System and method for breakdown voltage correction in a Geiger mode avalanche photodiode focal plane array

Abstract

The system and method are described for optical processing. According to some aspects, the apparatus may include a pixelated photodiode array (PDA), and each pixel of the PDA includes a radiation detector. Further, the optical processing apparatus may include a memory storing one or more characteristics for each pixel of the PDA, and a read out integrated circuit (ROIC) communicatively coupled to the FPA and the memory. In some aspects, the ROIC reads the one or more characteristics for each pixel of the PDA from the memory and adjusts an arm / disarm bias voltage for each pixel of the PDA based on the one or more characteristics of each pixel.

Description

Technical Field

[0001] The present disclosure generally relates to the operation of a focal plane array (FPA). More particularly, the present disclosure relates to implementing a system and method for improving the performance of an FPA by correcting the breakdown voltage of individual detectors of the FPA, resulting in overall performance improvement and maximizing manufacturing yield.

Background Art

[0002] Modern vehicles can be configured to operate in an autonomous mode in which the vehicle travels in an environment with little or no input from a driver. Such an autonomous vehicle (AV) may include one or more sensors that sense information about the environment in which the vehicle operates. The autonomous vehicle and associated computer-implemented controller use the sensed information to explore the environment. For example, if a sensor senses that the autonomous vehicle is approaching an obstacle, the controller adjusts the direction control of the autonomous vehicle to cause the autonomous vehicle to travel around the obstacle, as determined by the computer-implemented controller. Thereby, autonomous driving greatly depends on vehicle sensors for accurately sensing and mapping the environmental conditions in which the autonomous vehicle is placed. One such sensor is a lidar (Light detection and ranging) device. The lidar device scans a scene to generate a cloud of point positions indicating the three-dimensional shape of the environmental scene and actively evaluates the distance to environmental features. Individual points are measured by generating a laser pulse, sensing a reflected pulse, if present, from an environmental object, and determining the distance to the reflected object according to the time delay between reception of the emitted pulse and the reflected pulse. Other sensors may include an infrared sensor (IR) and other imaging sensors (e.g., a focal plane array (FPA)) that provide data points enabling autonomous driving.

[0003] The FPA is an image sensor that includes an array of light sensing elements (e.g., pixels) in the focal plane of a lens. The FPA can be used for imaging purposes (e.g., photography or video recording) as well as for non-imaging purposes such as spectroscopy, wavefront sensing, lidar, and other sensor applications.

[0004] Limitations in semiconductor device manufacturing (e.g., III-V semiconductor devices such as FPAs) often result in underperforming devices and / or large variations in device performance and characteristics in the fabricated wafers. In the case of Geiger-mode Avalanche Photodiode (GmAPD) devices, one of the characteristics that can vary at the wafer level is the breakdown voltage. For an FPA where each pixel includes a GmAPD device, variations in the breakdown voltage for such pixels lead to variations in pixel-level attributes such as photon sensing efficiency, noise ratio, and other performance characteristics. Existing FPAs operate by applying a single voltage bias V b across all pixels of the array. The main GmAPD performance parameter is the overbias voltage which is the difference between the total bias V b and the breakdown voltage V br , i.e., V 0V (i.e., V 0v = V b - V br ). Ideally, a focal plane array including GmAPDs can have the same performance for each pixel by applying the same overbias V 0V across all pixels. However, if a single value of voltage bias V b is applied across all pixels and the breakdown voltage V br varies from pixel to pixel, V 0V will vary according to the performance parameters that depend on V 0V .

Summary of the Invention

Problems to be Solved by the Invention

[0005] The inability to compensate for the variability of the breakdown voltage for each pixel of a system using an FPA leads to variability in the sensing ability of the FPA, causing a decrease in the accuracy and performance of the FPA and the underlying system using it (e.g., an autonomous vehicle). Therefore, improving the overall uniformity of the performance of an FPA with pixel-level variability is essential for the operation of the FPA, and through this, the sensing function of each sensor and the autonomous driving of an autonomous vehicle are improved. The current systems and methods of the present disclosure solve the aforementioned problems.

Means for Solving the Problems

[0006] According to some aspects, disclosed herein are systems and methods for optical processing. According to some aspects, a pixelated photoDiode Array (PDA) - each pixel of the pixelated photoDiode Array includes a radiation detector - , a memory configured to store one or more characteristics for each pixel of the pixelated photoDiode Array; and an optical processing device including a Read Out Integrated Circuit (ROIC) communicatively coupled to the pixelated photoDiode Array and the memory are disclosed. According to some aspects, the read out integrated circuit is configured to read the one or more characteristics for each pixel of the pixelated photoDiode Array from the memory and adjust an Arm / Disarm bias voltage for each pixel of the pixelated photoDiode Array based on the one or more characteristics.

[0007] Also, each pixel of the pixelated photoDiode Array includes one or more Geiger-mode Avalanche Photodiodes (GmAPDs).

[0008] In addition, the one or more characteristics read from the memory include the breakdown voltage of the one or more Geiger mode avalanche photodiodes.

[0009] In addition, the read integrated circuit is configured to adjust the arm / disarm bias voltage of the pixel upward in response to the breakdown voltage of the pixel being less than a preset threshold value.

[0010] In addition, the read integrated circuit is configured to adjust the arm / disarm bias voltage of the pixel downward in response to the breakdown voltage of the pixel exceeding a preset threshold value.

[0011] In addition, the read integrated circuit adjusts the arm / disarm bias voltage for each pixel of the pixelated photodiode array based on the respective breakdown voltages so that each pixel operates in the armed state.

[0012] In addition, it further includes a bias source configured to supply the arm / disarm bias voltage to each pixel of the pixelated photodiode array; the read integrated circuit is configured to adjust the arm / disarm bias voltage with a preset arm bias value to arm each pixel, and adjust the arm / disarm bias voltage with a preset disarm bias value to disarm each pixel.

[0013] In addition, the read integrated circuit is configured to adjust the arm / disarm bias voltage with the breakdown voltage value stored in the memory for each pixel of the pixelated photodiode array to arm each pixel of the pixelated photodiode array.

[0014] Further, the read integrated circuit is configured to adjust the arm / disarm bias voltage with a breakdown voltage value stored in a memory for each pixel of the pixelated photodiode array to disarm each pixel of the pixelated photodiode array.

[0015] Also, the one or more characteristics for the first pixel of the pixelated photodiode array are different from the one or more characteristics for the second pixel of the pixelated photodiode array.

[0016] Also, the first pixel and the second pixel are configured to operate at the same overbias voltage level after adjustment of the arm / disarm bias voltage.

[0017] Also, the device includes a focal plane array (FPA).

[0018] Also, the device includes a lidar (Light detection and ranging sensor).

[0019] Further, the read integrated circuit is configured to adjust the arm / disarm bias voltage for each pixel of the pixelated photodiode array so that each pixel of the pixelated photodiode array operates at the same bias voltage level.

[0020] According to one aspect, a method of optical processing is disclosed that includes reading, by a read integrated circuit (ROIC), one or more characteristics for each pixel of a pixelated photo diode array (PDA), wherein each pixel of the photo diodes each includes a radiation detector, and the read integrated circuit is communicatively coupled to the pixelated photo diode array and the memory. The method may further include adjusting, by the read integrated circuit, an arm / disarm bias voltage for each pixel of the pixelated photo diodes based on the one or more characteristics.

[0021] Also, the one or more characteristics read from the memory include a breakdown voltage of the pixel.

[0022] Also, the adjusting step may further include adjusting the arm / disarm bias voltage of the pixel upward in response to the breakdown voltage of the pixel being less than a predefined threshold that has already been set.

[0023] Also, the adjusting step may further include adjusting the arm / disarm bias voltage of the pixel downward in response to the breakdown voltage of the pixel exceeding a predefined threshold that has already been set.

[0024] According to one aspect, a pixelated photoDiode Array (PDA) and a Read Out Integrated Circuit (ROIC) and a memory communicatively coupled to the memory are disclosed. The readout integrated circuit can be configured to store characteristics for respective pixels of the pixelated photo diode array - each pixel of the pixelated photo diode array includes a radiation detector. The readout integrated circuit can be configured to read the characteristics for respective pixels of the pixelated photo diode array and adjust an arm / disarm bias voltage for respective pixels of the pixelated photo diode array based on respective characteristics of the respective pixels.

[0025] Also, the one or more characteristics read from the memory include a breakdown voltage for respective radiation detectors.

Brief Description of the Drawings

[0026] The accompanying drawings are included herein and constitute a part of the detailed description of the invention.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0027] In the drawings, like reference numerals generally indicate identical or similar elements. Also, generally, the leftmost digit of a reference numeral identifies the drawing in which the reference numeral is first shown.

Best Mode for Carrying Out the Invention

[0028] The development and mass production of autonomous vehicles (AVs) have the potential to revolutionize transportation mobility and safety. Autonomous vehicles combine a variety of sensors such as radar, lidar, sonar, GPS, odometry, and inertial measurement devices to recognize the surrounding environment. In some aspects, an advanced control system can not only analyze sensory information to detect obstacles and related signage but also identify an appropriate exploration route.

[0029] One of the main sensors that autonomous vehicles rely on is lidar, which depends on a system and method for determining distance by measuring the time it takes for light reflected from an object targeted by a laser to return to a receiver. According to some aspects, lidar can be used to create a digital 3D representation of a recognition area (e.g., the surrounding area of an autonomous vehicle). Within the 3D representation (also called a lidar grid), a lidar computing system or an on-board computing device (e.g., the computing device 220 described herein) can sense objects moving within the recognition area, generate one or more possible object trajectories for the sensed objects and the autonomous vehicle, and analyze the possible object trajectories to evaluate the likelihood of a collision between the object and the autonomous vehicle. The performance and accuracy of a sensor system including lidar enable an autonomous vehicle to successfully navigate a route regardless of obstacles. For this purpose, the hardware components that make up a sensor such as lidar need to operate with optimal performance.

[0030] Manufacturing a sensor such as a lidar may include acceptable tolerances for sub - performance parts. For example, manufacturing limitations of semiconductor devices (e.g., III - V semiconductor devices such as FPAs) often cause some sub - performance devices on the manufactured wafers and / or performance variations of such devices. In other words, the manufactured FPA may include a number of sub - performance pixels that can affect the overall performance of the FPA, thereby potentially affecting the overall performance of the sensor (e.g., lidar) and autonomous driving operations.

[0031] When manufacturing an FPA, a manufacturer can discover that a large number of FPAs have a high level of sub - performance elements (e.g., noisy, leaking, or sub - performance pixels, or pixels with variable turn - on voltages) that can degrade the performance of the FPA. Generally, such discoveries force the manufacturer to either discard such FPAs (thereby significantly reducing the production yield) or apply the FPAs in the field (thereby leading to reduced sensing accuracy and unoptimized sensor performance). To solve such problems, the present disclosure provides a system and method for selectively correcting the breakdown voltage of sub - performance elements. It can be understood that such a system may be applied during the manufacturing process, e.g., during testing, and may also be applied in the field, e.g., during operation.

[0032] According to aspects of the present disclosure, a system and method for improved object perception are provided by managing the Arming operation at the pixel level of the FPA. This enables the system to compensate for or correct changes in the breakdown voltage of the FPA pixels that can negatively impact performance and degrade it. The advantages provided by the embodiments described herein are to reduce processing time and bandwidth and enable the on-board computing device 220 to generate faster object trajectories. This is particularly important in autonomous vehicles operating in the field. In the field, faster and more accurate perception and decision-making functions (due to reduced processing time and bandwidth) can help the autonomous vehicle generate and execute faster driving base decisions, thereby causing improved autonomous driving behavior of the autonomous vehicle. As also mentioned herein, the reduction in processing time and bandwidth also improves power consumption, for example, thereby increasing the overall driving distance of an autonomous vehicle operating on a battery.

[0033] It will be appreciated that the techniques referred to herein provide several advantages over existing systems. For example, existing systems provide Global biasing in the Armed state for all PDA pixels. In this case, pixel-level performance variations and the resulting variable data can cause non-optimized output from the FPA. As described in the present disclosure, the ability to correct the breakdown voltage when the APD operates in Geiger mode provides a higher performance FPA and also enables the manufacturer to achieve a higher yield of FPA modules.

[0034] In one aspect, selective voltage bias adjustment to compensate for yield voltage variations may be performed during the test phase or in the field during module assembly. As described later in this specification, the present disclosure also provides circuits that can tolerate adjustments performed in the field. For example, in factory-level testing, the effective yield voltage of a given pixel is determined to be the voltage at which the pixel begins to generate a non-zero dark count rate for the first time for Geiger-mode measurements. Such types of measurements may also be made in the field. It is also possible to directly measure other performance parameters (e.g., photon detection efficiency (PDE)) and perform voltage bias correction to adjust the voltage bias to essentially equalize the PDE across the FPA. Thus, the disclosed solution provides a corrective measure for an FPA in which pixel performance variations occur during the process applied in the operating state. For example, when an FPA is applied to an autonomous vehicle and a decrease in pixel-level performance uniformity is detected, a voltage bias adjustment can be performed to compensate for yield voltage variations. Such performance improvements provide benefits to both the manufacturer and the system integrator. For example, the manufacturer can utilize the selective biasing techniques described herein to achieve a higher FPA module yield (without discarding the FPA). Additionally, a system integrator who integrates the FPA in the field, e.g., into a lidar system or other sensor, can utilize similar selective biasing techniques to compensate for yield voltage variations and extract higher performance from each applied FPA. Consequently, this leads to an improved sensing ability of the sensor (e.g., lidar) and to improved autonomous driving in terms of speed and accuracy.

[0035] Next is an exemplary description of a solution (autonomous vehicle and related sensors) that includes the systems and methodologies described herein. Such an exemplification is not limiting, and it will be understood by one of ordinary skill in the art that other sensors and other applications within the solution may also be applicable.

[0036] According to one aspect, a "vehicle" refers to any moving means of transportation that can carry one or more passengers and / or cargo and is driven by all forms of energy. "Vehicles" include, but are not limited to, automobiles, trucks, vans, trains, autonomous vehicles, airplanes, drones, etc. An "autonomous vehicle" (or AV) is a vehicle that includes a processor, programming instructions, and a drive unit that can be controlled by the processor without a human operator. The autonomous vehicle may be fully autonomous, requiring no human operator in most or all driving conditions and functions, or may be semi-autonomous, where a human operator can be required for specific conditions or specific operations, or where the human operator can override the vehicle's autonomous system and directly control the vehicle.

[0037] In particular, the solution is described herein in connection with autonomous vehicles. However, the solution is not limited to applications for autonomous vehicles. The solution can also be used in other applications such as robotic applications, rider system applications, measurement applications, and / or system performance applications. It will be understood that the embodiments used herein describe aspects of the solution. It will also be understood that all embodiments are exemplary and can be combined with other embodiments.

[0038] FIG. 1 shows an exemplary autonomous vehicle system 100 according to an aspect of the present disclosure. System 100 includes a vehicle 102a that travels on a road in a semi-autonomous or autonomous mode. The autonomous vehicle 102a may include, but is not limited to, a ground vehicle, an airplane, or a water vehicle (as shown in FIG. 1).

[0039] The self-driving vehicle 102a is generally configured to sense nearby objects 102b, object 114, and object 116. The objects may include, but are not limited to, vehicle 102b, bicycle users 114 (e.g., riders of bicycles, electric scooters, motorcycles, etc.), and / or pedestrians 116. When such sensing is performed, the self-driving vehicle 102a performs an operation of generating one or more possible object trajectories for the sensed objects, and analyzes at least one of the generated possible object trajectories to determine whether there is a probability that a collision between the self-driving vehicle and the objects at an unacceptable level will occur within a critical time (e.g., 1 minute). Hereinafter, this can also be referred to as a Collision probability assessment. If the probability of a collision occurring is high, the self-driving vehicle 102a determines whether the collision can be avoided when any one of a plurality of dynamically generated emergency operations accompanied by the vehicle trajectory provided by the self-driving vehicle 102a is performed within a preset period (e.g., N milliseconds). If the collision can be avoided, the self-driving vehicle 102a either takes no action or selectively performs a cautious operation (e.g., smoothly decelerates). On the contrary, if the collision cannot be avoided, the self-driving vehicle 102a immediately takes an emergency action (e.g., braking and / or changing the running direction). Other approach methods by the self-driving vehicle 102a for collision sensing and avoidance may be included in this specification as can be understood by a person of ordinary skill in the relevant technical field.

[0040] Referring to FIG. 3, and as will be described in further detail below, the autonomous vehicle 102a may be configured with a rider system 300. The rider system 300 may include a light emitter system 304 (transmitter) that emits light pulses 104 to sense objects located within the distance or distance range of the autonomous vehicle 102a. The light pulses 104 may be incident on one or more objects (e.g., autonomous vehicle 102b) and can be reflected back by the rider system 300. The reflected light pulses 106 that reach the photodetector 308 are processed by the rider system 300 to determine the distance from the object to the autonomous vehicle 102a. In some embodiments, the photodetector 308 may include a photon detector or an array of photon detectors positioned and configured to receive light reflected back by the system. For example, the photodetector 308 may include a focal plane array including a pixelated photodiode array (PDA) and a readout integrated circuit (ROIC). According to some aspects, each pixel of the PDA may be electrically coupled to a dedicated channel of the ROIC such that the ROIC controls the arming and disarming of individual PDA pixels via a biasing circuit as described hereinbelow. According to some aspects, the PDA may include a Geiger mode avalanche photodiode (GmAPD) that can provide a single photon sensing level.

[0041] On one side, a silicon photodiode converts light into an electrical signal. This conversion occurs when photons with energy greater than the bandgap of the detector material are absorbed, causing electrons to jump from the valence band to the conduction band of the semiconductor, which is read as a signal. GmAPD uses the same process but generates internal gain using an avalanche amplification process. The avalanche region is generated within the APD, forming a region of very high electric field strength. When photo-generated (or thermally generated) electrons in the conduction band move into the avalanche region, the electric field strength is sufficient to accelerate the electrons to a point where they can cause "impact ionization" and release other electrons. All of these electrons can form an avalanche amplification and can also be accelerated. This process causes the detector gain. The typical gain for an APD ranges from 10 to several hundred times.

[0042] Geiger mode operation can increase the typical gain of the APD to an even higher level. The gain of the APD increases with a stronger internal electric field but is maintained finite up to a critical breakdown voltage V b set by the corresponding breakdown electric field E b up to. At voltages applied less than V b , the output photocurrent of the APD is proportional to the input optical intensity, and the device operation below the breakdown voltage is called "linear mode". Conversely, at V bHigher applied voltages lead to a finite probability of causing a self-sustaining avalanche characterized by the divergent (i.e., infinite) gain of the single carriers injected into the avalanche region. The rapid generation of the avalanche current, simply measured by a single photoexcited carrier, allows for the effective sensing of a single photon. In actual operation, the self-sustaining Geiger mode avalanche disappears as soon as it is sensed. In this case, it can be said that the effective gain is given by the number of charges flowing into the avalanche region in response to the injection of a single electron (generally, >>10 5 ).

[0043] In some cases, the quenching and resetting of the GmAPD can be achieved passively by placing a sufficiently large resistor in series with the detector. A fixed bias voltage is applied across the series combination of the GmAPD and the resistor. When no current is flowing, the total bias is across the GmAPD and it is then in the "armed" state. When the junction breaks down, a large current flows through the resistor, and the resulting voltage drop across the resistor reduces the voltage across the GmAPD, allowing the avalanche process to passively disappear in the "disarmed" state. In other cases, when the avalanche breakdown is sensed, the bias voltage is actively reduced below the breakdown voltage and the GmAPD avalanche actively disappears. After the disappearance in both types of "disarmed" states, the bias voltage across the GmAPD is reset to a value greater than the breakdown voltage and it becomes armed again to perform subsequent detections. The discharge and reset cycles are referred to as the Geiger mode of operation.

[0044] As described hereinafter in this specification with reference to FIG. 4, aspects of the present disclosure are directed to selectively adjusting the voltage bias of pixels to compensate for variations in breakdown voltage in order to achieve a preferred (e.g., uniform or otherwise specified) sensing efficiency. In the case of an FPA using a GmAPD, the PDA may be armed or disarmed by operating the forward-applied reverse voltage in relation to the GmAPD breakdown voltage. For example, the PDA may be armed when the forward-applied reverse voltage exceeds the breakdown voltage of the GmPDA. Similarly, the PDA may be disarmed when the forward-applied reverse voltage is lower than the GmPDA breakdown voltage. It will be appreciated that by increasing the reverse voltage to a bias that exceeds the breakdown voltage, the PDA is considered to be armed. According to some aspects, the total voltage applied to the PDA may be the sum of a fixed negative DC bias voltage (Vdc) and an additional arming bias applied by the ROIC. For example, for an arming bias where the arming transistor switches between +5V and 0V (Ground), the (negative) sum V dc +5V maintains the PDA in the disarmed state. In other words, instead of arming the entire PDA, the present disclosure can perform voltage bias adjustment to compensate for breakdown voltage variations between each pixel to achieve a preferred sensing efficiency. As shown in FIG. 4, the selective biasing described herein can be accomplished via a biasing circuit.

[0045] Lidar information, such as sensed object information, is transmitted from the lidar device 300 to the on-board computing device 220 (see FIG. 2). Further, the autonomous vehicle 102a can transmit lidar information to a remote computing device 110 (e.g., a cloud processing system) via the communication network 108. The remote computing device 110 may be composed of one or more servers for processing one or more processes of the techniques described herein. Further, the remote computing device 110 may be configured to send / receive information / command words between autonomous vehicles 102a and between servers and / or databases 112 via the network 108.

[0046] Network 108 may include one or more wired or wireless networks. For example, network 108 may include a cellular network (e.g., a Long-Term Evolution (LTE) network, a Code Division Multiple Access (CDMA) network, a 3G network, a 4G network, a 5G network, and other next-generation types of networks). Also, the network may include a Public Land Mobile Network (PLMN), a Local Area Network (LAN), a Wide Area Network (WAN), a Metropolitan Area Network (MAN), a telephone network (e.g., a Public Switched Telephone Network (PSTN)), a private network, an Ad hoc network, an intranet, the Internet, an optical fiber infrastructure network, a cloud computing network, etc., and combinations of similar or such networks.

[0047] The autonomous vehicle 102a can search, receive, display, and edit information generated from a local application or transmitted from the database 112 via the network 108. The database 112 may be configured to store and supply raw data, indexed data, structured data, map data, program instruction words, or other known configuration information.

[0048] Figure 2 shows an exemplary architecture for a vehicle according to an aspect of the present disclosure. Vehicle 102a and / or vehicle 102b of FIG. 1 can have a system architecture that is the same as or similar to that shown in FIG. 2. Accordingly, the following description of system architecture 200 is sufficient to understand vehicle 102a and / or vehicle 102b of FIG. 1. However, other types of vehicles are considered to be within the scope of the technology described herein and may include more or fewer elements compared to those described with reference to FIG. 2. By way of non-limiting example, an airborne vehicle can exclude brakes or gear controllers but may include altitude sensors. As yet another non-limiting example, a water vehicle may include depth sensors. One of ordinary skill in the art will understand that other propulsion systems, sensors, and controllers may be included depending on the type of vehicle.

[0049] As shown in FIG. 2, system architecture 200 includes an engine or motor 202 and various sensors 204-218 for measuring various parameters of the vehicle. In a gas-powered or hybrid vehicle having a fuel-driven engine, the sensors may include, for example, an engine temperature sensor 204, a battery voltage sensor 206, an engine revolutions per minute (RPM) sensor 208, and a throttle position sensor 210. If the vehicle is an electric or hybrid vehicle, the vehicle may have an electric motor and accordingly the same sensors as a battery monitoring system 212 (for measuring the current, voltage, and / or temperature of the battery), a motor current sensor 214, a motor voltage sensor 216, and motor position sensors 218 such as a resolver and an encoder.

[0050] Operating parameter sensors common to all two types of vehicles include, for example, position sensors 236 such as accelerometers, gyroscopes and / or inertial measurement units; speed sensors 238; and an odometer sensor 240. Further, the vehicle may have a clock 242 used by the system to determine vehicle time during operation. The clock 242 may be built into the vehicle's on-board computing device, may be a separate device, or multiple clocks may be used.

[0051] In addition, the vehicle includes various sensors that operate to collect information about the environment in which the vehicle travels and to sense objects. For example, the sensors may include a position sensor 260 (e.g., a GPS device); one or more cameras 262; a lidar system 264; and / or a radar and / or sonar system 266. Further, the sensors may include environmental sensors 268 such as a precipitation sensor and / or a peripheral temperature sensor. The object sensing sensors can enable the vehicle to sense objects within a predetermined distance range around the vehicle 200, and the environmental sensors collect information about the environmental conditions within the vehicle's travel area.

[0052] During operation, information is transmitted from the sensors to the vehicle on-board computing device 220. The vehicle on-board computing device 220 analyzes the information collected by the sensors and selectively controls the operation of the vehicle based on the analysis results. For example, the vehicle on-board computing device 220 can control the brakes via the brake controller 222; the direction via the steering controller 224; the speed and acceleration via the throttle controller 226 (in the case of an internal combustion engine vehicle) or the motor speed controller 228 (e.g., the current level controller in an electric vehicle); the transmission gear controller 230 (in the case of a vehicle with a transmission); and / or other controllers. The auxiliary device controller 254 can be configured to control one or more auxiliary devices such as test systems, auxiliary sensors, and mobile devices mounted on the vehicle.

[0053] Geographical location information may be transmitted from the position sensor 260 to the vehicle on-board computing device 220, and the vehicle on-board computing device 220 can thereby determine characteristics of known fixed environments such as roads, buildings, stop signs, and / or traffic signals, approaching a map of the environment corresponding to the location information. Object sensing information collected from the camera 262 and / or from sensors such as the lidar system 264 is transmitted to the on-board computing device 220 (from the sensors). The object sensing information and / or the collected images are processed by the on-board computing device 220 to sense objects near the vehicle 200. Based on the sensor information and / or the collected images, all known or knowable techniques for sensing objects may be used in the embodiments disclosed in this document.

[0054] Lidar information (e.g., collected by the detector 308) is transmitted from the lidar system 264 to the on-board computing device 220. Further, the collected images are transmitted from the camera 262 to the vehicle on-board computing device 220. The lidar information and / or the collected images are processed by the vehicle on-board computing device 220 to sense objects proximate to the vehicle 200. The manner in which object sensing is performed by the vehicle on-board computing device 220 includes the functions described in this disclosure.

[0055] As can be understood by one of ordinary skill in the art, by improving the sensing function of the lidar system 264, and more specifically, the detector 308, the vehicle on-board computing device 220 can receive more accurate sensing and generate more accurate object tracking and the trajectories of the sensed objects. Since at least one sensor in the vehicle sensor module is improved to provide more accurate sensing information, this leads to improved autonomous driving. Such improvements provide many additional advantages. For example, processing more accurate information may consume less computing bandwidth when verifying sensor accuracy information, enabling the vehicle on-board computing device 220 to perform analysis at a faster speed and provide solutions.

[0056] FIG. 3 shows an exemplary architecture for a lidar system according to an aspect of the present disclosure. In some aspects, the lidar system 264 of FIG. 2 may be the same as or generally similar to the lidar system 300. Thereby, the description of the lidar system 300 is sufficient to understand the lidar system 264 of FIG. 2.

[0057] As shown in FIG. 3, the lidar system 300 includes a housing 306 that is rotatable 360° about a central axis such as the hub or shaft 315 of the motor 316. The housing may include a transmitter / receiver opening 312 made of a light-transmissive material. Although a single opening is shown in FIG. 3, the solution is not limited to this. In other situations, a plurality of openings for emitting and receiving light may be provided. In each situation, as the housing 306 rotates around the internal configuration, the lidar system 300 can emit light through one or more openings 312 and receive light that reflects back towards one or more openings 212. In an alternative situation, the outer shell of the housing 306 may be a fixed dome made of a material that is at least partially light-transmissive, and there may be a rotatable configuration inside the housing 306.

[0058] Inside the rotating shell or fixed dome, there is a light emission system 304 configured and positioned to generate and emit light pulses with one or more laser emission chips or other light emission devices through the opening 312 or through the transparent dome of the housing 306. The emission system 304 may include a predetermined number of individual emitters (e.g., 8 emitters, 64 emitters, or 128 emitters). The emitters can emit light having generally the same intensity or variable intensity. Also, the lidar system includes a photodetector or an array of photodetectors (e.g., a focal plane array (FPA) including a photodiode array and / or a Geiger mode PDA) positioned and configured to receive the light reflected back by the system. In one example, the light emission system 304 and the photodetector 308 can rotate with the rotating shell or rotate inside the fixed dome of the housing 306. However, it will be understood that the mechanical lidar system described herein can also embody other exemplary lidar systems, such as a solid-state lidar system, in an exemplary lidar system that depends on aspects of the solution.

[0059] On one side, one or more optical element structures 310 can function as one or more lenses or waveplates that are positioned in front of the light emission system 304 and / or the photodetector 308 to adjust the focus and direction of the light passing through the optical element structure 310.

[0060] One or more optical element structures 310 can be positioned in front of a mirror (not shown) (e.g., in a focal plane array) to adjust the focus and direction of the light passing through the optical element structure 310. The system includes an optical element structure 310 that is positioned in front of the mirror and is coupled to a rotating element of the system, and the optical element structure 310 rotates with the mirror. Alternatively or additionally, the optical element structure 310 may include such a plurality of structures (e.g., lenses and / or waveplates). Optionally, the plurality of optical element structures 310 may be arranged in a row in a shell portion of the housing 306 or may be arranged integrally.

[0061] According to one aspect, the lidar system 300 includes a light emission system 304, a motor 316, and a power supply unit 318 for supplying power to the electronic components. The lidar system 300 also includes an analysis unit 314 including an element such as a non-volatile computer-readable memory 320 configured with programming instructions that enable a processor 322 and the system to receive information collected by the light detection unit, analyze the information to measure the characteristics of the received light, and generate information that can be used to make decisions regarding the operation of the connected system in the environment where the information is collected. As shown, the analysis unit 314 can be selectively integrated with the lidar system 300 and can be partially or entirely located outside the lidar system and communicatively coupled to the lidar system via a wired or wireless communication network or link.

[0062] According to one aspect, the rider system 300 can generate and provide an output to a vehicle on-board computing system (e.g., the on-board computing device 220). Such an output may include a three-dimensional (3D) mapping of a recognition area (rider 264) or an area illuminated by the rider system 300. Also, according to some aspects, the 3D mapping, also referred to as a Lidar grid, in which grid cells can each provide a proportional representation of the recognition area. When an object is sensed within the Lidar grid, the on-board computing device 220 can generate a point cloud mapping (e.g., a Lidar grid) including the sensed object and attempt to generate a collision threat assessment and potential driving guidelines for other autonomous vehicle systems. In this regard, systems and methods for improving the sensing function and performance of the FPA are described later in this specification with reference to FIGS. 4 and 5.

[0063] FIG. 4 shows an exemplary partial overview of a focal plane array (FPA) 400 according to one embodiment. FPA 400 may include a photodiode 402, a high voltage source 404, an arm / disarm control circuit 406, a disarm voltage 408, an arm voltage 410, and a counter stop 412. It will be appreciated that the operation of the arm and disarm voltages can provide the biasing voltage adjustment necessary to compensate for variations in the breakdown voltage. According to some aspects, FPA 400 may include a pixelated photodiode array (PDA) that includes photodiode 402. According to some aspects, the PDA may include a Geiger-mode Avalanche Photodiode (GmAPD). According to some aspects, together with the disarm voltage 408, the arm voltage 410, and the counter stop 412, the arm / disarm control circuit 406 may be part of a readout integrated circuit (ROIC). It will be appreciated that the ROIC may be included as part of FPA 400. Also, according to some aspects, the ROIC may be manufactured external to FPA 400.

[0064] According to one aspect, the high voltage source 404 may be connected to the negative electrode of the photodiode 402. The photodiode 402 may be a GmAPD photodiode. According to one aspect, the arm / disarm control circuit 406 may be configured as a biasing circuit for dynamically increasing a bias voltage (e.g., high voltage supply) to exceed the breakdown voltage of the photodiode 402. In one example, when an avalanche event occurs (e.g., when light is received), the arm / disarm control circuit 406 extinguishes (i.e., interrupts) the avalanche current, and a counter stop mechanism is triggered. In some aspects, to prevent the photodiode from being armed above the breakdown voltage, the arm / disarm control circuit 406 may not output an arm control signal. According to one aspect, the arm / disarm control circuit 406 may be an independent device within the FPA 400. Or, the arm / disarm control circuit 406 may be a part of the ROIC within the FPA 400. It will be appreciated that the ROIC may be a silicon-based integrated circuit that performs a predetermined number of electronic functions beyond the output of the photodiodes within the PDA.

[0065] It will be appreciated that the PDA may be a pixelated photodiode array where each pixel of the PDA includes a radiation detector such as the photodiode 402. Also, although FIG. 4 shows a single biasing circuit, it will be appreciated that the PDA may interact with a plurality of biasing circuits each connected to a respective radiation detector (photodiode 402) to selectively compensate for breakdown voltage variations. As mentioned herein, the selective compensation of breakdown voltage variations may depend on the observed performance of each photodiode 402 within the PDA, and various pixels (e.g., pixels having an observed breakdown voltage different from the expected average proper amount of the circuit) may be selectively compensated by aspects of the present disclosure.

[0066] As described herein, aspects of the present disclosure provide compensation for pixel performance variations by providing a controllable pixel-level biasing circuit that, together with an arm / disarm control circuit 406, selectively compensates for variations in the breakdown voltage. In this regard, the arm / disarm circuit 406 can operate to supply an arm / disarm voltage to the arm transistor to compensate for breakdown voltage variations. In one example, the arm / disarm circuit 406 can operate the voltage supply for the arm transistor with a +5V voltage supply line and prevent the transistor from being pulled to ground. This forces the associated PDA pixel to be deselected (or maintained in a deselected state) and reset. To set the pixel to the armed state, the arm / disarm control circuit 406 can apply a forward-reverse voltage that exceeds the breakdown voltage of the photodiode 402.

[0067] It will be appreciated that pixel-level variation sensing may be performed during a test phase and the state of the pixel may be stored as part of a Deselect map. In some aspects, the Deselect map can display the state of each pixel within the PDA and, if present, the type of defect associated with each pixel including measurements and sensed predetermined variations with respect to the breakdown voltage. For example, the Deselect map may include a state indicating that the photodiode is in a sub-performance state in relation to the photodiode 402. Other sub-performance states may be stored in the Deselect map including an observed dark current value that exceeds a previously set dark current threshold and / or an observed leakage current level that exceeds a previously set leakage current threshold, although not limited thereto.

[0068] According to one aspect, the following is an illustration of selectable biasing for the breakdown voltage at which a photodiode is biased at a preferred bias voltage based on the physical attributes of the photodiode itself. As described above, the main GmAPD performance parameter depends on the overbias V 0V and the overbias is the difference between the total bias V b and the breakdown voltage V br (i.e., V 0v =IV b -V br l). Ideally, a focal plane array composed of GmAPDs can have the same performance for each pixel by applying the same overbias V 0V to all pixels. However, if a single value of voltage bias V b is applied to all pixels and the breakdown voltage V br varies from pixel to pixel, V 0V will vary from pixel to pixel along with the performance parameters that depend on V 0V . As mentioned in this specification, semiconductor wafer manufacturing and processing can lead to significant variations in device performance and characteristics. Such variations can appear in devices operating at different standard breakdown voltages (e.g., a first device of a PDA operating at a first standard breakdown voltage V br1 and a second device of a PDA operating at a second standard breakdown voltage V br2 ). The standard breakdown voltage value is the critical value at which, when exceeded, a single electron-hole pair can cause an avalanche phenomenon. In one example, V br1 may be a value different from V br2 (e.g., -80V and -79V). The values described in this specification are illustrative, and it will be understood that other standard values can be measured and compensated for. According to one aspect, the total voltage for the PDA is a fixed negative DC bias voltage (Vdc) and an additional arm / disarm bias V aidmay be the sum. In the current practice, the ROIC connected to the PDA is programmed to provide the same arm / disarm bias voltage (V arm and V disarm ) across the entire PDA. Thereby, when V dc is a same fixed value across the entire PDA, using an ROIC arm voltage V arm of 0V (i.e., ground) across the entire PDA can cause a first device having an overbias voltage V 0V different from that of the second device. For example, assuming V dc = -83V and V arm = 0V, the first device (where V br1 = -80V) can operate with an overbias of V 0V = 3V, and the second device (where V br2 = -79V) can operate with an overbias of V 0V = 4V. The value of the overbias V 0V is a core element in determining the performance of the GmAPD, and variations in V 0V for the PDA cause different sensing performances and characteristics when the device is armed. To solve such a defect, the arm / disarm control circuit 406 can change the arm bias V arm to make the first device and the second device having different values (e.g., V arm1 and V arm2 ) have the same overbias voltage value. In other words, regardless of the variations in the physical attributes of different photodiodes on the array, the arm / disarm control circuit 406 provides a voltage bias adjustment to compensate for the variations in the breakdown voltage. This ensures a uniform sensing efficiency of the APD.

[0069] According to one aspect, to compensate for the breakdown voltage fluctuations and generate various adjustments to the bias voltage to ensure the uniform sensing efficiency of the APD, the arm / disarm control circuit 406 can be arranged in the following manner: The photodiode 402 may be connected to the high voltage source 404 at the negative terminal and to the arm / disarm circuit 406 at the positive terminal. In one exemplary case, the high voltage source 404 can supply a high voltage sufficient to bias the photodiode 402 beyond the breakdown voltage and / or to a preferred voltage level exceeding the maximum breakdown voltage.

[0070] Next is an example showing the arm and disarm states controlled by the arm / disarm control circuit 406. When arming and disarming each PDA pixel, the arm / disarm control circuit also controls a bias value that compensates for a predetermined variation on the measured breakdown voltage of each pixel for each pixel. The values described in the situations described later are exemplary, and it will be understood that other values can also be considered and implemented as would be understood by a person of ordinary skill in the art.

[0071] Disarm state: In one exemplary case, the disarm voltage 408 may be a voltage of +5V, and the arm voltage 410 may be 0V (e.g., ground). In this exemplary case, the arm / disarm control circuit 406 can apply the disarm voltage 408 to the positive electrode of the photodiode 402 to generate a reverse bias voltage sufficient to disarm the photodiode 402. For example, if the high voltage 404 is -83V, the arm / disarm circuit 406 applying +5V to the positive electrode biases the photodiode 402 at a value of -78V, and the value of -78V is less than the standard breakdown voltage of -80V. This causes the disarm of the photodiode 402.

[0072] Arm state of the first device of the APD: In one exemplary case, the arm / disarm control circuit 406 applies a voltage V which is the standard breakdown voltage to the photodiode 402 br1An arm voltage sufficient to maintain a reverse bias value exceeding -80V can be applied. In this case, the arm voltage 410 may be set to 0V, and the photodiode 402 can operate at -83V, which is 3V overbias exceeding the standard breakdown voltage of -80V.

[0073] Arm state of the second device of the APD: Assume that the second device of the APD has different standard breakdown voltages. As mentioned in this specification, the standard breakdown voltage V br2 The example of is V br1 It may be higher or lower than. V br2 If is lower than V br1 (for example, -79V), the arm / disarm control circuit 406 can set the arm voltage 410 to +1V, and the second device (not shown) can operate at -82V, which is 3V overbias exceeding the standard breakdown voltage of -79V. Therefore, even though the two devices have different breakdown voltages from each other, the two devices can all operate at the same 3V overbias voltage. By compensating for the breakdown voltage variation, the arm / disarm control circuit 406 can achieve a uniform overbias voltage, which can lead to the corresponding uniformity of performance parameters that directly depend on the overbias, such as the photon detection efficiency.

[0074] Thereby, for example, aspects of the present disclosure provide for equalizing the applied overbias for all pixels (e.g., photodiodes) by implementing a pixel-dependent voltage bias adjustment range (Swing) (e.g., control of the arm voltage value) via the arm / disarm control circuit 406. In this process, each ROIC channel may be programmed to switch the corresponding PDA pixel from a disarm voltage (e.g., 5V supply line) to a selectable voltage value exceeding ground. In such a manner, variations in the breakdown voltage may be compensated by variations in the voltage bias at the correlated pixel level, and all pixel overbias voltage values may be equal. According to some aspects of the present disclosure, selectively applying different arm voltages by the ROIC leads to a uniform overbias voltage (V 0V = 3V) for all pixels of the PDA. As described in the above example, selectively applying different arm voltages to two pixels having different breakdown voltages (e.g., V br1 and V br2 being -80V and -79V respectively) leads to a uniform overbias voltage operation for the PDA and furthermore to a more uniform and predictable performance.

[0075] As mentioned herein in connection with existing GmAPD FPAs, inherent process variations within the PDA remain as a limiting factor to the uniformity of FPA performance. If the performance variations are too large to be acceptable in the application space, this can significantly affect the device yield. Existing FPAs use ROICs having the same voltage biasing for all array pixels, and PDA-level variations lead to variations in the overall FPA operation. According to some aspects, the advantages of the systems and methods of the present disclosure are that the inherent PDA-level variations and the limitations of current semiconductor process technologies are compensated using the additional functionality of the ROIC that equalizes the pixel-level biasing. This achieves a more uniform FPA performance and improves the overall yield of devices meeting the system-level requirements.

[0076] FIG. 5 shows an exemplary optical process 500 for performing the biasing operations described herein. According to some aspects, process 500 may include storing, in a memory of an optical processing device, one or more characteristics for each pixel of a pixelated photodiode array (PDA) within a focal plane array (FPA) (not shown). For example, the storing step may be performed during a test step of the FPA during a manufacturing process to determine performance metrics of the FPA. According to some aspects, one or more characteristics of each pixel may be related to performance observed during testing, e.g., noise level, leakage current, breakdown voltage (e.g., standard breakdown voltage), and other matters.

[0077] As shown in step 502, according to some aspects, process 500 may further include reading, by a read integrated circuit communicatively coupled to each pixel of the PDA and the memory, one or more characteristics for each pixel of the PDA. The reading step may include reading the standard breakdown voltage of a pixel to determine requirements for a predetermined potential bias voltage for operating the pixel in Geiger mode. As shown in step 504, according to some aspects, process 500 may further include adjusting an arm / disarm bias voltage for each pixel of the PDA based on the one or more characteristics read for each pixel. Each pixel of the PDA may include a Geiger mode avalanche photodiode (GmAPD), and it will be appreciated that the one or more characteristics include the breakdown voltage of the GmAPD. As mentioned herein, breakdown voltage variations may be compensated by the arm / disarm control circuit 406 to equalize pixel-level biasing. According to some aspects shown in FIG. 4, the bias voltage of each pixel may be adjusted upward in response to the breakdown voltage of the pixel being less than a threshold value (e.g., the standard breakdown voltage for the overall APD) that has already been set. Similarly, the bias voltage of a pixel may be adjusted downward in response to the breakdown voltage of the pixel exceeding the already set threshold value.

[0078] According to one aspect, the bias voltage for each pixel may be adjusted within the PDA based on the respective breakdown voltages to cause each pixel to operate in an armed state, thereby enabling the detection of incoming photons. According to one aspect, the reverse bias is adjusted with a preset arm bias value (e.g., a voltage exceeding the standard breakdown voltage for each pixel of the PDA) for arming each pixel from a bias source that supplies the reverse bias to each pixel of the PDA (e.g., disarm voltage 408), and a preset disarm bias value for disarming each pixel. In this connection, adjusting the reverse bias to arm each pixel of the PDA can be accomplished with a value that exceeds the breakdown voltage value stored in memory for each pixel of the PDA by the arm / disarm control circuit 406.

[0079] In one aspect, to disarm each pixel of the PDA, the reverse bias may be further adjusted with a value less than the breakdown voltage value stored in memory for each pixel of the PDA. From the perspective of the inconsistency of the performance variations of the PDA due to the manufacturing process, it can be understood that the performance characteristics stored for one pixel of the PDA may be different from the performance characteristics stored for other pixels of the PDA (e.g., the pixels may have different breakdown voltage characteristics).

[0080] It will be understood that this detailed description section is for the purpose of interpreting the claims and not for any other part. The other parts, although not all, can present one or more exemplary aspects considered by the inventors, and thus it can be understood that in no way is it intended to limit the present disclosure or the appended claims.

[0081] According to some aspects described with reference to FIGS. 1 through 5, an optical processing apparatus is disclosed. According to some aspects, the apparatus includes a pixelated photodiode array (PDA) where each pixel of the PDA includes a radiation detector, a memory configured to store one or more characteristics for each pixel of the PDA, and a readout integrated circuit (ROIC) communicatively coupled to the PDA and the memory. According to some aspects, the ROIC is configured to read one or more characteristics for each pixel of the PDA from the memory and adjust an arm / disarm bias voltage for each pixel of the PDA based on the one or more characteristics.

[0082] According to some aspects, each pixel of the PDA includes one or more Geiger mode avalanche photodiodes (GmAPDs) where the one or more characteristics read from the memory include the breakdown voltage of the one or more GmAPDs. According to some aspects, the ROIC is configured to adjust the arm / disarm bias voltage of a pixel upward in response to the breakdown voltage of the pixel being less than a preset threshold. According to some aspects, the ROIC is configured to adjust the arm / disarm bias voltage of a pixel downward in response to the breakdown voltage of the pixel exceeding a preset threshold. According to some aspects, the ROIC is configured to adjust the arm / disarm bias voltage for each pixel of the PDA based on the respective breakdown voltages such that each pixel can operate in an armed state.

[0083] Also, according to some aspects, the apparatus may include a bias source configured to supply an arm / disarm bias voltage to each pixel of the PDA, and the ROIC is configured to adjust the arm / disarm bias voltage at a preset arm bias value to arm each pixel and adjust the arm / disarm bias voltage at a preset disarm bias value to disarm each pixel. According to some aspects, the ROIC is configured to adjust the arm / disarm bias voltage to a value exceeding the yield voltage value stored in the memory for each pixel of the PDA to arm each pixel of the PDA. According to some aspects, the ROIC is configured to adjust the arm / disarm bias voltage to a value less than the yield voltage value stored in the memory for each pixel of the PDA to disarm each pixel of the PDA.

[0084] According to some aspects, one or more characteristics for a first pixel of the PDA are different from one or more characteristics for a second pixel of the PDA. According to some aspects, the first pixel and the second pixel are configured to operate at the same overbias voltage level after adjustment of the arm / disarm bias voltage.

[0085] It will be appreciated that the apparatus includes a focal plane array (FPA). Also, the apparatus may include a photodetector and a distance measurement sensor (lidar). According to some aspects, the ROIC is configured to adjust the arm / disarm bias voltage for each pixel of the PDA so that each pixel of the PDA operates at the same overbias voltage level.

[0086] According to one aspect, a step of reading, by a readout integrated circuit (ROIC) from a memory, one or more characteristics for each pixel of a pixelated photodiode array (PDA) - each pixel of each PDA includes a respective radiation detector, and the ROIC is communicatively coupled to the PDA and the memory - ; and a step of adjusting, by the ROIC, an arm / disarm bias voltage for each pixel of the PDA based on the one or more characteristics; are disclosed. According to one aspect, the one or more characteristics read from the memory include the breakdown voltage of the pixel. According to one aspect, the adjusting step further includes a step of adjusting upward the arm / disarm bias voltage of the pixel in response to the breakdown voltage of the pixel being less than a preset threshold value.

[0087] According to one aspect, the adjusting step further includes a step of adjusting downward the arm / disarm bias voltage of the pixel in response to the breakdown voltage of the pixel exceeding a preset threshold value.

[0088] According to one aspect, an apparatus, such as a readout integrated circuit (ROIC) is disclosed. According to one aspect, the ROIC is communicatively coupled to a pixelated photodiode array (PDA) and a memory configured to store characteristics for each pixel of the PDA, where each pixel of the PDA includes a radiation detector. According to one aspect, the ROIC is configured to read, from the memory, characteristics for each pixel of the PDA and adjust an arm / disarm bias voltage for each pixel of the PDA based on the respective characteristics of each pixel. According to one aspect, the one or more characteristics read from the memory include the breakdown voltage for each radiation detector.

[0089] Although the present disclosure describes exemplary aspects in exemplary fields and applications, it should not be understood to be limited thereto. Other aspects and variations are possible and are within the scope and spirit of the present disclosure. For example, and without limiting the generality of this paragraph, aspects are not limited to the software, hardware, firmware, and / or entities shown in the drawings and / or described herein. Further, aspects have significant utility in fields and applications beyond the examples described herein (whether or not explicitly described herein).

[0090] Aspects are described herein using functional components that describe the implementation of embodied functions and relationships. Here, the boundaries of such functional components are arbitrarily defined for convenience of explanation. Alternative boundaries may be defined as long as the specific functions and relationships (or their equivalents) are appropriately performed. Also, alternative aspects can perform functional configurations, steps, operations, methods, etc. using an order different from the order described herein.

[0091] As used herein, the terms "one aspect", "aspect", "exemplary aspect" or similar expressions indicate that the described aspect may include a particular feature, structure, or characteristic, but that not all aspects necessarily include the particular feature, structure, or characteristic. Also, such expressions do not necessarily refer to the same aspect. When a particular feature, structure, or characteristic is described in connection with one aspect, it will be within the knowledge of one of ordinary skill in the relevant art to apply such feature, structure, or characteristic to other aspects, whether or not explicitly recited or described herein. Additionally, some aspects may be described using the terms "coupled" and "connected" and their derivatives. This terminology is not necessarily intended to be synonymous. For example, some aspects may be described using the expressions "connected" and / or "coupled" to indicate that two or more elements are in direct physical or electrical contact with each other. However, the term "coupled" may also mean that two or more elements are not in direct contact with each other but still may cooperate or interact.

[0092] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary aspects, but should be defined solely by the following claims and their equivalents.

[0093] It will be understood that this detailed description section is for the purpose of interpreting the claims and not for any other part. The other parts, while not all, may present one or more exemplary embodiments contemplated by the inventors, and thus it can be understood that they are not intended to limit the present disclosure or the appended claims in any way.

[0094] Although this disclosure describes exemplary embodiments in exemplary fields and applications, it should not be understood that the disclosure is limited thereto. Other embodiments and variations are possible and are within the scope and spirit of this disclosure. For example, and without limiting the generality of this paragraph, embodiments are not limited to the software, hardware, firmware, and / or entities shown in the drawings and / or described herein. Further, (regardless of whether explicitly described herein) embodiments have significant utility in fields and applications beyond the examples described herein.

[0095] Embodiments are described herein using functional components that describe the implementation of embodied functions and relationships. Here, the boundaries of such functional components are arbitrarily defined for technical convenience. Alternative boundaries may be defined as long as the specific functions and relationships (or their equivalents) are appropriately performed. Also, alternative embodiments can perform functional configurations, steps, operations, methods, etc. using an order different from the order described herein.

[0096] As used herein, the terms "one embodiment," "an embodiment," "exemplary embodiment," or similar expressions indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments necessarily include the particular feature, structure, or characteristic. Also, such expressions do not necessarily refer to the same embodiment. When a particular feature, structure, or characteristic is described in connection with an embodiment, applying such feature, structure, or characteristic to other embodiments would be within the knowledge of a person of ordinary skill in the relevant technical field, whether or not explicitly mentioned or described herein. Additionally, some embodiments may be described using the expressions "coupled" and "connected" and their derivatives. This terminology is not necessarily intended to be synonymous. For example, some embodiments may be described using the expressions "connected" and / or "coupled" to indicate that two or more elements are in direct physical or electrical contact with each other. However, the term "coupled" may also mean that two or more elements are not in direct contact with each other but can still cooperate or interact.

[0097] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined solely by the following claims and their equivalents.

Claims

1. A pixelated photoDiode Array (PDA) wherein each pixel of the pixelated photoDiode Array includes a radiation detector; A memory configured to store one or more characteristics for each pixel of the pixelated photoDiode Array; and A Read Out Integrated Circuit (ROIC) communicatively coupled to the pixelated photoDiode Array and the memory; comprising The read out integrated circuit is configured to read the one or more characteristics for each pixel of the pixelated photoDiode Array from the memory and adjust an Arm / Disarm bias voltage for each pixel of the pixelated photoDiode Array based on the one or more characteristics. An apparatus.

2. Each pixel of the pixelated photoDiode Array includes one or more Geiger-mode Avalanche Photodiodes (GmAPDs); The apparatus of claim 1.

3. The one or more characteristics read from the memory include a breakdown voltage of the one or more Geiger-mode Avalanche Photodiodes; The apparatus of claim 2.

4. The read out integrated circuit is configured to adjust the Arm / Disarm bias voltage of the pixel upward in response to the breakdown voltage of the pixel being less than a preset threshold; The apparatus of claim 3.

5. The read integrated circuit is configured to adjust the arm / disarm bias voltage of the pixel downward in response to the breakdown voltage of the pixel exceeding a preset threshold value. The device according to claim 3.

6. The read integrated circuit adjusts the arm / disarm bias voltage for each pixel of the pixelated photodiode array based on each of the breakdown voltages, such that each pixel operates in an armed state. The device according to claim 3.

7. Further comprising a bias source configured to supply the arm / disarm bias voltage to each pixel of the pixelated photodiode array; The read integrated circuit is configured to adjust the arm / disarm bias voltage with a preset arm bias value to arm each pixel, and to adjust the arm / disarm bias voltage with a preset disarm bias value to disarm each pixel. The device according to claim 1.

8. The read integrated circuit is configured to adjust the arm / disarm bias voltage above the breakdown voltage value stored in a memory for each pixel of the pixelated photodiode array to arm each pixel of the pixelated photodiode array. The device according to claim 7.

9. The read integrated circuit is configured to adjust the arm / disarm bias voltage below the breakdown voltage value stored in a memory for each pixel of the pixelated photodiode array to disarm each pixel of the pixelated photodiode array. The device according to claim 8.

10. The one or more characteristics for the first pixel of the pixelated photodiode array are different from the one or more characteristics for the second pixel of the pixelated photodiode array, The apparatus according to claim 1.

Images