A photosensitive diode multispectral calibration device and method based on an integrating sphere light source

Abstract

The embodiment of the application provides a kind of based on integrating sphere light source's photosensitive diode multispectral calibration device and method, for by dark current measurement, photocurrent correction and wavelength response fitting, photosensitive diode array is carried out wide band multispectral calibration.The device of the application includes integrating sphere device, multi-band adjustable light source module, the photosensitive diode array to be calibrated and control and analysis unit;The inner wall of integrating sphere device is high reflectivity diffuse reflection material;Integrating sphere device further includes trap detector, and trap detector is used for real-time monitoring the reflection loss of the inner wall of integrating sphere device;Trap detector is connected with control and analysis unit communication;Multi-band adjustable light source module is accessed integrating sphere device;The photosensitive diode array to be calibrated is composed of multiple photosensitive diodes;Control and analysis unit and multi-band adjustable light source module, the photosensitive diode array to be calibrated establish communication connection.

Description

Technical Field

[0001] This application relates to the field of spectral calibration technology, and in particular to a photodiode multispectral calibration device and method based on an integrating sphere light source. Background Technology

[0002] Photodiode arrays are widely used in spectral measurement, optical imaging, and optical communication, and their performance directly affects the measurement accuracy and reliability of the system. Existing photodiode array calibration methods typically rely on a single light source or a narrow-band light source for calibration, making it difficult to obtain the complete photoelectric response characteristics of each photodiode over a wide wavelength range. This results in discontinuous wavelength responses or insufficient response accuracy. Furthermore, traditional calibration methods lack a systematic approach to correcting dark current and photocurrent, failing to achieve accurate spectral response fitting for each photodiode in the array and thus failing to meet the high precision and consistency requirements of multispectral measurements. Therefore, current technologies for wide-band multispectral calibration of photodiode arrays still suffer from insufficient spectral coverage, low calibration accuracy, and limited data reliability. Summary of the Invention

[0003] This application provides a photodiode multispectral calibration device and method based on an integrating sphere light source, which can perform wide-band multispectral calibration of a photodiode array through dark current measurement, photocurrent correction, and wavelength response fitting.

[0004] The first aspect of this application provides a photodiode multispectral calibration device based on an integrating sphere light source, including an integrating sphere device, a multi-band adjustable light source module, an array of photodiodes to be calibrated, and a control and analysis unit;

[0005] The inner wall of the integrating sphere is made of a high-reflectivity diffuse reflective material to ensure the uniformity of the light field; the integrating sphere also includes a trap detector; the trap detector is used to monitor the reflection loss of the inner wall of the integrating sphere in real time; the trap detector is communicatively connected to the control and analysis unit to transmit the reflection loss data to the control and analysis unit; The multi-band adjustable light source module is connected to the integrating sphere device to output a spectrum covering one or more bands of ultraviolet, visible and near-infrared light. The photodiode array to be calibrated consists of multiple photodiodes, each of which is used to respond to light of each band output from the multi-band tunable light source module and independently output the corresponding photocurrent signal. The control and analysis unit establishes a communication connection with the multi-band adjustable light source module and the photodiode array to be calibrated, and is used to adjust the output light of the multi-band adjustable light source module, collect the photocurrent signal output by the photodiode array to be calibrated, and generate corresponding calibration parameters for each photodiode.

[0006] Optionally, the integrating sphere device further includes an adjustable aperture stop; the adjustable aperture stop is used to control the output light flux and light field uniformity of the integrating sphere device.

[0007] Optionally, the type of the multi-band adjustable light source module includes a halogen tungsten lamp or multiple narrowband LED arrays; the photodiode array to be calibrated includes silicon-based photodiodes and / or III-V group semiconductor photodiodes.

[0008] A second aspect of this application provides a multispectral calibration method for a photodiode based on an integrating sphere light source, applicable to the multispectral calibration device for a photodiode based on an integrating sphere light source as described in the first aspect and any possible embodiment of the first aspect. The calibration parameters include a wavelength response function, and the multispectral calibration method for the photodiode includes: Measure the dark current of each photodiode in the array of photodiodes to be calibrated; The multi-band tunable light source module is controlled to output the target spectrum sequentially according to a preset wavelength sequence; At each preset wavelength, the reflection loss data of the inner wall of the integrating sphere device is obtained through the trap detector, and the original photocurrent of the photodiode responding to the preset wavelength is collected. Based on the dark current and the reflection loss data, the original photocurrent is corrected to obtain the target photocurrent; Based on the target photocurrent at each wavelength, fit the wavelength response function of each photodiode in the array of photodiodes to be calibrated; Optionally, the calibration parameters further include quantum efficiency. After fitting the wavelength response function of each photodiode in the photodiode array to be calibrated based on the target photocurrent at each wavelength, the photodiode multispectral calibration method further includes: The measurement quantum efficiency is determined based on the wavelength response function. Obtain the pre-stored theoretical quantum efficiency; The calibration coefficient is calculated based on the measured quantum efficiency and the theoretical quantum efficiency.

[0009] Optionally, before measuring the dark current of the photodiode array to be calibrated, the photodiode multispectral calibration method further includes: Connect a standard light source to the integrating sphere device; The spectral power distribution of the standard light source was measured using a spectrometer; The reflection uniformity of the inner wall of the integrating sphere device is calibrated according to the spectral power distribution; Under shading conditions, the zero-point error of the trap detector was measured and calibrated.

[0010] Optionally, the step of correcting the original photocurrent based on the dark current and the reflection loss data to obtain the target photocurrent includes: The dark current and the reflection loss data are applied to the correction formula to correct the original photocurrent and obtain the target photocurrent. The correction formula is as follows:

[0011] in, This represents the original photocurrent. This represents the target photocurrent. This refers to the dark current. This represents the reflection loss data. This represents the preset gain compensation coefficient of the photodiode.

[0012] Optionally, after calculating the calibration coefficient based on the measured quantum efficiency and the theoretical quantum efficiency, the photodiode multispectral calibration method further includes: Based on the calibration coefficient, verify whether the response signal of each photodiode in the photodiode array to be calibrated meets the preset consistency tolerance requirements after calibration. When the verification is successful, the calibration process data corresponding to the photodiode will be stored; the calibration process data includes the dark current, the reflection loss data, the original photocurrent, the target photocurrent, the wavelength response function, and the calibration coefficient.

[0013] A third aspect of this application provides an electronic device, comprising: Processor, memory, input / output units, and bus; The processor is connected to the memory, the input / output unit, and the bus; The memory stores a program, and the processor calls the program to execute the photodiode multispectral calibration method in the second aspect and any possible implementation of the second aspect.

[0014] The fourth aspect of this application provides a computer-readable storage medium storing a program that, when executed on a computer, causes the computer to perform the photodiode multispectral calibration method of the second aspect and any possible implementation thereof.

[0015] As can be seen from the above technical solutions, this application has the following advantages: In this application, the high reflectivity diffuse reflection inner wall of the integrating sphere device ensures the uniformity of the light field, the real-time monitoring of the trap detector realizes the compensation for reflection loss, and the wide spectrum output of the multi-band adjustable light source module and the precise adjustment of the control and analysis unit enable the calibration device to achieve high-precision multispectral calibration of photodiodes in the ultraviolet to near-infrared band, ensuring the stability and accuracy of the calibration results. Attached Figure Description

[0016] Figure 1 This is a structural block diagram of one embodiment of the photodiode multispectral calibration device based on an integrating sphere light source in this application; Figure 2 This is a flowchart illustrating an embodiment of the photodiode multispectral calibration method based on an integrating sphere light source in this application; Figure 3 This is a flowchart illustrating a sub-implementation of the photodiode multispectral calibration method based on an integrating sphere light source in this application. Figure 4 This is a flowchart illustrating another sub-implementation of the photodiode multispectral calibration method based on an integrating sphere light source in this application; Figure 5 This is a flowchart illustrating yet another sub-implementation of the photodiode multispectral calibration method based on an integrating sphere light source in this application. Figure 6 This is a schematic diagram of the structure of one embodiment of the electronic device in this application. Detailed Implementation

[0017] This application provides a photodiode multispectral calibration device and method based on an integrating sphere light source, which is used to perform wide-band multispectral calibration of a photodiode array through dark current measurement, photocurrent correction and wavelength response fitting.

[0018] The embodiments of this application will now be described with reference to the accompanying drawings.

[0019] Please see Figure 1 , Figure 1 An embodiment of the photodiode multispectral calibration device based on an integrating sphere light source provided in this application includes: Integrating sphere device 101, multi-band adjustable light source module 102, photodiode array to be calibrated 103, and control and analysis unit 104; The inner wall of the integrating sphere device 101 is made of a high reflectivity diffuse reflective material to ensure the uniformity of the light field. The integrating sphere device 101 also includes a trap detector, which is used to monitor the reflection loss of the inner wall of the integrating sphere device 101 in real time. The trap detector is communicatively connected to the control and analysis unit 104 to transmit the reflection loss data to the control and analysis unit 104. The multi-band adjustable light source module 102 is connected to the integrating sphere device 101 to output a spectrum covering the ultraviolet to near-infrared range; The photodiode array 103 to be calibrated consists of multiple photodiodes, and the photodiodes may be made of the same or different materials. Each photodiode is used to respond to light of different wavelengths output from the multi-band tunable light source module 102, and each is equipped with an independent amplification circuit and signal processing unit to output the corresponding photocurrent signal. The control and analysis unit 104 establishes a communication connection with the multi-band adjustable light source module 102 and the photodiode array 103 to be calibrated, and is used to adjust the output light of the multi-band adjustable light source module 102, collect the photocurrent signal output by the photodiode array 103 to be calibrated, and generate calibration parameters for each photodiode.

[0020] In this embodiment, the inner wall of the integrating sphere device 101 is made of a high-reflectivity (≥98%) diffuse reflective material to ensure the uniformity of the light field, and the spatial uniformity error can be controlled within ±1%. The integrating sphere device 101 includes a trap detector, which is used to monitor the reflection loss of the inner wall of the integrating sphere device 101 in real time and transmit the reflection loss data to the control and analysis unit 104 so as to dynamically correct the light field intensity during the calibration process.

[0021] A multi-band tunable light source module 102 is connected to an integrating sphere device 101, outputting a spectrum covering one or more wavelength ranges from ultraviolet, visible, to near-infrared. A control and analysis unit 104 is communicatively connected to the multi-band tunable light source module 102, used to adjust the light source parameters and achieve dynamic adjustment of the spectral power distribution. The photodiode array 103 to be calibrated is preferably composed of multiple photodiodes of different materials, covering the 300nm~1100nm wavelength band (expandable as needed). Each photodiode is equipped with an independent amplification circuit and signal processing unit to output a photocurrent signal for the corresponding wavelength band. The control and analysis unit 104 is communicatively connected to both the multi-band tunable light source module 102 and the photodiode array 103 to be calibrated, acquiring the output signal of the photodiode array 103 to be calibrated, and generating calibration parameters, including quantum efficiency and wavelength response coefficient, for each photodiode using calibration software.

[0022] In this embodiment, the high reflectivity diffuse reflection inner wall of the integrating sphere device 101 ensures the uniformity of the light field, and the real-time monitoring of the trap detector realizes the compensation for reflection loss. Combined with the wide spectrum output of the multi-band adjustable light source module 102 and the precise adjustment of the control and analysis unit 104, the calibration device can realize high-precision multi-spectral calibration of photodiodes in one or more bands of ultraviolet light, visible light and near-infrared light, ensuring the stability and accuracy of the calibration results.

[0023] Optionally, the integrating sphere device 101 may also include an adjustable aperture stop; the adjustable aperture stop is used to control the output light flux and light field uniformity of the integrating sphere device.

[0024] In this embodiment, the integrating sphere device 101 may further include an adjustable aperture stop. The adjustable aperture stop is used to control the output light flux and light field uniformity of the integrating sphere device, and the trap detector is used to monitor the reflection loss of the inner wall of the integrating sphere device 101 in real time. The control and analysis unit 104 is communicatively connected to the multi-band adjustable light source module 102 and the photodiode array 103 to be calibrated, and is used to adjust the light source parameters, acquire the output signal of the photodiode array 103 to be calibrated, and generate corresponding calibration parameters for each photodiode.

[0025] In this embodiment, the introduction of an adjustable aperture stop allows the light flux emitted from the integrating sphere to be flexibly adjusted according to different calibration conditions, thereby achieving light intensity control while maintaining the uniformity of the light field, and further improving the stability and consistency of the photodiode calibration process.

[0026] Optionally, the type of the multi-band adjustable light source module 102 includes a halogen tungsten lamp or multiple narrowband LED arrays; the photodiode array 103 to be calibrated includes silicon-based photodiodes and / or III-V semiconductor photodiodes.

[0027] The multi-band tunable light source module 102 includes halogen tungsten lamps or multiple narrowband LED arrays for outputting a spectrum covering the ultraviolet to near-infrared range. Halogen tungsten lamps can provide continuous wide-spectrum output, suitable for calibration of full-band photodiodes; multiple narrowband LED arrays can provide precise single-band or multi-band light output, and flexible control of the target band spectral power can be achieved by adjusting the driving current or voltage of each LED. The light source module can be designed in conjunction with a beam splitter or variable filter to achieve selective output of specific bands, so that the output light maintains stability and uniformity within the desired band. The III-V group semiconductor photodiode in this embodiment can include various devices based on materials such as gallium arsenide (GaAs), indium phosphide (InP), and their ternary and quaternary compounds (such as InGaAs), such as GaAs-based devices responsive to visible to near-infrared light, and InGaAs-based PIN or avalanche photodiodes covering short-wave infrared light, to achieve precise calibration of specific bands within one or more bands in the ultraviolet, visible, and near-infrared ranges.

[0028] In this embodiment, by selecting a halogen tungsten lamp (e.g., with a wide spectrum of 200nm~2500nm) or multiple narrowband LED arrays (e.g., covering one or more wavelength ranges in ultraviolet, visible, and near-infrared) as the light source, and combining it with a beam splitter or variable filter for wavelength control, the target wavelength light output can be accurately generated according to different calibration task requirements, thereby meeting the requirements of photodiode multispectral calibration for light intensity stability and wavelength selectivity, and improving the reliability and repeatability of calibration.

[0029] The following describes the multispectral calibration method for photodiodes based on an integrating sphere light source in this application. This method can be applied to… Figure 1 The embodiment shown is a photodiode multispectral calibration device based on an integrating sphere light source.

[0030] Please see Figure 2 , Figure 2 An embodiment of the photodiode multispectral calibration method based on an integrating sphere light source provided in this application, wherein the calibration parameters may include a wavelength response function, and this embodiment includes: 201. Measure the dark current of the photodiode array to be calibrated; First, the control and analysis unit 104 shuts down the multi-band adjustable light source module 102, creating a dark environment within the integrating sphere. Simultaneously, the photodiode array 103 to be calibrated is kept in a dark environment, and its power supply is turned on, putting it into operation. Through the independent amplification circuit and signal processing unit of the photodiode array 103, the control and analysis unit 104 acquires the output of each photodiode, records the dark current value, and generates a dark current dataset. This dataset is used in subsequent steps to correct the photocurrent signal, eliminating device background noise and zero-point deviation, ensuring the accuracy and reliability of the calibration calculation. In practical applications, measurements can be performed under different time and temperature conditions. Multiple measurements are taken under each measurement environment, and the average value is calculated. Interval measurements are used, and interpolation is performed to finally establish a baseline noise model of the dark current for the photodiode array 103 to be calibrated. When it is necessary to perform subsequent calculations involving the dark current of the photodiode array 103 to be calibrated, the corresponding dark current value can be directly found from the baseline noise model based on time and temperature.

[0031] 202. Control the multi-band adjustable light source module to output the target spectrum sequentially according to the preset wavelength sequence; The control and analysis unit 104 sequentially drives the multi-band adjustable light source module 102 to output the target spectrum according to a preset wavelength sequence. After the light output enters the integrating sphere device 101, a highly uniform light field is formed, and the light intensity of each wavelength band is stably controlled by adjusting the light source current or voltage. The control and analysis unit 104 records the light source output parameters and the current wavelength to provide reference data for subsequent photocurrent correction. It should be noted that the preset wavelength sequence can be specifically set according to the calibration accuracy requirements and the target spectral range. For example, to achieve dense spectral calibration in the ultraviolet to near-infrared band (e.g., 300nm to 1100nm), a step sequence with 10nm intervals can be set. The control and analysis unit 104 will sequentially drive the light source module to output monochromatic light with wavelengths of 300nm, 310nm, 320nm... up to 1100nm. This sequence covers the typical response range of silicon-based and some III-V group photodiodes, and the spacing between adjacent wavelength points is small enough to help construct high-resolution spectral response curves, thereby accurately obtaining key calibration parameters such as responsivity and linearity of photodiodes at various characteristic wavelengths.

[0032] 203. At each preset wavelength, the reflection loss data of the inner wall of the integrating sphere device is obtained through the trap detector, and the original photocurrent of the photodiode responding to the preset wavelength is collected. During each wavelength output period, the trap detector monitors the reflection loss of the integrating sphere's inner wall in real time and transmits the data to the control and analysis unit 104. Simultaneously, the photodiode array 103 to be calibrated generates a photocurrent signal under target spectrum illumination, and each independent amplification circuit and signal processing unit outputs the raw photocurrent to the control and analysis unit 104. The control and analysis unit 104 correlates and records the reflection loss data with the raw photocurrent signal, forming a complete dataset that provides a basis for subsequent calibration.

[0033] Optionally, the trap detector can also acquire the reflection loss data of the inner wall of the integrating sphere device 101 in a single measurement. Specifically, before the test begins or during the calibration phase, the control and analysis unit 104 drives the light source to output broadband light covering the target spectral range or a set single reference wavelength light, enabling the trap detector to perform a single measurement of the reflection loss of the inner wall of the integrating sphere, and storing the obtained reflection loss result as a universal reflection loss parameter across the entire wavelength band. Subsequently, during the output of each preset wavelength, the reflection loss data is no longer updated in real time for each wavelength; instead, the reflection loss parameter is directly retrieved and associated with the original photocurrent signal of the photodiode for recording and subsequent correction. Compared with acquiring the reflection loss separately for each preset wavelength, the single measurement method reduces the number of measurements and improves efficiency.

[0034] 204. Based on dark current and reflection loss data, the original photocurrent is corrected to obtain the target photocurrent; The control and analysis unit 104 uses the dark current data obtained in step 201 and the integrating sphere reflection loss data obtained in step 203 to correct the original photocurrent collected by the photodiode. First, the dark current is subtracted to eliminate the device's inherent noise and zero-point drift; then, compensation is performed based on the reflection loss data to obtain the corrected target photocurrent signal, which more accurately reflects the true response of the photodiode to each wavelength spectrum.

[0035] Furthermore, in some embodiments of this application, step 204, which corrects the original photocurrent based on dark current and reflection loss data to obtain the target photocurrent, may include the following steps: 2041. Apply the dark current and reflection loss data to the correction formula to correct the original photocurrent and obtain the target photocurrent; The correction formula is:

[0036] in, Represents the original photocurrent. Indicates the target photocurrent. Indicates dark current. This represents the reflection loss data. This represents the preset gain compensation coefficient for the photodiode.

[0037] The control and analysis unit 104 performs calculations for each channel (each photodiode) of the photodiode array 103 to be calibrated, subtracts the influence of dark current, compensates for reflection losses in the optical path, and corrects the signal amplitude through a gain compensation coefficient, thereby obtaining a more accurate target photocurrent. The gain compensation coefficient is derived from standard performance parameters provided by the device manufacturer or theoretical values ​​pre-determined in the laboratory.

[0038] By applying dark current and integrating sphere reflection loss data to the calibration formula, and combining this with gain compensation to correct the original photocurrent, the inherent noise of the device, the light intensity attenuation caused by non-ideal reflection of the integrating sphere's optical field, and the signal amplitude deviation can be effectively eliminated, thus obtaining a precise target photocurrent. This makes the multispectral calibration of the photodiode array 103 to be calibrated more accurate over a wide wavelength range, ensuring that the calibration results have high precision and repeatability throughout the entire spectral coverage, while also improving the multi-band adaptability and reliability of the calibration device.

[0039] 205. Based on the target photocurrent at each wavelength, fit the wavelength response function of each photodiode in the photodiode array to be calibrated; Using the target photocurrent data obtained in step 204, the relationship between the response of each photodiode in the photodiode array 103 to be calibrated and the wavelength is fitted to generate a wavelength response function. During the fitting process, differences in light intensity across wavelength bands, as well as differences in the material and characteristics of the photodiodes, are considered to accurately describe the spectral sensitivity characteristics of each photodiode, providing a reliable basis for calculating the calibration coefficients.

[0040] It should be noted that various curve fitting methods can be used for fitting, such as Gaussian fitting, polynomial curve fitting, spline interpolation fitting, or piecewise function fitting. Taking Gaussian fitting as an example, the wavelength response function of each photodiode can be represented as a superposition of single-peak Gaussian functions or multi-peak Gaussian functions, and the parameters such as peak amplitude, center wavelength, and full width at half maximum (FWHM) can be solved using the least squares method to characterize its sensitivity distribution within the target spectral range. Taking polynomial curve fitting as an example, polynomial regression can be performed on the target photocurrent-wavelength data to obtain polynomial coefficients that describe the trend of response with wavelength variation. The control and analysis unit 104 can select the fitting method and order / number of peaks according to the target spectral range, sampling point density, and the size of the fitting residual, and can perform residual verification or cross-validation on the fitting results to ensure the fitting accuracy and stability of the wavelength response function.

[0041] In this embodiment, the multi-band adjustable light source module 102 outputs a target spectrum covering the ultraviolet to near-infrared range. Combined with the integrating sphere device 101 and the signal correction and wavelength response fitting of the photodiode array, the photodiode array 103 to be calibrated can achieve accurate multi-spectral calibration over a wide range of wavelengths. The spectral coverage is wide and the calibration accuracy is high, which can meet the needs of measuring the response characteristics of photodiodes in different wavelength bands and improve the reliability and applicability of multi-spectral calibration of photodiodes.

[0042] Please see Figure 3 In some embodiments of this application, the calibration parameters may further include quantum efficiency. After step 205 in the above embodiments, which involves fitting the wavelength response function of each photodiode in the photodiode array to be calibrated based on the target photocurrent at each wavelength, the photodiode multispectral calibration method may further include the following steps: 301. Determining the measurement quantum efficiency based on the wavelength response function; The control and analysis unit 104 analyzes the wavelength response function of each photodiode and extracts key parameters, including peak response wavelength and response bandwidth. Using these parameters, the photocurrent of the photodiode in each wavelength band is converted into a measurable quantum efficiency to quantitatively describe the photoelectric conversion capability of the photodiode for specific wavelengths of light.

[0043] 302. Obtain the pre-stored theoretical quantum efficiency; The control and analysis unit 104 obtains the theoretical quantum efficiency corresponding to each photodiode from the database stored in the calibration device. This data comes from the standard performance parameters provided by the device manufacturer or the theoretical value pre-determined in the laboratory, and is used for subsequent comparison with the measured quantum efficiency.

[0044] 303. Calculate the calibration coefficient based on the measured quantum efficiency and the theoretical quantum efficiency.

[0045] In this embodiment, the measurement quantum efficiency is extracted based on the wavelength response function, and the calibration coefficient is calculated by comparing it with the theoretical quantum efficiency, thus achieving multi-band precise calibration of the photodiode array 103 to be calibrated. This method can ensure that the calibrated photocurrent signal remains consistent across the entire spectrum, guaranteeing high accuracy and reliability of the calibration results, and improving the spectral adaptability of the photodiode array 103 to be calibrated in different bands.

[0046] In this embodiment, the control and analysis unit 104 calculates the calibration coefficients of each photodiode in the photodiode array 103 to be calibrated, including the quantum efficiency or response coefficient of each band, based on the fitted wavelength response function. The calibration coefficients are used to standardize the photocurrent signal in subsequent multispectral measurements, achieving accurate calibration of the photodiode array 103. In this embodiment, by extracting the measured quantum efficiency based on the wavelength response function and comparing it with the theoretical quantum efficiency to calculate the calibration coefficients, accurate multi-band calibration of the photodiode array 103 to be calibrated is achieved. This method ensures that the calibrated photocurrent signal remains consistent across the entire spectral range, guarantees high accuracy and reliability of the calibration results, and improves the spectral adaptability of the photodiode array 103 to be calibrated in different bands.

[0047] Please see Figure 4 In some embodiments of this application, before step 201 of the above embodiments, which measures the dark current of the photodiode array to be calibrated, the photodiode multispectral calibration method based on an integrating sphere light source may further include the following steps: 401. Connect the standard light source to the integrating sphere device; The operator connects the standard light source to the inlet of the integrating sphere 101. The standard light source is responsible for outputting stable light. The integrating sphere 101 collects the light and generates a uniform light field, while simultaneously outputting light intensity data for subsequent analysis. The control and analysis unit 104 records the output status of the light source and the data collected by the integrating sphere, providing basic data for subsequent calibration. It should be noted that a standard light source refers to a reference light source with known and traceable spectral radiation characteristics, stable output, and suitable for integrating sphere calibration. For example, the standard light source can be a standard lamp or standard LED light source with a metrological traceability certificate, such as a NIST traceable A light source, D65 light source, or an equivalent standard illuminator / standard radiation source.

[0048] 402. Measure the spectral power distribution of a standard light source using a spectrometer; A spectrometer is used to measure the output light from the integrating sphere to obtain spectral power distribution (SPD) data for each wavelength band, reflecting the output characteristics of the light source across the entire spectral range. The integrating sphere device 101 provides an optical signal channel, uniformly outputting the light field to the spectrometer. The spectrometer transmits the measurement results to the control and analysis unit 104 for recording and analysis, forming a complete spectral power distribution dataset, providing an accurate reference for the calibration of the integrating sphere's reflection uniformity. It should be noted that the spectrometer can be integrated into a photodiode multispectral calibration device or be an external device; the specific method is not limited here.

[0049] 403. Calibrate the reflection uniformity of the inner wall of the integrating sphere device according to the spectral power distribution; The integrating sphere device 101 collects the distribution data of the light field inside the integrating sphere and transmits the light intensity distribution information to the control and analysis unit 104. The control and analysis unit 104 analyzes the deviation between the measured spectral power distribution and the preset reference value, and calculates the light field uniformity optimization command by combining the output parameters of the multi-band adjustable light source module 102 and the adjustable aperture stop. The integrating sphere device 101 adjusts the output light flux according to the command, and finally realizes the uniformity calibration of the reflection of the inner wall of the integrating sphere, ensuring the high uniformity of the output light field of the integrating sphere in space and band.

[0050] 404. Under shading conditions, measure and calibrate the zero-point error of the trap detector.

[0051] Under shading conditions, the trap detector acquires the zero-point output signal and transmits the data to the control and analysis unit 104. The control and analysis unit 104 analyzes the zero-point deviation, calculates and generates compensation parameters for subsequent measurement and correction of reflection loss within the integrating sphere. This step ensures that the trap detector can accurately reflect changes in reflection loss on the inner wall of the integrating sphere, improving the accuracy and reliability of reflection loss monitoring.

[0052] In this embodiment, by introducing a standard light source with traceability qualifications to calibrate the integrating sphere optical field, using a spectrometer to measure the output power distribution of the light source, calibrating the reflection uniformity of the inner wall of the integrating sphere, and correcting the zero-point error of the trap detector, the uniformity and stability of the integrating sphere optical field can be guaranteed, providing a reliable optical basis for the subsequent multispectral calibration of photodiodes and improving the accuracy, repeatability, and reliability of calibration data.

[0053] Please see Figure 5 In some embodiments of this application, after step 303 in the above embodiments calculates the calibration coefficient based on the measured quantum efficiency and the theoretical quantum efficiency, the photodiode multispectral calibration method based on an integrating sphere light source may further include the following steps: 501. Based on the calibration coefficient, verify whether the response signal of each photodiode in the photodiode array to be calibrated meets the preset consistency tolerance requirements after calibration. The control and analysis unit 104 corrects the output signal of the photodiode array 103 to be calibrated based on the calculated calibration coefficients, and automatically compares the response data of each photodiode before and after calibration. The control and analysis unit 104 analyzes the response changes of each photodiode at different wavelengths to ensure that the relative error after calibration does not exceed ±2%, thereby verifying the consistency of the overall array response and whether the calibration effect meets the preset requirements.

[0054] 502. When the verification is successful, the calibration process data of the corresponding photodiode will be stored. The calibration process data includes dark current, reflection loss data, original photocurrent, target photocurrent, wavelength response function and calibration coefficient.

[0055] After successful calibration and verification, the control and analysis unit 104 automatically saves all data and parameters from the calibration process, including dark current, reflection loss data, raw photocurrent, target photocurrent, wavelength response function, calibration coefficients, and corresponding spectra. The stored data supports subsequent repeated verification and traceability, ensuring the calibration process is traceable and reproducible.

[0056] Furthermore, if the calibration verification fails, the control and analysis unit 104 determines that the current calibration data cannot be used for subsequent measurements and records the reason for failure and the corresponding wavelength range, residual, or deviation index. At this point, a supplementary calibration process can be triggered: under the premise of maintaining the same optical path conditions and environmental parameters, the calibration steps are re-executed at least once to obtain new dark current, reflection loss data, original photocurrent, target photocurrent, and wavelength response function. Based on this, the calibration coefficients are recalculated, and calibration verification is performed again. If the calibration still fails to meet the passing conditions after multiple calibrations (preset number), the batch of calibration data is marked as invalid and ultimately discarded. The discard record and reason are stored for traceability. After discarding, a photodiode of the same material can be replaced for individual testing. Individual testing includes collecting the dark current and photocurrent of the replaced photodiode and fitting its wavelength response function to confirm device consistency and identify the source of anomalies, thereby ensuring the integrity and verifiability of the overall calibration scheme.

[0057] In this embodiment, the calibration device automatically compares the response consistency of the photodiode before and after calibration and strictly controls the relative error to ≤±2%. Combined with the automatic saving of calibration data and spectral graphs, it can ensure the response consistency and reliability of the photodiode array 103 to be calibrated in a multi-band range. At the same time, it provides complete data support for subsequent measurement, recalibration and traceability, and improves calibration accuracy and repeatability.

[0058] Please see Figure 6 , Figure 6 One embodiment of the electronic device provided in this application includes: Processor 601, memory 602, input / output unit 603, and bus 604; The processor 601 is connected to the memory 602, the input / output unit 603, and the bus 604; The memory 602 stores a program, which the processor 601 calls to execute. Figures 2 to 5 The steps in the illustrated embodiment.

[0059] In this embodiment, the function of processor 601 is the same as described above. Figures 2 to 5 The steps in the illustrated embodiments are the same and will not be repeated here.

[0060] This application also provides a computer-readable storage medium on which a program is stored. When the program is executed on a computer, it causes the computer to perform the aforementioned actions. Figures 2 to 5 The method in any possible implementation.

[0061] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0062] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0063] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0064] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0065] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A photodiode multispectral calibration device based on an integrating sphere light source, characterized in that, It includes an integrating sphere device, a multi-band adjustable light source module, a photodiode array to be calibrated, and a control and analysis unit; The inner wall of the integrating sphere is made of a high-reflectivity diffuse reflective material to ensure the uniformity of the light field; the integrating sphere also includes a trap detector, which is used to monitor the reflection loss of the inner wall of the integrating sphere in real time; the trap detector is communicatively connected to the control and analysis unit to transmit the reflection loss data to the control and analysis unit. The multi-band adjustable light source module is connected to the integrating sphere device to output a spectrum covering one or more bands of ultraviolet, visible and near-infrared light. The photodiode array to be calibrated consists of multiple photodiodes, each of which is used to respond to light of each band output from the multi-band tunable light source module and independently output the corresponding photocurrent signal. The control and analysis unit establishes a communication connection with the multi-band tunable light source module and the photodiode array to be calibrated, and is used to control the multi-band tunable light source module to output the target spectrum sequentially according to a preset wavelength sequence; to collect the dark current of each photodiode in the photodiode array to be calibrated and the original photocurrent responding to the preset wavelength; to correct the original photocurrent based on the dark current and the reflection loss data to obtain the target photocurrent; to fit the wavelength response function of each photodiode in the photodiode array to be calibrated according to the target photocurrent at each wavelength; and to calculate the calibration coefficient of each photodiode in the photodiode array to be calibrated according to the fitted wavelength response function.

2. The photodiode multispectral calibration device according to claim 1, characterized in that, The integrating sphere device also includes an adjustable aperture stop; the adjustable aperture stop is used to control the output light flux and light field uniformity of the integrating sphere device.

3. The photodiode multispectral calibration device according to claim 1, characterized in that, The type of the multi-band adjustable light source module includes halogen tungsten lamps or multiple narrowband LED arrays; the photodiode array to be calibrated includes silicon-based photodiodes and / or III-V group semiconductor photodiodes.

4. A multispectral calibration method for photodiodes based on an integrating sphere light source, applied to the multispectral calibration device for photodiodes based on an integrating sphere light source as described in any one of claims 1 to 3, characterized in that, The photodiode multispectral calibration method includes: Measure the dark current of each photodiode in the array of photodiodes to be calibrated; The multi-band tunable light source module is controlled to output the target spectrum sequentially according to a preset wavelength sequence; At each preset wavelength, the reflection loss data of the inner wall of the integrating sphere device is obtained through the trap detector, and the original photocurrent of the photodiode responding to the preset wavelength is collected. Based on the dark current and the reflection loss data, the original photocurrent is corrected to obtain the target photocurrent; Based on the target photocurrent at each wavelength, fit the wavelength response function of each photodiode in the array of photodiodes to be calibrated.

5. The multispectral calibration method for photodiodes according to claim 4, characterized in that, The calibration parameters also include quantum efficiency. After fitting the wavelength response function of each photodiode in the photodiode array to be calibrated based on the target photocurrent at each wavelength, the photodiode multispectral calibration method further includes: The measurement quantum efficiency is determined based on the wavelength response function. Obtain the pre-stored theoretical quantum efficiency; The calibration coefficient is calculated based on the measured quantum efficiency and the theoretical quantum efficiency.

6. The multispectral calibration method for photodiodes according to claim 4, characterized in that, Before measuring the dark current of each photodiode in the array of photodiodes to be calibrated, the photodiode multispectral calibration method further includes: Connect a standard light source to the integrating sphere device; The spectral power distribution of the standard light source was measured using a spectrometer; The reflection uniformity of the inner wall of the integrating sphere device is calibrated according to the spectral power distribution; Under shading conditions, the zero-point error of the trap detector was measured and calibrated.

7. The multispectral calibration method for photodiodes according to claim 4, characterized in that, The step of correcting the original photocurrent based on the dark current and the reflection loss data to obtain the target photocurrent includes: The dark current and the reflection loss data are applied to the correction formula to correct the original photocurrent and obtain the target photocurrent. The correction formula is as follows: in, This represents the original photocurrent. This represents the target photocurrent. This refers to the dark current. This represents the reflection loss data. This represents the preset gain compensation coefficient of the photodiode.

8. The multispectral calibration method for photodiodes according to claim 5, characterized in that, After calculating the calibration coefficient based on the measured quantum efficiency and the theoretical quantum efficiency, the photodiode multispectral calibration method further includes: Based on the calibration coefficient, verify whether the response signal of each photodiode in the photodiode array to be calibrated meets the preset consistency tolerance requirements after calibration. When the verification is successful, the calibration process data corresponding to the photodiode will be stored; the calibration process data includes the dark current, the reflection loss data, the original photocurrent, the target photocurrent, the wavelength response function, and the calibration coefficient.

9. An electronic device, characterized in that, include: Processor, memory, input / output units, and bus; The processor is connected to the memory, the input / output unit, and the bus; The memory stores a program, and the processor calls the program to execute the photodiode multispectral calibration method as described in any one of claims 4 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium contains a program that, when executed on a computer, causes the computer to perform the photodiode multispectral calibration method as described in any one of claims 4 to 8.

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