Microbolometer systems and methods for mitigating electrostatic pull-in

Abstract

Techniques are provided for facilitating electrostatic pull-in mitigation for microbolometer systems and methods. In one example, an infrared imaging device includes a readout circuit having a surface defining a plane. The infrared imaging device further includes a microbolometer coupled to the readout circuit. The microbolometer includes a bridge suspended above and parallel to the readout circuit's surface in a direction substantially perpendicular to the plane. The bridge includes a first bridge contact and a second bridge contact. The infrared imaging device further includes a first reflective layer readout circuit's surface and between the bridge and the readout circuit. The first bridge contact and the second bridge contact are associated with and suspended above only the first reflective layer and the second reflective layer, respectively, in the direction. Related methods and systems are also provided.

Description

P230044-723-W001 Docket No. 70052.2056W001MICROBOLOMETER SYSTEMS AND METHODS FOR MITIGATING ELECTROSTATIC PULL-INMarin Sigurdson and George D. SkidmoreCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 645,774 filed May 10, 2024 and entitled “MICROBOLOMETER SYSTEMS AND METHODS FOR MITIGATING ELECTROSTATIC PULL-IN,” which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] One or more embodiments relate generally to infrared imaging systems and more particularly, for example, to microbolometer systems and methods for mitigating electrostatic pull-in.BACKGROUND

[0003] Imaging systems may include an array of detectors arranged in rows and columns, with each detector functioning as a pixel to produce a portion of a two-dimensional image. For example, an individual detector of the array of detectors captures an associated pixel value. There are a wide variety of image detectors, such as visible-light image detectors, infrared image detectors, or other types of image detectors that may be provided in an image detector array for capturing an image. As an example, a plurality of sensors may be provided in an image detector array to detect electromagnetic (EM) radiation at desired wavelengths. In some cases, such as for infrared imaging, readout of image data captured by the detectors may be performed in a time-multiplexed manner by a readout integrated circuit (ROIC). The image data that is read out may be communicated to other circuitry, such as for processing, storage, and / or display. In some cases, a combination of a detector array and an ROIC may be referred to as a focal plane array (FPA). Advances in process technology for FPAs and image processing have led to increased capabilities and sophistication of resulting imaging systems.P230044-723-W001 Docket No. 70052.2056W001SUMMARY

[0004] In one or more embodiments, an infrared imaging device includes a readout circuit having a surface defining a plane. The infrared imaging device further includes a microbolometer coupled to the readout circuit. The microbolometer includes a bridge suspended above and parallel to the surface of the readout circuit in a direction substantially perpendicular to the plane. The bridge includes a first bridge contact and a second bridge contact. The infrared imaging device further includes a first reflective layer disposed on the surface of the readout circuit and disposed between the bridge and the readout circuit. The infrared imaging device further includes a second reflective layer adjacent to the first reflective layer and disposed on the surface of the readout circuit and disposed between the bridge and the readout circuit. The first bridge contact is associated with and suspended above only the first reflective layer in the direction. The second bridge contact is associated with and suspended above only the second reflective layer in the direction.

[0005] In one or more embodiments, a method includes applying one or more voltages to bias a bridge of a microbolometer via a first bridge contact and a second bridge contact of the bridge. The bridge is suspended above and parallel to a surface of a readout circuit in a direction substantially perpendicular to a plane defined by the surface of the readout circuit. The method further includes applying a respective voltage to a first reflective layer and / or a second reflective layer adjacent to the first reflective layer to minimize an electrostatic force between the bridge and each of the first and second reflective layers. The first bridge contact is associated with and suspended above only the first reflective layer in the direction. The second bridge contact is associated with and suspended above only the second reflective layer in the direction. The first and second reflective layers are disposed on the surface of the readout circuit and disposed between the bridge and the readout circuit. The method further includes capturing, by an infrared imaging element of the bridge, infrared radiation from a scene, the first reflective layer, and / or the second reflective layer. The method further includes generating, by the infrared imaging element, a detection signal based on the infrared radiation, a voltage at the first bridge contact, and a voltage at the second bridge contact. The method further includes providing the detection signal to the readout circuit.

[0006] The scope of the present disclosure is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the present disclosure will be afforded to those skilled in the art, as well as a realization of additionalP230044-723-W001 Docket No. 70052.2056W001advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 illustrates a block diagram of an example imaging system in accordance with one or more embodiments of the present disclosure.

[0008] FIG. 2 illustrates a block diagram of an example image sensor assembly in accordance with one or more embodiments of the present disclosure.

[0009] FIG. 3 shows a perspective view of an example system in which electrostatic pull-in mitigation may be implemented in accordance with one or more embodiments of the present disclosure.

[0010] FIG. 4 illustrates a cross-sectional view of an example system having a readout circuit and a microbolometer disposed on the readout circuit in which electrostatic pull-in mitigation may be implemented in accordance with one or more embodiments of the present disclosure.

[0011] FIG. 5 A illustrates example voltages on a readout surface during a bias period of a microbolometer in accordance with one or more embodiments of the present disclosure.

[0012] FIG. 5B illustrates an example voltage gradient / profile of a bridge of a microbolometer during a bias period in accordance with one or more embodiments of the present disclosure.

[0013] FIG. 5C illustrates an example deformation profile associated with a microbolometer during a bias period in accordance with one or more embodiments of the present disclosure.

[0014] FIG. 6 illustrates a flow diagram of an example process for facilitating electrostatic pull-in mitigation in accordance with one or more embodiments of the present disclosure.

[0015] Embodiments of the present disclosure and their advantages are best understood by referring to the detailed description that follows. It is noted that sizes of various components and distances between these components are not drawn to scale in the figures. It should be appreciated that like reference numerals are used to identify like elements illustrated in one or more of the figures.P230044-723-W001 Docket No. 70052.2056W001DETAILED DESCRIPTION

[0016] The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology can be practiced. The appended drawings are incorporated herein and constitute a part of the detailed description. The detailed description includes specific details for the purpose of providing a thorough understanding of the subject technology. However, it will be clear and apparent to those skilled in the art that the subject technology is not limited to the specific details set forth herein and may be practiced using one or more embodiments. In one or more instances, structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. One or more embodiments of the subject disclosure are illustrated by and / or described in connection with one or more figures and are set forth in the claims.

[0017] Various techniques are provided to facilitate electrostatic pull-in mitigation for microbolometer systems and methods. In some embodiments, an infrared imaging device may include a readout circuit and a plurality of microbolometers coupled to the readout circuit. Each microbolometer may include a bridge suspended above and parallel to a surface of the readout circuit and contacts (e.g., also referred to as ROIC contacts) coupled to the readout circuit. The bridge may include an infrared sensing element and bridge contacts. Each bridge contact may be coupled to a corresponding ROIC contact and to the infrared sensing element. The infrared imaging device may also include reflective layers (e.g., for each microbolometer in some cases) disposed on the surface of the readout circuit and between the bridge and the readout circuit for reflecting infrared radiation to the infrared sensing element of the microbolometer. As such, the infrared sensing element may capture infrared radiation from a scene and from the reflective layers. Each bridge contact may be associated with and disposed / suspended above only one corresponding reflective layer.

[0018] Electrostatic pull-in may occur when electrostatic attraction between the reflective layers and the bridge of the microbolometer during a bias period causes the bridge to be pulled-in toward the reflective layers (e.g., or, equivalently, toward the readout circuit on which the reflective layers are disposed). The electrostatic attraction may be due to a voltage difference between the reflective layers and the bridge. Such electrostatic pull-in may deform the microbolometer or even collapse the microbolometer.P230044-723-W001 Docket No. 70052.2056W001

[0019] In some embodiments, the bridge contacts may be positioned / suspended above and aligned parallel with the reflective layers to mitigate / prevent electrostatic pull-in during a bias period. During a bias period, the ROIC contacts may receive bias signals (e.g., voltages) for coupling to the infrared sensing element via the bridge contacts. During the bias period, signals (e.g., voltages) may also be applied to the reflective layers associated with the bridge contacts to minimize a voltage difference (and thus minimize an electrostatic force) between the bridge and the reflective layers, thus mitigating / preventing electrostatic pull-in.

[0020] To align a bridge contact to be parallel with a reflective layer, the bridge contact may be disposed / extended along a length of a portion of the bridge. In some cases, the infrared imaging device has at least two bridge contacts and at least two reflective layers. The two bridge contacts may cause / define a voltage gradient on the bridge during a bias period. The voltage gradient defined by the two bridge contacts may be a voltage that varies along a width of the bridge. In some cases, a length of the bridge contacts is larger than a width of the bridge contacts. With each bridge contact suspended above and aligned parallel with a corresponding one of the reflective layers, a voltage difference during a bias period between the reflective layers and the bridge may be minimized or nominally / substantially eliminated to mitigate / prevent electrostatic pull-in of the microbolometer (e.g., the bridge and / or other portions of the microbolometer suspended above the readout circuit) toward the reflective layers (e.g., or equivalently toward the surface of the readout circuit).

[0021] Using various embodiments, electrostatic pull-in may be mitigated even for microbolometer systems with a small distance (e.g., small vertical distance) between a microbolometer and an associated readout circuit and / or reflective layers disposed thereon. As one example, in some cases, a distance between the microbolometer and the readout circuit may be constrained due to space limitations needed to include all layers of the microbolometer. As another example, alternatively or in addition, a smaller distance between the microbolometer and the readout circuit may allow for shorter ROIC contacts, which are generally easier to manufacture than narrower and / or taller ROIC contacts. Further in this regard, various embodiments may allow for smaller distances between the microbolometer and the associated readout circuit wafer relative to conventional orientations in which two reflective layers are distributed under both bridge contacts and thus each reflective layer exerts a respective force under both bridge contacts during a bias period.P230044-723-W001 Docket No. 70052.2056W001

[0022] Referring now to the drawings, FIG. 1 illustrates a block diagram of an example imaging system 100 in accordance with one or more embodiments of the present disclosure. Not all of the depicted components may be required, however, and one or more embodiments may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, and / or fewer components may be provided.

[0023] The imaging system 100 may be utilized for capturing and processing images in accordance with an embodiment of the disclosure. The imaging system 100 may represent any type of imaging system that detects one or more ranges (e.g., wavebands) of EM radiation and provides representative data (e.g., one or more still image frames or video image frames). The imaging system 100 may include an imaging device 105. By way of non-limiting examples, the imaging device 105 may be, may include, or may be a part of an infrared camera (e.g., thermal infrared camera), a visible-light camera, a tablet computer, a laptop, a personal digital assistant (PDA), a mobile device, a desktop computer, or other electronic device. The imaging device 105 may include a housing (e.g., a camera body) that at least partially encloses components of the imaging device 105, such as to facilitate compactness and protection of the imaging device 105. For example, the solid box labeled 105 in FIG. 1 may represent a housing of the imaging device 105. The housing may contain more, fewer, and / or different components of the imaging device 105 than those depicted within the solid box in FIG. 1. In an embodiment, the imaging system 100 may include a portable device and may be incorporated, for example, into a vehicle or a non-mobile installation requiring images to be stored and / or displayed. The vehicle may be a land-based vehicle (e.g., automobile, truck), a naval-based vehicle, an aerial vehicle (e.g., unmanned aerial vehicle (UAV)), a space vehicle, or generally any type of vehicle that may incorporate (e.g., installed within, mounted thereon, etc.) the imaging system 100. In another example, the imaging system 100 may be coupled to various types of fixed locations (e.g., a home security mount, a campsite or outdoors mount, or other location) via one or more types of mounts.

[0024] The imaging system 100 includes, according to one implementation, a logic device 110, a memory component 115, an image capture component 120 (e.g., an imager, an image sensor device), an image interface 125, a control component 130, a display component 135, aP230044-723-W001 Docket No. 70052.2056W001sensing component 140, and / or a network interface 145. The logic device 110, according to various embodiments, includes one or more of a processor, a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), a single-core processor, a multicore processor, a microcontroller, a programmable logic device (PLD) (e.g., field programmable gate array (FPGA)), an application specific integrated circuit (ASIC), a digital signal processing (DSP) device, or other logic device, one or more memories for storing executable instructions (e.g., software, firmware, or other instructions), and / or or any other appropriate combination of processing device and / or memory to execute instructions to perform any of the various operations described herein. The logic device 110 may be configured, by hardwiring, executing software instructions, or a combination of both, to perform various operations discussed herein for embodiments of the disclosure. The logic device 110 may be configured to interface and communicate with the various other components (e.g., 115, 120, 125, 130, 135, 140, 145, etc.) of the imaging system 100 to perform such operations. For example, the logic device 110 may be configured to process captured image data received from the imaging capture component 120, store the image data in the memory component 115, and / or retrieve stored image data from the memory component 115. In one aspect, the logic device 110 may be configured to perform various system control operations (e.g., to control communications and operations of various components of the imaging system 100), design operations (e.g., simulate manufacturing processes), calibration operations, and other image processing operations (e.g., debayering, sharpening, color correction, offset correction, bad pixel replacement, data conversion, data transformation, data compression, video analytics, etc.).

[0025] The memory component 115 includes, in one embodiment, one or more memory devices configured to store data and information, including infrared image data and information. The memory component 115 may include one or more various types of memory devices including volatile and non-volatile memory devices, such as random access memory (RAM), dynamic RAM (DRAM), static RAM (SRAM), non-volatile random-access memory (NVRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, hard disk drive, and / or other types of memory. As discussed above, the logic device 110 may be configured to execute software instructions stored in the memory component 115 so as to perform method and process steps and / orP230044-723-W001 Docket No. 70052.2056W001operations. The logic device 110 and / or the image interface 125 may be configured to store in the memory component 115 images or digital image data captured by the image capture component 120. In some aspects, the memory component 115 may include non-volatile memory to store various non-uniformity correction (NUC) maps and / or other parameters and / or maps determined or derivable from factory calibration and / or run-time / in-field calibration.

[0026] In some embodiments, a separate machine-readable medium 150 (e.g., a memory, such as a hard drive, a compact disk, a digital video disk, or a flash memory) may store the software instructions and / or configuration data which can be executed or accessed by a computer (e.g., a logic device or processor-based system) to perform various methods and operations, such as methods and operations associated with processing image data. In one aspect, the machine-readable medium 150 may be portable and / or located separate from the imaging device 105, with the stored software instructions and / or data provided to the imaging device 105 by coupling the machine-readable medium 150 to the imaging device 105 and / or by the imaging device 105 downloading (e.g., via a wired link and / or a wireless link) from the machine-readable medium 150. It should be appreciated that various modules may be integrated in software and / or hardware as part of the logic device 110, with code (e.g., software or configuration data) for the modules stored, for example, in the memory component 115.

[0027] The imaging device 105 may be a video and / or still camera to capture and process images and / or videos of a scene 175. In this regard, the image capture component 120 of the imaging device 105 may be configured to capture images (e.g., still and / or video images) of the scene 175 in a particular spectrum or modality. The image capture component 120 includes an image detector circuit 165 (e.g., a visible-light detector circuit, a thermal infrared detector circuit) and a readout circuit 170 (e.g., an ROIC). For example, the image capture component 120 may include an IR imaging sensor (e.g., an IR imaging sensor array) configured to detect IR radiation in the near, middle, and / or far IR spectrum and provide IR images (e.g., IR image data or signal) representative of the IR radiation from the scene 175. For example, the image detector circuit 165 may capture (e.g., detect, sense) IR radiation with wavelengths in the range from around 700 nm to around 2 mm, or portion thereof. For example, in some aspects, the image detector circuit 165 may be sensitive to (e.g., better detect) SWIR radiation, mid-wave IR (MWIR) radiation (e.g., EM radiation with wavelengthP230044-723-W001 Docket No. 70052.2056W001of 2 pm to 5 pm). and / or long-wave IR (LWIR) radiation (e.g., EM radiation with wavelength of 7 gm to 14 gm), or any desired IR wavelengths (e.g., generally in the 0.7 gm to 14 gm range). In other aspects, the image detector circuit 165 may capture radiation from one or more other wavebands of the EM spectrum, such as visible light, ultraviolet light, and so forth.

[0028] The image detector circuit 165 may capture image data (e.g., infrared image data) associated with the scene 175. To capture an image, the image detector circuit 165 may detect image data of the scene 175 (e.g., in the form of EM radiation) received through an aperture 180 of the imaging device 105 and generate pixel values of the image based on the scene 175. An image may be referred to as a frame or an image frame. In some cases, the image detector circuit 165 may include an array of detectors (e.g., also referred to as an array of pixels) that can detect radiation of a certain waveband, convert the detected radiation into electrical signals (e.g., voltages, currents, etc.), and generate the pixel values based on the electrical signals. Each detector in the array may capture a respective portion of the image data and generate a pixel value based on the respective portion captured by the detector. The pixel value generated by the detector may be referred to as an output of the detector. By way of non-limiting examples, each detector may be a photodetector, such as an avalanche photodiode, an infrared photodetector, a quantum well infrared photodetector, a microbolometer, or other detector capable of converting EM radiation (e.g., of a certain wavelength) to a pixel value. The array of detectors may be arranged in rows and columns. In some embodiments, each detector may be referred to as a pixel and may include a bridge and a leg structure to propagate signals from the bridge to the readout circuit 170.

[0029] The image may be, or may be considered, a data structure that includes pixels and is a representation of the image data associated with the scene 175, with each pixel having a pixel value that represents EM radiation emitted or reflected from a portion of the scene 175 and received by a detector that generates the pixel value. Based on context, a pixel may refer to a detector of the image detector circuit 165 that generates an associated pixel value or a pixel (e.g., pixel location, pixel coordinate) of the detector output image formed from the generated pixel values. In an embodiment, the image may be an infrared image (e.g., a thermal infrared image). For a thermal infrared image (e.g., also referred to as a thermal image), each pixel value of the thermal infrared image may represent a temperature of a corresponding portion of the scene 175.P230044-723-W001 Docket No. 70052.2056W001

[0030] In an aspect, the pixel values generated by the image detector circuit 165 may be represented in terms of digital count values generated based on the electrical signals obtained from converting the detected radiation. For example, in a case that the image detector circuit 165 includes or is otherwise coupled to an analog-to-digital (ADC) circuit, the ADC circuit may generate digital count values based on the electrical signals. For an ADC circuit that can represent an electrical signal using 14 bits, the digital count value may range from 0 to 16,383. In such cases, the pixel value of the detector may be the digital count value output from the ADC circuit. In other cases (e.g., in cases without an ADC circuit), the pixel value may be analog in nature with a value that is, or is indicative of, the value of the electrical signal. As an example, for infrared imaging, a larger amount of IR radiation being incident on and detected by the image detector circuit 165 (e.g., an IR image detector circuit) is associated with higher digital count values and higher temperatures.

[0031] The readout circuit 170 may be utilized as an interface between the image detector circuit 165 that detects the image data and the logic device 110 that processes the detected image data as read out by the readout circuit 170, with communication of data from the readout circuit 170 to the logic device 110 facilitated by the image interface 125. An image capturing frame rate may refer to the rate (e.g., detector output images per second) at which images are detected / output in a sequence by the image detector circuit 165 and provided to the logic device 110 by the readout circuit 170. The readout circuit 170 may read out the pixel values generated by the image detector circuit 165 in accordance with an integration time (e.g., also referred to as an integration period).

[0032] In various embodiments, a combination of the image detector circuit 165 and the readout circuit 170 may be, may include, or may together provide an FPA. In some aspects, the image detector circuit 165 may be a thermal image detector circuit that includes an array of microbolometers, and the combination of the image detector circuit 165 and the readout circuit 170 may be referred to as a microbolometer FPA. In some cases, the array of microbolometers may be arranged in rows and columns. A microbolometer is an example of a type of infrared detector that may be used within an infrared imaging device (e.g., an infrared camera). For example, the microbolometer may be fabricated on a monolithic silicon substrate to form an infrared (image) detector array, with each microbolometer of the infrared detector array functioning as a pixel to produce a two-dimensional image. The change in resistance of each microbolometer may be translated into a time-multiplexedP230044-723-W001 Docket No. 70052.2056W001electrical signal by an ROIC. Additional details regarding FPAs and microbolometers may be found, for example, in U.S. Patent Nos. 5,756,999, 6,028,309, 6,812,465, 7,034,301, and 11,824,078, which are herein incorporated by reference in their entireties.

[0033] The microbolometers may detect IR radiation and generate pixel values based on the detected IR radiation. For example, in some cases, the microbolometers may be thermal IR detectors that detect IR radiation in the form of heat energy and generate pixel values based on the amount of heat energy detected. The microbolometers may absorb incident IR radiation and produce a corresponding change in temperature in the microbolometers. The change in temperature is associated with a corresponding change in resistance of the microbolometers. With each microbolometer functioning as a pixel, a two-dimensional image or picture representation of the incident IR radiation can be generated by translating the changes in resistance of each microbolometer into a time-multiplexed electrical signal. The translation may be performed by the ROIC. The microbolometer FPA may include an IR sensing element formed of IR detecting materials such as amorphous silicon (a-Si), vanadium oxide (VOx), a combination thereof, and / or other detecting material(s). In an aspect, for a microbolometer FPA, the integration time may be, or may be indicative of, a time interval during which the microbolometers are biased. In this case, a longer integration time may be associated with higher gain of the IR signal, but not more IR radiation being collected. The IR radiation may be collected in the form of heat energy by the microbolometers. Further descriptions of ROIC and microbolometer circuits may be found in U.S. Patent No.6,028,309, which is incorporated by reference in its entirety herein for all purposes.

[0034] In some cases, the image capture component 120 may include one or more optical components and / or one or more filters. The optical component(s) may include one or more windows, lenses, mirrors, beamsplitters, beam couplers, and / or other components to direct and / or focus radiation to the image detector circuit 165. The optical component(s) may include components each formed of material and appropriately arranged according to desired transmission characteristics, such as desired transmission wavelengths and / or ray transfer matrix characteristics. The filter(s) may be adapted to pass radiation of some wavelengths but substantially block radiation of other wavelengths. For example, the image capture component 120 may be an IR imaging device that includes one or more filters adapted to pass IR radiation of some wavelengths while substantially blocking IR radiation of other wavelengths (e.g., MWIR filters, thermal IR filters, and narrow-band filters). In thisP230044-723-W001 Docket No. 70052.2056W001example, such filters may be utilized to tailor the image capture component 120 for increased sensitivity to a desired band of IR wavelengths. In an aspect, an IR imaging device may be referred to as a thermal imaging device when the IR imaging device is tailored for capturing thermal IR images. Other imaging devices, including IR imaging devices tailored for capturing infrared IR images outside the thermal range, may be referred to as non-thermal imaging devices.

[0035] In one specific, not-limiting example, the image capture component 120 may include an IR imaging sensor having an FPA of detectors responsive to IR radiation including near infrared (NIR), SWIR, MWIR, LWIR, and / or very-long wave IR (VLWIR) radiation. In some other embodiments, alternatively or in addition, the image capture component 120 may include a complementary metal oxide semiconductor (CMOS) sensor or a charge-coupled device (CCD) sensor that can be found in any consumer camera (e.g., visible light camera).

[0036] In some embodiments, the imaging system 100 includes a shutter 185. The shutter 185 may be operated to be selectively inserted into an optical path between the scene 175 and the image capture component 120 to expose or block the aperture 180. In some cases, the shutter 185 may be moved (e.g., slid, rotated, etc.) manually (e.g., by a user of the imaging system 100) and / or via an actuator (e.g., controllable by the logic device 110 in response to user input or autonomously, such as an autonomous decision by the logic device 110 to perform a calibration of the imaging device 105).

[0037] When the shutter 185 is outside of the optical path to expose the aperture 180, the electromagnetic radiation from the scene 175 may be received by the image detector circuit 165 (e.g., via one or more optical components and / or one or more filters). As such, the image detector circuit 165 captures images of the scene 175. The shutter 185 may be referred to as being in an open position or simply as being open. When the shutter 185 is inserted into the optical path to block the aperture 180, the electromagnetic radiation from the scene 175 is blocked from the image detector circuit 165. As such, the image detector circuit 165 captures images of the shutter 185. The shutter 185 may be referred to as being in a closed position or simply as being closed. In some cases, the shutter 185 may block the aperture 180 during a calibration process, in which the shutter 185 may be used as a uniform blackbody (e.g., a substantially uniform blackbody). For example, in some cases, a surface of the shutter 185 imaged by the image detector circuit 165 may be implemented by a uniform blackbody coating. In some cases, such as for an imaging device without a shutter or with a brokenP230044-723-W001 Docket No. 70052.2056W001shutter or as an alternative to the shutter 185, a case or holster of the imaging device 105, a lens cap, a cover, a wall of a room, or other suitable object / surface may be used to provide a uniform blackbody (e.g., substantially uniform blackbody).

[0038] Other imaging sensors that may be embodied in the image capture component 120 include a photonic mixer device (PMD) imaging sensor or other time of flight (ToF) imaging sensor, LIDAR imaging device, RADAR imaging device, millimeter imaging device, positron emission tomography (PET) scanner, single photon emission computed tomography (SPECT) scanner, ultrasonic imaging device, or other imaging devices operating in particular modalities and / or spectra. It is noted that for some of these imaging sensors that are configured to capture images in particular modalities and / or spectra (e.g., infrared spectrum, etc.), they are more prone to produce images with low frequency shading, for example, when compared with a typical CMOS-based or CCD-based imaging sensors or other imaging sensors, imaging scanners, or imaging devices of different modalities.

[0039] The images, or the digital image data corresponding to the images, provided by the image capture component 120 may be associated with respective image dimensions (also referred to as pixel dimensions). An image dimension, or pixel dimension, generally refers to the number of pixels in an image, which may be expressed, for example, in width multiplied by height for two-dimensional images or otherwise appropriate for relevant dimension or shape of the image. Thus, images having a native resolution may be resized to a smaller size (e.g., having smaller pixel dimensions) in order to, for example, reduce the cost of processing and analyzing the images. Filters (e.g., a non-uniformity estimate) may be generated based on an analysis of the resized images. The filters may then be resized to the native resolution and dimensions of the images, before being applied to the images.

[0040] The image interface 125 may include, in some embodiments, appropriate input ports, connectors, switches, and / or circuitry configured to interface with external devices (e.g., a remote device 155 and / or other devices) to receive images (e.g., digital image data) generated by or otherwise stored at the external devices. In an aspect, the image interface 125 may include a serial interface and telemetry line for providing metadata associated with image data. The received images or image data may be provided to the logic device 110. In this regard, the received images or image data may be converted into signals or data suitable for processing by the logic device 110. For example, in one embodiment, the image interfaceP230044-723-W001 Docket No. 70052.2056W001125 may be configured to receive analog video data and convert it into suitable digital data to be provided to the logic device 110.

[0041] The image interface 125 may include various standard video ports, which may be connected to a video player, a video camera, or other devices capable of generating standard video signals, and may convert the received video signals into digital video / image data suitable for processing by the logic device 110. In some embodiments, the image interface 125 may also be configured to interface with and receive images (e.g., image data) from the image capture component 120. In other embodiments, the image capture component 120 may interface directly with the logic device 110.

[0042] The control component 130 includes, in one embodiment, a user input and / or an interface device, such as a rotatable knob (e.g., a potentiometer), push buttons, slide bar, keyboard, and / or other devices, that is adapted to generate a user input control signal. The logic device 110 may be configured to sense control input signals from a user via the control component 130 and respond to any sensed control input signals received therefrom. The logic device 110 may be configured to interpret such a control input signal as a value, as generally understood by one skilled in the art. In one embodiment, the control component 130 may include a control unit (e.g., a wired or wireless handheld control unit) having push buttons adapted to interface with a user and receive user input control values. In one implementation, the push buttons and / or other input mechanisms of the control unit may be used to control various functions of the imaging device 105, such as calibration initiation and / or related control, shutter control, autofocus, menu enable and selection, field of view, brightness, contrast, noise filtering, image enhancement, and / or various other features.

[0043] The display component 135 includes, in one embodiment, an image display device (e.g., a liquid crystal display (LCD)) or various other types of generally known video displays or monitors. The logic device 110 may be configured to display image data and information on the display component 135. The logic device 110 may be configured to retrieve image data and information from the memory component 115 and display any retrieved image data and information on the display component 135. The display component 135 may include display circuitry, which may be utilized by the logic device 110 to display image data and information. The display component 135 may be adapted to receive image data and information directly from the image capture component 120, logic device 110, and / or image interface 125, or the image data and information may be transferred from the memoryP230044-723-W001 Docket No. 70052.2056W001component 115 via the logic device 110. In some aspects, the control component 130 may be implemented as part of the display component 135. For example, a touchscreen of the imaging device 105 may provide both the control component 130 (e.g., for receiving user input via taps and / or other gestures) and the display component 135 of the imaging device 105.

[0044] The sensing component 140 includes, in one embodiment, one or more sensors of various types, depending on the application or implementation requirements, as would be understood by one skilled in the art. Sensors of the sensing component 140 provide data and / or information to at least the logic device 110. In one aspect, the logic device 110 may be configured to communicate with the sensing component 140. In various implementations, the sensing component 140 may provide information regarding environmental conditions, such as outside temperature, lighting conditions (e.g., day, night, dusk, and / or dawn), humidity level, specific weather conditions (e.g., sun, rain, and / or snow), distance (e.g., laser rangefinder or time-of-flight camera), and / or whether a tunnel or other type of enclosure has been entered or exited. The sensing component 140 may represent conventional sensors as generally known by one skilled in the art for monitoring various conditions (e.g., environmental conditions) that may have an effect (e.g., on the image appearance) on the image data provided by the image capture component 120.

[0045] In some implementations, the sensing component 140 (e.g., one or more sensors) may include devices that relay information to the logic device 110 via wired and / or wireless communication. For example, the sensing component 140 may be adapted to receive information from a satellite, through a local broadcast (e.g., radio frequency (RF)) transmission, through a mobile or cellular network and / or through information beacons in an infrastructure (e.g., a transportation or highway information beacon infrastructure), or various other wired and / or wireless techniques. In some embodiments, the logic device 110 can use the information (e.g., sensing data) retrieved from the sensing component 140 to modify a configuration of the image capture component 120 (e.g., adjusting a light sensitivity level, adjusting a direction or angle of the image capture component 120, adjusting an aperture, etc.). The sensing component 140 may include a temperature sensing component to provide temperature data (e.g., one or more measured temperature values) various components of the imaging device 105, such as the image detection circuit 165 and / or the shutter 185. By wayP230044-723-W001 Docket No. 70052.2056W001of non-limiting examples, a temperature sensor may include a thermistor, thermocouple, thermopile, pyrometer, and / or other appropriate sensor for providing temperature data.

[0046] In some embodiments, various components of the imaging system 100 may be distributed and in communication with one another over a network 160. In this regard, the imaging device 105 may include a network interface 145 configured to facilitate wired and / or wireless communication among various components of the imaging system 100 over the network 160. In such embodiments, components may also be replicated if desired for particular applications of the imaging system 100. That is, components configured for same or similar operations may be distributed over a network. Further, all or part of any one of the various components may be implemented using appropriate components of the remote device 155 (e.g., a conventional digital video recorder (DVR), a computer configured for image processing, and / or other device) in communication with various components of the imaging system 100 via the network interface 145 over the network 160, if desired. Thus, for example, all or part of the logic device 110, all or part of the memory component 115, and / or all of part of the display component 135 may be implemented or replicated at the remote device 155. In some embodiments, the imaging system 100 may not include imaging sensors (e.g., image capture component 120), but instead receive images or image data from imaging sensors located separately and remotely from the logic device 110 and / or other components of the imaging system 100. It will be appreciated that many other combinations of distributed implementations of the imaging system 100 are possible, without departing from the scope and spirit of the disclosure.

[0047] Furthermore, in various embodiments, various components of the imaging system 100 may be combined and / or implemented or not, as desired or depending on the application or requirements. In one example, the logic device 110 may be combined with the memory component 115, image capture component 120, image interface 125, display component 135, sensing component 140, and / or network interface 145. In another example, the logic device 110 may be combined with the image capture component 120, such that certain functions of the logic device 110 are performed by circuitry (e.g., a processor, a microprocessor, a logic device, a microcontroller, etc.) within the image capture component 120.

[0048] FIG. 2 illustrates a block diagram of an example image sensor assembly 200 in accordance with one or more embodiments of the present disclosure. Not all of the depicted components may be required, however, and one or more embodiments may include additionalP230044-723-W001 Docket No. 70052.2056W001components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, and / or fewer components may be provided. In an embodiment, the image sensor assembly 200 may be an FPA, for example, implemented as the image capture component 120 of FIG. 1.

[0049] The image sensor assembly 200 includes a unit cell array 205, column multiplexers 210 and 215, column amplifiers 220 and 225, a row multiplexer 230, control bias and timing circuitry 235, a digital-to-analog converter (DAC) 240, and a data output buffer 245. In some aspects, operations of and / or pertaining to the unit cell array 205 and other components may be performed according to a system clock and / or synchronization signals (e.g., line synchronization (LSYNC) signals). The unit cell array 205 includes an array of unit cells. In an aspect, each unit cell may include a detector (e.g., a pixel) and interface circuitry. The interface circuitry of each unit cell may provide an output signal, such as an output voltage or an output current, in response to a detection signal (e.g., detection current, detection voltage) provided by the detector of the unit cell. The output signal may be indicative of the magnitude of EM radiation received by the detector and may be referred to as image pixel data or simply image data. The column multiplexer 215, column amplifiers 220, row multiplexer 230, and data output buffer 245 may be used to provide the output signals from the unit cell array 205 as a data output signal on a data output line 250. The output signals on the data output line 250 may be provided to components downstream of the image sensor assembly 200, such as processing circuitry (e.g., the logic device 110 of FIG. 1), memory (e.g., the memory component 115 of FIG. 1), display device (e.g., the display component 135 of FIG. 1), and / or other component to facilitate processing, storage, and / or display of the output signals. The data output signal may be an image formed of the pixel values for the image sensor assembly 200. In this regard, the column multiplexer 215, the column amplifiers 220, the row multiplexer 230, and the data output buffer 245 may collectively provide an ROIC (or portion thereol) of the image sensor assembly 200. In an aspect, the interface circuitry may be considered part of the ROIC, or may be considered an interface between the detectors and the ROIC. In some embodiments, components of the image sensor assembly 200 may be implemented such that the unit cell array 205 and the ROIC may be part of a single die.P230044-723-W001 Docket No. 70052.2056W001

[0050] The column amplifiers 225 may generally represent any column processing circuitry as appropriate for a given application (analog and / or digital), and is not limited to amplifier circuitry for analog signals. In this regard, the column amplifiers 225 may more generally be referred to as column processors in such an aspect. Signals received by the column amplifiers 225, such as analog signals on an analog bus and / or digital signals on a digital bus, may be processed according to the analog or digital nature of the signal. As an example, the column amplifiers 225 may include circuitry for processing digital signals. As another example, the column amplifiers 225 may be a path (e.g., no processing) through which digital signals from the unit cell array 205 traverses to get to the column multiplexer 215. As another example, the column amplifiers 225 may include an ADC for converting analog signals to digital signals (e.g., to obtain digital count values). These digital signals may be provided to the column multiplexer 215.

[0051] Each unit cell may receive a bias signal (e.g., bias voltage, bias current) to bias the detector of the unit cell to compensate for different response characteristics of the unit cell attributable to, for example, variations in temperature, manufacturing variances, and / or other factors. For example, the control bias and timing circuitry 235 may generate the bias signals and provide them to the unit cells. By providing appropriate bias signals to each unit cell, the unit cell array 205 may be effectively calibrated to provide accurate image data in response to light (e.g., visible-light, IR light) incident on the detectors of the unit cells. In an aspect, the control bias and timing circuitry 235 may be, may include, or may be a part of, a logic circuit.

[0052] The control bias and timing circuitry 235 may generate control signals for addressing the unit cell array 205 to allow access to and readout of image data from an addressed portion of the unit cell array 205. The unit cell array 205 may be addressed to access and readout image data from the unit cell array 205 row by row, although in other implementations the unit cell array 205 may be addressed column by column or via other manners.

[0053] The control bias and timing circuitry 235 may generate bias values and timing control voltages. In some cases, the DAC 240 may convert the bias values received as, or as part of, data input signal on a data input signal line 255 into bias signals (e.g., analog signals on analog signal line(s) 260) that may be provided to individual unit cells through the operation of the column multiplexer 210, column amplifiers 220, and row multiplexer 230. For example, the DAC 240 may drive digital control signals (e.g., provided as bits) toP230044-723-W001 Docket No. 70052.2056W001appropriate analog signal levels for the unit cells. In some technologies, a digital control signal of 0 or 1 may be driven to an appropriate logic low voltage level or an appropriate logic high voltage level, respectively. In another aspect, the control bias and timing circuitry 235 may generate the bias signals (e.g., analog signals) and provide the bias signals to the unit cells without utilizing the DAC 240. In this regard, some implementations do not include the DAC 240, data input signal line 255, and / or analog signal line(s) 260. In an embodiment, the control bias and timing circuitry 235 may be, may include, may be a part of, or may otherwise be coupled to the logic device 110 and / or image capture component 120 of FIG. 1.

[0054] In an embodiment, the image sensor assembly 200 may be implemented as part of an imaging device (e.g., the imaging device 105). In addition to the various components of the image sensor assembly 200, the imaging device may also include one or more processors, memories, logic, displays, interfaces, optics (e.g., lenses, mirrors, beamsplitters), and / or other components as may be appropriate in various implementations. In an aspect, the data output signal on the data output line 250 may be provided to the processors (not shown) for further processing. For example, the data output signal may be an image formed of the pixel values from the unit cells of the image sensor assembly 200. The processors may perform operations such as non-uniformity correction (e.g., flat-field correction or other calibration technique), spatial and / or temporal filtering, and / or other operations. The images (e.g., processed images) may be stored in memory (e.g., external to or local to the imaging system) and / or displayed on a display device (e.g., external to and / or integrated with the imaging system). The various components of FIG. 2 may be implemented on a single chip or multiple chips. Furthermore, while the various components are illustrated as a set of individual blocks, various of the blocks may be merged together or various blocks shown in FIG. 2 may be separated into separate blocks.

[0055] It is noted that in FIG. 2 the unit cell array 205 is depicted as an 8x8 (e.g., 8 rows and 8 columns) array of unit cells. However, the unit cell array 205 may be of other array sizes. By way of non-limiting examples, the unit cell array 205 may include 512x512 (e.g., 512 rows and 512 columns of unit cells), 1024x1024, 2048x2048, 4096x4096, 8192x8192, and / or other array sizes. In some cases, the array size may have a row size (e.g., number of detectors in a row) different from a column size (e.g., number of detectors in a column).P230044-723-W001 Docket No. 70052.2056W001Examples of frame rates may include 30 Hz, 60 Hz, and 120 Hz. In an aspect, each unit cell of the unit cell array 205 may represent a pixel.

[0056] FIG. 3 shows a perspective view of a system 300 in which electrostatic pull-in mitigation may be implemented in accordance with one or more embodiments of the present disclosure. Not all of the depicted components may be required, however, and one or more embodiments may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional components, different components, and / or fewer components may be provided. Structures associated with the system 300 may extend along three directions (e.g., three orthogonal directions) x, y, and z, as shown by the coordinate system in FIG. 3. In an embodiment, the system 300 or portion thereof may be, may include, or may be a part of a unit cell of the unit cell array 205 of FIG. 2 and / or the image capture component 120 of FIG. 1.

[0057] The system 300 includes a microbolometer 305. In an embodiment, the microbolometer 305 is one microbolometer of an array of microbolometers of an infrared imaging device and may be referred to as a pixel. Each pixel of an infrared imaging device may have a structure similar to or the same as that shown for the microbolometer 305 in FIG.3. The microbolometer 305 includes a bridge 310, contacts 315A and 315B (e.g., basket contacts), and legs 320A and 320B that couple the bridge 310 to the contacts 315A and 315B, respectively. The bridge 310 includes an infrared sensing element 325 and bridge contacts 330A and 330B. In an aspect, the bridge 310 may be referred to as a bolometer bridge, a bolometer body, or a body. The bridge contact 330A may include / form a portion / region of the bridge 310 at which the infrared sensing element 325 couples to a first end of the leg 320A. The bridge contact 330B may include / form a portion / region of the bridge 310 at which the infrared sensing element 325 couples to a first end of the leg 320B. In some cases, the bridge contacts 330A and / or 330B each include a respective portion / region of the bridge 310 at which the legs 320A and 320B, respectively, are in physical contact with the infrared sensing element 325. A second end of the legs 320A and 320B couples to the contacts 315A and 315B, respectively. The legs 320A and 320B may be formed from one or more layers of conductive material such as, by way of non-limiting examples, titanium (Ti), titanium nitride (TiN), nickel-chromium (Ni-Cr) alloy, and / or other suitable conductive materials. In an aspect, the conductive material of the legs 320A and 320B may be referred to as leg metal orP230044-723-W001 Docket No. 70052.2056W001leg metal layer(s). In some cases, the legs 320A and / or 320B may include insulating material on one or more sides of a conductive portion of the legs 320A and / or 320B.

[0058] The legs 320A and 320B may be used to thermally isolate the infrared sensing element 325 (e.g., a thermistor / resistive element of the infrared sensing element 325) while maintaining mechanical and electrical connectivity to an ROIC (e.g., via the contacts 315A and 315B). In this regard, the legs 320A and 320B may be formed with shape and dimensions appropriate to provide structural integrity and electrical conductivity while minimizing thermal conductivity (e.g., to limit heat transmission between the bridge 310 and the ROIC) and / or fill factor.

[0059] In order to provide the legs 320A and 320B having a size (e.g., dimensions along the x, y, and z-directions) and a shape sufficient to provide suitable performance for the microbolometer 305 without reducing the fill-factor of an array of microbolometers in which the microbolometer 305 is included, the legs 320A and 320B may be legs that run along paths in and / or parallel to the xy-plane of FIG. 3 as shown and have a height that extends in a direction parallel to the z-direction (i.e., perpendicular to the xy-plane) of FIG. 3. In an aspect, as shown in FIG. 3, a length of the leg 320A extends along the xy-plane in a serpentine shape / path between the first end of the leg 320A coupled to the bridge contact 330A and the second end of the leg 320A coupled to the contact 315A, and, similarly, a length of the leg 320B extends along the xy-plane in a serpentine shape / path between the first end of the leg 320B coupled to the bridge contact 330B and the second end of the leg 320B coupled to the contact 315B. The leg 320A may include bend portions (e.g., a bend portion 335A) associated with changes in direction of the leg 320A as the leg 320A extends to form its serpentine shape / path. The leg 320B may include bend portions (e.g., a bend portion 335B) associated with changes in direction of the leg 320B as the leg 320B extends to form its serpentine shape / path.

[0060] The contacts 315A and 315B may couple the microbolometer 305 to associated readout circuitry of a readout circuit wafer (e.g., also referred to simply as a readout circuit or an ROIC). The readout circuit wafer may include and / or may be referred to as a substrate. As such, in an aspect, the contacts 315A and 315B may be referred to as substrate contacts or ROIC contacts. The legs 320A and 320B may include a portion that runs at a nonperpendicular angle to the readout circuit wafer from a height above the readout circuit wafer such as the height of the bridge 310 downward to a contact on the readout circuit wafer)P230044-723-W001 Docket No. 70052.2056W001and / or each of the contacts 315A and 315B may include a portion that extends downward (e.g., in the negative z-direction of FIG. 3) from the legs 320A and 320B to a surface of the readout circuit wafer. In an embodiment, the microbolometer 305 is one microbolometer of an array of microbolometers of an infrared imaging device, where each microbolometer of the array may be coupled to the readout circuit wafer via corresponding contacts of the microbolometer.

[0061] The system 300 also includes reflective layers 340A and 340B. In some aspects, the reflective layers 340A and 340B may be disposed on a surface of the readout circuit wafer and between the bridge 310 and the readout circuit wafer. The reflective layers 340A and 340B may be formed of a metal layer, a metallic layer, or generally any sufficiently conductive material dependent on application and may be referred to as a reflective conductive layer, a reflective metal layer (RML), or simply a reflector. As non-limiting examples, the reflective layers 340A and 340B may be or may include titanium (Ti) and / or aluminum (Al). In an aspect, the reflective layers 340A and 340B may be referred to as electrodes. The reflective layer 340A is adjacent to the reflective layer 340B. The reflective layers 340A and 340B may be separated in the x-direction (e.g., spaced out along the x-direction) by a distance d. An example of the distance d may be between approximately 0.25 pm and approximately 0.35 pm. In some aspects, the reflective layers 340A and 340B may be considered a part of the microbolometer 305. In other aspects, the reflective layers 340A and 340B may be considered components separate from the microbolometer 305. In an embodiment, the system 300 (e.g., with or without the reflective layers 340A and 340B) may be, may include, or may be a part of a unit cell of the unit cell array 205 of FIG. 2.

[0062] The reflective layers 340A and 340B may be used to reflect infrared radiation to the microbolometer 305 (e.g., to the infrared sensing element 325) for facilitating infrared detection by the infrared sensing element 325 of the microbolometer 305. For example, infrared radiation that is incident upon the infrared sensing element 325 of the bridge 310 may pass through the infrared sensing element 325 and not be absorbed by the infrared sensing element 325. The reflective layer 340A and / or 340B may reflect this unabsorbed infrared radiation back towards the infrared sensing element 325 for potential absorption by the infrared sensing element 325. In some aspects, each microbolometer (e.g., 305) of a microbolometer array may be associated with a corresponding pair of reflective layers (e.g., 340A, 340B) coupled to a corresponding pair of contacts (e.g., 315A, 315B) and configuredP230044-723-W001 Docket No. 70052.2056W001to reflect infrared radiation to the associated microbolometer. In some aspects, a pair of reflective layers (e.g., 340 A, 340B) may be shared by multiple microbolometers of a microbolometer array. For example, the same pair of reflective layers may be shared by a column (or portion thereof) or a row (or portion thereof) of microbolometers of a microbolometer array and a respective portion of each reflective layer used to reflect infrared radiation to a respective microbolometer.

[0063] The infrared sensing element 325 may convert infrared light into detectable electrical signals based on changes in electrical properties of the infrared sensing element 325 (e.g., changes in resistivity) due to changes in temperature of the infrared sensing element 325 when the light is incident. The infrared sensing element 325 may receive infrared light directly from a scene (e.g., the scene 175) as well as receive infrared light reflected by the reflective layers 340A and 340B. In an aspect, the infrared sensing element 325 has a width defined by its size / dimension along the x-direction and a length defined by its size / dimension along the y-direction.

[0064] In an aspect, the infrared sensing element 325 may include a resistive material, which may be formed of a high temperature coefficient of resistivity (TCR) material (e.g., vanadium oxide (VOx), titanium oxide (TiOx), or amorphous silicon). The resistive material may be suspended above the readout circuit wafer on the bridge 310. The resistive material may be coupled to the contacts 315A and 315B via the legs 320A and 320B to allow providing of the electrical signals generated by the infrared sensing element 325 for readout by the readout circuit.

[0065] The bridge contact 330A may include, or may be formed at, a portion / region of the bridge 310 at which the leg 320A (e.g., leg metal(s) of the leg 320A) contacts (e.g., physically contacts) the infrared sensing element 325 (e.g., the resistive material of the infrared sensing element 325), and the bridge contact 330B may include, or may be formed at, a portion / region of the bridge 310 at which the leg 320B (e.g., leg metal(s) of the leg 320B) contacts (e.g., physically contacts) the infrared sensing element 325 (e.g., the resistive material of the infrared sensing element 325). As shown in FIG. 3, the bridge contacts 330A and 330B run along the length (e.g., y-direction) of the bridge 310. In this regard, the bridge contact 330A runs along the length of a portion / side of the bridge 310 adjacent to (e.g., closer / proximate to) the contact 315A. The bridge contact 330B runs along the length of a portion / side of the bridge 310 adjacent to (e.g., closer / proximate to) the contact 315B. In anP230044-723-W001 Docket No. 70052.2056W001aspect, as shown in FIG. 3, the bridge contacts 330A and 330B have lengths longer than their widths.

[0066] The infrared sensing element 325 may be operated to detect infrared radiation during bias periods. In an aspect, a bias period may refer to a time duration when a bias signal (e.g., provided as a voltage pulse) is applied to the contacts 315A and 315B to facilitate infrared radiation detection by the infrared sensing element 325 of the bridge 310. The bias signal applied to the contact 315 A propagates through the leg 320A to the bridge contact 330A that contacts the infrared sensing element 325 and the bias signal applied to the contact 315B propagates through the leg 320B to the bridge contact 330B that contacts the infrared sensing element 325. In this regard, biasing the contacts 315A and 315B may be referred to as biasing the infrared sensing element 325. In an embodiment, the bias signals may be generated and applied by the control bias and timing circuitry 235 to the contacts 315A and 315B.

[0067] The infrared sensing element 325 may generate a current in response to the applied bias signals. The contact 315B may provide a signal path through which this current propagates to the readout circuit to allow read out. The current may be referred to as a detection signal of the infrared sensing element 325. By measuring this current, a resistance of the infrared sensing element 325 can be determined to detect / measure the infrared radiation. As would be understood by one skilled in the art, the resistance of the infrared sensing element 325 is a function of a temperature of the infrared sensing element 325, and the temperature of the infrared sensing element 325 in turn is based on the infrared radiation absorbed by the infrared sensing element 325. As such, the current generated by the infrared sensing element 325 corresponds to and can be used to quantify / measure infrared light absorbed by the infrared sensing element 325. In an aspect, infrared image data captured by the infrared sensing element 325 may be, or may be derived from, detection signals generated by the infrared sensing element 325.

[0068] FIG. 4 illustrates a cross-sectional view of a system 400 having a readout circuit wafer 405 and the microbolometer 305 of FIG. 3 disposed on the readout circuit wafer 405 (e.g., ROIC wafer or simply ROIC) in accordance with one or more embodiments of the present disclosure. Not all of the depicted components may be required, however, and one or more embodiments may include additional components not shown in the figure. Variations in the arrangement and type of the components may be made without departing from theP230044-723-W001 Docket No. 70052.2056W001spirit or scope of the claims as set forth herein. Additional components, different components, and / or fewer components may be provided. Structures associated with the system 400 may extend along three directions (e.g., three orthogonal directions) x, y, and z, as shown by the coordinate system in FIG. 4. In an embodiment, the cross-sectional view may include a front view of the system 300 of FIG. 3 when the system 300 is viewed in the y-direction from a front side of the system 300. In an embodiment, the system 400 or portion thereof may be, may include, or may be a part of a unit cell of the unit cell array 205 of FIG.2 and / or the image capture component 120 of FIG. 1.

[0069] The readout circuit wafer 405 includes a substrate 410 (e.g., also referred to as an ROIC substrate), an overglass layer 415 disposed on the substrate 410, and conductive layers 420A and 420B disposed on the substrate 410 and extending through the overglass layer 415. As non-limiting examples, the substrate 410 may include a silicon substrate and / or the overglass layer 415 may include a silicon dioxide (SiO2) layer. Although FIG. 4 shows a single microbolometer (e.g., the microbolometer 305) disposed on and coupled to the readout circuit wafer 405, an array of microbolometers may be disposed on and coupled to the readout circuit wafer 405. In this regard, the cross-sectional view of FIG. 4 may show a portion of the readout circuit wafer 405 associated with the microbolometer 305.

[0070] A conductive pad 425A is disposed on the conductive layer 420A and a conductive pad 425B is disposed on the conductive layer 420B. The contacts 315A and 315B are disposed on the conductive pads 425A and 420B, respectively, thus coupling the readout circuit wafer 405 to the microbolometer 305. In some cases, the conductive layer 420A, the pad 425 A, and the contact 315 A collectively provide a first signal path for facilitating communication between (e.g., to and / or from) the readout circuit wafer 405 and the microbolometer 305, and the conductive layer 420B, the pad 425B, and the contact 315B collectively provide a second signal path for facilitating communication between (e.g., to and / or from) the readout circuit wafer 405 and the microbolometer 305. In some cases, a detection signal (e.g., a current) generated by the infrared sensing element 325 propagates through the leg 320B, the contact 315B, the pad 425B, and the conductive layer 420B to reach the substrate 410.

[0071] The reflective layers 340A and 340B are disposed on the readout circuit wafer 405 and disposed between the bridge 310 and the readout circuit wafer 405. As shown in FIG. 4, the reflective layers 340A and 340B may be disposed on a surface (e.g., a top surface) of theP230044-723-W001 Docket No. 70052.2056W001overglass layer 415. A surface (e.g., a top surface) of the reflective layers 340A and 340B may face a surface (e.g., a bottom surface) of the bridge 310 of the microbolometer 305. An example distance h (e.g., also referred to as a gap, height, or spacing) between the bridge 310 (e.g., the bottom surface of the bridge 310) and the reflective layers 340A and 340B (e.g., the top surface of the reflective layers 340A and 340B facing the bottom surface of the bridge 310) may be between approximately 0.35 pm and approximately 0.45 pm.

[0072] In an aspect, a plane such as the xy-plane of FIGS. 3 and 4 may be, or may be referred to as being, defined by the bridge 310 of the microbolometer 305 (e.g., the infrared sensing element 325 of the bridge 310 may include a planar sensor layer such as a resistive layer that defines a plane or a plane may be defined that passes through multiple bridges in a microbolometer array) or by a surface of the readout circuit wafer 405 to which the microbolometer array is coupled and disposed / suspended above. In an aspect, a surface of the readout circuit wafer 405 may be, or may refer to, a surface of the substrate 410 or a surface of the overglass layer 415.

[0073] As shown collectively by the views of FIGS. 3 and 4, the bridge 310 is disposed / suspended above (e.g., in the z-direction) and substantially / nominally parallel to the surface of the readout circuit wafer 405. The bridge contact 330A may be considered as being associated with, as being disposed on, and / or as forming a first portion / region of the bridge 310 that is adjacent to the contact 315A. The bridge contact 330A may be associated with and disposed / suspended above only the reflective layer 340A (e.g., the bridge contact 330A is not disposed / suspended above the reflective layer 340B). In this regard, the first portion of the bridge 310 may be disposed / suspended directly above (e.g., in the z-direction) at least a portion of the reflective layer 340A. The reflective layer 340A has a surface (e.g., a portion of its top surface) facing the first portion of the bridge 310. The bridge contact 330B may be considered as being associated with, as being disposed on, and / or as forming a second portion / region of the bridge 310 that is adjacent to the contact 315B. The bridge contact 330B may be associated with and disposed / suspended above only the reflective layer 340B (e.g., the bridge contact 330B is not disposed / suspended above the reflective layer 340A). In this regard, the second portion of the bridge 310 may be disposed / suspended directly above at least a portion of the reflective layer 340B. The reflective layer 340B has a surface (e.g., a portion of its top surface) facing the second portion of the bridge 310. It is noted that the index / identifier associated with each portion of the bridge 310 (e.g., first portion and secondP230044-723-W001 Docket No. 70052.2056W001portion) may be arbitrary and utilized for convenience in describing different portions / parts of the bridge 310 relative to the reflective layers 340A and 340B.

[0074] The contact 315 A and the leg 320A may be associated with only the reflective layer 340A. At least a portion of the leg 320A may be disposed / suspended above (e.g., in the z-direction) only the reflective layer 340A (e.g., no portion of the leg 320A is disposed / suspended above the reflective layer 340B). A portion of the leg 320A adjacent to the bridge 310 may have a length that is substantially parallel to a length of the bridge contact 330A. The contact 315B and the leg 320B may be associated with only the reflective layer 340B. At least a portion of the leg 320B may be disposed / suspended above (e.g., in the z-direction) only the reflective layer 340B (e.g., no portion of the leg 320B is disposed / suspended above the reflective layer 340A). A portion of the leg 320B adjacent to the bridge 310 may have a length that is substantially parallel to a length of the bridge contact 330B.

[0075] It is noted that structures and / or portions thereof (e.g., a layer(s) of material)) in the present disclosure, such as those shown in FIGS. 3 and 4, may be described using terms such as flat, vertical, parallel, perpendicular, and so forth, and / or depicted as being flat, vertical, parallel, perpendicular, and so forth. Due to tolerances associated with dimensional aspects and / or fabrication processes / flows, such terms and / or depictions generally characterize the structures and / or portions thereof in a nominal / substantial sense. Further in this regard, aspects related to positions / orientations (e.g., above, below, top, bottom, above, below, vertical, horizontal, etc.) between features (e.g., different layers) may refer to an arbitrary frame of reference primarily to provide positions / orientations of features relative to one another (e.g., as shown in and described in relation to the various figures). As one example, a surface or layer described and / or depicted as being a flat surface or a flat layer may correspond to a nominally / substantially flat surface or a nominally / substantially flat layer. The x- and y-directions may be nominally / substantially parallel to a plane defined by the surface or the layer, whereas the z-direction (e.g., also referred to as a vertical direction) may be nominally / substantially perpendicular to the plane. As another example, two or more structures (e.g., the bridge 310 and the reflective layers 340A and 340B below the bridge 310) described and / or depicted as being oriented / aligned parallel to each other may correspond to these structure(s) being nominally / substantially oriented / aligned parallel to each other. In some aspects, a direction / plane may be referred to as being substantiallyP230044-723-W001 Docket No. 70052.2056W001perpendicular to another plane / direction if an angle between them is within ±10° of 90°. In some aspects, a direction / plane may be referred to as being substantially parallel to another plane / direction if an angle between them is within ±10° of 0°.

[0076] In some embodiments, as shown in FIGS. 3 and 4, the bridge contacts 330A and 330B are positioned / suspended above and aligned parallel with the reflective layers 340A and 340B, respectively, to mitigate / prevent electrostatic pull-in. In an aspect, electrostatic pull-in may occur when electrostatic attraction between the reflective layers 340A and 340B and the bridge 310 of the microbolometer 305 during a bias period causes the bridge 310 to be pulled-in (e.g., pulled downward) toward the reflective layers 340A and 340B (e.g., or, equivalently, toward the readout circuit wafer 405). The electrostatic attraction may be due to a voltage difference between the reflective layers 340A and 340B and the bridge 310. Such electrostatic pull-in may deform the microbolometer 305 or even collapse the microbolometer 305. For example, the electrostatic attraction / force associated with the systems 300 and 400 may be considered as that between parallel plates. For parallel plates, the electrostatic attraction / force between the plates is dependent on plate separation, overlapping area of the plates, and voltage difference between the plates. The bridge 310 (or portion thereof) may be considered one plate and the reflective layers 340A and 340B (or portions thereof) may be considered another plate (e.g., with a portion of the reflective layer 340A and 340B each parallel to a corresponding portion of the bridge 310).

[0077] In some embodiments, to align the bridge contact 330A to be parallel with the reflective layer 340A, the bridge contact 330A may be disposed / extended along the length of the first portion of the bridge 310. Similarly, to align the bridge contact 330B parallel with the reflective layer 340B, the bridge contact 330B may be extended along the length of the second portion of the bridge 310. With the bridge contacts 330A and 330B suspended above (e.g., in the z-direction) and aligned parallel with the reflective layers 340A and 340B, respectively, a voltage difference during a bias period between voltages on the reflective layers 340A and 340B and voltages (e.g., a voltage gradient) on the bridge 310 may be minimized or nominally / substantially eliminated to mitigate / prevent electrostatic pull-in of the microbolometer 305 (e.g., the bridge 310 and / or other portions of the microbolometer 305 suspended above the readout circuit wafer 405) toward the reflective layers 340A and 340B (e.g., or equivalently toward the surface of the readout circuit wafer 405).P230044-723-W001 Docket No. 70052.2056W001

[0078] FIGS. 5 A through 5C illustrate electrostatic pull-in mitigation in accordance with one or more embodiments of the present disclosure. For explanatory / exemplary purposes, FIGS. 5 A through 5C are described in relation to the systems 300 and 400 of FIGS. 3 and 4, although electrostatic pull-in mitigation may be implemented in other systems. FIG. 5 A illustrates example voltages on a readout surface during a bias period of the microbolometer 305 of the system 300 of FIG. 3 in accordance with one or more embodiments of the present disclosure. With reference to the system 400 of FIG. 4, the readout surface may include a surface of the overglass layer 415. During the bias period, the contact 315A and / or the contact 315B may receive a respective voltage to provide a bias voltage for the bridge 310 (e.g., a voltage drop will occur across the bridge 310). In some cases, the contact 315A may receive a voltage Vi and the contact 315B may receive a voltage V2 such that the bridge contact 330A coupled to the contact 315A is substantially at the voltage Vi and the bridge contact 330B coupled to the contact 315B is substantially at the voltage V2. During the bias period, voltages may also be applied to the reflective layers 340A and 340B such that the reflective layers 340A and 340B are substantially at the voltages Vi and V2, respectively, to minimize a voltage difference (and thus an electrostatic force) between the bridge 310 and the reflective layers 340A and 340B as further described herein. The reflective layers 340A and 340B may receive the voltages from a bias circuit via appropriate electrical coupling / routing (not shown in FIG. 4). In one example, the voltage Vi may be around 0 V and the voltage V2 may be around 1.6 V. In this example, the reflective layer 340A and the bridge contact 330A may be referred to as being nominally / substantially at the voltage Vi when at a voltage between Vi ± 0.1 V, and / or the reflective layer 340B and the bridge contact 330B may be referred to as being nominally / substantially at the voltage V2 when at a voltage between V2 ± 0.1 V. Other voltage tolerances dependent on application may be applicable. In an embodiment, the signals (e.g., the voltages) may be generated and applied by the control bias and timing circuitry 235 to the contacts 315A and 315B and to the reflective layers 340A and 340B.

[0079] In cases where each microbolometer is associated with two reflective layers, the reflective layers may receive their respective voltages to set their voltage levels.Alternatively in such cases, the reflective layers may be electrically coupled to their respective contacts. For example, the reflective layer 340A and 340B may be electrically coupled to the contact 315A and 315B, respectively.P230044-723-W001 Docket No. 70052.2056W001

[0080] FIG. 5B illustrates an example voltage gradient / profile of the bridge 310 of the microbolometer 305 during a bias period in accordance with one or more embodiments of the present disclosure. A voltage bar 505 provides a representation of a mapping between a color or greyscale value shown in a position on the bridge 310 and a voltage value in units of volts associated with that position on the bridge 310. In accordance with one or more embodiments, during the bias period, a voltage at the contact 315 A is coupled to the bridge contact 330A (e.g., via the leg 320A) and a voltage at the contact 315B is coupled to the bridge contact 330B (e.g., via the leg 320B). As such, a voltage gradient varies along the width (e.g., the x-direction) of the bridge 310 with the bridge contact 330A along the length (e.g., the y-direction) of the first portion / region of the bridge 310 substantially at the voltage Vi (e.g., voltage of the bridge contact 330A at Vi ± 0.1 V) and the bridge contact 330B along the length of the second portion / region of the bridge 310 substantially at the voltage V2 (e.g., voltage of the bridge contact 330B at V2 ± 0.1 V). The voltage gradient increases from around the voltage Vi at the bridge contact 330A to around the voltage V2 at the bridge contact 330B. The reflective layer 340A disposed under the bridge contact 330A is substantially at the voltage Vi and aligns with the voltage gradient along the width of the first portion / region of the bridge 310. The reflective layer 340B disposed under the bridge contact 330B is substantially at the voltage V2 and aligns with the voltage gradient along the width of the second portion / region of the bridge 310. In this regard, the voltage gradient of the bridge 310 aligns with the voltages Vi and V2 of the reflective layers 340A and 340B such that a voltage difference (and thus an electrostatic force) is minimized between the bridge 310 and the reflective layers 340A and 340B, thus mitigating / preventing electrostatic pull-in.

[0081] FIG. 5C illustrates an example deformation profile associated with the microbolometer 305 during a bias period in accordance with one or more embodiments of the present disclosure. A bar 510 provides a representation of a mapping between a color or greyscale value shown in a position on the microbolometer 305 and an amount of deformation value in units of pm (e.g., 10'3in the bar 510 represents 10'3pm or 1 nm) associated with that position on the microbolometer 305. The deformation profile shows a deformation for each position of the microbolometer 305. The deformation may be provided as a deflection (e.g., a pull-in) of the bridge 310 downward (e.g., in the negative z-direction) toward the reflective layers 340A and 340B. The deformation profile may be based on a difference between the voltage gradient of the bridge 310, such as shown in FIG. 5B, and theP230044-723-W001 Docket No. 70052.2056W001voltages Vi and V2 of the reflective layers 340A and 340B, such as shown in FIG. 5 A. With the voltage gradient of the bridge 310 aligned with the voltages Vi and V2 on the readout surface, the minimal or no voltage difference between the bridge 310 and the reflective layers 340A and 340B is associated with low or no deformation associated with the microbolometer 305 as shown in the deformation profile. In some cases, as shown in FIG. 5C, the deformation may be less than 1 nm for the microbolometer 305. As such, using various embodiments, electrostatic pull-in may be mitigated / prevented by positioning / suspending the bridge contacts 330A and 330B above the reflective layers 340A and 340B, respectively, and aligning the bridge contacts 330A and 330B parallel with (e.g., in terms of physical orientation and associated alignment in voltage values) the reflective layers 340A and 340B, respectively.

[0082] In some aspects, the distance d may have a value appropriate to define a voltage gradient below the bridge 310 to allow voltage alignment between the bridge 310 and the reflective layers 340A and 340B so as to minimize a voltage difference (and thus minimize an electrostatic force) between the bridge 310 and the reflective layers 340A and 340B, thus mitigating / preventing electrostatic pull-in. In some cases, the distance d may further be determined to minimize an associated coupling between the reflective layer 340A and the reflective layer 340B dependent on materials of the reflective layers 340A and 340B, processing size, and / or general application as would be understood by one skilled in the art. In some cases, a non-conductive barrier may be disposed on the readout surface and between the reflective layers 340A and 340B to further isolate the reflective layers 340A and 340B from each other.

[0083] Microbolometer systems in which a microbolometer is closer to an associated readout circuit wafer are generally more susceptible to electrostatic pull-in. Using various embodiments, electrostatic pull-in is mitigated / prevented even for microbolometer systems with a small distance between a microbolometer and an associated readout circuit wafer and / or reflective layers disposed thereon, such as distances h between approximately 0.35 pm and approximately 0.45 pm as shown in the system 400 of FIG. 4 in accordance with one or more embodiments. Dependent on application (e.g., associated voltages, structure dimensions), electrostatic pull-in may be mitigated for larger or smaller distances than those provided by way of non-limiting examples in the present disclosure. Further in this regard, various embodiments may allow for smaller distances between the microbolometer and theP230044-723-W001 Docket No. 70052.2056W001associated readout circuit wafer relative to conventional orientations in which two reflective layers are distributed under both bridge contacts and thus each reflective layer exerts a respective force under both bridge contacts during a bias period.

[0084] FIG. 6 illustrates a flow diagram of an example process 600 for facilitating electrostatic pull-in mitigation in accordance with one or more embodiments of the present disclosure. For exemplary / explanatory purposes, the process 600 is primarily described herein with reference to the systems 300 and 400 of FIGS. 3 and 4. However, the process 600 can be performed in relation to other systems and associated components. Note that one or more operations in FIG. 6 may be combined, omitted, and / or performed in a different order as desired.

[0085] At block 605, voltages may be applied to the microbolometer 305 during a bias period to bias the microbolometer 305. In some aspects, the microbolometer 305 may be biased such that a voltage gradient varies along a width (e.g., the x-direction in FIG. 3) of the bridge 310 with the bridge contact 330A substantially at a voltage Vi and the bridge contact 330B substantially at a voltage V2. In some aspects, to bias the microbolometer 305, bias signals may be provided to the contacts 315A and 315B. For example, the voltage Vi may be applied to the contact 315A and the voltage V2 may be applied to the contact 315B. The contact 315A may couple the voltage V 1 to the bridge contact 330A via the leg 320 A. The contact 315B may couple the voltage V2 to the bridge contact 330B via the leg 320B.

[0086] At block 610, during the bias period, voltages may also be applied to the reflective layers 340A and 340B disposed on the surface of the readout circuit wafer 405 such that the reflective layer 340A may be substantially at the voltage Vi and the reflective layer 340B may be substantially at the voltage V2. According to various embodiments, with the bridge contacts 330A and 330B suspended above and aligned parallel with (e.g., physical orientation and associated voltage alignment) the reflective layers 340A and 340B, respectively, electrostatic attraction between the microbolometer 305 (e.g., the bridge 310) and the reflective layers 340A and 340B may be minimized and thus electrostatic pull-in may be mitigated. In an embodiment, the control bias and timing circuitry 235 may generate and apply bias signals to the microbolometer 305 (e.g., the contacts 315A and 315B of the microbolometer 305) and apply signals to the reflective layers 340A and 340B.

[0087] At block 615, infrared radiation may be captured by the microbolometer 305 (e.g., the infrared imaging element 325 of the microbolometer 305). The infrared radiation mayP230044-723-W001 Docket No. 70052.2056W001include infrared radiation from a scene, infrared radiation reflected by the reflective layer 340A to the infrared imaging element 325, and / or infrared radiation reflected by the reflective layer 340B to the infrared imaging element 325. At block 620, a detection signal may be generated by the microbolometer 305 (e.g., the infrared imaging element 325) based on the captured infrared radiation. The detection signal may be indicative of an intensity of infrared radiation received by the infrared imaging element 325. As an example, the detection signal may be a current generated by the infrared imaging element 325 based on the infrared radiation captured by the infrared imaging element 325 and the voltages at the bridge contacts 330A and 330B (e.g., substantially at the voltages Vi and V2, respectively). At block 625, the detection signal may be provided / output by the microbolometer 305 for read out. In some cases, the detection signal may be provided to the contact 315B and to the readout circuit wafer 405.

[0088] While FIGS. 3 and 4 illustrate example systems having a readout circuit wafer and a microbolometer coupled to and having components disposed / suspended above the readout circuit wafer, systems for implementing / facilitating electrostatic pull-in in accordance with one or more embodiments may have a different readout circuit wafer and / or a different microbolometer. Additional examples of readout circuit wafers and / or microbolometers (or components therefore such as leg structures, contacts, etc.) can be found in U.S. Patent Nos.11,031,432 and 11,955,504 and U.S. Patent Application Nos. 17 / 471,159, 63 / 636,643, and 63 / 636,647, each of which is incorporated by reference in its entirety.

[0089] Further in this regard, although the foregoing describes embodiments having two bridge contacts (e.g., the bridge contacts 330A and 330B) and two reflective layers (e.g., the reflective layers 340A and 340B), in some embodiments more than two bridge contacts and / or more than two reflective layers may be utilized, with for example each bridge contact suspended above and parallel with a corresponding reflective layer and with voltages applied such that a voltage difference between the bridge and the reflective layers during a bias period is minimized to mitigate electrostatic pull-in.

[0090] Where applicable, various embodiments provided by the present disclosure can be implemented using hardware, software, or combinations of hardware and software. Also where applicable, the various hardware components and / or software components set forth herein can be combined into composite components comprising software, hardware, and / or both without departing from the spirit of the present disclosure. Where applicable, theP230044-723-W001 Docket No. 70052.2056W001various hardware components and / or software components set forth herein can be separated into sub-components comprising software, hardware, or both without departing from the spirit of the present disclosure. In addition, where applicable, it is contemplated that software components can be implemented as hardware components, and vice versa.

[0091] Software in accordance with the present disclosure, such as non-transitory instructions, program code, and / or data, can be stored on one or more non-transitory machine readable mediums. It is also contemplated that software identified herein can be implemented using one or more general purpose or specific purpose computers and / or computer systems, networked and / or otherwise. Where applicable, the ordering of various steps described herein can be changed, combined into composite steps, and / or separated into sub-steps to provide features described herein.

[0092] The foregoing description is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. Embodiments described above illustrate but do not limit the invention. It is contemplated that various alternate embodiments and / or modifications to the present invention, whether explicitly described or implied herein, are possible in light of the disclosure. Accordingly, the scope of the invention is defined only by the following claims.

Claims

P230044-723-W001 Docket No. 70052.2056W001CLAIMS1. An infrared imaging device comprising:a readout circuit having a surface defining a plane;a microbolometer coupled to the readout circuit, wherein the microbolometer comprises a bridge suspended above and parallel to the surface of the readout circuit in a first direction substantially perpendicular to the plane, wherein the bridge comprises a first bridge contact and a second bridge contact;a first reflective layer disposed on the surface of the readout circuit and disposed between the bridge and the readout circuit; anda second reflective layer adjacent to the first reflective layer and disposed on the surface of the readout circuit and disposed between the bridge and the readout circuit, wherein the first bridge contact is associated with and suspended above only the first reflective layer in the first direction, and wherein the second bridge contact is associated with and suspended above only the second reflective layer in the first direction.

2. The infrared imaging device of claim 1, wherein the microbolometer further comprises:a first substrate contact coupled to the readout circuit;a second substrate contact coupled to the readout circuit;a first leg structure extending between and coupled to the first substrate contact and to the first bridge contact; anda second leg structure extending between and coupled to the second substrate contact and to the second bridge contact,wherein the first substrate contact and the first leg structure are associated with only the first reflective layer, and wherein the second substrate contact and the second leg structure are associated with only the second reflective layer.

3. The infrared imaging device of claim 2, wherein at least a portion of the first leg structure is suspended above only the first reflective layer in the first direction, and wherein at least a portion of the second leg structure is suspended above only the second reflective layer in the first direction.P230044-723-W001 Docket No. 70052.2056W0014. The infrared imaging device of claim 2, wherein the first bridge contact has a first dimension that extends in a second direction substantially parallel to the plane and a second dimension that extends in a third direction that is perpendicular to the second direction and substantially parallel to the plane, and wherein the second dimension is greater than the first dimension.

5. The infrared imaging device of claim 4, wherein the first dimension is a width of the first bridge contact, wherein the second dimension is a length of the first bridge contact, and wherein a portion of the first leg structure adjacent to the bridge has a length that is substantially parallel to the length of the first bridge contact.

6. The infrared imaging device of claim 2, further comprising a bias circuit configured to, during a bias period:apply a respective voltage to the first substrate contact and / or the second substrate contact to bias the bridge via the first bridge contact and the second bridge contact; and apply a respective voltage to the first reflective layer and / or the second reflective layer to minimize an electrostatic force between the bridge and each of the first and second reflective layers.

7. The infrared imaging device of claim 6, wherein the bias circuit is configured to, during the bias period:apply the respective voltage to the first substrate contact and / or the second substrate contact such that the first bridge contact is substantially at a first voltage and the second bridge contact is substantially at a second voltage different from the first voltage; and apply the respective voltage to the first reflective layer and / or the second reflective layer such that the first reflective layer is substantially at the first voltage and the second reflective layer is substantially at the second voltage.

8. The infrared imaging device of claim 1, further comprising a bias circuit configured to, during a bias period:apply one or more voltages to bias the bridge via the first bridge contact and the second bridge contact; andP230044-723-W001 Docket No. 70052.2056W001apply a respective voltage to the first reflective layer and / or the second reflective layer to minimize an electrostatic force between the bridge and each of the first and second reflective layers.

9. The infrared imaging device of claim 8, wherein the bias circuit is configured to, during the bias period:apply the one or more voltages to bias the bridge such that the first bridge contact and the second bridge contact are at different voltages; andapply the respective voltage to the first reflective layer and / or the second reflective layer such that the first reflective layer and the second reflective layer are at different voltages to minimize the electrostatic force between the bridge and the first and second reflective layers.

10. The infrared imaging device of claim 1, wherein the first bridge contact has a first dimension that extends in a second direction substantially parallel to the plane and a second dimension that extends in a third direction that is perpendicular to the second direction and substantially parallel to the plane, wherein the second dimension is greater than the first dimension, wherein the second bridge contact has a third dimension that extends in the second direction and a fourth dimension that extends in the third direction, and wherein the fourth dimension is greater than the third dimension.

11. The infrared imaging device of claim 1 , wherein the first reflective layer and the second reflective layer are separated in a second direction substantially parallel to the plane and perpendicular to the first direction.

12. The infrared imaging device of claim 11, wherein the first reflective layer and the second reflective layer are separated in the second direction by a distance between approximately 0.25 pm and approximately 0.35 pm.

13. The infrared imaging device of claim 1, wherein a distance in the first direction between a surface of the bridge and a surface of the first reflective layer disposed below the bridge is between approximately 0.35 pm and approximately 0.45 pm.P230044-723-W001 Docket No. 70052.2056W00114. The infrared imaging device of claim 1, wherein:the first reflective layer and the second reflective layer are each configured to reflect infrared radiation to the bridge; andthe bridge further comprises an infrared sensing element, wherein the first and second bridge contacts are coupled to the infrared sensing element, and wherein the infrared sensing element is configured to:receive infrared radiation from a scene, the first reflective layer, and / or the second reflective layer;generate a detection signal based on the received infrared radiation, a voltage at the first bridge contact, and a voltage at the second bridge contact; and provide the detection signal to the readout circuit.

15. The infrared imaging device of claim 1, further comprising:one or more additional microbolometers coupled to the readout circuit, wherein each additional microbolometer comprises a respective bridge comprising a respective first bridge contact and a respective second bridge contact; anda plurality of additional reflective layers, wherein each additional microbolometer is associated with a respective two reflective layers of the plurality of additional reflective layers.

16. A method of operating the infrared imaging device of claim 1, the method comprising during a bias period of the microbolometer:applying one or more voltages to bias the bridge via the first bridge contact and the second bridge contact; andapplying a respective voltage to the first reflective layer and / or the second reflective layer to minimize an electrostatic force between the bridge and each of the first and second reflective layers.

17. A method comprising:applying one or more voltages to bias a bridge of a microbolometer via a first bridge contact and a second bridge contact of the bridge, wherein the bridge is suspended above and parallel to a surface of a readout circuit in a first direction substantially perpendicular to a plane defined by the surface of the readout circuit;P230044-723-W001 Docket No. 70052.2056W001applying a respective voltage to a first reflective layer and / or a second reflective layer adjacent to the first reflective layer to minimize an electrostatic force between the bridge and each of the first and second reflective layers, wherein the first bridge contact is associated with and suspended above only the first reflective layer in the first direction, wherein the second bridge contact is associated with and suspended above only the second reflective layer in the first direction, and wherein the first and second reflective layers are disposed on the surface of the readout circuit and disposed between the bridge and the readout circuit;capturing, by an infrared imaging element of the bridge, infrared radiation from a scene, the first reflective layer, and / or the second reflective layer;generating, by the infrared imaging element, a detection signal based on the infrared radiation, a voltage at the first bridge contact, and a voltage at the second bridge contact; and providing the detection signal to the readout circuit.

18. The method of claim 17, wherein:the applying the one or more voltages to bias the bridge comprises applying a respective voltage to a first substrate contact coupled to the first bridge contact via a first leg structure and / or a second substrate contact coupled to the second bridge contact via a second leg structure such that the first bridge contact is substantially at a first voltage and the second bridge contact is substantially at a second voltage different from the first voltage; and the respective voltage is applied to the first reflective layer and / or the second reflective layer such that the first reflective layer is substantially at the first voltage and the second reflective layer is substantially at the second voltage.

19. The method of claim 18, wherein the first substrate contact and the first leg structure are associated with only the first reflective layer, and wherein the second substrate contact and the second leg structure are associated with only the second reflective layer.

20. The method of claim 19, wherein at least a portion of the first leg structure is suspended above only the first reflective layer in the first direction, and wherein at least a portion of the second leg structure is suspended above only the second reflective layer in the first direction.P230044-723-W001 Docket No. 70052.2056W00121. The method of claim 17, wherein the first bridge contact has a first dimension that extends in a second direction substantially parallel to the plane and a second dimension that extends in a third direction that is perpendicular to the second direction and substantially parallel to the plane, and wherein the second dimension is greater than the first dimension.

22. The method of claim 21, wherein the second bridge contact has a third dimension that extends in the second direction and a fourth dimension that extends in the third direction, and wherein the fourth dimension is greater than the third dimension.

23. The method of claim 17, wherein the first reflective layer and the second reflective layer are separated in a second direction substantially parallel to the plane and perpendicular to the first direction.

24. The method of claim 23, wherein the first reflective layer and the second reflective layer are separated in the second direction by a distance between approximately 0.25 pm and approximately 0.35 pm.

25. The method of claim 17, wherein a distance in the first direction between a surface of the bridge and a surface of the first reflective layer disposed below the bridge is between approximately 0.35 pm and approximately 0.45 pm.

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