An automated testing system and method for position sensitive detector position characteristics

Abstract

This invention discloses an automated testing system and method for the position characteristics of a position-sensitive detector. The system includes a detector fixture, a position-sensitive detector, a laser, a two-dimensional precision motion platform, a transimpedance amplifier circuit, a data acquisition card, and a control and processing unit. The laser illuminates the front of the detector via an optical fiber. The detector fixture fixes the detector to the precision motion platform and places it in an anechoic chamber. The transimpedance amplifier circuit converts the current signal into a voltage signal, which is then synchronously acquired by the data acquisition card. The control and processing unit sends displacement control commands to the two-dimensional precision motion platform and receives the voltage signal from the data acquisition card to calculate the position coordinates. The detector fixture integrates a temperature sensing array and a semiconductor cooling chip, and works with a spatiotemporal dual-domain collaborative control module to correct temperature drift errors. During testing, a bias voltage is applied and the laser is adjusted to illuminate the center of the detector. After performing geometric deviation calibration, the system automatically scans point by point, calculates the position coordinates, and calculates the difference between the calculated position coordinates and the actual position to obtain the position detection error.

Description

Technical Field

[0001] This invention relates to the field of position-sensitive detector measurement technology, and specifically to an automated testing system and method for the position characteristics of position-sensitive detectors. Background Technology

[0002] Position-sensitive detectors, as highly sensitive semiconductor sensors capable of real-time, continuous, and precise detection of the incident light spot position, possess advantages such as fast response speed, high position resolution, wide dynamic range, continuous photosensitive surface structure, and small size, making them widely used in precision measurement, automatic control, and laser alignment. The positional characteristics of a position-sensitive detector are the fundamental and core performance indicator determining its high-precision measurement capability. When the detector operates, based on the transverse photoelectric effect, the incident light signal excites photogenerated carriers within the photosensitive surface of the device. At this time, under the influence of the built-in electric field of the PN junction or an applied reverse bias voltage, photogenerated electrons and holes are separated and enter the uniform resistive layer on the device surface. Due to the uniformly distributed surface resistance of the resistive layer, the photogenerated carriers entering the resistive layer diffuse or drift from the incident point to the surrounding electrodes. During this process, the magnitude of the photocurrent flowing to each electrode depends on the equivalent resistance value between the incident light spot position and each electrode. This charge-splitting mechanism enables the position-sensitive detector to output a continuous analog position signal. By precisely measuring the proportion of photocurrent collected by each electrode, the precise coordinates of the incident light spot on the photosensitive surface can be calculated. The position characteristics of a position-sensitive detector are closely related to the uniformity of the resistive layer on the device surface and the symmetry of the electrode structure. An ideal and uniform resistive layer can ensure a strict linear relationship between photocurrent and position, thereby eliminating geometric distortion and helping to improve the position linearity and position resolution of the position-sensitive detector.

[0003] Currently, testing the positional characteristics of position-sensitive detectors typically requires integrating multiple discrete devices, including a highly stable laser source, a high-precision displacement platform, a complex probe station or wire bonding process, and a supporting multi-channel transimpedance amplification and data acquisition system. This complex testing architecture not only places extremely high demands on the optical path alignment accuracy and the motion resolution of the displacement platform, but also often involves cumbersome and unstable operations during device clamping and electrode contact, easily introducing noise that interferes with weak photocurrent signals. Furthermore, the tedious data scanning and calculation process significantly reduces the feedback efficiency of device performance evaluation, resulting in lengthy testing cycles and hindering rapid product iteration and mass production screening.

[0004] Furthermore, during long-term, continuous, high-density scanning tests, the sustained laser irradiation causes localized heat accumulation on the photosensitive surface, while the internal current of the device also generates Joule heating. The resistive layer of the semiconductor material exhibits temperature dependence, and even a small temperature gradient can disrupt the uniform and symmetrical distribution of the surface resistivity. Traditional testing systems often overlook this dynamic thermal effect, leading to nonlinear errors caused by temperature drift in the later-stage position calculation results, severely limiting the high-precision evaluation of the intrinsic positional characteristics of the device. Summary of the Invention

[0005] This invention proposes an automated testing system and method for the position characteristics of a position-sensitive detector, which solves the problems of low testing accuracy and efficiency in existing testing systems.

[0006] To address the aforementioned technical problems, this invention provides an automated testing system for the position characteristics of a position-sensitive detector, comprising: Detector clamp: The detector clamp is equipped with multiple SMA interfaces; Position-sensitive detector: Installed in the detector fixture, the position-sensitive detector has a photosensitive surface, a first electrode and a second electrode on one side, and a third electrode and a fourth electrode on the other side; Laser: The laser is connected to an optical fiber, and the output end of the optical fiber is used to irradiate the photosensitive surface; Two-dimensional precision motion platform: used to fix the detector fixture and drive the detector fixture to move, so as to adjust the illumination position of the output end of the optical fiber on the photosensitive surface; Transimpedance amplifier circuit: The four current input terminals of the transimpedance amplifier circuit are connected to the first electrode, the second electrode, the third electrode and the fourth electrode respectively via the SMA interface. The transimpedance amplifier circuit converts the current signal into a voltage signal. Data acquisition card: The four synchronous acquisition channels of the data acquisition card are respectively connected to the four voltage output terminals of the transimpedance amplifier circuit; Control and processing unit: It is communicatively connected to the two-dimensional precision motion platform and the data acquisition card, respectively, and is used to send displacement control commands to the two-dimensional precision motion platform, receive voltage signals acquired by the data acquisition card, and calculate the position coordinates of the light spot on the photosensitive surface based on the voltage signals.

[0007] Preferably, the detector fixture includes an upper cover and a lower cover, the upper cover and the lower cover cooperating to form a receiving cavity, and the position-sensitive detector is fixed in the receiving cavity; the lower cover is provided with a conductive connection structure and a circuit board, the conductive connection structure includes multiple independent floating contacts, each of the floating contacts has elastic extension and retraction capability and is installed in the array socket of the lower cover in a pluggable manner, when the position-sensitive detector is installed in the receiving cavity, the floating contacts elastically contact the pins of the position-sensitive detector to achieve electrical connection, and the current signal is conducted through the floating contacts to the circuit board and then through multiple SMA interfaces to the current input terminal of the transimpedance amplifier circuit respectively.

[0008] Preferably, the detector fixture further includes a heat-conducting plate, a temperature sensing array, a heat-insulating pad, and a thermoelectric cooler; the heat-conducting plate is disposed on one side of the back of the position-sensitive detector; the temperature sensing array consists of four miniature temperature sensors, which are respectively embedded at the four vertices of the heat-conducting plate to collect temperature distribution information on the back of the position-sensitive detector; the thermoelectric cooler is installed between the heat-conducting plate and the lower cover, with the lower cover serving as a heat dissipation substrate; the heat-insulating pad is disposed between the temperature sensing array and the thermoelectric cooler to prevent the heat from the thermoelectric cooler from being directly conducted to the temperature sensing array.

[0009] Preferably, the testing system further includes a spatiotemporal dual-domain collaborative control module, which is implemented by the main control program of the control and processing unit. The module is configured to control the sampling operation of the data acquisition card and the driving operation of the thermoelectric cooler to be executed alternately. During the sampling period of the data acquisition card, the driving current of the thermoelectric cooler is cut off synchronously. After the sampling is completed, the driving current is restored, and the temperature data of the temperature sensing array is received to generate a global temperature matrix for the correction of the position calculation.

[0010] Preferably, the transimpedance amplifier circuit includes a voltage boosting module, a transimpedance amplification module, and an output bias adjustment module; the voltage boosting module is used to provide a reverse bias voltage to the position-sensitive detector; the transimpedance amplification module is used to amplify the current signal generated by the position-sensitive detector and convert it into a voltage signal with the same amplification factor for each channel; the output bias adjustment module is used to input the voltage signal into the data acquisition card after offsetting the DC bias caused by the non-ideal factors of the operational amplifier.

[0011] This invention also provides an automated testing method for the position characteristics of a position-sensitive detector, implemented based on the aforementioned automated testing system for the position characteristics of a position-sensitive detector, comprising the following steps: Step S1: Install the position-sensitive detector in the detector fixture and fix it on the two-dimensional precision motion platform. Place it in the dark room and complete the circuit connection between the SMA interface and the transimpedance amplifier circuit and between the transimpedance amplifier circuit and the data acquisition card. Step S2: Under dark conditions, apply a bias voltage to the position-sensitive detector and adjust the output bias of the transimpedance amplifier circuit; Step S3: Select the wavelength of the laser and adjust the output light power so that the light signal is irradiated onto the photosensitive surface through the optical fiber; Step S4: Control the two-dimensional precision motion platform to move point by point, so that the light spot generated at the output end of the optical fiber sequentially illuminates different positions of the photosensitive surface, and synchronously collects the voltage signals of each channel of the data acquisition card; Step S5: Calculate the position coordinates of the light spot on the photosensitive surface based on the voltage signal, and subtract the position coordinates from the preset displacement coordinates of the two-dimensional precision motion platform to obtain the position detection error.

[0012] Preferably, before step S4, the light signal is directed to the center position of the photosensitive surface. The alignment of the center position is achieved by closed-loop control, which includes the following steps: real-time acquisition of the voltage signals of each channel and calculation of the current spot coordinates; calculation of the spatial deviation between the current spot coordinates and the center coordinates of the photosensitive surface; driving the two-dimensional precision motion platform to perform compensation motion; re-acquiring and re-calculating the current spot coordinates; repeating the above compensation motion until the spatial deviation is less than a preset threshold.

[0013] Preferably, automatic geometric deviation calibration is performed before step S4, including the following steps: the light spot is sequentially brought to the center point and each vertex of the preset scanning area by the two-dimensional precision motion platform, the platform coordinates of each point in the coordinate system of the two-dimensional precision motion platform and the detector coordinates obtained by the voltage signal are recorded respectively, the mean value of the deviation angle between the line connecting each vertex to the center point and the coordinate axis direction is calculated as the rotation deviation between the intrinsic coordinate system of the position sensitive detector and the coordinate system of the two-dimensional precision motion platform, the scanning coordinates in the subsequent step S4 are rotated and compensated, and the center alignment is re-executed after the rotation compensation is completed.

[0014] Preferably, the testing system includes a spatiotemporal dual-domain collaborative control module, a temperature sensing array, and a semiconductor cooling chip, characterized in that: temperature compensation is performed during the data acquisition process at each test point in step S4, including the following steps: After the two-dimensional precision motion platform moves to the preset position and stops, the driving current of the semiconductor cooling chip is cut off, and the driving current is restored after the data acquisition card collects the voltage signals of each channel. With current spot coordinates The local temperature rise is modeled as a Gaussian decaying perturbation field centered on the light spot. Based on the two-dimensional thin-plate transient heat transfer analytical model, the local peak temperature rise at the current light spot center is calculated. The calculation formula is: ; In the formula, The photothermal absorption rate of the material; The thermal conductivity of the material; The thermal diffusivity of the material; The effective thickness of the material; This refers to the laser output power. The laser beam waist radius; This refers to the laser dwell time; The local peak temperature rise was calculated in the coordinates of the four miniature temperature sensors. The residual Gaussian temperature rise generated at the point, and the actual readings from each micro temperature sensor. The Gaussian temperature rise residual value is a priori subtracted to extract the pure background temperature decoupled from the current hot spot. : ; The four pure background temperatures A continuous boundary temperature distribution was constructed using bilinear interpolation, serving as a pure macroscopic background temperature field. ; Generate the global temperature matrix using the following formula: ; In the formula, The thermal diffusion attenuation constant of the photosensitive surface material of the position-sensitive detector; Perform linear integration on the global temperature matrix along the shortest geometric straight path from the light spot coordinates to each electrode to obtain the equivalent average temperature rise of each channel. Calculate the compensation coefficient for each channel: ; ; In the formula, The temperature coefficient of the resistive layer on the surface of the position-sensitive detector; The coordinates of the light spot are up to the first... The shortest geometric straight path length for each electrode; The compensation coefficient The coordinates after temperature compensation are obtained by introducing the position calculation formula: ; ; In the formula, The length of the photosensitive surface, The width of the photosensitive surface; to The voltage signals are acquired from four synchronous acquisition channels.

[0015] Preferably, in step S4, the two-dimensional precision motion platform moves from the center of the photosensitive surface to a corner of the preset scanning area as the starting point, and scans point by point along a serpentine path at a preset step size to the opposite corner of the preset scanning area; The formula for calculating the position coordinates in step S5 is: ; ; In the formula, The length of the photosensitive surface, The width of the photosensitive surface; and These are the voltage signals for the corresponding channels of the first and second electrodes, respectively; and These are the voltage signals for the corresponding channels of the third and fourth electrodes, respectively.

[0016] The advantages of this invention include at least the following: 1. A two-dimensional precision motion platform is used to perform two-dimensional displacement control on the illumination position of the light spot on the detector, so as to achieve high resolution and high repeatability of displacement output. The linkage between displacement, scanning and data acquisition is realized through an automated program to ensure the timing stability of displacement, scanning and sampling, reduce random errors, and effectively improve test accuracy and data consistency. 2. The detector fixture uses the upper and lower covers to snap together for positioning, which realizes a reliable electrical connection between the device pins and the circuit without the need for soldering or bonding. This significantly simplifies the sample loading process while ensuring connection stability. Combined with an automated scanning program, it enables rapid characterization of the entire photosensitive surface of the device, shortening the single test cycle. 3. The detector fixture integrates conductive connection structures and PCB traces, and achieves near-end direct connection with the transimpedance amplifier circuit through a shielded SMA interface, making the weak current transmission path from the detector to the transimpedance amplifier input short and closed, reducing interference coupling introduced by parasitic capacitance and inductance; at the same time, the detector fixture, transimpedance amplifier circuit and data acquisition card adopt a common ground design to unify the system reference potential and suppress noise and zero-point drift caused by ground loop and common impedance coupling. 4. The temperature sensing array and semiconductor cooling chip are integrated into the detector fixture. Through the coordinated operation of global temperature control at the hardware level and temperature compensation algorithm at the software level, the influence of temperature on the surface resistivity and dark current of the detector is effectively suppressed, the position measurement error caused by temperature drift is eliminated, and the test results have good reproducibility and cross-batch comparability under different environmental conditions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system structure according to an embodiment of the present invention; Figure 2 This is a cross-sectional structural diagram of the fixture of the present invention; Figure 3 This is a schematic diagram of the front and back sides of an example device according to an embodiment of the present invention, where a is the front side of the device and b is the back side of the device. Figure 4 This is a schematic diagram of the electrode wiring of an example device according to an embodiment of the present invention; Figure 5 This is a flowchart of a method for testing the position characteristics of a position-sensitive detector according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the verification of the positional characteristics of an example device in the implementation of this invention when temperature control is not enabled; Figure 7 This is a schematic diagram illustrating the verification of the positional characteristics of an example device implemented in this invention when temperature control is enabled. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0019] Position-sensitive detectors are semiconductor optoelectronic devices capable of continuously simulating the position of an incident light spot. Based on the transverse photoelectric effect and charge segmentation mechanism, they deduce the coordinates of the light spot on the photosensitive surface by measuring the ratio of photocurrent collected by different electrodes. The positional characteristics of position-sensitive detectors are key indicators for their use in precision displacement measurement, beam alignment, and closed-loop control. Existing tests typically rely on multi-device combinations and complex clamping or bonding methods, making optical path alignment and electrical connection operations cumbersome. Furthermore, the scanning and calculation processes require high levels of manual intervention, resulting in limitations in repeatability, accuracy, and efficiency. In contrast, the testing system and method provided in this invention can quickly and accurately characterize device performance, has a wide range of applications, a high degree of automation, and provides convenient and stable electrical connections for the devices. It reduces the introduction of random human errors, significantly saves testing time, and improves testing accuracy.

[0020] like Figure 1 and Figure 3As shown, this embodiment of the invention provides an automated testing system for the position characteristics of a position-sensitive detector. The testing system includes a laser 1, an optical fiber 2, a position-sensitive detector 3, a detector fixture 4, a piezoelectric two-dimensional precision motion platform 5, a transimpedance amplifier circuit 6, a data acquisition card 7, a computer terminal 8, and an anechoic chamber 9.

[0021] In this embodiment of the invention, the piezoelectric two-dimensional precision motion platform 5 is a two-dimensional platform with high resolution and high repeatability displacement control capabilities. It can achieve precise displacement output in the X and Y directions to drive the detector fixture 4 and its position-sensitive detector 3 to move, with a movement step size of up to 50 nm, thereby changing the illumination position of the light spot output from the optical fiber 2 on the photosensitive surface of the position-sensitive detector 3. The piezoelectric two-dimensional precision motion platform 5 can be automatically controlled by displacement commands output from the computer terminal 8, and can remain stable after each positioning for sampling. In this embodiment of the invention, the dwell time of the piezoelectric two-dimensional precision motion platform 5 at each test point is set within the range of 0.1 seconds to 1 second, preferably 0.5 seconds. When facing extremely high background noise, the system can extend the silent sampling window to a maximum of 3 seconds, sacrificing some testing efficiency for a longer data integration time, thereby ensuring the signal-to-noise ratio of weak temperature difference signals.

[0022] like Figure 3 As shown, in this embodiment of the invention, the position-sensitive detector 3 is mounted on the detector fixture 4 with its front side facing upwards. The front side of the position-sensitive detector 3 includes a photosensitive surface and a first electrode 301 and a second electrode 302. The back side of the position-sensitive detector 3 includes a third electrode 303 and a fourth electrode 304. As a preferred embodiment, the directions of the first electrode 301 and the second electrode 302 are parallel to the vertical direction of the piezoelectric two-dimensional precision motion platform 5, and the directions of the third electrode 303 and the fourth electrode 304 are parallel to the horizontal direction of the piezoelectric two-dimensional precision motion platform 5, so as to correspond the X and Y direction position calculations to the signals of the two pairs of opposing electrodes respectively.

[0023] like Figure 4As shown, in this embodiment of the invention, the first electrode 301 of the position-sensitive detector 3 is connected to the first input terminal 601 of the transimpedance amplifier circuit. The output terminal corresponding to the first input terminal 601 of the transimpedance amplifier circuit is the first output terminal 605 of the transimpedance amplifier circuit, which is connected to channel 701 of the data acquisition card. The second electrode 302 of the position-sensitive detector 3 is connected to the second input terminal 602 of the transimpedance amplifier circuit. The output terminal corresponding to the second input terminal 602 of the transimpedance amplifier circuit is the second output terminal 606 of the transimpedance amplifier circuit, which is connected to channel 702 of the data acquisition card. The third electrode 303 of the position-sensitive detector 3 is connected to the third input terminal 603 of the transimpedance amplifier circuit. The output terminal corresponding to the third input terminal 603 of the transimpedance amplifier circuit is the third output terminal 607 of the transimpedance amplifier circuit, which is connected to channel 703 of the data acquisition card. The fourth electrode 304 of the position-sensitive detector 3 is connected to the fourth input terminal 604 of the transimpedance amplifier circuit. The output terminal corresponding to the fourth input terminal 604 of the transimpedance amplifier circuit is the fourth output terminal 608 of the transimpedance amplifier circuit. The fourth output terminal 608 of the transimpedance amplifier circuit is connected to the fourth channel 704 of the data acquisition card.

[0024] In this embodiment of the invention, the detector fixture 4 includes an upper cover and a lower cover, as well as a connecting structure and a circuit board disposed on the upper and lower covers. The upper and lower covers cooperate to form a receiving cavity for fixing the position-sensitive detector device. The lower cover is provided with a conductive connection structure. When the position-sensitive detector device is installed in the receiving cavity, its pins are electrically connected to the corresponding circuit nodes disposed on the lower cover, thereby transmitting the current signal output by the position-sensitive detector to the integrated circuit board below, and further transmitting it to the current signal input terminal of the transimpedance amplifier circuit through the SMA interface.

[0025] In this embodiment of the invention, the conductive connection structure includes multiple independent floating contacts. These floating contacts serve as the interface between the conductive connection structure and the position-sensitive detector device. Each contact has elastic extension and spherical deflection capabilities and is pluggably mounted in an array of sockets on the fixture base plate to accommodate devices with different electrode layouts. When the position-sensitive detector 3 is installed in the receiving cavity, the floating contacts form elastic contact with the device electrodes. The current signal is conducted through the floating contacts to the leads and then transmitted to the circuit board, and further conducted to the transimpedance amplifier circuit via the SMA interface. The fixture also integrates a pressure sensor to monitor the contact pressure between the contacts and the die, preventing damage to the die.

[0026] In this embodiment of the invention, the detector fixture 4 further includes a temperature sensing array and a semiconductor cooling chip. The temperature sensing array consists of four miniature temperature sensors, which are embedded at the four vertices of the contact area between the detector fixture 4 and the back of the position-sensitive detector 3, respectively, for collecting temperature distribution information on the back of the position-sensitive detector 3. Figure 2 As shown, the detector fixture 4 consists of, from top to bottom, an upper heat-conducting plate, a thermoelectric cooler, and a lower cover. The lower cover also serves as a heat dissipation substrate, and the thermoelectric cooler is mounted between the upper heat-conducting plate and the lower cover. Four miniature temperature sensors of the temperature sensing array are embedded at the four vertices of the upper heat-conducting plate. A heat-insulating pad is placed between the temperature sensing array and the thermoelectric cooler to prevent the heat generated by the thermoelectric cooler during operation from being directly conducted to the temperature sensing array, ensuring that the temperature data collected by the temperature sensing array reflects the true temperature distribution on the back of the position-sensitive detector rather than temperature interference from the cooler itself.

[0027] In this embodiment of the invention, the thermal isolation design between the temperature sensing array and the thermoelectric cooler ensures stable measurement of the photosensitive surface temperature. The thermoelectric cooler operates continuously during non-sampling periods, maintaining the global base temperature of the detector near a room temperature reference, thereby suppressing the global cumulative thermal effect caused by prolonged laser irradiation. During the data acquisition window, the system needs to briefly cut off the drive current of the thermoelectric cooler to eliminate electromagnetic interference. At this time, a local transient temperature rise may occur at the center of the laser spot, while the detector edge also experiences a slight temperature rebound due to environmental heat exchange. The thermoelectric cooler is responsible for macroscopic temperature stabilization at the hardware level, while the temperature compensation algorithm at the software level is responsible for accurately correcting local transient thermal disturbances during the acquisition window. The control method of the cooler involves calculating and adjusting the magnitude and direction of the drive current of the cooler in real time based on the error between the temperature fed back by the temperature sensor and the initial temperature, stabilizing the photosensitive surface temperature near the target value.

[0028] In this embodiment of the invention, the transimpedance amplifier circuit 6 includes a voltage application module, a transimpedance amplification module, and an output bias adjustment module. The transimpedance amplification module has four current signal input terminals and four voltage signal output terminals. The four current signal input terminals are respectively connected to the first electrode 301, second electrode 302, third electrode 303, and fourth electrode 304 of the position-sensitive detector 3 through the SMA interface of the detector fixture 4, and are used to amplify the four photocurrent signals across the transimpedance and convert them into four voltage signals. The voltage application module applies a reverse bias voltage to the position-sensitive detector 3 to establish a stable operating state. The output bias adjustment module is used to compensate for the DC bias caused by non-ideal factors in the operational amplifier and the circuit itself, ensuring that it falls within the acquisition range of the data acquisition card 7 and facilitates subsequent data processing. The operational amplifier itself has non-ideal factors such as offset voltage and quiescent current. This voltage, after amplification, is superimposed on the output terminal, causing a certain voltage at the output terminal even without a signal input, affecting position calculation. Therefore, it needs to be eliminated by the output bias adjustment module.

[0029] In this embodiment of the invention, the data acquisition card 7 is a multi-channel synchronous acquisition device used to acquire four voltage signals output by the transimpedance amplifier circuit 6 and transmit them to the computer terminal 8 for storage and processing. The four acquisition channels are connected one-to-one with the four voltage output terminals of the transimpedance amplifier circuit 6 to achieve synchronous acquisition of four channels, each corresponding to the electrode signals in the X and Y directions.

[0030] In this embodiment of the invention, the laser 1 includes a laser controller and a laser source. The laser controller drives the laser source to generate continuous light or pulsed light. The laser source includes ultraviolet, visible, and near-infrared light sources, and different wavelengths can be selected for output according to testing requirements. An optical fiber 2 is connected to the laser 1, and the output end of the optical fiber 2 is used to illuminate the front photosensitive surface of the position-sensitive detector 3 to generate a photoresponse. Preferably, the incident path of the optical fiber 2 is perpendicular to the front plane of the position-sensitive detector 3 to reduce the light spot deformation and geometric projection error caused by oblique incidence, thereby improving the accuracy of position calculation.

[0031] Furthermore, to ensure the accuracy of the test, the detector fixture 4 and the piezoelectric two-dimensional precision motion platform 5 should be placed inside a sealed anechoic chamber 9. The detector fixture 4, transimpedance amplifier circuit 6, and data acquisition card 7 are preferably connected to a common ground to reduce electrical interference and zero-point drift caused by ground loops and common impedance coupling. The test is conducted inside the anechoic chamber 9 to avoid additional photocurrent interference from ambient light to the position-sensitive detector 3.

[0032] In this embodiment of the invention, the test system further includes a spatiotemporal dual-domain collaborative control module. In the time domain, the system employs an electromagnetic silence sampling strategy based on time-division multiplexing. The system's main control program controls the alternating execution of the drive current of the thermoelectric cooler and the sampling window of the data acquisition card. During sampling by the data acquisition card, the system synchronously cuts off the drive current of the thermoelectric cooler, placing the test environment in an electromagnetic silence state to eliminate electromagnetic coupling interference caused by high-current drive. After sampling is completed, the system resumes the current drive of the thermoelectric cooler.

[0033] In the spatial domain, the system employs a position correction algorithm based on the global temperature matrix. This algorithm, based on the principle of thermodynamic linear superposition, decomposes the temperature distribution of the detector in the quasi-steady state into the superposition of two linear components. The first component is the background temperature field, constructed using the discrete readings of four temperature sensors distributed around the perimeter of the photosensitive surface as vertices through first-order linear interpolation. Since the perimeter of the detector is far from the central laser heat island and is subject to global temperature uniformity control by the semiconductor cooler, the thermal gradient distribution in the edge region is gentle, and the linear transition assumption between adjacent sensors is reasonable. The second component is the local perturbation field. The system uses the initial coordinates output in real-time by the current position-sensitive detector as the anchor point of the heat source center, and considers the laser spot as a Gaussian heat source. Based on the spatial distribution characteristic that the local temperature rise is maximum at the center of the spot and monotonically decays outwards, a Gaussian function is used to approximate the local perturbation field. The system directly calculates the local peak temperature rise at the center of the current spot based on the two-dimensional thin-plate transient heat transfer analytical model. The calculation formula is: ; In the formula, The photothermal absorption rate of the material; The thermal conductivity of the material; The thermal diffusivity of the material; The effective thickness of the material; This refers to the laser output power. The laser beam waist radius; This refers to the laser dwell time.

[0034] Because the Gaussian decay of the local temperature rise at the edge of the photosensitive surface is extremely small under short-term residence conditions, the disturbance component mixed into the sensor reading is limited. However, to avoid mixing this disturbance component into the background field and causing repeated calculations, the system first calculates the background temperature field before constructing the background temperature field. The Gaussian temperature rise residual values ​​generated at the coordinates of the four sensors are subtracted a priori from the actual readings of each sensor to obtain the pure background temperature decoupled from the current hot spot. The background temperature field is then constructed by bilinear interpolation using the pure background temperature.

[0035] The formula for reconstructing the global temperature matrix is: ; In the formula, The background temperature field is constructed by linear interpolation of readings from four edge sensors; The peak temperature rise parameter to be solved; , The coordinates of the current light spot; The thermal diffusion attenuation constant of the photosensitive surface material of the position-sensitive detector characterizes the spatial attenuation rate of the local temperature rise caused by laser irradiation along the plane of the photosensitive surface. It is determined by factors such as the thermal diffusion coefficient, layer thickness, and heat dissipation boundary conditions of the semiconductor resistive layer of the photosensitive surface.

[0036] When the system is equipped with an active temperature control system The following theoretical relationship must be satisfied: ; In the formula, The laser beam waist radius; It is the steady-state heat distribution constant; The thermal conductivity of the material; The effective thickness of the material; It is the longitudinal equivalent heat transfer coefficient.

[0037] in The value of is difficult to obtain accurately through theoretical calculations, so in practice, the inversion calibration method is usually chosen to determine it. Specifically, during the system's factory initialization phase, infrared thermal imaging equipment is used to capture a true two-dimensional transient temperature field image of the photosensitive surface under standard test power and residence time; radial temperature rise profile data with the light spot center as the origin is extracted; and the profile data is fitted with a one-dimensional Gaussian function using the least squares method to inversely extract the true attenuation constant under this specific assembly system. For conventional silicon-based detectors and submillimeter-scale laser spots, The typical value range is from 1 mm to 3 mm.

[0038] After obtaining the global temperature matrix, the system further converts the spatial temperature field into impedance interference parameters along the electrical signal transmission path, completing closed-loop coordinate compensation. The specific implementation path is as follows: The system uses the reconstructed global temperature matrix to perform line integration along the path from the laser spot center to each electrode, extracting the equivalent average temperature rise of each channel. Here, the path is defined as starting from the laser spot position and extending along the plane of the photosensitive surface to the... i The shortest geometric straight path of the effective receiving boundary of each electrode. From a physical perspective, the conduction of charge carriers in the surface resistive layer is a continuous two-dimensional electric field diffusion distribution. However, the dominant component of the current is concentrated in the direction of lowest impedance and largest electric field gradient, while the current in other directions contributes less to the overall effect. Therefore, the aforementioned shortest straight path is used as the equivalent integration path to simplify the calculation and retain high accuracy. The formula for calculating the equivalent average temperature rise of each channel is: ; Based on the linear temperature-resistivity coupling equation, calculate the independent compensation coefficients for each channel: ; in The coordinates of the light spot are up to the first... The shortest geometric straight path length for each electrode; This represents the temperature coefficient of the resistive layer on the surface of the position-sensitive detector.

[0039] compensation coefficient Introducing the solution formula, the corrected Axis coordinates and The axis coordinates are as follows: ; ; in The length of the photosensitive surface, The width of the photosensitive surface; to The voltage signals are acquired from four synchronous acquisition channels.

[0040] The semiconductor resistive layer of the position-sensitive detector has a positive temperature coefficient, and its surface resistivity changes with temperature in a linearly coupled manner. ; Based on the principle of equivalent voltage division calculation for the detector, when a local temperature rise causes the average value of the equivalent resistance path across the detector to be approximately... When the equivalent temperature difference is calculated, an absolute position drift error will be introduced, and its engineering estimation model is as follows: ; In this embodiment, the effective length of the photosensitive surface Taking a 10mm device as an example, if closed-loop temperature control is not implemented, the equivalent temperature difference during scanning will be... When the temperature reaches 2℃, take Substituting 0.004 / ℃ into the calculation, this asymmetric temperature rise will directly lead to a spurious displacement of 20μm. If... Taking the upper limit of 0.006 / ℃, the system error will reach 30μm. In summary, quantitative verification shows that even extremely small local temperature differences can cause severe drift on the order of tens of micrometers. Therefore, this embodiment obtains the underlying real-time temperature matrix through a temperature sensing array and performs reverse correction and compensation, combined with a hardware cooling chip, greatly reducing the impact of this nonlinear temperature drift error.

[0041] In this embodiment of the invention, the testing system includes an automatic geometric deviation calibration module. This module performs point scanning on the center point of the detector's photosensitive surface and each vertex of a preset scanning area to obtain the platform coordinates of each key feature point in the two-dimensional precision motion platform coordinate system, as well as the detector coordinates calculated from four voltage signals. By calculating the average deviation angle between the line connecting each vertex to the center point and the coordinate axis direction, the rotational deviation between the intrinsic coordinate system of the position-sensitive detector and the two-dimensional precision motion platform coordinate system is quantified, and rotational compensation is performed on subsequent scanning coordinates accordingly. The selection of vertices is related to the preset scanning area range; that is, the vertices are the four corner points of the preset scanning area.

[0042] Based on the above testing system, such as Figure 5 As shown in the figure, this embodiment of the invention provides an automated testing method for the position characteristics of a position-sensitive detector, including the following steps: Step S1: Place the position-sensitive detector 3 to be tested into the receiving cavity of the detector fixture 4 in the dark chamber 9 and fasten the locking structure to connect the position-sensitive detector 3 to the conductive connection structure of the lower cover. Fix the detector fixture 4 on the piezoelectric two-dimensional precision motion platform 5. Connect the SMA interface on the detector fixture 4 to the four current input terminals of the transimpedance amplifier circuit 6, and connect the four voltage output terminals of the transimpedance amplifier circuit 6 to the four channels of the data acquisition card 7.

[0043] Step S2: Under dark conditions, a preset reverse bias voltage is provided to the position-sensitive detector 3 through the voltage application module of the transimpedance amplifier circuit 6. Subsequently, the output bias adjustment module adjusts the bias of the four output voltages to near 0V, thus offsetting the DC bias caused by non-ideal factors in the operational amplifier and the circuit itself. Simultaneously, the output of the temperature sensor array is acquired, and the initial temperature readings of each sensor are recorded to establish an ambient temperature baseline. This temperature baseline represents the room temperature at the start of the test. During subsequent testing, the cooler and the acquisition system work in tandem. Specifically, during the movement and waiting periods of the displacement stage, the cooler remains continuously operational to maintain the detector's macroscopic temperature consistent with the initial reference. When the displacement stage reaches the test point and the data acquisition card is sampling, the system cuts off the cooler's current to avoid electromagnetic noise interference with the test results.

[0044] Step S3: Select a suitable wavelength laser 1 according to the test requirements, and adjust the output optical power of laser 1 through the laser controller to ensure stable optical power that meets the test requirements. The optical power setting should ensure that the output of the position-sensitive detector 3 is within the linear operating range of the transimpedance amplifier circuit 6 and the data acquisition card 7, avoiding saturation, while also avoiding excessively low optical power that would lead to a low signal-to-noise ratio. Illuminate the front of the position-sensitive detector 3 through the optical fiber 2. The process of illuminating the center position of the photosensitive surface with the optical signal is achieved using closed-loop control. Specifically, it involves real-time acquisition of voltage signals from each channel and calculation of the current spot coordinates, calculation of the spatial deviation between the current spot coordinates and the center coordinates of the photosensitive surface, driving the two-dimensional precision motion platform to perform compensation motion, re-acquiring and re-calculating, and repeating the compensation motion until the spatial deviation is less than a preset threshold. That is, when the voltage signals of channel one and channel two of the data acquisition card 7 are equal, and the voltage signals of channel three and channel four are equal, it is considered that the optical signal has illuminated the center position of the position-sensitive detector 3, thus completing the center alignment. Even if there is a rotational deviation in the device, = This indicates that the center has been reached along the X-axis. = This indicates that the Y-axis direction has reached the center, and the intersection of the two lines is the geometric center. Zero-position calibration can then be completed by alternately adjusting the coordinates in both directions. When there is a rotational deviation between the intrinsic coordinate system of the position-sensitive detector and the coordinate system of the motion platform, adjusting the Y-axis coordinates... = The process will simultaneously cause and Changes in X cause the X direction to deviate from its aligned state. Therefore, the system employs an alternating iterative approach, first adjusting the X direction to... = Then adjust the Y direction to make = Then, the X direction is readjusted, and this process is repeated iteratively until the difference between the position of the light spot calculated from the voltage of both pairs of channels and the electrical zero point of the device itself is less than a preset threshold, thus completing the center alignment. Since the rotational deviation is usually small, this alternating iterative process can converge quickly within a few rounds.

[0045] Under the condition of maintaining stable bias voltage and optical power, the four voltage signals acquired by the data acquisition card 7 are monitored in real time by the computer terminal 8 to confirm that the output signal is stable and has no obvious drift or saturation, and this is used as the initial state for subsequent automatic scanning.

[0046] Step S4: Perform automatic geometric deviation calibration. Using a two-dimensional precision motion platform 5, the laser spot scans 64% of the central area of ​​the photosensitive surface of the detector. A signal intensity distribution map is generated based on the voltage response of the four channels, automatically identifying the approximate position and orientation of the photosensitive surface. The translational and rotational deviations between the detector's intrinsic coordinate system and the motion platform coordinate system are calculated using the detector's output signal. Based on the scanned dot matrix, the position where the calculated output is zero is taken as the electrical zero point of the device. The calculated coordinates of the four corner points of the preset scanning area in the detector coordinate system are used as the four vertices. The tangent of the line connecting each vertex to the zero point and the horizontal direction is calculated, and the actual angle of each line is deduced. Theoretically, the front electrode should be completely parallel to the vertical direction of the motion platform, and the back electrode should be completely parallel to the horizontal direction. Therefore, the theoretical angle between the line connecting each vertex and the coordinate axis is 45 degrees. The average of the difference between the actual angle of each line and 45 degrees is the deflection angle, completing the automatic deviation compensation. For a 10mm x 10mm photosensitive surface, 64% of the area corresponds to a scanning area of ​​approximately 8mm x 8mm. After calibration, re-align the center to ensure the accuracy of the starting position in the new coordinate system.

[0047] Step S5: The piezoelectric two-dimensional precision motion platform 5 is controlled by an automated program to move point by point according to a preset step length and path, so that the light spot output by the optical fiber 2 sequentially illuminates different positions on the photosensitive surface of the position-sensitive detector 3.

[0048] Preferably, the platform moves from the center of the photosensitive surface to the upper left corner, then scans along a serpentine path to the lower right corner. The scanning range, step size, and path are determined based on the size of the photosensitive surface of the detector being tested. The scanning range is typically set to 60% to 80% of the effective area of ​​the photosensitive surface to cover the main working area while preventing some light spots from exceeding the boundary of the photosensitive surface. The scanning step size is selected based on a combination of the required spatial resolution and testing efficiency; a smaller step size results in more detailed positional characterization but a longer testing time. The preferred scanning path is a serpentine path to ensure line-by-line coverage and reduce the idle travel of the motion platform.

[0049] The automated program's logic is as follows: Each time the platform moves to a preset test position and comes to a stop, the system instantly cuts off the semiconductor cooling chip's drive current to establish an electromagnetic silence environment. Data acquisition card 7 then rapidly acquires and averages the voltage signals output from channels one through four within this interference-free window. After sampling, the cooling chip current is immediately restored. Following this, the system executes a temperature compensation process, calculating the local peak temperature rise at the center of the current light spot based on a two-dimensional thin-plate transient heat transfer analytical model. Then, the residual Gaussian temperature rise at the four sensor coordinates is calculated based on the peak temperature rise. This residual value is then subtracted a priori from the actual sensor readings to obtain the pure background temperature. The four pure background temperatures are then bilinearly interpolated to construct a background temperature field, which is then superimposed with a Gaussian attenuation perturbation field centered on the current spot coordinates to generate a global temperature matrix. Line integration is performed along the path from the spot coordinates to each electrode to obtain the equivalent average temperature rise of each channel. Based on this, compensation coefficients are calculated and incorporated into the position calculation formula. Finally, the system saves the corrected precise position coordinates and the original voltage signal to the computer 8. Subsequently, the two-dimensional precision motion platform 5 automatically moves to the next preset position and repeats the above process until a serpentine scan of the entire photosensitive surface is completed.

[0050] If we take the center of the photosensitive surface of the position-sensitive detector as the origin and the length of the photosensitive surface is... Width is In the basic solution without temperature compensation, the voltage of channel one of the data acquisition card is read. Voltage of Channel 2 Voltage of Channel 3 and the voltage of channel four Calculate the coordinates of the spot's centroid on the position-sensitive detector: ; ; This formula applies to double-sided position-sensitive detectors. The position detection error of the position-sensitive detector 3 is obtained by subtracting the calculated coordinates from the theoretical displacement coordinates of the piezoelectric two-dimensional precision motion platform 5. and : ; ; Based on all the above data, the position error distribution map, maximum error, and root mean square error position characteristic indicators can be further obtained to evaluate the position linearity and consistency of the position-sensitive detector 3 across the entire photosensitive surface.

[0051] In this embodiment, a position-sensitive detector is selected as the device under test. The position-sensitive detector is a double-sided type with a photosensitive surface size of 10mm × 10mm. A 658nm laser is selected, and the optical power is adjusted to 400μW. The optical fiber is positioned 15cm above the photosensitive surface of the device, and a 500μm aperture is used to limit the spot diameter. A reverse bias voltage of 10V is applied to the device through the voltage application module in the transimpedance amplifier circuit, which has a magnification of 10,000 times. Room temperature of approximately 25℃ is selected as the temperature baseline. A geometric scan calibration is performed on an 8mm × 8mm area near the center of the photosensitive surface. After calibration, a re-scan is performed with a scan step size of 800μm, totaling 11 × 11 (121 points).

[0052] See the actual effect diagram for details. Figures 1 to 7 . Figure 1 This is a schematic diagram of the test system according to an embodiment of the present invention, which clearly shows the design concept and each system module. Figure 2 This is a cross-sectional structural diagram of the fixture of the present invention, which includes a temperature sensor 201, a heat insulation pad 202, a heat conduction plate 203, a semiconductor cooling chip 204, and a heat dissipation substrate 205. This diagram shows the overall stacking relationship and heat conduction path. Figure 3 The front and back views of the position-sensitive detector used in the example experiment are shown, including a first electrode 301, a second electrode 302, a third electrode 303, and a fourth electrode 304. The first electrode 301 and the second electrode 302 represent the X-axis direction. Figure 4 The diagram shows the electrode wiring of the example device, further detailing the connection methods between each electrode and the transimpedance amplifier circuit and data acquisition card. Figure 5 This is a flowchart of the testing method, which can clearly illustrate the testing process. Figure 6 and Figure 7 This is a two-dimensional position scan point plot of the position-sensitive detector in the example, illustrating the relationship between the position output calculated from four signals and the position of the motion platform when the light spot is controlled by the two-dimensional platform to scan at different actual positions. This provides data for evaluating the detector's position characteristics. The positions of the points in the plot represent the calculated positions, and the numbers on the coordinate axes represent the actual positions of the displacement stage. Figure 6 As can be seen from the above test conditions, without temperature control and compensation, the root mean square value of the position detection error is approximately 71 μm. Figure 7It can be seen that under the above test conditions, when temperature control and compensation are enabled, the root mean square value of the position detection error is approximately 64 μm, and the position detection error gradually increases from the center outwards, exhibiting a clear and continuous variation pattern, which is consistent with the properties of the device itself. Overall, it can be seen that the calculated position changes regularly with the scanning displacement and the deviation is small, indicating that the system and method are feasible. Under the test conditions of this embodiment, the laser power is 400 μW and the scanning step size is 800 μm. The total irradiation time of a single scan is relatively short, and the local temperature rise of the device is relatively limited. Therefore, the improvement brought by temperature compensation is approximately 10%. Under conditions of higher laser power, denser scanning step size, or longer continuous test time, the local heat accumulation effect of the photosensitive surface is more significant, and the improvement effect of temperature compensation will be more obvious.

[0053] This invention enables rapid clamping and stable electrical connection of position-sensitive detectors using a detector fixture. A shielded interface leads the weak photocurrent signal near the detector to a transimpedance amplifier circuit for conversion and amplification, followed by synchronous four-channel acquisition by a data acquisition card. Simultaneously, a piezoelectric two-dimensional precision motion platform and automated program are used to link displacement, sampling, and storage. This allows for highly efficient and repeatable testing of the positional characteristics of position-sensitive detectors while ensuring alignment accuracy and signal quality, significantly shortening testing time and improving testing accuracy.

[0054] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; only preferred embodiments of the present invention are illustrated. The descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. As long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0055] It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. An automated testing system for the position characteristics of a position-sensitive detector, characterized in that, include: Detector clamp: The detector clamp is equipped with multiple SMA interfaces; Position-sensitive detector: installed in the detector fixture, the position-sensitive detector has a photosensitive surface, a first electrode and a second electrode on one side, and a third electrode and a fourth electrode on the other side; Laser: The laser is connected to an optical fiber, and the output end of the optical fiber is used to irradiate the photosensitive surface; Two-dimensional precision motion platform: used to fix the detector fixture and drive the detector fixture to move, so as to adjust the illumination position of the output end of the optical fiber on the photosensitive surface; Transimpedance amplifier circuit: The four current input terminals of the transimpedance amplifier circuit are connected to the first electrode, the second electrode, the third electrode and the fourth electrode respectively via the SMA interface. The transimpedance amplifier circuit converts the current signal into a voltage signal. Data acquisition card: The four synchronous acquisition channels of the data acquisition card are respectively connected to the four voltage output terminals of the transimpedance amplifier circuit; Control and processing unit: It is communicatively connected to the two-dimensional precision motion platform and the data acquisition card, respectively, and is used to send displacement control commands to the two-dimensional precision motion platform, receive voltage signals acquired by the data acquisition card, and calculate the position coordinates of the light spot on the photosensitive surface based on the voltage signals.

2. The automated testing system for the position characteristics of a position-sensitive detector according to claim 1, characterized in that: The detector fixture includes an upper cover and a lower cover. The upper cover and the lower cover cooperate to form a receiving cavity, and the position-sensitive detector is fixed in the receiving cavity. The lower cover is provided with a conductive connection structure and a circuit board. The conductive connection structure includes multiple independent floating contacts. Each floating contact has elastic extension and retraction capability and is installed in the array socket of the lower cover in a pluggable manner. When the position-sensitive detector is installed in the receiving cavity, the floating contact makes elastic contact with the pin of the position-sensitive detector to achieve electrical connection. The current signal is conducted through the floating contact to the circuit board and then through multiple SMA interfaces to the current input terminal of the transimpedance amplifier circuit.

3. The automated testing system for the position characteristics of a position-sensitive detector according to claim 2, characterized in that: The detector fixture also includes a heat-conducting plate, a temperature sensing array, a heat-insulating pad, and a thermoelectric cooler; the heat-conducting plate is disposed on one side of the back of the position-sensitive detector; the temperature sensing array consists of four miniature temperature sensors, which are respectively embedded at the four vertices of the heat-conducting plate to collect temperature distribution information on the back of the position-sensitive detector; the thermoelectric cooler is installed between the heat-conducting plate and the lower cover, with the lower cover serving as a heat dissipation substrate; The heat insulation pad is disposed between the temperature sensing array and the thermoelectric cooler to prevent the heat from the thermoelectric cooler from being directly conducted to the temperature sensing array.

4. The automated testing system for the position characteristics of a position-sensitive detector according to claim 3, characterized in that: The testing system also includes a spatiotemporal dual-domain collaborative control module, which is implemented by the main control program of the control and processing unit. The module is configured to control the sampling operation of the data acquisition card and the driving operation of the thermoelectric cooler to be executed alternately. During the sampling period of the data acquisition card, the driving current of the thermoelectric cooler is cut off synchronously. After the sampling is completed, the driving current is restored, and the temperature data of the temperature sensing array is received to generate a global temperature matrix for the correction of the position calculation.

5. An automated testing system for the position characteristics of a position-sensitive detector according to claim 1, characterized in that: The transimpedance amplifier circuit includes a voltage boosting module, a transimpedance amplification module, and an output bias adjustment module. The voltage boosting module provides a reverse bias voltage to the position-sensitive detector. The transimpedance amplification module amplifies the current signal generated by the position-sensitive detector and converts it into a voltage signal with the same amplification factor for each channel. The output bias adjustment module compensates for the DC bias caused by non-ideal factors of the operational amplifier and then inputs the voltage signal into the data acquisition card.

6. An automated testing method for the position characteristics of a position-sensitive detector, implemented based on an automated testing system for the position characteristics of a position-sensitive detector as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step S1: Install the position-sensitive detector in the detector fixture and fix it on the two-dimensional precision motion platform. Place it in the dark room and complete the circuit connection between the SMA interface and the transimpedance amplifier circuit and between the transimpedance amplifier circuit and the data acquisition card. Step S2: Under dark conditions, apply a bias voltage to the position-sensitive detector and adjust the output bias of the transimpedance amplifier circuit; Step S3: Select the wavelength of the laser and adjust the output light power so that the light signal is irradiated onto the photosensitive surface through the optical fiber; Step S4: Control the two-dimensional precision motion platform to move point by point, so that the light spot generated at the output end of the optical fiber sequentially illuminates different positions of the photosensitive surface, and synchronously collects the voltage signals of each channel of the data acquisition card; Step S5: Calculate the position coordinates of the light spot on the photosensitive surface based on the voltage signal, and subtract the position coordinates from the preset displacement coordinates of the two-dimensional precision motion platform to obtain the position detection error.

7. An automated testing method for the position characteristics of a position-sensitive detector according to claim 6, characterized in that: Before step S4, the light signal is directed to the center position of the photosensitive surface. The alignment of the center position is achieved by closed-loop control, which includes the following steps: real-time acquisition of the voltage signals of each channel and calculation of the current spot coordinates, calculation of the spatial deviation between the current spot coordinates and the center coordinates of the photosensitive surface, driving the two-dimensional precision motion platform to perform compensation motion, re-acquiring and re-calculating the current spot coordinates, and repeating the above compensation motion until the spatial deviation is less than a preset threshold.

8. An automated testing method for the position characteristics of a position-sensitive detector according to claim 6, characterized in that: Before step S4, automatic geometric deviation calibration is performed, including the following steps: the light spot is sequentially brought to the center point and each vertex of the preset scanning area by the two-dimensional precision motion platform, the platform coordinates of each point in the coordinate system of the two-dimensional precision motion platform and the detector coordinates obtained by the voltage signal are recorded respectively, the mean value of the deviation angle between the line connecting each vertex to the center point and the coordinate axis direction is calculated as the rotation deviation between the intrinsic coordinate system of the position sensitive detector and the coordinate system of the two-dimensional precision motion platform, the scanning coordinates in the subsequent step S4 are rotated and compensated, and the center alignment is re-executed after the rotation compensation is completed.

9. An automated testing method for the position characteristics of a position-sensitive detector according to claim 6, wherein the testing system comprises a spatiotemporal dual-domain collaborative control module, a temperature sensing array, and a semiconductor cooling chip, characterized in that: Temperature compensation is performed on the data acquisition process at each test point in step S4, including the following steps: After the two-dimensional precision motion platform moves to the preset position and stops, the driving current of the semiconductor cooling chip is cut off, and the driving current is restored after the data acquisition card collects the voltage signals of each channel. With current spot coordinates The local temperature rise is modeled as a Gaussian decaying perturbation field centered on the light spot. Based on the two-dimensional thin-plate transient heat transfer analytical model, the local peak temperature rise at the current light spot center is calculated. The calculation formula is: ； In the formula, The photothermal absorption rate of the material; The thermal conductivity of the material; The thermal diffusivity of the material; The effective thickness of the material; This refers to the laser output power. The laser beam waist radius; This refers to the laser dwell time; The local peak temperature rise was calculated in the coordinates of the four miniature temperature sensors. The residual Gaussian temperature rise generated at the point, and the actual readings from each micro temperature sensor. The Gaussian temperature rise residual value is a priori subtracted to extract the pure background temperature decoupled from the current hot spot. : ； The four pure background temperatures A continuous boundary temperature distribution was constructed using bilinear interpolation, serving as a pure macroscopic background temperature field. ; Generate the global temperature matrix using the following formula: ； In the formula, The thermal diffusion attenuation constant of the photosensitive surface material of the position-sensitive detector; Perform linear integration on the global temperature matrix along the shortest geometric straight path from the light spot coordinates to each electrode to obtain the equivalent average temperature rise of each channel. Calculate the compensation coefficient for each channel: ； ； In the formula, The temperature coefficient of the resistive layer on the surface of the position-sensitive detector; The coordinates of the light spot are up to the first... The shortest geometric straight path length for each electrode; The compensation coefficient The coordinates after temperature compensation are obtained by introducing the position calculation formula: ； ； In the formula, The length of the photosensitive surface, The width of the photosensitive surface; to The voltage signals are acquired from four synchronous acquisition channels.

10. An automated testing method for the position characteristics of a position-sensitive detector according to claim 6, characterized in that: In step S4, the two-dimensional precision motion platform moves from the center of the photosensitive surface to a corner of the preset scanning area as the starting point, and scans point by point along a serpentine path at a preset step size to the opposite corner of the preset scanning area; The formula for calculating the position coordinates in step S5 is: ； ； In the formula, The length of the photosensitive surface, The width of the photosensitive surface; and These are the voltage signals for the corresponding channels of the first and second electrodes, respectively; and These are the voltage signals for the corresponding channels of the third and fourth electrodes, respectively.

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