Patent Application
20180052056
The systems and methods disclosed herein are directed to thermal imaging sensors.
Instruments for detecting and imaging the power of incident electromagnetic radiation, for example thermal or infrared (“IR”) radiation, are becoming increasingly important for a variety of commercial and non-commercial applications. For example, thermal imaging has been used to detect changes in temperature in or across physical constructions such as buildings, bridges, and power lines. In such applications, an increase in temperature may be indicative of impending failure. Similarly, thermal imaging has numerous medical applications, military, surveillance, and other imaging applications.
Various devices exist that may be utilized in an instrument to measure incident electromagnetic radiation. These devices may be implemented in infrared detectors, for example, a thermal imaging camera or bolometer. In such devices, incident electromagnetic radiation may be measured via the heating of a material with a temperature-dependent-electrical resistance (e.g., resistive bolometric sensors), or in some cases with a temperature-dependent structural deformation characteristic (e.g., thermomechanical bolometric sensors). One problem with the existing approaches is that ambient radiation may saturate these conventional bolometers, making it difficult to detect a small change in electromagnetic radiation emitted from an object. Accordingly, it would be advantageous for devices that detect radiation emitted from an object to reduce the effects of the ambient temperatures and thermally isolate the various components of the detectors.
The system, methods, and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein. Combinations of the innovations, aspects, and features described herein can be incorporated in various embodiments of systems, methods, and devices, and such combinations are not limited by the examples of embodiments described herein, including the summary described below.
Some embodiments may include a device for sensing radiation emitted by an object. The device may include a substrate and a movable layer coupled to the substrate. The movable layer can be configured to receive radiation from the object and move relative to the substrate to a position in response to a change in temperature. The device may also include a sensor that is configured to produce a signal responsive to the position of the movable layer. In some embodiments, the signal may be indicative of the radiation emitted by the object.
In some embodiments, the movable layer may include an absorber layer that is configured to absorb infrared radiation. In at least one embodiment, the movable layer may further include a reflector that is at least partially transmissive and partially reflective to visible light. The device may also include a visible light absorber layer between the reflector and the first side of the substrate, and the sensor may include a light sensing element configured to detect an optical signal indicative of the position of the movable layer. The substrate may include a first side and a second side, the second side being positioned proximate to the movable layer and the first side being positioned distal to the movable layer. In another embodiment, either alternatively or in combination, the movable layer may include a conductive layer positioned between the absorber layer and the second side of the substrate. In this embodiment, the sensor may include a conductor on the second side of the substrate and in electrical communication with the conductive layer. The sensor can be configured to produce the signal based on a difference in capacitance as measured between the conductive layer and the sensor.
In some embodiments, the device may also include a frame. The frame may be coupled to the substrate and the movable layer may be coupled to the frame. In various embodiments, the frame may be thermally isolated from the substrate. In other embodiments, alternatively or in combination, the frame may be thermally isolated from the movable layer. In some embodiments, the movable layer may be configured to move relative to the frame in response to radiation emitted by the object, and the frame may be configured to move relative to the substrate in response to ambient radiation incident on the device.
In some embodiments, the device may include one or more beams that each have a first end and a second end. In some embodiments including a frame, the first end of the beams may be coupled to the frame, and the second end of each beam may be coupled to the movable layer. In one embodiment, coupling of the second end of the beam to the movable layer may be configured to conduct thermal energy from the movable layer to the beam. Each beam may be configured to deform in response to a temperature change of the beam. In some embodiments, deforming the beams moves the movable relative to the substrate. In another embodiment, alternatively or in combination, coupling between each beam and the frame may thermally isolate the frame from the coupled beam. In some embodiments, the beams may have a mechanical discontinuity that causes the beam to change the position of the movable layer relative to the substrate in response to the temperature change of the beam.
In some embodiments, the movable layer may include multiple planar structures that are each coupled to one or more of the beams. The planar structures may be arranged in a square-shaped configuration or a triangular-shaped configuration, among other configurations. In some embodiments, the movable layer may include multiple movable layers, and the sensor may be configured to produce a signal responsive to the position of each the movable layers. The device may also be able to save information corresponding to the signals to a memory component. In some embodiments, alternatively or in combination, the frame may include multiple frame elements. Each frame element may correspond to one of the movable layers. In one embodiment, alternatively or in combination, the frame elements and corresponding movable layers may be arranged in a two dimensional array.
According to another aspect, a method for sensing radiation emitted by an object is disclosed. This method may include receiving radiation on a substrate. The method may also include receiving radiation from the object on a movable layer coupled to the substrate. The method may further include producing a signal, by a sensor, responsive to a change in position of the movable layer relative to the substrate in response to a change in temperature. The signal may be indicative of the radiation emitted by the object.
In some embodiments, the movable layer may be coupled to the substrate by a beam. The movable layer may be configured to conduct thermal energy from the movable layer to the beam, causing the beam to deform in response to a change in temperature. The deformation of the beam may cause the movable layer to move relative to the substrate. In one embodiment, alternatively or in combination, the movable layer may be coupled to a frame and the frame may be coupled to the substrate by a hinge configured to isolate the frame from contraction and expansion in the substrate.
According to another aspect, a device for sensing radiation emitted by an object is disclosed. This device may include first means for receiving radiation and second means for receiving radiation. The second means for receiving radiation is coupled to the first means for receiving radiation. The device also includes means for producing a signal responsive to a change in position of the second means for receiving radiation relative to the first means for receiving radiation. The signal may be indicative of the radiation emitted by the object.
The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements.
In the following description, specific details are given to provide a thorough understanding of the examples. However, it will be understood by one of ordinary skill in the art that the examples may be practiced without these specific details. For example, electrical components/devices may be shown in block diagrams in order not to obscure the examples in unnecessary detail. In other instances, such components, other structures, and techniques may be shown in detail to further explain the examples. Combinations of the examples, aspects, and features described herein can be incorporated in the various embodiments of systems, methods, and devices described herein, and such combinations are not limited by the examples of embodiments described herein.
Bolometric sensors may include one or more absorptive elements that absorb radiation. An absorptive element may be, in some embodiments, a thin layer of metal, connected to a thermal reservoir (a body of constant, or near-constant, temperature) through a thermal link. The result of such a configuration is that radiation incident on an absorptive element raises the temperature of the absorptive element above that of the reservoir (the greater the absorbed power, the higher the temperature). The temperature change can be measured directly, for example, with an attached resistor, or the resistance of the absorptive element itself. Thus, as infrared radiation strikes an individual bolometer absorptive element, the element increases in temperature, and its electrical resistance changes. This resistance change is measured and then processed into temperature values that can be represented graphically in an infrared image. However, some bolometers may be unable to detect a small change in temperature at an object where the ambient temperature is high. For example, ambient radiation may raise the temperature of the traditional bolometer to 100°, but the radiation of the object may cause a temperature rise of approximately 0.1° at the detector. Thus, an object may impart a 0.1° temperature change, which for some implementations of a bolometer, may not be detectable by the bolometer because it is currently saturated due to the ambient temperature. To compensate for this, traditional resistive bolometers may include reference pixels along the edges of the sensor array. One non-limiting advantage of the embodiments of thermomechanical bolometers described herein is that the bolometers may be configured for compensation for ambient temperatures at every pixel of the sensor array. Some implementations of thermomechanical bolometers described herein may be useful in automotive or robotic applications where ambient temperatures may be high and the thermomechanical bolometers may be used to detect humans, animals, or other objects emitting temperature changes.
The embodiments disclosed herein describe methods, devices, and systems configured to detect and generate a signal indicative of a temperature difference in an object based on an amount of radiation emitted by the object. The embodiments herein also describe a thermomechanical infrared (“IR”) focal plane array (“FPA”) that may be implemented in an infrared detecting device, for example for use in a thermal imaging camera. In some embodiments, the FPA may include a substrate configured to receive incident radiation and move in response to a temperature change in the substrate due to the received radiation.
In certain embodiments, a device for sensing radiation may also include a frame that is coupled to the substrate on the radiation receiving side of the substrate. The frame may be coupled to the substrate by a connecting structure that permits the frame to move in response to temperature changes in the frame due to the incident radiation. The connecting structure may also isolate, either completely or at least partially, the frame structure from movement of the substrate, for example, due to thermal changes. The frame may be coupled to one or more signal elements comprising one or more movable layers (also referred to as sensing elements throughout the present application) and one or more beams. The movable layer may include a plurality of planar structures that are each coupled to the one or more beams. The beams may couple the one or more movable layers to the frame and may be configured to bend proportionally with a temperature difference between the beam and the frame. The movable layers can be configured to move relative to the frame in response to a temperature change in the one or more movable layers due to incident radiation. The amount that the movable layers move may be based on the bend in the beam and may be representative of a temperature change in the object (e.g., the amount of radiation emitted by the object). In some embodiments, the focal plane array includes a plurality of sensors (which, for example, may each represent a plurality of pixels in a thermal imaging device) that are made up of a combination of one or more of the above components, as described below in the present disclosure. For example, each sensor may include a plurality of movable layers, each movable layer being independently movable relative to each other.
One non-limiting advantage of the embodiments disclosed herein is that the devices may be configured to self compensate to correct for, minimize, or cancel, partially or completely, ambient or background radiation. Ambient or background radiation may be electromagnetic radiation emitted from the environment surrounding an object to be thermally imaged, which may produce ambient temperature fluctuations in or across the components of thermal imaging devices (sometimes referred to as an ambient temperature common mode signal). For example, the frame and movable layer may receive ambient radiation that is similar to such radiation received by the substrate, thereby causing each component to move or expand in response to temperature changes imparted into the components from the radiation. Connections and/or connecting structures may be provided between the various components, as described in the present disclosure, configured to isolate, either thermally or mechanically, the components so as to permit the frame to be at least partially isolated or independent from movement in the substrate due to temperature changes in or across the substrate (sometimes referred to herein as “floating”). Similarly, the signal element may be partially isolated or independent from movement in the substrate, and configured to experience a temperature change due to incident radiation. As described above, the signal element may include one or more movable layers coupled to one or more beams (sometimes referred to as a “buckling beam,” “deformable member,” or the like). In various implementations, the beams may be configured to bend or deflect proportional to the temperature difference between the beam and the frame thereby causing the movable layer to move, where the temperature difference is indicative of the radiation received from the object.
As used herein, the term “move” may refer to a displacement over a distance of a component, or may refer to movement of a material composition of the various components (e.g., that substrate, the frame, the beams, etc.) of the devices described herein. For example, each component may be made up of materials having a coefficient of thermal expansion (CTE) that cause each component to expand, contract, shift vertically or horizontally in real space, or be displaced in relation to the various other components due to temperature changes. Accordingly, the term “move” may also be referred to herein as “displace,” “deform,” “shift,” “deflect,” “bend,” “expand,” “contract,” or the like.
As used herein, the term “bend” or “bent” generally refers to a subset of movement types, as described above. For example, to bend may refer to thermal expansion of a component that causes a first end of the component to move relative to the second end (e.g., a straight component may become a curved component) in response to temperature changes in the component. Accordingly, the term “bend” or “bent” may also be referred to herein as “buckle,” “deform,” “deflect,” or the like.
In various embodiments, FPA 110 may be a thermomechanical IR FPA implemented as an infrared detector. The FPA 110 may comprise a plurality of sensors 115 (which also may be referred to as pixels) disposed in an array arrangement and positioned at the focal plane of the optical element 120. The plurality of sensors 115 may be configured to detect radiation 155 focused thereon and provide an output based on the detected radiation. In some embodiments, the plurality of sensors 115 may be configured to detect a change in temperature indicative of the detected radiation in accordance with the present disclosure. The sensors 115 may have a structure and operation as described herein with reference to the various figures and examples described throughout the present disclosure. In various embodiments, the plurality of sensors 115 may be configured to detect thermal radiation, for example, radiation from the object 150 having a wavelength in the IR spectrum which may be capable of imparting a temperature change to the various components of the FPA 110 as described herein. For example, the plurality of sensors 115 may include one or more movable layers that are independently movable in response to a temperature change, and the sensors 115 may be configured to produce a signal responsive to the position of the each of the movable layers. In other embodiments, the FPA 110 may be configured to detect radiation of any wavelength spectrum based on a temperature change due to said radiation. While
Referring again to
In various embodiments, the sensing circuit 140 may be configured to generate an output indicative of the response of each of the sensors 115 due to the radiation from object 150. For example, incident radiation or changes in temperature from the object 150 may be read directly via an optical readout, as schematically illustrated in
In the illustrated embodiment, the substrate 220 has a first and second side 222 and 224, respectively. In some embodiments, one or both sides may be planar. As illustrated in
As schematically illustrated in
In some embodiments, the frame 230 comprises a material composition configured to permit thermal expansion along the body of the frame 230, and the connecting structures 201 may be a flexible connecting structures or connection means (e.g., a hinge, a pin-type connector, or the like) configured to at least partially isolate the substrate 220 from the frame 230 (e.g., at least partially mechanically isolate the frame 230 from the substrate 220). For example, radiation may be incident on the frame 230 and the substrate 220, thereby causing the components to either expand or contract based on their corresponding CTE. The connecting structures 201 may be configured to allow the frame 230 to move, away from or towards the substrate 220 based on the thermal expansion of the frame 230. In some embodiments, the frame may move in a direction substantially perpendicular to the substrate 220. At least in part due to the connecting structures 201, the frame 230 may be at least partially isolated from movement in the substrate 220. Thus, the movement of frame 230 may be partially or fully independent of movement in the substrate 220. Therefore, in some embodiments, the connecting structure 201 may be at least one means partially isolating the frame 230 from the substrate 220. In some implementations, such isolation may be one means for compensating for or minimizing the ambient temperature common mode signal imparted onto the substrate. Therefore, in some embodiments, such isolation of the frame 230 from substrate 220 may represent at least one means for at least partially isolating.
In some embodiments, the material of the frame 230 is selected to have a high CTE corresponding to a high thermal expansion and contraction dependent on incident radiation. For example, a relatively high CTE may be approximately equal to or greater than 20 parts per million per degree Celsius. In some embodiments, the CTE of the material of the frame 230 may be approximately equal to or greater than 50 ppm/° C. In some embodiments, the material composition of frame 230 is selected have a high thermal expansion relative to the substrate 220. In some embodiments, the material composition of frame 230 may include polymers (e.g., SU-8, polyimide, polystyrene, etc.). In other embodiments, either in the alternative or in combination, the material of the frame 230 may have a relatively low thermal conductivity.
In various implementations, the beam 240 is an elongated beam having a length longer than its width. In some embodiments, the beam 240 comprises a material composition configured to permit thermal expansion along the body of the beam 240. The material composition of the beam 240 may be configured to permit the beam 240 to bend in a direction substantially perpendicular to the second side 224 of the substrate 220 in response to temperature changes in or across the beam 240 due to incident radiation. In some embodiments, the beam 240 may be made of a single material configured to permit bending, however, this need not be limiting. In some embodiments, the beam 240 may be configured to bend in response a temperature difference between the beam 240 and the frame. For example, as described above, incident radiation may be received by the frame 230, which moves in response to a temperature change. Similarly, the beam 240 receives the same incident radiation, but is configured to absorb radiation emitted from an object. The absorbed radiation may cause the beam 240 to bend, as illustrated in
In some embodiments, beam 240 may be coupled to the frame 230 by a connector 205 configured to isolate the beam 240 from the temperature change in the frame 230. For example, the beam 240 may have a first region 242 and a second region 244; the first region may be coupled to the frame 230 by the connector 205. The connector 205 may be configured to thermally isolate the beam 240 from the frame 230. Incident radiation or a portion thereof may be received by the beam 240 causing the material of the beam 240 to expand or contract based on its corresponding CTE, which causes beam 240 to bend as shown as bent beam 245. The connectors 205 may be configured to allow the beam 240 to bend, away from or towards the frame 230, in a direction substantially perpendicular to the second side 224 of the substrate 220. As the beam 240 bends, a gap 260 may be formed between the second region 244 and the frame 230 or the substrate 220. The gap 260 may be indicative of radiation emitted by an object and based on the temperature difference between the beam 240 and the frame 230. In some embodiments, the connector 205 may be a connection point that is narrow relative to the beam 240 and/or frame 230. In another embodiment, alternatively or in combination, the connector 205 may be made of a material that has a CTE that is low relative to the beam 240 and/or frame 230, for example but not limited to, silicon dioxide and/or polymers.
In some embodiments, the material of the beam 240 is selected to have a high CTE. For example, a relatively high CTE may be approximately equal to or greater than 20 ppm/° C. In some embodiments, the CTE of the material of the beam 240 may be approximately equal to or greater than 50 ppm/° C. In some embodiments, the material composition of beam 240 is selected to be the same as frame 230. In some embodiments, the material composition of beam 240 may include polymers (e.g., SU-8, polyimide, polystyrene, etc.). In some embodiments, the beam 240 may be thin and narrow as compared to the frame 230, which, without subscribing to any particular scientific theory, may produce improved thermal isolation between the frame 230 and beam 240. Accordingly, as the beam 240 experiences a temperature change based on the received radiation, the beam may bend proportionally with the temperature difference with respect to the frame 230 (e.g., the bent beam 245). In other embodiments, either in the alternative or in combination, the material of the beam 240 may have a relatively low thermal conductivity.
Sensor 315 may be configured to be substantially similar to the sensors disclosed in the present disclosure (e.g., sensors 115 of
Returning to
In some embodiments, the substrate 320 may be substantially similar to the substrate 220 of
As illustrated in
The sensor 315 also comprises the connecting structure 301a-301d. The connecting structure 301a-301d may be substantially similar to the connecting structure 201 of
In the embodiment of
In some embodiments, each beam 340 may include a mechanical discontinuity 345 positioned along the length of the corresponding beam 340. In some embodiments, the mechanical discontinuity 345 may be a preferred location for bending the beam 340 in a specific direction. In some embodiments, the mechanical discontinuity may be a step or kink formed within the beam 340. In another embodiment, alternatively or in combination, the mechanical discontinuity may be a change in thickness at a preferred location, either an increase or decrease in thickness as needed to impart the desired bending effect. While
The mechanical discontinuity 345 (illustrated as mechanical discontinuity 345a, 345b, 345c, and 345d) may be an asymmetrically positioned along the body of the beam 340. For example, as depicted in
In the embodiment of sensor 315 depicted in
As described above, the frame 330 may be mechanically isolated from the substrate 320 via connecting structure 301, which permits the frame 330, beams 340, and sensing elements 350 to move at least partially independent of the movement in the substrate 320. The various components may move, expand, or contract freely from movement in the substrate due to temperature changes in the substrate 320. Thus, the connecting structure 301 may be one means for minimizing, partially or full cancelling, or partially or fully compensating for thermal expansion in the substrate 320 due to the ambient radiation. In some embodiments, because the frame 330 and beams 340 experience the same ambient radiation, they may move due to said ambient radiation in the same or similar manner depending on their corresponding material composition. The sensing elements 350 may then collect incident radiation and channel the thermal energy into the beams 340 such that the beams 340 bend relative to the frame 330 and/or substrate 320. The bending of the beams 340 may be proportional to the temperature difference between the frame 330 and beams 340. The sensing elements 350 may be displaced based on the bending of the beams, thereby forming the gap 360. The sensing element 350 may be configured to produce an output, based on the gap 360, indicative of the temperature difference between the beams 340 and the frame 330. Accordingly, the gap 360 may be indicative of a temperature difference across the object and an amount of radiation emitted by the object.
In some embodiments, the sensor 315 may be manufactured through the use of methods and procedures useful for manufacturing microelectromechanical systems. For example, the various components, elements, wires, electrical connections, layers, and materials described throughout the present disclosure may be deposited (e.g., physical vapor deposition, chemical deposition, etc.), sputtered, patterned, etched, etc. so as to form the components in accordance with the embodiments disclosed here. For example, as illustrated in
In some embodiments, the sensing elements 450 (e.g., 450a and 450c) may comprise a stacked structure as illustrated in
In some embodiments, the absorber layer 454 may be positioned so as to receive radiation, while the reflective layer 456 maybe configured to reflect visible radiation in a direction toward the substrate 320 to facilitate an optical readout of the detected IR radiation via an IMOD effect. The reflective layer 456 may be may be positioned on a readout side (e.g., readout side 226 of
In some embodiments, the reflected light may be received at the reflective layer 456 from a light source (not shown). In some embodiments, the light source may emit light in the visible, infrared, or any spectral range. In some embodiments, the light source may be the surrounding environment or a front lighting system (e.g., optional illumination system 130 of
In some embodiments, the absorber 460 may be configured to absorb visible light reflected by the reflective layer 456. In some embodiments, the absorber 460 may be made of a material comprising molybdenum, a chrome alloy, vanadium, etc. The material may be selected so as to absorb the light (visible or otherwise) reflected from the reflective layer 456. While the absorber 460 is described as absorbing visible light, this need not be limiting and absorber 460 may be configured to absorb radiation of any spectral bandwidth range. For example, in some situations the reflective layer 456 may reflect any spectral bandwidth (e.g., IR, UV, etc.) and the absorber may be configured to absorb such reflected light.
In some embodiments, the first and second layers 452 and 458 may comprise a material composition of a polymer, which may be the same or different for each of the first and second layers 452 and 458. The material of the first layer 452 may be selected to be transmissive to IR radiation, and the material of the second layer 458 may be selected to be transmissive to visible radiation. In some embodiments, the absorber layer 454 may be an IR radiation absorbing layer, and may comprise a material composition of at least one of a carbon and nitride materials configured to absorb incident IR radiation. In some embodiments, the absorber layer 454 may be made of carbon. In another embodiment, alternatively or in combination, the absorber layer 454 may be a silicon nitride. Other materials are possible. The reflective layer 456 may be at least partially transmissive to visible light and partially reflective to visible light. In another embodiment, the reflective layer 456 may be substantially reflectively to visible light. In some embodiments, the reflective layer 456 may comprise a material composition including a reflective metal. For example, but not limited to, aluminum, gold, or silver metals may be used as for the reflective layer 456. In some embodiments, the sensing elements 450 may be mechanically symmetric to remain flat at operating temperatures. The absorber layer 454 may be configured to operate in resonant or broadband absorption. The sensing elements 450 may have a surface area that is larger than the beams 340 and frame 330, thereby absorbing a larger amount of incident radiation that may then be transferred as heat to other components of the sensor 315. In various embodiments, as described above, the various layers of the sensing element 450 may have a thickness selected to minimize bending of the absorber layer 454 and reflective layer 456 due to thermal expansion or other external effects. Without subscribing to any particular scientific theory, it is believed that by selecting an appropriate thickness for one or more of the layers of the sensing element 450, the bimetallic bending effects may be reduced and improve accuracy and consistency of the sensor 315.
In one implementation, the various layers of the sensing element 450 may have thickness between 2 nanometers and 1000 nanometers. For example, the absorber layer 454 may have a thickness between 50 nanometers and 1000 nanometers. The reflective layer 456 may have a thickness between 50 nanometers and 1000 nanometers. The absorber 460 may have a thickness between 2 nanometers and 20 nanometers. While specific examples are provided herein, these are not intended to be limiting, and any thickness may be applicable.
While
In some embodiments, the sensing elements 450 may be operatively coupled to a sensing circuit (not shown) disposed on the first side 322 of the substrate 320 (e.g., sensing circuit 140 of
One non-limiting advantage of the FPA 310 comprising a plurality of sensors 315 including the sensing elements 450 as described herein, is that the FPA 310 may provide improved thermal isolation amongst the components of a thermal imaging camera, because the need for electrical connections to detect resistive differences (e.g., as in conventional bolometers) to measure incident radiation is removed. For example, the sensing elements 450 are configured to provide a direct optical readout indicative of the incident radiation emitted from an object. However, in some embodiments, an electrical circuit based sensing element may be possible through utilizing capacitive sensing, as shown in
In the embodiment illustrated in
While
In some embodiments, the sensing elements 550 may be implemented in sensor 315 as schematically illustrated in
In one embodiment, the sensing circuit 540 includes at least one source 542, connected to a switch S1 at the positive terminal of source 542, which may be connected to a first node N1, and ground G at the negative terminal of source 542. A capacitor C1 may be connected to the node N1 and a switch S2. The switch S2 may be connected to a node N2 so as to be connected to a negative terminal of an amplifier 545 and to the first conductor portion 562, as illustrated in
Referring to
The sensing elements 650 may be substantially similar to the sensing elements 350, except as provided in reference to
As illustrated in
In the embodiment of
In some embodiments, each beam 640 may include a mechanical discontinuity 645 positioned along the length of the corresponding beam 640. The mechanical discontinuity 645 may be substantially similar to mechanical discontinuity 345 of
In some embodiments, the connecting structure 601 may be substantially similar to the connecting structure 601 of
For example, radiation may be incident on the substrate 620 and the frame 630, resulting in movement and or thermal expansion of the substrate 620 and frame 630. However, thermal expansion of the frame 630 may be isolated from the thermal expansion of the substrate 620 via connection structure 301. Accordingly, the frame 630 may be permitted to move, expand, or contract, based on its CTE, freely or independent of the movement in the substrate 620. In the embodiment of
In the embodiment of sensor 615 depicted in
As described above, the beams 640 may be mechanically isolated from the substrate 620 via connecting structure 601, which permits the frame 630, beams 640, and sensing elements 650 to move at least partially independent of the movement in the substrate 620. The various components may move, expand, or contract freely from movement in the substrate due to temperature changes in the substrate 620. Thus, the connecting structure 601 may be one means for minimizing, partially or full cancelling, or partially or fully compensating for thermal expansion in the substrate 620 due to the ambient radiation. In some embodiments, because the frame 630 and beams 640 experience the same ambient radiation, they may move due to said ambient radiation in the same or similar manner depending on their corresponding material composition. The sensing elements 650 may then collect incident radiation and channel the thermal energy into the frame 630 and the beams 640 may bend relative to the frame 630 and/or substrate 620 due to incident radiation. The bending of the beams 640 may be proportional to the temperature difference between the frame 630 and beams 640. The sensing elements 650 may be displaced based on the bending of the beams, thereby forming the gap 660. The sensing element 650 may be configured to produce an output, based on the gap 660, indicative of the temperature difference between the beams 640 and the frame 630. Accordingly, the gap 660 may be indicative of a temperature difference across the object and an amount of radiation emitted by the object.
In some embodiments, the substrate 720 may have a first and second side 722 and 724, respectively. In some embodiments, one or both sides may be planar. As illustrated in
As schematically illustrated in
In some embodiments, the one or more first beams 701 may have a first end 709 connected to a connection region 725 of the substrate 720 and a second end 708 coupled to the frame 730 by a connector 707. In some embodiments, the connector 707 comprises a flexible, rotatable, or otherwise movable connection type (e.g., a pin-type connection that permits movement within the connection). In some embodiments, the first end 709 is connected to the connection region 725 by a fixed connection (e.g., a fixed type connection). The first beam 701 may be a connection means (e.g., a hinge, a bi-morph hinge, or the like) configured to at least partially isolate the frame 730, and sensors 715 thereon, from the substrate 720 (e.g., at least partially mechanically isolate the frame 730 from the substrate 720). For example, radiation may be incident on the frame 730 and the substrate 720, thereby causing the components to either expand or contract based on their corresponding CTE. The first beams 701 may be configured to allow the frame 730 to move through the gap 780, away from or towards the substrate 720 based on the thermal expansion of the frame 730 and/or first beams 701. At least in part due to the first beams 701, the frame 730 may be configured to counteract or minimize movement with respect to the substrate 720 due to ambient temperature (e.g., the common mode ambient temperature changes). Therefore, in some embodiments, the first beam 701 may be at least one means partially isolating the sensors 715 from the substrate 720. In some embodiments, isolation of the frame 730 from substrate 720 may represent at least one means for at least partially isolating the sensors 715 from the common mode ambient temperature change.
In some embodiments, the first beam 701 may include two (or more) materials, referred to as a bi-material composition, which is configured to permit thermal expansion along the body of the first beam 701, which causes the first beam 701 to bend. For example, a hinge may include two materials, each of the materials having a different coefficient of thermal expansion which cause it to bend when the material changes temperature (e.g., a bi-morph hinge). In some embodiments, the first beam 701 comprises multiple materials selected to have high thermal mismatch. For example, first beam 701 may comprise a first material 703 and a second material 704 having different material composition so as to induce bending in response to a temperature change based on the difference in their respective CTEs. In some embodiments, the first and second material 703 and 704, respectively, may be selected to be one of a metal and oxide, a metal and polymer, or an oxide and a polymer. In some embodiments, using an oxide and a polymer may provide a high thermal mismatch while also providing low thermal conduction between the materials. It will be understood that material 703 or 704 may be a metal, oxide, or polymer as needed to provide the desired direction of the bend in the first beam 701. Example materials, not intended to be limiting, may include silicon dioxide, aluminum, and polymers such as SU-8, polyimide, polystyrene, etc. In some embodiments, the first and second material 703 and 704 may be arranged in a planar stacked arrangement (e.g., layered with a first material 703 stacked on top of the second material 704) or a corrugated arrangement. Other arrangements are possible, such that the high thermal mismatch between the first and second material causes a bend in the beam 701 when exposed to a temperature change.
In some embodiments, the first beam 701 may be thin and narrow as compared to the frame 730 and sensor 715, which, without subscribing to any particular scientific theory, may produce improved thermal isolation between the frame 730 and substrate 720. Accordingly, as the first beam 701 experiences a temperature change based on the received radiation, the first beam 701 may bend proportionally with the temperature difference with respect to the frame 730 and substrate 720. In other embodiments, either in the alternative or in combination, the material of the beam 701 may have a relatively low thermal conductivity (e.g., polymers and/or oxides in some embodiments).
In some embodiments, the material composition of the first beams 701 may be configured to permit the first beams 701 to bend in a direction substantially perpendicular to the second side 724 of the substrate 720 in response to temperature changes in or across the first beam 701 due to incident radiation. For example, as described above, incident radiation may be received by the first beam 701 causing a temperature change in the first beam 701, which may cause the beam 701 to bend based on the thermal mismatch of material 703 and 704 in response to the temperature change. The first beams 701 may be configured to bend relative to the substrate 720 in an amount that is proportional to, and counteracts or minimizes the, common mode ambient temperature changes. Therefore, the first beams 701 may represent at least one example of a bending means.
In some embodiments, a plurality of sensors 715 may be disposed on the second side 732 of frame 730 having a gap 760 between the sensors 715 and second side 724 of substrate 720 and a gap 765 between the sensors 715 and the second side 734 of the frame 730. The plurality of sensors 715 may be arranged in an array or grid-like pattern, as described above and may operate in a substantially similar manner as described in connection with sensor 115, except as described in the following description with reference to
In some embodiments, the second beams 740 comprise a first end 742 connected to the frame 730 via a connector 705 and a second end 744 connected to the sensor 715. In some embodiments, the connector 705 is flexible, rotatable, or otherwise movable connection type (e.g., a pin-type connection that permits movement within the connection). In some embodiments, the second end 744 is connected to the sensor 715 by a fixed connection (e.g., a fixed type connection). The second beams 740 may be a connection means (e.g., a hinge, a bimorph hinge, or the like) configured to move or deflect the sensors 715 in response to a temperature change in second beams 740. For example, radiation may be incident on the second beams 740 and the sensor 715, thereby causing the components to either expand or contract based on their corresponding CTE. The second beams 740 may be configured to allow the sensor 715 to move through gap 765, away from or towards the frame 730 based on the thermal expansion of the sensor 715 and/or second beams 740. The gap 765 may be indicative of an amount of radiation emitted from an object being imaged (e.g., radiation 155 from object 150 of
In some embodiments, the sensor 715 may be operatively coupled to a sensing circuit (e.g., sensing circuit 140 of
In some embodiments, the second beams 740 are similar to the first beams 701. In some embodiments, the second beams 740 may comprise a bi-material composition (e.g., a bi-morph hinge) configured to permit thermal expansion along the body of the second beams 740, which causes the second beams 740 to bend. In some embodiments, the second beam 740 comprises multiple materials selected to have high thermal mismatch, as described above with reference to the first beam 701. In some embodiments, the second beam 740 may comprise the same materials as the first beam 701. However, this need not be the case, and a first material 745 and second material 749 of second beam 740 may be different than that of the first beam 701. In some embodiments, the second beam 740 may be thin and narrow as compared to the frame 730 and sensor 715, which, without subscribing to any particular scientific theory, may produce improved thermal isolation between the frame 730 and sensor 715. Accordingly, as the second beam 740 experiences a temperature change based on the received radiation, the beam may bend proportionally with the temperature difference with respect to the frame 730 and sensor 715. In other embodiments, either in the alternative or in combination, the material of the second beam 740 may have a relatively low thermal conductivity (e.g., polymers and/or oxides in some embodiments).
In some embodiments, the material composition of the second beams 740 may be configured to permit the second beam 740 to bend in a direction substantially perpendicular to the second side 724 of the substrate 720 in response to temperature changes in or across the second beam 740 due to incident radiation. For example, as described above, incident radiation may be received by the second beams 740 causing a temperature change in the second beams 740, which may cause the second beam 740 to bend based on the thermal mismatch of material 745 and 749 in response to the temperature change. The second beam 740 may be configured to bend relative to the frame 730 in an amount that is proportional to the temperature difference between the frame 730 and the second beam 740. The distance that second beams 740 bends may be indicative of the temperature change across the object. Therefore, the second beam 740 may represent at least one example of a bending means.
In some embodiments, the connector 705 may be configured to isolate the second beam 740 from the temperature change in the frame 730. For example, the beam 740 may have a first end 742 and a second end 744; the first end 742 may be coupled to the frame 730 by the connector 705 and the second end may be coupled to the sensor 715. The second beam 740 may be configured to thermally isolate the sensor 715 from the frame 730. In some embodiments, a relatively high thermal isolation between the sensor 715 and frame 730 may generate temperature variations across the array of sensors 715 for thermal images that are produced. Incident radiation or a portion thereof may be received by the second beams 740 causing the material of the second beam 740 to expand or contract based on its corresponding CTE, which causes second beam 740 to bend. The connectors 705 may be configured to allow the second beam 740 to bend, away from or towards the frame 730, in a direction substantially perpendicular to the second side 724 of the substrate 720. As the beam 740 bends, the gap 765 and gap 760 may be formed between sensor 715 and the frame 730 and the substrate 720, respectively. The gap 765 or 760 may be indicative of radiation emitted by an object and based on the temperature difference between the beam 740 and the frame 730. In some embodiments, gap 760 is indicative of radiation emitted by an object after compensating for the common mode temperature.
Sensors 815 are configured to be substantially similar to the sensors disclosed in the present disclosure (e.g., sensors 715 of
Returning to
Each sensor 815 may comprise one or more movable layers 850 coupled to the second side 834 of frame 830 by a plurality of second beams 840. Each of the second beams 840 may include a first end 842 connected to the second side 834 of the frame 830 by a connector 805 and a second end 844 coupled to the movable layer 850 via second end 844. The movable layers 850 may be substantially similar to the movable layers and sensing elements disclosed throughout the present disclosure (e.g., sensing elements 450 and 550 of
In some embodiments, the substrate 820 may be substantially similar to the substrate 720 of
As illustrated in
In some embodiments, the frame 830 is coupled to the second side 824 of the substrate 820 by one or more first beams 801. The first beams 801 may be substantially similar to the first beams 701 of
In the embodiment of
Each second beam 840 may comprise a first end 842 and a second end 844, where the first end 842 is coupled to the frame 830 by a connector 805. In some embodiments, the connector 805 may connect to a connection region 811 on the second side 834 of the frame 830. The connector 805 may be substantially similar to connector 705 of
In the embodiment, each sensor 815 includes one or more movable layers 850. In some embodiments, the movable layer 850 may be thermally coupled to the second end 844 of one or more beams 840 to thermally conduct heat absorbed by the movable layer to the beams 840. As illustrated in
As described above, the frame 830 may be isolated from the substrate 820 via the first beam 801, which permits the frame 830, the second beams 840, and movable layers 850 to move at least partially independent of the movement in the substrate 820. The various components may move, expand, or contract freely from movement in the substrate 820 due to temperature changes in the substrate 820. For example, the movable layers 850 may collect incident radiation and channel the thermal energy into the second beams 840 such that the second beams 840 bend relative to the frame 830 and move the movable layers 850 through gap 865. The first beams 801 may also experience a temperature change causing them to bend relative to the substrate 820 and move the frame 830, in a substantially opposite direction than the movement in the movable layer 850, relative to the substrate 820 and through gap 880 (e.g., as illustrated in
In various embodiments, the thermal imaging device 900 may be a computer, cell phone, digital camera, tablet computer, personal digital assistant, or the like. In some embodiments, the thermal imaging device 900 may be included in a robot, automotive vehicle (e.g., self-driving vehicles or vehicles driven by a user), unmanned aerial vehicles (UAVs), or the like. A plurality of imaging applications may be available to the user on thermal imaging device 900. These applications may include traditional photographic and video applications, high dynamic range imaging, panoramic photo and video, stereoscopic imaging such as 3D images or 3D video, or multispectral imaging, to name a few. The thermal imaging device 900 as illustrated includes the thermal imaging sensor 910 for capturing external images. The thermal imaging sensor 910 may include various components that are not explicitly shown in
The image processor 942 may be configured to perform various processing operations on received image data including a number of images of the image scene in order to output an accurately aligned image set, as will be described in more detail below. Image processor 942 may be a general purpose processing unit or a processor specially designed for imaging applications. Examples of image processing operations include cropping, scaling (e.g., to a different resolution), image stitching, image format conversion, color interpolation, color processing, image filtering (e.g., spatial image filtering), lens artifact or defect correction, etc. Image processor 942 may, in some embodiments, comprise a plurality of processors. Certain embodiments may have a processor dedicated to each image sensor. Image processor 942 may be one or more dedicated image signal processors (ISPs) or a software implementation of a processor.
Image processor 942 is connected to a memory 950 and the working memory 946. In the illustrated example, the memory 950 stores thermal sensor processing information module 952 and operating system module 954. These modules include instructions that configure the image processor 942 and/or device processor 944 to perform various image processing and device management tasks. Working memory 946 may be used by image processor 942 to store a working set of processor instructions contained in the modules of memory 950. Alternatively, working memory 946 may also be used by image processor 942 to store dynamic data created during the operation of thermal imaging device 900.
Operating system module 954 may configure the image processor 942 to manage the working memory 946 and the processing resources of the thermal imaging device 900 for various operational tasks. For example, operating system module 954 may include device drivers to manage hardware resources such as the thermal imaging sensor 910. Therefore, in some embodiments, instructions contained in the image processing modules discussed above may not interact with these hardware resources directly, but instead interact through standard subroutines or APIs located in operating system module 954. Instructions within operating system module 954 may then interact directly with these hardware components. Operating system module 954 may further configure the image processor 942 to share information with device processor 944.
Device processor 944 may be configured to control the display 920 to display the captured image, or a preview of the captured image, to a user. The display 920 may be external to the thermal imaging device 900 or may be part of the thermal imaging device 900. The display 920 may also be configured to provide a view finder displaying a preview image for a use prior to capturing an image, or may be configured to display a captured image stored in memory or recently captured by the user. The display 920 may comprise, for example, an LCD or LED screen, and may implement touch sensitive technologies.
Device processor 944 may write data to storage module 960, for example data representing captured images, image alignment data, intensity value data, measured voltages, and the like. While storage module 960 is represented graphically as a traditional disk device, those with skill in the art would understand that the storage module 960 may be configured as any storage media device. For example, the storage module 960 may include a disk drive, such as a floppy disk drive, hard disk drive, optical disk drive or magneto-optical disk drive, or a solid state memory such as a FLASH memory, RAM, ROM, and/or EEPROM. The storage module 960 can also include multiple memory units, and any one of the memory units may be configured to be within the thermal imaging device 900, or may be external to the thermal imaging device 900. For example, the storage module 960 may include a ROM memory containing system program instructions stored within the thermal imaging device 900. The storage module 960 may also include memory cards or high speed memories configured to store captured images which may be removable from the thermal imaging device 900.
Although
Example Method of Sensing Radiation from an Object
The method 1000 begins at start block 1005 and then moves to block 1010, where radiation is received on a substrate. In some embodiments, the substrate may comprise a first and second side, wherein the second side may be configured to receive incident radiation. The substrate may be substantially similar to the various substrates described in the present disclosure (e.g., substrate 220 of
After, or while, the radiation is received by the substrate, the method 1000 moves to block 1020 where radiation is received on at least one movable layer. In some embodiments, the at least one movable layer receives radiation at least partially from an object. In some embodiments, the at least one movable layer is part of multiple movable layers included in a signal element, for example, as described in the present disclosure in reference to
After the radiation is received by the at least on moveable layer, the method 1000 moves to block 1030 where a signal is produced in response to a change in temperature in the movable layer. For example, the signal may be produced responsive to the position of the at least one movable layer in response to a change in temperature in the movable layer. In some embodiments, the signal may be produced by a sensor, a signal element, and/or one or more movable layers, as described throughout the present application. In some embodiments, the signal may be indicative of the radiation emitted by the object. For example, the signal may be indicative of the response of the sensing element and/or each of the movable layers independently moving in response to received radiation. In some embodiments, the signal may be received by a sensing circuit (e.g., sensing circuits, 140, 440, and/or 540 of
In some embodiments, the moveable layer is moved to the position in response to a change in temperature, for example, in the moveable layer. In another embodiment, alternatively or in combination, the moveable layer may be coupled to one end of a beam, a second end of the beam coupled to the frame, and thermal energy in the at least one moveable layer from the radiation may be conducted into the beam. The beam may be substantially similar to the various beams described in the present disclosure (e.g., beams 240 of
Implementations disclosed herein provide systems, methods, and apparatus for actively and optimally aligning an optical system during assembly. One skilled in the art will recognize that these embodiments may be implemented in hardware, software, firmware, or any combination thereof.
Those having skill in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and process steps described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. One skilled in the art will recognize that a portion, or a part, may comprise something less than, or equal to, a whole. For example, a portion of a collection of pixels may refer to a sub-collection of those pixels.
In some embodiments, the circuits, processes, and systems discussed above may be utilized in a wireless communication device. The wireless communication device may be a kind of electronic device used to wirelessly communicate with other electronic devices. Examples of wireless communication devices include cellular telephones, smart phones, Personal Digital Assistants (PDAs), e-readers, gaming systems, music players, netbooks, wireless modems, laptop computers, tablet devices, etc.
The wireless communication device may include one or more image sensors, two or more image signal processors, a memory including instructions or modules for carrying out the CNR process discussed above. The device may also have data, a processor loading instructions and/or data from memory, one or more communication interfaces, one or more input devices, one or more output devices such as a display device and a power source/interface. The wireless communication device may additionally include a transmitter and a receiver. The transmitter and receiver may be jointly referred to as a transceiver. The transceiver may be coupled to one or more antennas for transmitting and/or receiving wireless signals.
The wireless communication device may wirelessly connect to another electronic device (e.g., base station). A wireless communication device may alternatively be referred to as a mobile device, a mobile station, a subscriber station, a user equipment (UE), a remote station, an access terminal, a mobile terminal, a terminal, a user terminal, a subscriber unit, etc. Examples of wireless communication devices include laptop or desktop computers, cellular phones, smart phones, wireless modems, e-readers, tablet devices, gaming systems, etc. Wireless communication devices may operate in accordance with one or more industry standards such as the 3rd Generation Partnership Project (3GPP). Thus, the general term “wireless communication device” may include wireless communication devices described with varying nomenclatures according to industry standards (e.g., access terminal, user equipment (UE), remote terminal, etc.).
The functions described herein may be stored as one or more instructions on a processor-readable or computer-readable medium. The term “computer-readable medium” refers to any available medium that can be accessed by a computer or processor. By way of example, and not limitation, such a medium may comprise RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. It should be noted that a computer-readable medium may be tangible and non-transitory. The term “computer-program product” refers to a computing device or processor in combination with code or instructions (e.g., a “program”) that may be executed, processed, or computed by the computing device or processor. As used herein, the term “code” may refer to software, instructions, code or data that is/are executable by a computing device or processor.
The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.
It should be noted that the terms “couple,” “coupling,” “coupled” or other variations of the word couple as used herein may indicate either an indirect connection or a direct connection. For example, if a first component is “coupled” to a second component, the first component may be either indirectly connected to the second component or directly connected to the second component. As used herein, the term “plurality” denotes two or more. For example, a plurality of components indicates two or more components.
The term “determining” encompasses a wide variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” can include resolving, selecting, choosing, establishing, and the like.
The phrase “based on” does not mean “based only on,” unless expressly specified otherwise. In other words, the phrase “based on” describes both “based only on” and “based at least on.”
Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements or steps. Thus, such conditional language is not generally intended to imply that features, elements or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. In addition, the articles “a,” “an,” and “the” as used in this application and the appended claims are to be construed to mean “one or more” or “at least one” unless specified otherwise.
As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: A, B, or C” is intended to cover: A, B, C, A and B, A and C, B and C, and A, B, and C. Conjunctive language such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be at least one of X, Y or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y and at least one of Z to each be present.
In the foregoing description, specific details are given to provide a thorough understanding of the examples. However, it will be understood by one of ordinary skill in the art that the examples may be practiced without these specific details. For example, electrical components/devices may be shown in block diagrams in order not to obscure the examples in unnecessary detail. In other instances, such components, other structures and techniques may be shown in detail to further explain the examples.
Headings are included herein for reference and to aid in locating various sections. These headings are not intended to limit the scope of the concepts described with respect thereto. Such concepts may have applicability throughout the entire specification.
It is also noted that the examples may be described as a process, which is depicted as a flowchart, a flow diagram, a finite state diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel, or concurrently, and the process can be repeated. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a software function, its termination corresponds to a return of the function to the calling function or the objective function.
The previous description of the disclosed implementations is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these implementations will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the implementations shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
