a substrate. For example, the mapping elements of the detector can be formed of a thermal detector material and an absorber material, with the absorber material disposed across the thermal detector material in a segmented fashion to define the mapping elements. Alternatively, thermal detector material can be disposed on absorber material in a segmented fashion to define the mapping elements. In other words, a continuous material is simply a means for supporting a segmented layer such that the continuous material and the segmented layer together provide a focal plane array with mapping elements such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map. Thus, a sensor can be constructed with one or the other of the elements, i.e. thermal detector material or absorber material, performing the supporting function and the other material being segmented. In addition, while some embodiments describe examples of detectors as including a thermal detector material and an absorber material, the embodiments are not limited to this type of construction. That is, exemplary detectors map one form of energy to another form of energy to provide a visual thermal energy map. For example, a detector may be any device that performs the function of mapping thermal energy to a visual display. In one exemplary embodiment, a radiation detection sensor includes a thermal conversion material that converts incident radiation into heat energy and also includes a plurality of mapping elements, or detectors, each of which receives heat energy from the thermal conversion material in proximity to the mapping element. A thermal map is produced corresponding to the incident radiation energy received by the sensor, in accordance with sufficiently limited lateral energy dispersion between detectors.

In another exemplary embodiment, a radiation detection sensor includes mapping elements formed with a substrate, and protruding from the top surface of the substrate is an array of columns. The sensor includes radiation detectors having a radiation sensitive layer, such as a radiation sensitive film, and a thermal conversion material, such as an absorber, that may be disposed upon a top surface of the individual columns within the array. The columns provide thermal isolation between the radiation detectors and the substrate. Spatial separation of columns within the array provide thermal and radiant isolation between the radiation detectors upon the tops of individual columns. An array of radiation detectors allows detection, or identification, of the radiation emitted from an object.

In one exemplary embodiment, the radiation detection sensor has a substrate that is planar. In other embodiments, the substrate may be constructed to be a non-planar shape or constructed of a pliable material so that it can be formed to non-planar shapes. For example, the substrate may be shaped or formed to be concave, convex, or other complex surfaces.

In another exemplary embodiment, the radiation detectors include a radiation sensitive layer comprised of a thermochromic liquid crystal (TLC) material and include a thermal conversion material comprised of an infrared absorbing layer disposed on a top most surface. For example, the absorbing layer may comprise black cupric oxide. In this embodiment, the absorbing layer converts radiation that impinges on it into heat that is detected by the TLC radiation sensitive layer. The radiation detection sensor may also include thermal elements that are used to control the temperature of the substrate. The substrate may be heated or cooled, for example, using heaters/thermoelectric coolers so as to enable biasing of the sensor. In another embodiment, the radiation detection sensor may include thermal shunts. The thermal shunts may be placed at various locations in the radiation detection sensor, for example, the thermal shunts may be located between the substrate and the base of the columns in the array. The thermal shunts may also be located between a source of radiation input and the array of radiation detectors, for example, in the optics used to focus an image of the radiation source onto the array, or in a plane on top of the radiation detectors. The thermal shunts may also be located between the radiation detectors and the column tops.

The thermal shunts may be controllably operable so as to provide a high thermal conductance path, or a low thermal conductance path, between the substrate and the column/sensor element combination or between the source of the radiation and detectors. In one embodiment the thermal shunts may be constructed from thermoelectric cooler material, such as, bismuth telluride or other types of solid state heating/cooling materials. In addition, thermal shunts may be magnetically or electrically alignable carbon nanotubes and ferro-fluids.

The columns of the radiation detection sensor can be various shapes and sizes. For example, in one embodiment the columns are cylinders. In another embodiment a top surface of the column is larger than the base of the column thereby maximizing the amount of incoming radiation that impinges upon an individual detector. The columns can have any desired cross section, for example, circular, oval, square, rectangular, or any other multi-sided polygon shape desired. In addition, there may be multiple detectors supported by a single column or multiple columns may support a single detector. For example, a detector may have a spherical shape and there may be three columns supporting the detector. Other configurations of detectors and support structures may also be used. An exemplary embodiment of a radiation detection system uses a radiation detection sensor that has multiple radiation mapping elements or radiation detectors. The sensor receives radiated energy emitted by an object and converts the received energy into thermal energy. Then a received thermal energy map of the object is produced. In one exemplary embodiment, a radiation detection system may include a focal plane array that has a substrate and a plurality of columns protruding from the substrate. Radiation detectors are disposed on tops of the plurality of columns thereby creating an array of radiation detectors. In one embodiment the radiation detectors include a thermochromic liquid crystal material. The system also may include collection optics that focus radiation emitted from an object onto the focal plane array. The system may include imaging optics that focus an image of the focal plane array radiation detectors onto an imaging sensor. The imaging sensor may be a video camera, for example, a CCD camera. The system may also include an illumination source that illuminates the focal plane array. The system may also include an environmental control unit. For example, the environmental control unit may operate to maintain a substrate of the focal plane array at a desired temperature, or vacuum, or humidity level or control any combination of environmental characteristics including magnetic field and electric field environments. The system may also include an image processor configured to accept an output from the imaging sensor. A null sensor radiation detection system may include a focal plane array that includes a substrate and a plurality of mapping elements disposed in an array on the substrate, wherein radiation detectors are a layer on the mapping elements, thereby creating an array of radiation detectors. The system may also include collection optics that focus radiation emitted from an object onto the focal plane array. In addition, the system may include an illumination source configured to illuminate the focal plane array, and imaging optics that focus an image of the array of detectors onto an imaging sensor. An image processor may be configured to accept and analyze the output from the image sensor and generate a command for a controllable radiation source. The command for the controllable radiation source may cause the controllable radiation source to output radiation that is directed to the focal plane array and maintains the detectors at a predetermined value. A controllable radiation source may also be used to output a known radiation directed to the focal plane array to characterize the sensitivity and response of detectors with the focal plane array. For example, the focal plane array may be exposed to a constant radiation level, a step change in radiation level, a gradient radiation level, or other variable radiation level. In addition, a target with a known radiation profile may be exposed to the focal plane array. For example a target "shutter" may be placed in front of, or in the entrance pupil, of the radiation detector system and thereby be exposed to the focal plane array. The performance of the detectors within the focal plane array when exposed to a known radiation can be evaluated. For example, the performance characteristics of the detectors, such as sensitivity and response to a step, or varying radiation input can be evaluated.

In another exemplary embodiment of a radiation detection system a target illumination source illuminates, or "paints" an object. Radiation reflected from the object may then be collected by collection optics and focused onto the focal plane array. The target illumination source may be tunable. For example, the target illumination source may include optics or controls to shape the spectrum of the radiation output by the target illumination source. In another example, the target illumination source may include multiple sources, each of which outputs a desired spectrum of radiation. The output of the target illumination source may be mixed, or combined, in any desired combination so that a desired output spectrum is achieved. In this manner the object may be painted with radiation of a desired spectral content which may improve the detection of specific objects.

Other features and advantages of the present invention should be apparent from the following description of exemplary embodiments, which illustrate, by way of example, aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram illustrating an embodiment of a radiation detector system constructed in accordance with the invention. Figure 2 is plan view of an exemplary embodiment of a portion of a focal plane array.

Figure 3 is a cross sectional view of one embodiment of a focal plane array. Figure 4 is a cross sectional view of another embodiment of a focal plane array.

Figure 5 is a plan view of a focal plane array 16 illustrating another embodiment of a focal plane array.

Figure 6 is a cross sectional view of an embodiment of a focal plane array. Figure 7 is a cross sectional view of another embodiment of a focal plane array.

Figure 8 is a cross sectional view of yet another embodiment of a focal plane array.

Figure 9 is an elevation view of another embodiment of a focal plane array.

Figure 10 is a plan view of an embodiment of a focal plane array providing increased active area.

Figure 11 is an isometric illustration of an exemplary embodiment of a focal plane array 16.

Figure 12 is a cross sectional view of one embodiment of a focal plane array such as illustrated in Figure 11. Figure 13 is a cross sectional view of another embodiment of a focal plane array constructed in accordance with the invention.

Figure 14 is a cross sectional view of yet another embodiment of a focal plane array.

Figure 15 is a schematic diagram illustrating additional aspects of a portion of the focal plane array.

Figure 16 is a cross sectional view of another embodiment of a focal plane array.

Figure 17 is a schematic diagram illustrating additional aspects of a portion of the focal plane array.

Figure 18 is a schematic diagram illustrating an exemplary arrangement of components of a radiation detector constructed in accordance with the invention.

Figure 19 is a schematic diagram illustrating additional detail of an exemplary arrangement of imaging components that may be used in a radiation detector constructed in accordance with the invention.

Figure 20 is a schematic diagram illustrating another exemplary arrangement of components of a radiation detector.

Figure 21 is a block diagram of another embodiment of a radiation detection system in accordance with the invention. Figure 22 is a schematic diagram illustrating an exemplary design of a focal plane array.

Figure 23 is a schematic diagram illustrating another exemplary design of a focal plane array. Figure 24 is a schematic diagram illustrating yet another exemplary design of a focal plane array.

Figure 25 A is a schematic diagram of a support column with a circular cross section.

Figure 25B is a schematic diagram of another support column with a circular cross section.

Figure 25C is a schematic diagram of yet another support column.

Figure 25D is a schematic diagram of still another embodiment of a support column.

Figure 26 is an schematic diagram of an embodiment of a non-planar focal plane array.

Figure 27 is an schematic diagram of another embodiment of a non-planar focal plane array.

Figure 28 is an schematic diagram of an yet another embodiment of a non-planar focal plane array. Figure 29 is an schematic diagram of still another embodiment of a non-planar focal plane array.

Figure 30 is a block diagram of an embodiment of an environmental control unit.

Figure 31 is a block diagram of a null sensor arrangement.

Figure 32 is a block diagram of another embodiment of a radiation detector system.

Figure 33 is a schematic diagram illustrating another embodiment of a radiation detection system.

Figure 34 is a flow chart illustrating detection of radiation from an object.

Figure 35 is an elevation view of another embodiment of a focal plane array. DETAILED DESCRIPTION

The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Embodiment described herein are "exemplary" and are not necessarily to be construed as preferred or advantageous over other embodiments. In accordance with the invention, a radiation detection sensor includes a radiation detector that is segmented into an array of mapping elements, also referred to herein as detectors. The mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map. The radiation detector receives thermal energy and generates the visual thermal energy map, which is provided by the sensor for viewing. The mapping elements of the radiation detector may be minimally connected to adjacent mapping elements, or the mapping elements may be substantially physically isolated from each other. The mapping elements may be micro-disposed, such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map. Techniques and apparatus for improved radiation detection are described. Figure

1 is an exemplary block diagram illustrating an embodiment of a radiation detector system 10 constructed in accordance with the invention. As shown in Figure 1 , radiation emitted from an object 12 is collected by collection optics 14 and focused onto a focal plane array 16. An illumination source 18 provides illumination of the focal plane array 16 and an optical image of the focal plane array 16 is focused by imaging optics 20 onto an image sensor 22.

The object 12 may be any object that emits radiation. For example, the object 12 may emit infrared, visible, ultraviolet, Terahertz, or other radiation. The radiation emitted from the source 12 is collected by appropriate collection optics 14. The collection optics 14 may differ depending on the type of radiation desired to be detected. For example, if it is desired to detect infrared radiation, then the collection optics 14 may be configured so as to pass infrared radiation and block other types of radiation. The collection optics 14 can be configured to pass any desired spectrum of radiation that can be focused by the optical means. For example, if the radiation detection system 10 is configured to be operated in a dark environment, such as at night, the collection optics 14 may be configured to focus all radiation onto the focal plane array 16. The collection optics 14 are well known in the art, and may be one or more of any number of lenses or other optic components. The collection optics 14 produce a focused image of the object 12 onto the focal plane array 16, so that focal plane array 16 may sense the radiant flux emitted by the object 12. The collection optics 14 may include lenses that are made of various types of optical glasses, and optical coatings, to achieve a desired spectral transmittance. The collection optics 14 may also include other types of optical material so that a desired overall spectral transmittance of the collection optics 14 is achieved. In other words, the collection optics 14 may include any device that focuses radiation within a desired spectrum onto the focal plane array 16. For example, for infrared radiation in the range of approximately 0.6 to 21 microns, Zinc Selenium (Zn Se) lenses and windows with antireflective coatings may be used. In addition, the lenses may be of the type piano convex for image formation upon the focal plane array. The collection optics 14 may also include other optical devices, such as, Fresnel lenses, zone plates, pin hole apertures and fish-eye lenses, biconvex, biconcave, and piano concave. The focal plane array 16, as described in further detail below, includes a plurality of radiation detectors onto which radiation from the object 12 is detected. Each detector within the focal plane array 16 senses a portion of the field of view of the radiation detection system 10. In other words, each individual detector in the focal plane array 16 represents a single pixel, or mapping element, of the radiation detection system 10. As described further below, in one embodiment of the focal plane array 16, when exposed to radiation, the individual radiation detectors in the array change color in response to the intensity of the radiation incident upon the individual detector. The illumination source 18 illuminates the focal plane array 16 with minimal disturbance to the incoming radiation. For example, in the path between the illumination source 18 and the focal plane array may be placed an optional filter 21. The filter may be configured to block radiation from the illumination source that the detectors within the focal plane array would sense, while passing other radiation. For example, if the detectors are sensitive to heat, the filter 21 may be configured to block infrared radiation but pass other radiation. In one embodiment, the filter 21 may be constructed of glass which substantially blocks infrared radiation so as to minimize any disturbance, or influence, of the illumination source upon the focal plane array detectors that sense infrared radiation, while still allowing the focal plane array to be imaged through the filter 21. The illumination source 18 may have a broad or a narrow spectral output. In addition, the illumination source may be tunable. In one embodiment, the illumination source 18 may be constructed of one or more narrow band sources so as to be able to enhance specific response ranges of the detectors. That is, the illumination source may have one or more narrow band sources, such as narrow band LEDs, that output a spectrum matched to a specific spectral range of interest in the spectrum of a thermochromic liquid crystal (TLC) detector. For example, a TLC detector may change color from red to yellow to green to blue as its temperature increases in response to radiation incident on an absorber that is converted to thermal energy. If a particular radiance level, corresponding to a particular color of the TLC, is of interest, then the illumination source may be selected or "tuned" to that particular color. In this way, as the TLC changes to the particular color the sensitivity of the readout of the TLC may be improved. For example, if the radiance level of interest corresponds to a TLC color of green, then the illumination source may be tuned to green. When the TLC is red or yellow or blue, the TLC readout will be low because the source illuminating the TLC does not include these colors. When the TLC changes to green the TLC readout will increase because the illumination source matches the TLC color. Because the TLC readout increases, the sensitivity or the ability to detect small color changes, and corresponding radiation level changes, is improved. The imaging optics 20 focus an image of the focal plane array 16 detectors onto an image sensor 22. The imaging optics 20 are well known in the art, and may be one or more of any number of lenses or other optic components. The imaging optics 20 produce a focused image of the detectors of the focal plane array 16 onto the image sensor 22. The image sensor 22 then produces an output corresponding to an image of the detectors of the focal plane array 16. The image sensor 22 may be, for example, a camera such as a CCD camera. The image produced by the CCD camera may be displayed to a user, or it may be provided to an image processor for further processing.

Figure 2 is plan view of an exemplary embodiment of a portion of a focal plane array 16. As shown in Figure 2, a substrate 24 is coated with a thermal detector material 262 (illustrated as a shaded region). In each case, the focal plane array includes a plurality of mapping elements, In the example illustrated in Figure 2, regions 264 of the substrate 24 and thermal detector material 262 are removed thereby producing an array of detectors, or mapping elements, 266. Removal of the substrate 24 and thermal detector material 262 produce a "perforated" pattern between the detectors 266 within the array. In the example illustrated in Figure 26 the detectors 266 are shows as rectangular shapes, but the detectors may be any desired shape, for example, triangular, pentagonal, octagonal, or any other desired shape.

As illustrated in Figure 2, removal of regions 264 of the substrate 24 and thermal detector material 262 provide thermal isolation between the individual detectors 266. In the example shown, individual detectors 266 are minimally connected to adjacent detectors 266 at their corners 268. While there may be some thermal conductivity between adjacent detectors 266 by way of the material at the connecting corners, the thermal conductivity can be reduced to a desirable level by minimizing the area of the connection between the detectors 266. In another embodiment, the thermal detector material 262 between adjacent detectors 266 is removed entirely, with the underlying substrate 24 remaining. In this way, the underlying substrate 24 provides mechanical support for the detectors 266 and also provides thermal isolation between adjacent detectors 266. Selection of different materials for the substrate 24 can provide different levels of thermal isolation as desired.

In one example, perforations define detectors, or pixels, that are approximately 500 microns in diameter or diagonal size. It is anticipated that the detectors may be much smaller, such as about 50 microns, depending on operating environment, desired energy spectrum of detection, and desired application. The perforations may be produced using a cutting source such as a laser that "burns" the substrate and thermal material to create the voids that provide the segmentation. Smaller detector size may be achieved, in part, using improved power and control of the laser to minimize the detector size. The size of the detector, or pixel, selected for a particular sensor may vary depending on factors such as the sensor operating environment, including the wavelength of the light and/or preconditioning light being used.

The focal plane array can be made of a substrate and detectors. In one example, the detectors include TLC and an absorber. The detector may be applied directly to the substrate, or it may be attached to the substrate using a binder material. In one example, the layers of the focal plane array 16 are deposited, or sprayed on, by starting with a substrate, such as polystyrene, of about 25 microns thickness, then a layer of binder such as PVA, of about 10 microns thickness, next a layer of TLC of about 10 to 30 microns thickness, and then an absorber layer coating of about 10 to 20 microns thickness.

In the example shown in Figure 2, the perforation pattern is comprised of square cuts, i.e., four cuts to define a generally square-shaped detector, or pixel.. The pattern, however, could also be provided in other patterns, for example, triangular (three sided) pixels, or octagonal (eight-sided), or any other desired shape. The particular shape may be selected to achieve or provide a desire characteristic. For example, octagonal detectors may provide improved thermal isolation between adjacent detectors, or pixels, at their corners over square-shaped detectors and therefore might be preferred. The perforations thermally isolate the detectors, or pixels, thereby substantially preventing, or minimizing, temperature changes in one detector from affecting the temperature in adjacent detectors. In other words, the detector size and shape may be selected for desired characteristics, for example, selected to provide sufficient pixel thermal isolation for the operating environment, given the anticipated ambient temperature, or the wavelengths being used for conditioning and detecting.

Figure 3 is a cross sectional view of the Figure 2 embodiment of a focal plane array 16 taken along the line 3-3 in Figure 2. As shown in Figure 3, the focal plane array 16 includes a substrate 24. Disposed on the substrate are an array of detectors 266. As shown in Figure 3, the perforations 264 will segment, or separate, the individual detectors 266. As discussed in relation to Figure 2, the cut-out regions, or perforations 264, of the focal plane array 16 provide thermal isolation between the individual detectors 266.

Various techniques can be used to produce the focal plane array 16 as illustrated in Figure 3. For example, a substrate 24 can be provided, and thermal detector material may be disposed on the substrate 24. For example, the thermal detector material may be sprayed onto the substrate 24, or it may be rolled onto the substrate, or sputtered onto the substrate 24, or any other techniques as will be known to those skilled in the art. After the thermal detector material has been disposed onto the substrate, various techniques may be used to remove portions to provide the cut-out regions 272. For example, a cutting source, such as a laser beam, may be used to cut away the material between the detectors 266 and produce the perforated pattern between the detectors 266. Other techniques may also be used to produce the perforated pattern, such as etching, photolithography techniques, cutting blades, or others that will be known to those skilled in the art.

Figure 4 is a cross sectional view of another embodiment of a focal plane array 16. As shown in Figure 4, the focal plane array 16 includes a substrate 24 and an array of detectors 282 disposed on the substrate. In the embodiment illustrated in Figure 4, cutaway regions 284 are located between the individual detectors 282 but the substrate underlying the cutaway regions 284 remains. In the example illustrated in Figure 4, the thermal material between detectors 282 is removed so that thermal connection between individual detectors 282 is limited to being through the substrate 24. Figure 5 is a plan view of a focal plane array 16 illustrating an embodiment of a focal plane array 16 as described in Figure 4. As shown in Figure 5 the array includes a substrate 24 and an array of detectors 282. In the Figure 5 embodiment, no thermal material is transferred between adjacent detectors 282, but the substrate 24 is substantially continuous so as to provide mechanical support of the array of detectors 282. In one embodiment, the substrate can be continuous, in other embodiments, portions of the substrate may be removed, for example, portions of the substrate between the individual detectors may be removed, or portions of the array under the individual detectors 292 may be removed, or any other combinations of removing and leaving the respective layers. In the embodiment illustrated in Figure 5, using appropriate materials for the substrate, the array of detectors 282 can be thermally isolated from each other.

Various techniques can be used to produce the focal plane array 16 as illustrated in Figure 5. For example, a substrate 24 can be provided. Upon the substrate 24 thermal detector material may be disposed. For example, the thermal detector material may be sprayed onto the substrate 24, or it may be rolled onto the substrate, or sputtered onto the substrate 24, or any other techniques as would be known to those skilled in the art. After the thermal detector material has been disposed onto the substrate, various techniques may be used to remove the thermal detector material so as to form the array of detectors 282. For example, a cutting source, such as a laser beam, may be used to cut away the material between the detectors 282, while leaving the substrate 24 substantially unchanged, and thereby produce the array of detectors 282. Other techniques may also include use of a mask, such as a wire mesh, that defines a desired pattern and is placed on the substrate prior to application or deposition of the thermal detector material. After the thermal detector material has been disposed, the mask may be removed, thereby also removing the corresponding thermal detector material, and producing the array of detectors 282. In addition, techniques such as those used in the manufacture of semiconductors, such as photolithography techniques, may be used to remove portions of the thermal detector material to produce the array of detectors 282. The detectors can include materials as discussed previously.

Figure 6 is a cross sectional view of an embodiment of a focal plane array 16. As shown in Figure 6, the focal plane array 16 includes a substrate 24 and an array of detectors 300. An individual detector 300 may include a radiation sensitive layer 32 disposed upon the substrate 24. On the side of the radiation sensitive layer 32 opposite the substrate, the detector 300 may include a thermal conversion material 34, also referred to as an absorber material.

Figure 7 is a cross sectional view of an embodiment of a focal plane array 16. As shown in Figure 7, the focal plane array 16 includes a substrate 24 and an array of detectors 310. An individual detector 310 may include a thermal conversion material layer 34, or absorber, disposed on the substrate 24. On the side of the thermal conversion material layer 34 opposite the substrate, the detector 310 may include a radiation sensitive layer 32.

Figure 8 is a cross sectional view of yet another embodiment of a focal plane array 16. As shown in Figure 8, the focal plane array 16 includes a substrate 24 and an array of detectors 320. An adhesive layer 322 is disposed on the substrate 24. A radiation sensitive layer 32 may be disposed on the adhesive material 322. On the side of the radiation sensitive layer 32 opposite the substrate, the detector 320 may include a thermal conversion material, or absorber 34. In other embodiments, the thermal conversion material 34 may be disposed on the adhesive layer 322 and the radiation sensitive layer 32 may be disposed on the thermal conversion material 34, opposite the substrate 24.

In previous embodiments described above, thermal isolation was achieved, at least in part, by separated detectors in a common plane. Figure 9 is an elevation view of another embodiment of a focal plane array 16 in which the detectors are in different planes. As shown in Figure 9, a detector array includes a substrate 330 and two arrays of detectors 332 and 334. As illustrated in Figure 9, adjacent detectors 332 and 334 are located in different planes. That is, one set of detectors 332 has an outer surface that is at a different distance from the substrate 330 as compared with the other set of detectors 334. Separation of the individual adjacent detectors into different planes provides thermal isolation between the two sets of detectors 332 and 334. An advantage to the focal plane array of Figure 9 is that it increases the active area of the focal plane array by decreasing the lateral separation between pixels .

Figure 10 is a plan view of an embodiment of a focal plane array providing increased active area. As shown in Figure 10, the focal plane array 16 includes a substrate 342 and a first array of detectors 332, illustrated in black, and a second array of detectors 334, illustrated in cross hatching. The first and second arrays of detectors 332 and 334 can be produced, in one example, as shown in Figure 9. That is, the first array of detectors 332 can be located in one plane, and the second array of detectors 334 can be located in a different plane. The separation between the two planes provides thermal isolation between individual detectors. As shown in Figure 9, arranging arrays of detectors on different planes may be used to maximize the active array of the focal plane array 16.

Figure 11 is an isometric illustration of an exemplary embodiment of a focal plane array 16. As shown in Figure 11 the focal plane array 16 includes a substrate 24. In the example illustrated in Figure 1 1, the substrate 24 is generally the shape of a rectangular slab. Protruding outward from a top surface 26 of the slab are a plurality of columns 28. As described further below, on the top surface 30 of each column 28 a radiation detector is disposed. In this way, each of the columns with the disposed detector corresponds to an individual mapping element, or pixel, of the focal plane array 16.

The columns 28 provide physical support for disposing a radiation detector. Each column 28 also provides thermal isolation between the detectors and the substrate 24. The thermal conductance of the column may be selected to be a desired value. For example, it may be desirable for the column to have a low thermal conductance to thereby provide a high thermal isolation between the detectors and the substrate. But, it may also be desirable to have the column thermal conductance high enough so that there is a thermal path from the detector to the substrate 24 allowing the detector to "bleed off¹ heat to the substrate when a source of radiation causing the detector to heat is removed. In other words, it may be desirable to select the thermal conductance of the column to be a value that allows a desired amount of heat transfer between the radiation detector and the substrate. This technique may also be used to change the response time of the radiation detection sensor to changes in radiation.

As described further below, the location of the columns 28 relative to one another provide radiant and thermal isolation between individual detectors within the array. There are several tradeoffs to consider in the placement of the columns 28. For example, it is desirable to have the detectors close to each other to increase the active area of the focal plane area, the portion of the focal-plane array covered by detectors, so as to increase resolution. However, it is also desirable to have the columns and detectors separated from adjacent columns and detectors to increase isolation between adjacent detectors and reduce "bleeding" of signals between adjacent detectors. "Bleeding" can have the effect of blurring high contrast detail in the image.

In one embodiment, a radiation detection sensor includes a thermal conversion material that converts radiation into heat energy. The sensor also includes a plurality of mapping elements, or detectors, located on the tops of the columns 28 shown in Figure 11. Each of the mapping elements, or detectors, receives heat energy from the thermal conversion material, thereby creating a thermal map corresponding to the radiation energy. In another embodiment, individual pieces of thermal conversion material are associated with individual detectors.

One embodiment of a radiation detection system using the described radiation detection sensor, includes receiving radiated energy from an object. The received energy is converted into thermal energy. Then a received thermal energy map of the object is produced.

Figure 12 is a cross sectional view of one embodiment of a focal plane array 16. As shown in Figure 12, the focal plane array 16 includes a substrate 24 that has columns 28 protruding from a top surface 26 of the substrate 24. On the top surface 30 of the columns 28 a detector 31 is deposed. In the exemplary embodiment illustrated in Figure 12, the detector 31 includes a radiation sensitive layer 32. In one embodiment, the radiation sensitive layer is a thermochromic liquid crystal (TLC). In another embodiment the radiation sensitive layer 32 may be mixtures, of blends, of TLC materials with one or more configurations, or ranges of sensitivities. For example, two different TLCs with different red-onset temperatures may be combined within a single detector. In other words, different combinations of TLC materials may be used to construct a radiation sensitive layer with desired characteristics.

In the embodiment of Figure 12, placed on top of the radiation sensitive layer 32 is a thermal conversion material 34, commonly referred to as an absorber, that converts radiation into heat energy. The absorber 34 converts radiation that impinges upon it into thermal energy that is sensed by the radiation sensitive layer 32. The absorber may be made of black cupric oxide. In general, absorbers may be made of any material that has high absorptivity and low emissivity characteristics. In addition, it is noted that absorber material may be transparent to some radiation while absorbing other radiation. For example, glass may absorb infrared radiation even while it is nearly transparent to radiation in the visible part of the spectrum. Although the absorber has been described as converting radiation into thermal energy, the absorber may be constructed of any type of material that converts radiation into a physical characteristic that can be sensed by the radiation sensitive layer. In one embodiment, the focal plane array illustrated in Figure 12 is constructed using an optically transparent material for the substrate 24 and the columns 28. Constructing the substrate 24 and the columns 28 of optically transparent material allows the sensing element to be viewed from the "back" 36 of the focal plane array, as described further below. Figure 13 is a cross sectional view of another embodiment of a focal plane array

16. The embodiment of the focal plane array 16 illustrated in Figure 13 is similar to that illustrated in Figure 12 except that the absorber 34 is placed on the top 30 of the column 28. The radiation sensitive layer 32 is disposed on top of the absorber 34. Arranging the absorber 34 and radiation sensitive layer 32 in this manner allows the detector 31 to be viewed from the "front" 38 of the focal plane array as described further below.

Figure 14 is a cross sectional view of yet another embodiment of a focal plane array 16. In the embodiment of the focal plane area illustrated in Figure 14, the columns 28 have an expanded area forming the top surface 30 of the column. Having an expanded top surface 30 on the column helps to increase the active area of the focal plane area while providing increased separation 502, and therefore increased isolation, between the regions of the columns 28 beneath the expanded top surface 30. An expanded top surface 30 supports a larger absorber area thereby increasing the received irradiance per pixel. In general, an increase in the irradiance per pixel increases the signal level thereby improving the signal to noise ratio (SNR) of individual detectors. In addition, a narrow column can provide a lower thermal conductance path and thereby improve thermal isolation between the detectors and the substrate. Figure 15 is a schematic diagram illustrating additional aspects of a portion of the focal plane array 16. In the example in Figure 15, the focal plane array 16 is configured with a detector 31 disposed onto the top surface 30 of a column 28. In the embodiment illustrated in Figure 15, an absorber 34 is placed on top of a radiation sensitive layer 32. Radiation 52 that impinges onto the absorber 34 is converted into thermal energy. As the intensity of the radiation 52 onto the absorber 34 increases, the thermal energy produced by the absorber increases. Likewise, as the intensity of the radiation 52 onto the absorber 34 decreases, the thermal energy produced by the absorber decreases. The radiation sensitive layer 32 detects the level of thermal energy of the absorber 34.

The column 28 provides a low thermal conductance path, i.e. a high thermal isolation path, from the detector 31 to the substrate 24. The low thermal conductance path provides thermal isolation between the detector and the substrate. The separation 64 between the detectors 31, provided by placement of the columns 28, provides thermal and radiant isolation between individual detectors within the focal plane array 16. The thermal and radiant isolation provided by the separation between columns 28 may be provided in many different ways. In one embodiment, the focal plane array 16 can be located within an enclosure that has been evacuated of a substantial portion of air so as to produce a deep vacuum. In another embodiment, the separation 64 between the columns 28 may be made of a low thermal conductance materials, such as, aerogel material.

In another embodiment, the relative positions of the radiation sensitive layer 32 and absorbers 34 may be changed, as illustrated in Figure 13. In this embodiment the radiation 52 would pass through the layer 32 and impinge on the absorber 34 which would generate heat that is sensed by the layer 32. The remaining thermal characteristics would be similar to .those described in relation to the embodiment of Figure 14.

Figure 16 is a cross sectional view of another embodiment of a focal plane array 16. Figure 16 includes thermal shunts 72 between the top surface 26 of the substrate 24 and the base 74 of the column 28 The thermal shunt 72 may provide controllably variable thermal conductance paths. For example, the thermal shunts 72 may operate in different states. In one state the thermal shunt 72 may operate to provide a low thermal conductance path, i.e. a high thermal isolation, between the substrate 24 and the column 28. In another state, the thermal shunt 72 may operate to provide a high thermal conductance path, i.e. a low thermal isolation path, between the substrate 24 and the column 28. When the thermal shunt 72 is included the column 28 may be constructed with a high thermal conductance material so that when the thermal shunt 72 provides a high thermal conductance path, the column 28 and sensor element 32 will quickly approach thermal equilibrium with the substrate 24. When the thermal shunt 72 provides a low thermal conductance path, the column 28 and sensor element 32 will be thermally isolated from the substrate 24.

The thermal shunt 72 may be constructed of various types of materials. For example, thermoelectric cooler/heater material, such as bismuth telluride, may be used as the substrate 24 with columns made of a low conductance material sitting on top of the substrate 24. The thermal shunt 72 may also be constructed using carbon nanotubes and a ferro-fluid. Operation of the shunt may be controlled in different ways. For example, if the thermal shunt is constructed of a thermoelectric cooler/heater material, it may be controlled by varying a current through the material using typical electrical control circuits, as are well known. If the thermal shunt is constructed of carbon nanotubes and a ferro-fluid, it may be controlled by a controllable magnetic or electric field. In other embodiments the relative positions of the radiation sensitive layer 32 and absorbers 34 may be changed, as illustrated in Figure 13.

Figure 17 is a schematic diagram illustrating additional aspects of a portion of a focal plane array 16. The example in Figure 17 illustrates the focal plane array 16 configured with detectors 31 constructed with a radiation sensitive layer 32 disposed onto the top surface 30 of a column 28. An absorber 34 is placed on top of the layer 32.

Radiation 52 that impinges onto the absorber 34 is converted to thermal energy. As the intensity of the radiation 52 onto the absorber 34 increases the thermal energy produced by the absorber increases. Likewise, as the intensity of the radiation 52 onto the absorber 34 decreases the thermal energy produced by the absorber decreases. The layer 32 detects the level of thermal energy of the absorber 34.

Between the base 74 of the column 28 and the top surface 26 of the substrate 24 there is a thermal shunt 72. As described in relation to Figure 16, the thermal shunt 72 may be controllably operable in different states between conduction and isolation to provide a higher thermal conductance path, i.e. low thermal isolation, or a lower thermal conductance path, i.e. high thermal isolation. Operation of the thermal shunt 72 can be used to periodically set the detectors to a desired bias level. For example, during an initial operation the thermal shunt 72 may be in a high thermal conductance state and thereby provide low thermal isolation between the substrate 24 and the column 28. In this state, the column 28 and detector 31 will reach thermal equilibrium with the substrate 24. As explained further below, the substrate 24 can be controlled to be at a desired temperature. In this manner the detector 31 can be biased to a desired temperature. For example, if the radiation sensitive layer 32 is TLC it can be biased to a desired operating point, such as temperature of red onset for the particular TLC material. After the detector 31 has been biased to a desired operating point the thermal shunt can be operated to change to a state of low thermal conductance and thereby provide a high thermal isolation between the substrate 24 and the column 28. While the thermal shunt 72 is in its low thermal conductance it will provide a high thermal isolation between the column and the substrate. With the thermal shunt in this state, any radiation that impinges onto the absorber 34 will be converted to heat. Due to the high thermal isolation between the column 28 and the substrate 24, the heat will remain in the absorber and be sensed by the radiation sensitive layer 32. In this manner the amount of radiation impinging on the absorber 34 can be detected. Due to the high thermal isolation, even when momentarily blocking the impinging radiation, the absorber will remain at an elevated temperature and be sensed by the layer 32. It may be desirable to periodically "reset" the detector 31 to the predetermined bias operating point. To "reset" the detector 31, the thermal shunt 72 can be operated to change states so that there is a high thermal conductance path, providing low thermal isolation, between the column 28 and the substrate 24 so that the column 28 and detector 31 return to thermal equilibrium with the substrate. In this manner, the focal plane array 16 can be periodically set to a predetermined operating point.

In another embodiment the relative positions of the radiation sensitive layer 32 and absorbers 34 may be changed, as illustrated in Figure 13. In addition, in other embodiments the thermal shunt 72 may be located in other positions relative to the substrate 24, radiation sensitive layer 32, and absorber 34. For example, the thermal shunt 72 may by located between the top surface 30 of the column 28 and the detector 31. In another example, the thermal shunt may be located on top of the focal plane array, or between the focal plane array and the entrance pupil of the detection system, such as within the collection optics 14, to prevent radiation from impinging onto the focal plane array.

Figure 18 is a schematic diagram illustrating an exemplary arrangement of components of a radiation detector system 10. The system includes a focal plane array 16 that is configured according to any one of the embodiments described above and constructed such that the focal plane array 16 is optically transparent. With the focal plane array constructed in this manner, the sensing element may be viewed from the back side 36 of the focal plane array (where "back" is relative to the collection optics 14).

Thus, in Figure 18, an image of an object 12 is focused onto the focal plane array 16 by the collection optics 14. The focal plane array 16 is illuminated by an illumination source 18. An image of the focal plane array 16 detectors is focused onto an image sensor element 22 by imaging optics 20.

Figure 19 is a schematic diagram illustrating additional detail of an exemplary arrangement of imaging components that may be used in a radiation detector. As shown in Figure 19, imaging optics 20 includes a beam splitter 102 and an imaging lens 104. The output of illumination source 18 is reflected in the beam splitter 102 and directed to illuminate the back of the focal plane array 16. In the path between the illumination source 18 and the focal plane array 16 may be placed an optional filter 105. The filter 105 may be configured to block radiation emitted from the illumination source that the detectors within the focal plane array would sense, while passing other radiation. For example, if the detectors are sensitive to heat, the filter 105 may be configured to block infrared radiation but pass other radiation. In one embodiment, the filter 105 may be constructed of glass which blocks infrared radiation so as to minimize any disturbance, or influence, of the illumination source upon the focal plane array detectors while still allowing the focal plane array to be imaged through the filter 21. The illumination source 18 may be a broad or a narrow spectral output. In addition, the illumination source may be tunable. In one embodiment, the illumination source 18 may be made of one or more narrow band sources so as to be able to enhance specific response ranges of the detectors. That is, the illumination source may have one or more narrow band sources, such as narrow band LEDs, that output a spectrum matched to a specific spectral range of interest. An image of the detectors of the focal plane array 16 passes through the filter 105 and the beam splitter 102 and is focused onto the image sensor 22 by the imaging lens 104.

Figure 20 is a schematic diagram illustrating another exemplary arrangement of components of a radiation detector 10. In the example of Figure 20, the focal plane array is configured according to any one of the embodiments described above and constructed such that the focal plane array 16 is may be viewed from the front side 38 of the focal plane array (where "front" is relative to the collection optics 14; compare Figure 18).

Thus, in Figure 20, an image of an object 12 is focused onto the focal plane array 16 by the collection optics 14. The front of the focal plane array 16 is illuminated by the illumination source 18. An image of the focal plane array 16 detectors is focused onto a sensor element 22 by imaging optics 20. In this configuration, because the detectors of the focal plane array 16 are directly viewed, rather than viewing the detectors "through" the focal plane array substrate, the substrate and columns of the focal plane array may be constructed of non-transparent material. An optional filter, not shown, may be placed between illumination source 18 and the focal plane array 16. The filter may be configured to block radiation emitted from the illumination source that the detectors within the focal plane array would sense, while passing other radiation.

Figure 21 is a block diagram of another embodiment of a radiation detection system 10. The block diagram of Figure 21 is similar to Figure 1 in that an image of an object 12 is focused onto the focal plane array 16 by collection optics 14. An illumination source 18 illuminates the focal plane array 16 and an image of the focal plane array detectors is focused onto image sensor 22 by imaging optics 20. Figure 21 also includes an environmental control unit 122. In one embodiment, the environmental control unit 122 may control the temperature of the substrate to bias the focal plane array 16 to a desired operating point. In another embodiment, the environmental control unit 122 may evacuate the region around the focal plane array 16 to create a deep vacuum. In other embodiments, other environmental features may be controlled, for example, controlling both temperature and vacuum, and controlling humidity or any other combination of environmental aspects including magnetic field and electrical field environment.

The example of Figure 21 also includes an image processor 124 and a display 126. Image processing techniques are well known in the art and may be used to enhance the visual display presented on the display 126. For example, it may be desirable to re-map the color thermal output originating in the focal plane array 16 to conform the output to generally accepted color maps for features such as hue, saturation, and intensity (HSI). It may also be desirable to re-map the color thermal output for contrast enhancement, red- green-blue (RGB) analysis, geometric distortion correction, etc. The image processor 124 may be configured to control the illumination source.

The image processor may also be configured to control the environmental control unit 122. For example, the image processor 124 may control the environmental control unit 122 so as to bias the focal plane array to a desired operating point.

Figure 22 is a schematic diagram illustrating a plan view of an exemplary design of a focal plane array 16. As shown in Figure 22, the focal plane array 16 includes a substrate 24 and an array 132 of support columns 28. In the example of Figure 22, the support columns 28 have a circular cross section. As described above, detectors may be disposed upon the tops of the support columns 28 in various configurations.

Figure 23 is a schematic diagram illustrating a plan view of another exemplary design of a focal plane array 16. As shown in Figure 23, the focal plane array 16 includes a substrate 24 and an array 132 of support columns 28. In the example of Figure 23, the support columns 28 have a triangular cross section. As described above, detectors may be disposed upon the tops of the support columns 28 in various configurations. An aspect to the triangular cross section of the support columns is that each side of one of the triangular cross sectional columns is directed toward, or facing, an apex, or point, of an adjacent column. In this manner isolation between adjacent columns may be increased by minimizing the surface areas exposed to adjacent support columns.

Figure 24 is a schematic diagram illustrating yet another exemplary design of a focal plane array 16. As shown in Figure 24, the focal plane array 16 includes a substrate 24 and an array 132 of support columns 28. In the example of Figure 24, the support columns 28 have a hexagonal cross section. As described above, detectors may be disposed upon the tops of the support columns 28 in various configurations. As illustrated by Figures 22-24, the focal plane arrays can include support columns constructed in many different shapes. Figure 256 (comprising 25A, 25B, 25C, and 25D) includes four different examples of detector support column shapes.

Figure 25 A is a schematic diagram of a support column 28 with a circular cross section. As shown in Figure 25A, the support column 28 is a cylindrical column with a circular cross section. In one embodiment, a radiation sensitive layer or absorber may be disposed onto the top surface 166 of the column 28. In another embodiment, there may be an optional recessed cavity 162 (indicated by dashed lines) in the top of the column 28 where a radiation sensitive layer, an absorber (such as a thermal conversion material), or both may be disposed. The recess 162 can provide further insulation between adjacent columns to reduce lateral dispersion of incident energy.

Figure 25B is a schematic diagram of another support column 28 with a circular cross section. As shown in Figure 25B, the support column 28 has a cylindrical base column 164 with an extended circular cross section top 166 that has a larger diameter than the cylindrical base column 164. The cylindrical base column can be constructed as a solid, or as a hollow structure. In one embodiment, a radiation sensitive layer or absorber may be disposed onto the top surface 166 of the column 28. In another alternative, a recessed cavity 162 (indicated by dashed lines) is located in the top surface 166 of the column 28, where the radiation sensitive layer, absorber, or both may be disposed. As noted above, in the discussion of Figure 14, the support column illustrated in Figure 25B may increase the active area of the focal plane array while also increasing the isolation between adjacent detectors. As noted, the isolation can be improved by the recess cavity 162 in the columns.

Figure 25C is a schematic diagram of yet another support column 28. As shown in Figure 25C, the support column 28 may have a cylindrical base column 164. In other embodiments, the base column may have solid, hollow, or structural aspects. The base column 164 can have other cross sectional shapes, for example, oval, or multisided polygons such as triangles, squares, rectangles, pentagons, hexagons, etc. Similarly, the column construction may be constructed to have top surfaces of such varied shapes and configurations, including circular, oval, or multisided polygons. In the example of Figure 16C, the top surface 166 of the support column 28 has a triangular cross section. In one embodiment, a radiation sensitive layer or absorber may be disposed onto the top surface 166 of the column 28. In another embodiment, there may be a recessed cavity 162 (indicated by dashed lines) in the top surface 166 of the column 28 where the radiation sensitive layer, absorber, or both may be disposed.

In the examples shown in Figures 25A-25C, the recess 162 was the same cross sectional shape as the corresponding support column 28 (in Figure 16A), or the top surface 166 (in Figure 25B and Figure 25C). In other embodiments, the recess 162 may be a different shape than the corresponding top surface of the column. Figure 25D is still another embodiment of a support column 28, this one having different recess and top surface shapes. Figure 25D is similar to Figure 25C, where the support column 28 has a cylindrical base column 164 and the top surface 166 of the support column 28 has a triangular cross section. In Figure 25D, however, the recess 162 is not the same cross section as the top surface 166. As shown in Figure 25D, even though the top surface 166 is one cross sectional shape, a triangle, the recess 162 may be a different cross sectional shape, for example an oval, as shown in Figure 25D, or the recess may be any other desired shape.

In the examples illustrated in Figures 25A-25D the base support column was described as having a circular cross section. Other cross sections of the base support columns are possible. For example, the base support column may be oval, or any polygon shape. Figure 26 is a schematic diagram of an embodiment of a non-planar focal plane array 16. In the embodiment of Figure 26, the substrate of the focal plane array 16 may be made of a pliable material such as polyester. If the substrate 24 material is pliable, the focal plane array can be formed to shapes other than flat surface shapes. Likewise, the substrate of the focal plane array 16 can be formed to a non-planar shape even if the substrate is a non-pliable material. For example, as illustrated in Figure 26, the focal plane array 16 is formed into a concave shape. The concave shaped focal plane array can be constructed using a non-pliable material that has been "shaped" into a concave form, or it can be constructed using a pliable material that is "formed" into a concave form. A concave shape of the focal plane array 16 may be desired in some applications. For example in a reflective system, such as illustrated in Figure 20, it may be beneficial to have a concave shaped focal plane array 16. Also, if the object emitting the radiation is small in size, such as in microscopy applications, then it may be possible to improve the resolution, and detail, of the mapping of the radiation.

An additional aspect of making the focal plane array a concave shape is that the separation 172 between the detectors 31 is decreased, thereby increasing spatial resolution of the focal plane array. In addition, the separation 174 of the support columns 28 is increased, thereby improving isolation between adjacent columns 28.

Figure 27 is a schematic diagram of another embodiment of a non-planar focal plane array 16. In the embodiment of Figure 27, the substrate of the focal plane array 16 may be made of a pliable material such as polyester. If the substrate 24 material is pliable, the focal plane array can be formed to shapes other than flat surface shapes. Likewise, the substrate of the focal plane array 16 can be formed to a non-planar shape even if the substrate is a non-pliable material. For example, as illustrated in Figure 27, the focal plane array 16 is formed into a convex shape. The convex shaped focal plane array can be constructed using a non-pliable material that has been "shaped" into a convex form, or it can be constructed using a pliable material that is "formed" into a convex form. A convex focal plane array 16 may be desired in some applications, such as, in the scenario where an object emitting radiation is large in size relative to the focal plane array. A convex focal plane array 16 may also be desirable, for example, if a "fish- eye" lens is used in the collection optics. Figure 28 is a schematic diagram of an yet another embodiment of a non-planar focal plane array 16. The support columns of the focal plane array 16 in Figure 28 have an enlarged top surface 30. Again, the focal plane array can be "shaped" or "formed" to shapes other that flat surface shapes. For example, the focal plane array 16 in Figure 28 has a concave shape. Again, making the focal plane array a concave shape the separation 172 between the detectors 31 is decreased, thereby increasing special resolution of the focal plane array. In addition, the separation 174 of the support columns 28 is increased, thereby improving isolation between adjacent columns 28.

Figure 29 is a schematic diagram of still another embodiment of a non-planar focal plane array 16. The support columns of the focal plane array 16 in Figure 29 have an enlarged top surface 30. The focal plane array can be "shaped" or "formed" to shapes other that flat surface shapes. For example, the focal plane array 16 in Figure 29 may formed into a convex shape. The shapes of the focal plane array illustrated in Figures 26-29 are merely examples. The focal plane array can be "shaped" or "formed" into other shapes, for example, hyperbolic, circular, spherical, etc. In other words, the shape of the focal plane array can be selected as desired for use in a particular application. The ability to have a focal plane array of different shapes can reduce, or eliminate, the need for expensive optics needed to focus an image onto a planar focal plane array. In addition, the focal plane array may be constructed in a large format, for example, in a health care application it may be desirable to construct a focal plane array that is large enough to image an area of interest, such as a human face. Constructing a focal plane array in a large format may allow the focal plane array to be directly viewed without the need for an imaging sensor or imaging optics.

Figure 30 is a block diagram of an embodiment of an environmental control unit. As shown in Figure 30, temperature elements 212 are in thermal connection with the substrate 24 of a focal plane array 16. A controller 214 is connected to the temperature element 212 so as to adjust the temperature of the temperature element 212. As the temperature of the temperature element 122 varies the temperature of the focal plane array 16 substrate 24 varies accordingly. In this way the focal plane array substrate 24 can be set to a desired temperature. Also, in thermal connection with the substrate 24 is a temperature sensor 216 that detects the substrate 24 temperature. The thermal sensor 216 is in communication with the controller 214 thereby providing the substrate 24 temperature for use by the controller 214 in controlling the temperature elements 212. As described above, control of the substrate temperature can be used to bias some detectors, such as TLC, to desired operating points, such as red onset, or some other point in their operating range. The temperature element 212 may be any type of heating or cooling apparatus that can be controlled. For example, the temperature element 212 may be a thermoelectric cooler, an electric heating element, or other device capable of controlling temperature. The embodiment of Figure 30 describes controlling the temperature of the substrate. Other embodiments of an environmental control unit may control other environmental characteristics. For example, the environmental control unit may operate to maintain a desired temperature, or vacuum, or humidity level or control any combination of environmental characteristics including magnetic field and electric field environments. Figure 31 is a block diagram of a null sensor 221 arrangement. As shown in Figure 31, an image of an object 12 passes through a beam splitter 222 and is focused onto a focal plane array 16 by collection optics 14. The focal plane array 16 is illuminated by illumination source 18. An image of the detectors of the focal plane array 16 is focused onto image sensor 22 by imaging optics 20. The output of the image sensor 22 is input to an image processor 224. The output of the image processor may be presented on a display 226. The image processor 224 is also in communication with a controllable radiation source 228 and an environmental control unit 122 controlling a bias operating point of the focal plane array. In one embodiment, the focal plane array 16 includes sensing elements, such as

TLC. The environmental control unit may be controlled by the image processor 224 to establish a desired bias, or operating point for the focal plane array 16. For example, the environmental control unit 122 may establish a bias point for TLC detectors included on the focal plane array so that the TLC detectors are at red onset. Thus, with no radiation impinging upon the focal plane array, the entire array of sensing elements would be biased to red onset. The elimination of radiation impinging onto the focal plane array may be accomplished in many ways, for example, placing a shutter over the entrance pupil of the null sensor 221, or have thermal shunts located so as to block radiation from impinging on the focal plane array as described above. After the focal plane array 16 has reached its bias operating point, the controllable radiation source 228 may be commanded to output radiation that is reflected off of the beam splitter 222 so as to impinge upon the focal plane array 16. The radiation from the controllable radiation source 228 that impinges the focal plane array 16 is controlled so as to set the detectors in the focal plane array to a known, desired, operating point. For example, if the detectors include TLC, the controllable radiation source may be commanded by the image processor 224 to input radiation sufficient to set the detectors in the focal plane array to green, or other desired, operating point. It is noted that the controller radiation source 228 may include a scanning mechanism to scan the radiation source output across the focal plane array 16. In other embodiments the scanning mechanism may be separate from the controllable radiation source 228.

During operation of the null sensor 221, as radiation from the object 12 impinges on the focal plane array the detectors that include TLC color will change accordingly. The change in color will be detected at the image sensor 22. The output of the image sensor 22 is connected to the image processor 224 that generates commands to the controllable radiation source to increase or decrease the output of the controllable radiation source as it scans across the focal plane array so that the TLC color remains at its desired operating color, for example green. The signal for controlling the controllable radiation source 228 corresponds to the radiation received from the object 12. The image processor 224 may generate an image corresponding to the control signal and generate a display be presented on the display 226.

The description of Figure 31 was of an embodiment when the "back" of the focal plane array 16 is imaged. In another embodiment, rearrangement of components within the null sensor 221 can support imaging of the "front" of the focal plane array 16. The controllable radiation source 228 may also be used to output a known radiation directed to the focal plane array to characterize, or calibrate, the sensitivity and response of detectors with the focal plane array. For example, the controllable radiation source 228 may be controlled so as to expose the focal plane array 16 to a constant radiation level, a step change in radiation level, a gradient radiation level, or other variable radiation level. In addition, a target with a known radiation profile may be exposed to the focal plane array 16. For example a target "shutter" may be placed in front of, or in the entrance pupil of, the radiation detector system and thereby be exposed to the focal plane array. The performance of the detectors within the focal plane array when exposed to a known radiation can be evaluated. For example, the performance characteristics of the detectors, such as sensitivity and response to a step, or varying radiation input can be evaluated.

Figure 32 is a block diagram of another embodiment of a radiation detector system. As shown in Figure 32 the radiation detection system includes a pressure vessel 232. One end of the pressure vessel 232 allows radiation to enter the vessel. For example, one end of the pressure vessel 232 may be formed by at least a portion of the collection optics 14 that includes a glass plate, or lens, that forms the end of the pressure vessel. Inside the pressure vessel is a focal plane array 16. Also located in the pressure vessel is a temperature control unit 234. For example, the temperature control unit 234 may be constructed so as to be near or in contact with the back of the focal plane array 16. As described above, the temperature control unit may be used to bias the focal plane array to a desired operating temperature.

In the example shown in Figure 32, also located in the pressure vessel are imaging optics 20 and an imaging sensor 22. The imaging optics 20 focus an image of the focal plane array onto the imaging sensor. In another embodiment, at least a portion of the imaging optics 20 includes a glass plate, or lens, that forms another end of the pressure vessel 232. In this way, the imaging sensor 22, as well as additional optics, may be located external to the pressure vessel 232. Penetrating the pressure vessel 232 is a port 236 for the pressure control of the internal environment. This port allows the pressure vessel 232 to be pressurized, or to have a vacuum drawn within the pressure vessel.

Figure 33 is a schematic illustrating another embodiment of a radiation detection system 240. The radiation detection system 240 in Figure 33 is similar to the radiation detection system 10 illustrated in Figure 18 and includes an object 12, collection optics 14, focal plane array 16, illumination source 18, imaging optics 20 and imaging sensor 22. The radiation detection system 240 illustrated in Figure 33 includes a target illumination source. The target illumination source 242 illuminates, or "paints", the object 12. Radiation reflected from the object 12 is then collected by collection optics and focused onto the focal plane array. The target illumination source 242 may be tunable. For example, the target illumination source 242 may include optics or controls to shape the spectrum, such as the color and geometry, of the radiation output by the target illumination source 242. In another example, the target illumination source 242 may include multiple sources, each of which outputs a desired spectrum of radiation. In one embodiment, the output of the multiple sources may be mixed, or combined, in any desired combination into a composite source with a desired output spectrum. In another embodiment, the sources may be multiplexed so that only desired ones of the sources, or individual sources, are on at any given moment.

In this manner the object may be painted with radiation of a desired spectral content which may improve the detection of specific objects. For example, if it is desired to identify a particular object, the target illumination source 242 may have its spectral output configured such that radiation that will be reflected from the object of interest will be increased. The radiation detection system 240 may also include an input filter 244. The input filter may be configured to pass a desired spectrum. For example, the input filter 244 may be configured to have a spectral response, that is pass spectral energy, matched to the spectral output of the target illumination source 242. In another example, the input filter may be configured to have a spectral response that matches a spectral profile of a specific object. The input filter 244 may also be tunable, that is its spectral response may be configurable. In other embodiments, the input filter 244 may include multiple filters that ate individually, or in combination, used to produce the desired spectral response. Figure 34 is a flow chart illustrating detection of radiation from an object. Flow begins in block 252 where radiation emitted from an object is collected. For example the object may be viewed with collection optics that gather, and form, the radiation in a desired way. In block 254 the collected radiation is focused onto a focal plane array. For example, the collection optics can collect the radiation emitted from an object and focus the radiation onto the focal plane array. The focal plane array may include a plurality of detectors that are formed in an array upon the focal plane array. In block 256 the array of detectors are imaged. For example, an imaging sensor, such as a camera, may produce an image of the array of detectors.

For example, if the detectors include TLC, so that the individual detectors change color in relationship to the amount of radiation that impinges on them, then an image of the detector array can be used to map the radiation that was emitted by the object.

Figure 35 is an elevation view of another exemplary embodiment of a focal plane array 16. As shown in Figure 35 a substrate 24 has an array of columns 3502 and 3504 protruding from a surface of the substrate. Upon the top of each column is a detector 31. In the embodiment of Figure 35 a first array of columns 3502 are a different height than a second set of columns 3504. Because the columns are different heights, they can be located so that the physical spacing between the detectors 31 when view from the top 3506 is minimized. As shown in Figure 35, if the detectors 31 cross sectional area is larger than the cross section of the columns 3502 and 3504, the detectors 31 may be located such that they overlay when viewed from the top 3506. In this manner, the active area of the focal plane array can be maximized.

In the embodiments described the focal plane array has included a substrate. In other embodiments, the focal plane array does not need to include a substrate. For example, the thermal detector material may be continuous and patches of absorber material may define the detectors. Likewise, an absorber material may be continuous and thermal detector material disposed upon the absorbed thereby defining detectors. In other words, the substrate is simply a means for supporting the detectors, and it is possible to made a focal plane array with one of the other elements, i.e. detector, or absorber, performing the supporting function.

In addition, while some embodiments have described examples of detectors as including a thermal detecting material and an absorbed, they are not limited to this type of detector. That is, exemplary detectors map one form of energy to another form of energy. For example, a detector may be any device that performs the function of mapping thermal energy to a visual display.

In general, a radiation detection sensor can include a radiation detector on a substrate. The radiation detector may be segmented into an array of mapping elements, or detectors, such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map. The radiation detection sensor may have the radiation detectors within the array of mapping elements minimally connected to adjacent radiation detectors.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

WE CLAIM:

Claims

1. A radiation detection sensor comprising: a radiation detector that is segmented into an array of mapping elements that are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map; and an image sensor that receives the visual thermal energy map and produces a corresponding image.

2. A radiation detection sensor as defined in Claim 1, wherein the array of mapping elements comprises mapping elements that are minimally physically connected to adjacent mapping elements.

3. A radiation detection sensor as defined in Claim 1, wherein the mapping elements of the radiation detector are formed by a substrate material and a thermal detection material.

4. A radiation detection sensor as defined in Claim 3, wherein the mapping elements are defined by voids in portions of the thermal detection material.

5. A radiation detection sensor as defined in Claim 4, wherein the voids are formed by perforations in the thermal detection material.

6. A radiation detection sensor as defined in Claim 1, wherein the mapping elements are formed with micro-deposition techniques.

7. A radiation detection sensor as defined in Claim 1, wherein the mapping elements of the radiation detector comprise a radiation sensitive layer and a thermal conversion material.

8. A radiation detection sensor as defined in Claim 7, wherein the radiation sensitive layer is a thermochromic liquid crystal material.

9. A radiation detection sensor as defined in Claim 7, wherein the thermal conversion material has high absorptivity and low emissivity.

10. A radiation detection sensor as defined in Claim 7, further comprising thermal elements that are used to control a temperature of the substrate.

11. A radiation detection sensor as defined in Claim 10, wherein the thermal elements comprise thermoelectric coolers.

12. A radiation detection sensor as defined in Claim 10, further comprising an environmental control unit.

13. A radiation detection system, comprising: a focal plane array that includes a radiation detector that is segmented into an array of mapping elements such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map; collection optics that focus radiation emitted from an object onto the focal plane array; and imaging optics that focus an image of the focal plane array pixels onto an image sensor.

14. A radiation detection system as defined in Claim 13, further comprising an image processor configured to accept graphics output from the image sensor and provide an enhanced visual image.

15. A radiation detection system as defined in Claim 14, wherein the image processor analyzes the output of the image sensor and generates a command for a controllable radiation source.

16. A radiation detection system as defined in Claim 15, wherein the command for the controllable radiation source causes the controllable radiation source to output radiation that is directed to the focal plane array and maintains the mapping elements at a predetermined value.

17. A radiation detection system as defined in Claim 13, wherein the image sensor is a camera.

18. A method of detecting radiation emitted from an object, the method comprising: focusing radiation emitted from an object onto a focal plane array, wherein the focal plane array includes a radiation detector that is segmented into an array of mapping elements such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map; and focusing an image of the array of detectors onto an imaging sensor thereby producing an image of the visual thermal energy map.

19. An apparatus for detecting radiation emitted from an object; the apparatus comprising: means for focusing radiation emitted from an object onto a focal plane array, wherein the focal plane array includes a radiation detector that is segmented into an array of mapping elements such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map; and means for focusing an image of the array of detectors onto an imaging sensor thereby producing an image of the visual thermal energy map.

20. A method of producing a radiation detection sensor, the method comprising: providing a thermal detection material; and segmenting the thermal detection material into an array of mapping elements that are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map.

21. A method as defined in Claim 20, wherein segmenting comprises removal of portions of the thermal detection material.

22. A method as defined in Claim 20, wherein the thermal detection material includes a radiation detector material and substrate.

23. A method as defined in Claim 20, wherein segmenting comprises removing portions of the thermal detection material.

24. A method as defined in Claim 20, wherein segmenting comprises micro- disposing thermal detection material into pixel-sized portions.

25. A method as defined in Claim 24, wherein segmenting comprises photolithography processing.

26. A method as defined in Claim 25, wherein segmenting comprises depositing radiation detector material onto a substrate.

27. An apparatus for producing a radiation detection sensor, the apparatus comprising: means for disposing a radiation detector material onto a substrate; and means for segmenting the radiation detector material into an array of mapping elements that are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map.

28. A method of producing a radiation detector, the method comprising segmenting a radiation detector material into an array of mapping elements such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map.

29. A radiation detection sensor comprising: a substrate; an array of columns protruding from a top surface of the substrate; and an array of radiation detectors disposed upon a top surface of the columns within the array, the detectors comprising a radiation sensitive layer and a thermal conversion material, wherein the columns provide thermal isolation between the radiation detectors and the substrate, and spatial separation of columns within the array provide radiant isolation between the radiation detectors upon the tops of individual columns.

30. A radiation detection sensor as defined in Claim 29, wherein the substrate is planar.

31. A radiation detection sensor as defined in Claim 29, wherein the substrate is constructed of pliable material.

32. A radiation detection sensor as defined in Claim 29, wherein the substrate is configured in a non-planar shape.

33. A radiation detection sensor as defined in Claim 29, wherein the radiation sensitive layer is a thermochromic liquid crystal material.

34. A radiation detection sensor as defined in Claim 29, wherein the thermal conversion material has high absorptivity and low emissivity.

35. A radiation detection sensor as defined in Claim 29, further comprising thermal elements that are used to control a temperature of the substrate.

36. A radiation detection sensor as defined in Claim 35, wherein the thermal elements comprise thermoelectrical coolers.

37. A radiation detection sensor as defined in Claim 29, further comprising an environmental control unit.

38. A radiation detection sensor as defined in Claim 29, further comprising thermal shunts.

39. A radiation detection sensor as defined in Claim 38, wherein the thermal shunts are located between the substrate and a base of the column.

40. A radiation detection sensor as defined in Claim 38, wherein the thermal shunts are located between a source of radiation input and the array of radiation sensor elements.

41. A radiation detection sensor as defined in Claim 38, wherein the thermal shunt is a thermoelectric cooler.

42. A radiation detection sensor as defined in Claim 38, wherein the thermal shunt is constructed of carbon nanotubes.

43. A radiation detection sensor as defined in Claim 29, wherein the columns are cylinders.

44. A radiation detection sensor as defined in Claim 29, wherein the columns have a top surface that is larger than a base of the column.

45. A radiation detection system, comprising: a focal plane array that includes a substrate and a plurality of columns protruding from the substrate, wherein radiation detectors are disposed on tops of the plurality of columns thereby creating an array of radiation detectors; collection optics that focus radiation emitted from an object onto the focal plane array; and imaging optics that focus an image of the focal plane array sensor elements onto an image sensor.

46. A radiation detection system as defined in Claim 45further comprising an image processor configured to accept an output from the image sensor.

47. A radiation detection system as defined in Claim 46, wherein the image processor analyzes the output of the image sensor and generates a command for a controllable radiation source.

48. A radiation detection system as defined in Claim 47, wherein the command for the controllable radiation source causes the controllable radiation source to output radiation that is directed to the focal plane array and maintains the detectors at a predetermined value.

49. A radiation detection system as defined in Claim 45, wherein the image sensor is a camera.

50. A radiation detection system as defined in Claim 49, wherein the camera is a video camera.

51. A radiation detection system as defined in Claim 49, wherein the camera is a film camera.

52. A radiation detection sensor as defined in Claim 45, further comprising a filter between an illumination source and the focal plane array.

53. A radiation detection sensor as defined in Claim 52, wherein the filter is tunable.

54. A radiation detection sensor as defined in Claim 52, wherein the filter is glass.

55. A radiation detection system as defined in Claim 45, wherein the focal plane array is viewed directly.

56. A radiation detection system as defined in Claim 45, further comprising an illumination source that illuminates the focal plane array.

57. A radiation detection system as defined in Claim 56, wherein the illumination source is tunable to a desired spectrum.

58. A radiation detection system as defined in Claim 56, wherein the illumination source comprises a plurality of controllable sources.

59. A radiation detection system as defined in Claim 58, wherein the plurality of controllable sources are tunable to a desired spectrum.

60. A radiation detection system as defined in Claim 45, wherein the collection optics further comprises a tunable filter.

61. A radiation detection system as defined in Claim 45, wherein the detectors include a thermochromic liquid crystal material.

62. A radiation detection system as defined in Claim 45, further comprising an environmental control unit.

63. A radiation detection system as defined in Claim 34, wherein the environmental control unit operates to maintain the substrate of the focal plane array at a desired temperature.

64. A radiation detection system as defined in Claim 45, further comprising thermal shunts.

65. A radiation detection system as defined in Claim 64, wherein the thermal shunts are located between the substrate and a base of the column.

66. A radiation detection system as defined in Claim 64, wherein the thermal shunts are located between the object that is radiating and the array of radiation detectors.

67. A radiation detection system as defined in Claim 64, wherein the thermal shunt is constructed with a thermoelectric cooler.

68. A radiation detection system as defined in Claim 3664 wherein the thermal shunt is constructed with carbon nanotubes.

69. A radiation detection system, comprising: a focal plane array that includes a substrate and an array of columns protruding from the substrate, wherein a detector is disposed on tops of the columns; collection optics that focus radiation emitted from an object onto the focal plane array; an illumination source configured to illuminate the focal plane array; imaging optics that focus an image of the array of detectors onto an imaging sensor for viewing.

70. A system as defined in Claim 69, further including an image processor configured to accept and analyze an output from the image sensor and generate a command for a controllable radiation source, wherein the command for the controllable radiation source causes the controllable radiation source to output radiation that is directed to the focal plane array and maintains the sensor elements at a predetermined value.

71. A radiation detection system as defined in Claim 69, further comprising a beam splitter configured to pass radiation emitted from the object to the collection optics and to reflect the output radiation from the controllable radiation source to the collection optics.

72. A radiation detection system as defined in Claim 69, further comprising a scanning mechanism to deflect the output radiation from the controllable radiation source across the focal plane array.

73. A radiation detection system as defined in Claim 72, wherein the scanning mechanism is included within the controllable radiation source.

74. A method of detecting radiation emitted from an object; the method comprising: focusing radiation emitted from an object onto a focal plane array, wherein the focal plane array includes a substrate and a plurality of columns protruding from the substrate, wherein detectors are deposed on tops of the plurality of columns so as to produce an array of detectors; and focusing an image of the array of detectors onto an imaging sensor thereby producing an image of the array of detectors.

75. A radiation detection system comprising: means for focusing radiation emitted from an object onto a focal plane array, wherein the focal plane array includes a substrate and a plurality of columns protruding from the substrate, wherein detectors are deposed on tops of the plurality of columns so as to produce an array of detectors; and means for focusing an image of the array of detectors onto an imaging sensor thereby producing an image of the array of detectors.

76. A method of radiation detection comprising: receiving radiated energy from an object; converting the received energy into thermal energy; and imaging the thermal energy to produce a visual thermal energy map of the object.

77. A radiation detection method as defined in Claim 76, further comprising processing the map to produce an enhanced visual image.

78. A radiation detection sensor comprising: a thermal conversion material that converts incident radiation into heat energy; and a plurality of mapping elements each of which receives heat energy from the thermal conversion material and which collectively produces a visual thermal map corresponding to the incident radiation.

79. A radiation detection method as defined in Claim 78, wherein the mapping elements include thermochromic liquid crystal material.

80. A radiation detection system, comprising: a target illumination source that emits radiation that impinges onto a target; a radiation detection sensor comprising a thermal conversion material that converts radiation into heat energy and a plurality of mapping elements each of which receives heat energy from the material; and collection optics that focus radiation emitted from the target onto the radiation detection sensor.

81. A radiation detection system as defined in Claim 80, wherein the target illumination source is tunable.

82. A radiation detection system as defined in Claim 80, wherein the mapping elements include thermochromic liquid crystal material.

83. A radiation detection system as defined in Claim 80, wherein the collection optics further comprises a filter.

84. A radiation detection system as defined in Claim 83, wherein the filter is tunable.

85. A radiation detection system as defined in Claim 80, further including imaging optics that focus an image of the radiation detection sensor onto an imaging sensor.

86. A radiation detection system as defined in Claim 85, further comprising an image processor configured to accept an output from the imaging sensor.

87. A radiation detection system as defined in Claim 86, wherein the image processor analyzes the output of the image sensor and generates a command for a controllable radiation source.

88. A radiation detection system as defined in Claim 87, wherein the command for the controllable radiation source causes the controllable radiation source to output radiation that is directed to the radiation detection sensor and maintains the sensor at a predetermined value.

89. A radiation detection system as defined in Claim 80, wherein the radiation detection sensor is viewed directly.

90. A radiation detection system as defined in Claim 80 further comprising an illumination source that illuminates the radiation detection sensor.

91. A radiation detection system as defined in Claim 90, wherein the illumination source is tunable.

92. A radiation detection system as defined in Claim 90, further comprising a filter between the illumination source and the radiation detection sensor.

93. A radiation detection system as defined in Claim 92, wherein the filter is tunable.

94. A radiation detection system as defined in Claim 92, wherein the filter is glass.

95. A radiation detection sensor as defined in Claim 78, wherein each mapping element comprises a radiation sensitive layer and a thermal conversion material, wherein each mapping element comprises a pixel of the radiation detection sensor and is substantially thermally isolated from other mapping elements.

96. A radiation detection sensor as defined in Claim 95, wherein the radiation sensitive layer and thermal conversion material of each mapping element are disposed on a top surface of a column that protrudes from a top surface of a substrate.

97. A radiation detection sensor as defined in Claim 96, wherein the substrate that supports the mapping elements is planar.

98. A radiation detection sensor as defined in Claim 96, wherein the substrate is constructed of pliable material.

99. A radiation detection sensor as defined in Claim 96, wherein the substrate is configured in a non-planar shape.

100. A radiation detection sensor as defined in Claim 78, wherein the thermal conversion material has high absorptivity and low emissivity.

101. A radiation detection sensor as defined in Claim 78, further comprising thermal elements that are used to control a temperature of the substrate.

102. A radiation detection sensor as defined in Claim 101, wherein the thermal elements comprise thermoelectrical coolers.

103. A radiation detection sensor as defined in Claim 95, further comprising an environmental control unit.

104. A radiation detection sensor comprising a radiation detector on a substrate, wherein the radiation detector is segmented into an array of mapping elements such that individual mapping elements are substantially thermally isolated from each other and comprise pixels of a visual thermal energy map.

105. A radiation detection sensor as defined in Claim 104, wherein the radiation detectors within the array of mapping elements are minimally connected to adjacent radiation detectors.