A method, device, system and storage medium for detecting an LED lamp bead

Abstract

The application relates to a kind of detection method, device, system and storage medium of LED lamp bead, comprising the following steps, the electrode of the LED lamp bead is tested, and the initial current value of the LED lamp bead is obtained;Based on the initial current value, the LED lamp bead is applied to step voltage, and voltage-current curve is obtained;The LED lamp bead corresponding to the rated operating point in the voltage-current curve is detected by optical detector, and the light spot image is obtained;Based on the light spot image, the LED lamp bead is tested by reverse voltage, and the reverse leakage current value is obtained;Based on the voltage-current curve, light spot image and reverse leakage current value, the quality of the LED lamp bead is evaluated, and the quality evaluation result of the LED lamp bead is obtained, which solves the technical problem that the traditional detection method is mainly concentrated on simple on-off test or single parameter measurement, and it is difficult to comprehensively reflect the comprehensive performance of LED lamp bead.

Description

Technical Field

[0001] This invention relates to the field of LED lamp bead technology, and in particular to a method, apparatus, system and storage medium for testing LED lamp beads. Background Technology

[0002] With the rapid development of LED technology, LED chips have been widely used in lighting, displays, backlighting, and automotive industries due to their high energy efficiency, long lifespan, and environmental friendliness. However, the photoelectric performance of LED chips varies due to factors such as material defects and packaging process fluctuations during production, and some are at risk of early failure. Therefore, accurate and comprehensive quality testing of LED chips has become a key link in ensuring product reliability and consistency. Traditional testing methods mostly focus on simple continuity tests or single parameter measurements, which are insufficient to comprehensively reflect the overall performance of LED chips and can no longer meet the stringent quality control requirements of high-end applications. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a method, apparatus, system, and storage medium for detecting LED beads.

[0004] The technical solution adopted in this invention is:

[0005] On one hand, embodiments of the present invention provide a method for detecting LED beads, comprising the following steps:

[0006] The electrodes of the LED bead are energized to obtain the initial current value of the LED bead;

[0007] Based on the initial current value, a stepped voltage is applied to the LED chip to obtain a voltage-current curve;

[0008] An optical detector is used to detect the light emission of the LED beads corresponding to the rated operating point in the voltage-current curve to obtain a light spot image.

[0009] Based on the light spot image, the LED bead is subjected to a reverse voltage test to obtain the reverse leakage current value;

[0010] Based on the voltage-current curve, spot image, and reverse leakage current value, the quality of the LED is evaluated, and the quality evaluation result of the LED is obtained.

[0011] Furthermore, the electrodes of the LED bead are subjected to an energization test to obtain the initial current value of the LED bead, including:

[0012] The test probes are brought into contact with the positive and negative electrodes of the LED beads by a probe station to apply a preset test voltage, obtain electrode contact signals, and verify the continuity of the electrode contact signals to obtain contact continuity results.

[0013] Based on the contact continuity results, a preset test voltage is maintained on the LED beads with good contact to obtain real-time current data, and the stable value is extracted from the real-time current data to obtain the initial current value.

[0014] Furthermore, based on the initial current value, a stepped voltage is applied to the LED chip to obtain a voltage-current curve, including:

[0015] Based on the initial current value, the voltage starting point is determined, and an incremental voltage starting from the voltage starting point is applied to the LED beads to obtain multiple sets of voltage-current corresponding data. The voltage-current corresponding data is then filtered for outliers to obtain valid voltage and current data.

[0016] The effective voltage and current data are continuously recorded to obtain a voltage and current time series sequence, wherein the voltage and current time series sequence includes voltage and current data pairs arranged in chronological order; and data point smoothing processing is performed based on the voltage and current time series sequence to obtain smooth curve data;

[0017] The smooth curve data is mapped to obtain a voltage-current scatter distribution, wherein the voltage-current scatter distribution includes discrete data points with voltage as the horizontal axis and current as the vertical axis; and a continuous curve is fitted based on the voltage-current scatter distribution to obtain a voltage-current curve.

[0018] Furthermore, based on the emission detection of the LED beads corresponding to the rated operating point in the voltage-current curve using an optical detector to obtain a light spot image, the method includes:

[0019] An optical detector is used to collect the light emitted by LED beads at their rated operating point in the voltage-current curve to obtain raw light signal data. The light signal data is then converted into photoelectric data to obtain an initial light spot image.

[0020] Based on the initial spot image, a region is cropped to obtain an effective spot region, and the effective spot region is then grayscale calibrated to obtain a calibrated spot image.

[0021] The calibrated spot image is pixel-sharpened to obtain a clear spot image, and the edge contour of the clear spot image is extracted to obtain a spot image.

[0022] Furthermore, based on the light spot image, a reverse voltage test is performed on the LED chip to obtain the reverse leakage current value, including:

[0023] The brightness distribution of the light spot image is scanned to obtain light spot brightness data, and the uniformity of the light spot brightness data is analyzed to obtain a brightness distribution map;

[0024] Based on the brightness distribution map, a reverse voltage is applied to the LED beads to obtain reverse current sampling data, and time-domain analysis is performed on the reverse current sampling data to obtain a reverse current curve.

[0025] The steady-state current value is obtained by numerically extracting the current stability interval in the reverse current curve, and the steady-state current value is calibrated and compensated to obtain the reverse leakage current value.

[0026] Furthermore, based on the brightness distribution map, a reverse voltage is applied to the LED beads to obtain reverse current sampling data, including:

[0027] The timing control module turns off the light emission of the LED beads to obtain an off state signal, and then performs a stability judgment on the off state signal to obtain an off confirmation result.

[0028] Based on the extinguishing confirmation result, a step-increasing reverse voltage is applied to the LED beads through a voltage switching device to obtain a reverse voltage response signal, and the rising edge of the reverse voltage response signal is detected to obtain the voltage switching time point.

[0029] Based on the voltage switching time point, the reverse current of the LED beads is collected in a timely manner by the synchronous sampling unit to obtain the original current sampling sequence, and the original current sampling sequence is subjected to time-domain filtering to obtain the reverse current sampling data.

[0030] Furthermore, the feature is that, based on the voltage-current curve, the light spot image, and the reverse leakage current value, the quality of the LED chip is evaluated to obtain the quality evaluation result of the LED chip, including:

[0031] Feature parameters are extracted from the voltage-current curve to obtain electrical performance parameters, and luminescence characteristics are analyzed from the spot image to obtain optical performance parameters. Stability analysis is performed on the reverse leakage current value to obtain leakage current stability parameters.

[0032] The electrical performance parameters, optical performance parameters, and leakage current stability parameters are compared with preset electrical performance threshold ranges, optical performance threshold ranges, and leakage current stability threshold ranges, respectively, to obtain a comprehensive comparison result set.

[0033] The quality of the LED beads is evaluated based on the comprehensive comparison result set, and the quality evaluation result of the LED beads is obtained.

[0034] The present invention also provides an LED bead detection device, comprising:

[0035] The first test module is used to perform an energization test on the electrodes of the LED lamp bead to obtain the initial current value of the LED lamp bead;

[0036] An application module is used to apply a stepped voltage to the LED based on the initial current value to obtain a voltage-current curve;

[0037] The detection module is used to detect the light emission of the LED beads corresponding to the rated operating point in the voltage-current curve using an optical detector, and obtain a light spot image.

[0038] The second test module is used to perform a reverse voltage test on the LED beads based on the light spot image to obtain the reverse leakage current value;

[0039] The evaluation module is used to evaluate the quality of the LED beads based on the voltage-current curve, the spot image, and the reverse leakage current value, and to obtain the quality evaluation result of the LED beads.

[0040] The present invention also provides an LED bead detection system, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of any of the methods described above.

[0041] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of any of the methods described above.

[0042] This invention provides a method for testing LED beads, comprising the following steps: performing an energization test on the electrodes of the LED bead to obtain the initial current value of the LED bead; applying a stepped voltage to the LED bead based on the initial current value to obtain a voltage-current curve; performing light emission detection on the LED bead corresponding to the rated operating point in the voltage-current curve using an optical detector to obtain a light spot image; performing a reverse voltage test on the LED bead based on the light spot image to obtain a reverse leakage current value; and performing a quality assessment on the LED bead based on the voltage-current curve, the light spot image, and the reverse leakage current value to obtain a quality assessment result. This method solves the technical problem that traditional testing methods often focus on simple on / off tests or single parameter measurements, making it difficult to comprehensively reflect the overall performance of LED beads. It enables reverse voltage testing after obtaining the light spot image to acquire the reverse leakage current value, effectively identifying potential failure factors such as PN junction defects, encapsulation contamination, or internal short circuits. This step, combined with the light spot image, can determine whether there are abnormal light emission and leakage phenomena caused by structural defects, significantly enhancing the predictive ability for early failure risks. Attached Figure Description

[0043] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0044] Figure 1 This is a flowchart illustrating the steps of the LED bead detection method in an embodiment of the present invention.

[0045] Figure 2 This is a structural block diagram of the LED bead detection device in an embodiment of the present invention;

[0046] Figure 3 This is a schematic block diagram of an LED bead detection system according to an embodiment of the present invention.

[0047] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0048] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0049] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0050] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0051] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0052] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0053] Reference Figure 1 This invention provides a method for detecting LED beads, comprising the following steps:

[0054] Step S1: Perform an energization test on the electrodes of the LED lamp bead to obtain the initial current value of the LED lamp bead.

[0055] Specifically, the electrodes of the LED bead are energized to obtain the initial current value of the LED bead. This step is implemented as follows: First, the LED bead to be tested is fixed in the testing carrier, and a stable electrical connection is established between the LED bead and its electrodes using a precision probe, ensuring minimal contact resistance to avoid measurement errors. Next, a preset low-amplitude DC voltage signal is applied to the electrodes of the LED bead. This voltage value is set near the LED bead's conduction threshold but insufficient to fully illuminate it, for example, between 0.5V and 1.5V. The specific value is adapted according to the LED material type (e.g., GaN-based blue light or AlInGaP-based red light). Then, a high-precision current acquisition module is used to read the current response flowing through the LED bead in real time, and the recorded current value is the initial current value of the LED bead. This process must be carried out in a constant-temperature environment free from strong light interference to ensure data stability, such as at the online testing station in an LED packaging factory when a batch of SMD... When the 2835 white LED bead enters the testing process, the automatic probe station contacts its positive and negative electrodes in sequence. If the initial current value collected after applying a 1.2V voltage is within the normal batch statistical range (e.g., 5~8μA), the subsequent step voltage loading continues. If the initial current value is abnormally high or zero, it is preliminarily determined that there is a short circuit or open circuit defect, thereby ensuring the effectiveness and safety of subsequent tests.

[0056] Step S2: Based on the initial current value, apply a stepped voltage to the LED bead to obtain a voltage-current curve.

[0057] Specifically, based on the initial current value, a stepped voltage is applied to the LED bead to obtain a voltage-current curve. This step is implemented as follows: After obtaining the initial current value of the LED bead, this initial current value is used as a reference to determine the starting point and stepping strategy for voltage scanning. Then, starting from a voltage below the LED bead's conduction threshold, the voltage applied to the electrodes of the LED bead is gradually increased. Each voltage increment is set to a fixed value, such as 0.1V or 0.2V, and is maintained at each voltage step for a certain period to allow the current to stabilize. Simultaneously, the actual current value at the corresponding voltage is collected, and the current change trend is continuously monitored during the collection process. If an abnormal current change is detected... If the current growth rate is abnormally steep, the subsequent voltage step size is automatically reduced to improve data resolution. The multiple sets of voltage and current data points recorded are connected in sequence to form the voltage-current curve. The entire process is completed by the automatic control system coordinating the power supply module and the data acquisition module. For example, in the detection of SMD2835 white LED beads, when the initial current value is measured to be 6μA, the system starts a stepped voltage loading from 1.5V, applying 1.5V, 1.7V, 1.9V... in sequence until the rated operating voltage of 3.0V is reached. Finally, the current data collected at each stage is plotted into a complete voltage-current curve to identify conduction characteristics, series resistance, and nonlinear regions.

[0058] Step S3: Use an optical detector to detect the light emission of the LED beads corresponding to the rated operating point in the voltage-current curve to obtain a light spot image.

[0059] Specifically, an optical detector is used to detect the light emission of the LED bead corresponding to the rated operating point in the voltage-current curve, obtaining a light spot image. This step is implemented as follows: after acquiring the voltage-current curve, the rated operating point of the LED bead is identified from the curve. This rated operating point corresponds to the normal operating voltage and current combination specified by the manufacturer, for example, for SMD LEDs. The 2835 white LED bead typically operates at a rated operating point of 3.0V, generating a 20mA current. The control system then applies a DC voltage or constant current drive signal, identical to this rated operating point, to the LED bead's electrodes, placing it in its standard luminous state for practical applications. Simultaneously, an optical inspection instrument located above it is activated. This instrument, equipped with a high-resolution industrial camera and a standard light source calibration module, operates in a darkroom environment to eliminate ambient light interference. The optical inspection instrument performs static or short-term dynamic imaging of the LED bead's luminous surface, capturing a visual image of its stable luminous state at the rated operating point. The acquired image is saved as a digital spot image via a data transmission interface. This spot image contains spatial information such as the brightness distribution, shape integrity, and the presence of dark or overexposed areas in the LED bead's luminous region. For example, during the inspection of the same batch of SMD 2835 white LED beads, if a bead is photographed with a noticeable dark spot in the center of its spot under 3.0V drive, this image will be marked and used for defect determination in subsequent quality assessment stages.

[0060] Step S4: Based on the light spot image, perform a reverse voltage test on the LED bead to obtain the reverse leakage current value.

[0061] Specifically, based on the light spot image, a reverse voltage test is performed on the LED bead to obtain the reverse leakage current value. This step is implemented as follows: After acquiring the light spot image, the LED bead is maintained in the testing carrier. The drive signal applied to the electrodes of the LED bead is switched from positive power supply to reverse voltage output mode. At this time, the power module applies a negative DC voltage to the electrodes of the LED bead according to a preset program. This reverse voltage value is typically set to 5V or the standard reverse withstand voltage value specified in the device datasheet. Simultaneously with the application of the reverse voltage, a high-sensitivity current measurement unit collects the minute current signal flowing through the LED bead in real time. This current is the reverse leakage current value. During the acquisition process, the ambient temperature is kept stable and free from electromagnetic interference to ensure measurement accuracy. The data acquisition system stores the recorded current value as the reverse leakage current value and establishes a data association with the aforementioned light spot image, for example, in SMD... In the testing process of the 2835 white LED lamp bead, when the light spot image of a certain lamp bead shows that there is a dark corner at the edge of the light-emitting area, a reverse voltage test is then performed on it. After applying a -5V voltage, the reverse leakage current value is measured to be 0.8μA. If this value exceeds the qualified product threshold (e.g., >0.5μA), it indicates that the lamp bead not only has optical defects, but also has PN junction leakage problems, thus providing a consistent criterion for subsequent comprehensive evaluation.

[0062] Step S5: Based on the voltage-current curve, light spot image and reverse leakage current value, perform quality assessment on the LED beads to obtain the quality assessment result of the LED beads.

[0063] Specifically, based on the voltage-current curve, light spot image, and reverse leakage current value, the quality of the LED chip is evaluated to obtain the quality evaluation result. This step is implemented as follows: After completing the aforementioned detection process, the acquired voltage-current curve is input into a data analysis system. Key characteristic parameters are extracted using an algorithm, including the turn-on voltage, current stability under operating voltage, and the trend of curve slope change. Simultaneously, an image processing module is called to perform grayscale analysis and region recognition on the light spot image to detect abnormal light emission patterns such as uneven brightness, central dark spots, or edge defects. The reverse leakage current value is then used to determine whether the insulation performance of the device under reverse bias meets the standard. Subsequently, the above three types of data are compared according to a preset evaluation rule. This rule sets the threshold range and weight of each parameter based on a historical qualified sample database. For example, for SMD... For the 2835 white LED bead, if the voltage-current curve shows that the operating current deviates from the nominal value by more than ±10%, or if a dark area with an area exceeding 5% of the total number of pixels appears in the light spot image, or if the reverse leakage current value is greater than 0.5μA, it is judged as unqualified. After comprehensive interpretation of all parameters, the system automatically generates the quality assessment result of the LED bead, marking it as "qualified", "downgraded", or "scrapped", and stores the result in the test record database with the corresponding serial number for traceability.

[0064] In a specific embodiment, the electrodes of the LED bead are energized to obtain the initial current value of the LED bead, including:

[0065] The test probes are brought into contact with the positive and negative electrodes of the LED beads by a probe station to apply a preset test voltage, obtain electrode contact signals, and verify the continuity of the electrode contact signals to obtain contact continuity results.

[0066] Based on the contact continuity results, a preset test voltage is maintained on the LED beads with good contact to obtain real-time current data, and the stable value is extracted from the real-time current data to obtain the initial current value.

[0067] Specifically, the step of performing a power-on test on the electrodes of the LED bead to obtain the initial current value of the LED bead includes contacting the test probes with the positive and negative electrodes of the LED bead using a probe station to apply a preset test voltage, obtaining an electrode contact signal, and verifying the continuity of the electrode contact signal to obtain a contact continuity result; based on the contact continuity result, maintaining the preset test voltage on the well-contacting LED bead to obtain real-time current data, and extracting a stable value from the real-time current data to obtain the initial current value. The specific implementation method of this step is as follows: in SMD After the 2835 white LED bead enters the automatic testing station, a robotic arm precisely positions it onto the probe station carrier. The probe station then drives a set of fine metal probes to physically contact the positive and negative electrodes of the LED bead according to a preset trajectory. Slight pressure is applied during contact to ensure reliable electrical connection while avoiding damage to the electrode plating. Immediately after contact, a low-amplitude DC voltage, such as 1.2V, is applied as a preset test voltage. This voltage is lower than the typical turn-on voltage of the LED bead but sufficient to elicit a weak current response. At this time, the system collects the electrical signal fed back from the electrodes of the LED bead, which is the electrode contact signal. This signal includes the voltage readback value and the initial current response state. The electrode contact signal is then verified for continuity by determining whether a measurable current path exists and whether the voltage is stably applied to confirm the connection validity. If the current is zero or fluctuating... If the current surges violently, it is determined to be a poor connection or open circuit, resulting in a "not conducting" connection. This LED will be marked and skipped from subsequent testing. If the current rises steadily and remains within a reasonable range, it is determined to be a good electrical connection, resulting in a "conducting" connection. Based on this, the LED with good contact continues to be powered by the same preset test voltage of 1.2V for approximately 200 to 500 milliseconds. During this period, the high-speed data acquisition module records the real-time current data flowing through the LED at a frequency of over 1000 times per second, forming a current response sequence that varies over time. This real-time current data is then filtered to eliminate noise interference, and a moving average algorithm or a set threshold window is used to extract the range of values ​​that tend to stabilize from multiple consecutive sampling points. The average value is taken as the final stable value, which is the initial current value of the LED. For example, in a batch of SMD... In the testing of the 2835 white LED lamp bead, the real-time current data of a certain lamp bead stabilized within the range of 6.3μA±0.2μA after 300 milliseconds at a voltage of 1.2V. Based on this, the system extracted 6.3μA as its initial current value, which was used to set the starting parameters for subsequent stepped voltage tests, thereby ensuring the accuracy and consistency of the entire testing process.

[0068] In a specific embodiment, based on the initial current value, a stepped voltage is applied to the LED chip to obtain a voltage-current curve, including:

[0069] Based on the initial current value, the voltage starting point is determined, and an incremental voltage starting from the voltage starting point is applied to the LED beads to obtain multiple sets of voltage-current corresponding data. The voltage-current corresponding data is then filtered for outliers to obtain valid voltage and current data.

[0070] The effective voltage and current data are continuously recorded to obtain a voltage and current time series sequence, wherein the voltage and current time series sequence includes voltage and current data pairs arranged in chronological order; and data point smoothing processing is performed based on the voltage and current time series sequence to obtain smooth curve data;

[0071] The smooth curve data is mapped to obtain a voltage-current scatter distribution, wherein the voltage-current scatter distribution includes discrete data points with voltage as the horizontal axis and current as the vertical axis; and a continuous curve is fitted based on the voltage-current scatter distribution to obtain a voltage-current curve.

[0072] Specifically, based on the initial current value, a stepped voltage is applied to the LED bead to obtain a voltage-current curve. This includes determining the voltage starting point based on the initial current value, applying an increasing voltage to the LED bead starting from the voltage starting point, obtaining multiple sets of voltage-current corresponding data, and filtering outliers from the voltage-current corresponding data to obtain valid voltage and current data. The valid voltage and current data are continuously recorded to obtain a voltage-current time series sequence, wherein the voltage-current time series sequence includes voltage and current data pairs arranged in chronological order. Data point smoothing is performed based on the voltage-current time series sequence to obtain smoothed curve data. Coordinate mapping is performed on the smoothed curve data to obtain a voltage-current scatter distribution, wherein the voltage-current scatter distribution includes discrete data points with voltage as the horizontal axis and current as the vertical axis. Continuous curve fitting is performed based on the voltage-current scatter distribution to obtain the voltage-current curve. The specific implementation method of this step is: when acquiring SMD... After obtaining the initial current value of the 2835 white LED bead, this value is input as a parameter to the test control system. The system determines the corresponding voltage starting point according to the pre-stored mapping table. For example, when the initial current value is 6.3μA, the corresponding voltage starting point is set to 1.5V. Then, the DC power supply module is controlled to apply voltage to the electrodes of the LED bead in increments of 0.2V starting from this voltage starting point. After each voltage step, a 300-millisecond pause is maintained to allow the current response to stabilize. Simultaneously, the currently applied voltage value and the current value flowing through the LED bead are collected to form a set of voltage-current corresponding data. The loading of 11 voltage steps from 1.5V to 3.6V is completed in sequence to obtain 11 sets of raw data. Then, the voltage-current corresponding data is screened for outliers. By setting the current change rate threshold and upper and lower limits, data points with current mutations exceeding ±20% or negative or saturated values ​​are removed. Data that conforms to the trend is retained as valid voltage and current data. For example, the 8th set (2.After the current was 45mA at 9V (significantly deviating from the exponential growth trend), the remaining 10 sets of data entered the next processing stage. The effective voltage and current data were then continuously recorded according to the loading sequence, generating a voltage and current time-series sequence containing timestamps. Each item in this sequence is a voltage and current data pair arranged chronologically. Next, a moving average filtering algorithm was applied to smooth the data points of this voltage and current time-series sequence, with a window size of 3 points to eliminate minor jitter caused by power fluctuations or acquisition noise. The resulting smoothed current response sequence is the smoothed curve data. Each pair of voltage and current values ​​in the smoothed curve data was then used as coordinate points for coordinate mapping, with the horizontal axis representing voltage (unit: V) and the vertical axis representing current (unit: mA), to plot a set of discrete data points, forming a voltage-current scatter distribution. Finally, based on this voltage-current scatter distribution, the least squares method was used for nonlinear curve fitting, selecting the exponential function model I = a·e^(bV) + c approximates the data points, and after fitting, outputs a continuous mathematical expression and a graphical curve. This curve is the final voltage-current curve, used for subsequent identification of the rated operating point and conduction characteristics.

[0073] In a specific embodiment, the method of obtaining a light spot image based on the emission detection of the LED bead corresponding to the rated operating point in the voltage-current curve using an optical detector includes:

[0074] An optical detector is used to collect the light emitted by LED beads at their rated operating point in the voltage-current curve to obtain raw light signal data. The light signal data is then converted into photoelectric data to obtain an initial light spot image.

[0075] Based on the initial spot image, a region is cropped to obtain an effective spot region, and the effective spot region is then grayscale calibrated to obtain a calibrated spot image.

[0076] The calibrated spot image is pixel-sharpened to obtain a clear spot image, and the edge contour of the clear spot image is extracted to obtain a spot image.

[0077] Specifically, the step of detecting the light emission of LED beads corresponding to the rated operating point in the voltage-current curve using an optical detector to obtain a light spot image includes: acquiring the light emission of LED beads at the rated operating point in the voltage-current curve using an optical detector to obtain raw light signal data; performing photoelectric conversion on the light signal data to obtain an initial light spot image; performing region cropping based on the initial light spot image to obtain an effective light spot area; performing grayscale calibration on the effective light spot area to obtain a calibrated light spot image; performing pixel sharpening processing on the calibrated light spot image to obtain a clear light spot image; and extracting the edge contours of the clear light spot image to obtain a light spot image. The specific implementation of this step is as follows: in SMD... After the 2835 white LED bead completes the voltage-current curve test, the system identifies the rated operating point from the voltage-current curve. This rated operating point corresponds to the normal operating state of generating 20mA current at 3.0V. Subsequently, the control system applies a stable 3.0V DC voltage to the electrodes of the LED bead, keeping it in a continuous luminous state. Simultaneously, the optical inspection instrument located directly above it is activated. This optical inspection instrument is equipped with a 5-megapixel industrial CMOS camera and a standard fixed-focus lens. In a darkroom environment, it performs static photography on the luminous surface of the LED bead, collecting the emitted visible light signal as raw light signal data. This raw light signal data undergoes photoelectric conversion through the photosensitive array inside the camera, converting the light intensity distribution into a digital electrical signal, generating a two-dimensional image containing the luminous area and background noise, which is the initial light spot image. This initial light spot image then enters the image processing flow, first based on the preset ROI (Region of Interest). The initial spot image is cropped using an interest template to exclude edge distortion and interference from adjacent LEDs, retaining only the luminous portion within the central circular or rectangular area as the effective spot region. Next, grayscale calibration is performed on this effective spot region. A standard whiteboard reference image is used to linearly map pixel grayscale values, compensating for brightness deviations caused by lens vignetting and uneven sensor response, ensuring consistent grayscale across areas of the same brightness, resulting in a calibrated spot image. Subsequently, the Laplacian operator is applied to this calibrated spot image for pixel sharpening, enhancing contrast at the boundary between light and dark areas, highlighting details, eliminating slight blur, and generating a clear spot image. Finally, the Canny edge detection algorithm is used to extract edge contours from this clear spot image, setting high and low thresholds of 80 and 150 respectively, detecting the continuous outer boundary and internal structure boundary of the spot, forming a contour layer composed of closed curves. This contour layer is fused with the original pixel information to output the final spot image, for example, on a certain SMD... During the testing of the 2835 white LED lamp bead, the light spot image showed that the central area had uniform brightness, but there was a clear dark band in the lower right corner, and the edge contour locally contracted in this area. This image will serve as an important basis for subsequent reverse voltage testing and quality assessment.

[0078] In a specific embodiment, the pixel sharpening process performed on the calibrated spot image to obtain a clear spot image includes:

[0079] Pixel grayscale fluctuation analysis is performed on the calibration spot image to obtain noise region markers, and connected component partitioning is performed on the noise region markers to obtain noise accumulation regions;

[0080] Based on the noise accumulation region, a partitioned noise reduction process is applied to the calibration spot image to obtain a noise-reduced image, and edge pixel enhancement is performed on the noise-reduced image to obtain a noise-enhanced image.

[0081] Noise residue detection is performed on the denoised and enhanced image to obtain the noise residue rate. The noise residue rate is then compared with a preset noise reduction threshold to select the denoised and enhanced images that meet the threshold requirements, thus obtaining a clear light spot image.

[0082] Specifically, the pixel sharpening process for the calibration spot image to obtain a clear spot image includes: performing pixel grayscale fluctuation analysis on the calibration spot image to obtain noise region markers; dividing the noise region markers into connected components to obtain noise accumulation regions; applying partitioned denoising processing to the calibration spot image based on the noise accumulation regions to obtain a denoised image; and enhancing the edge pixels of the denoised image to obtain a denoised enhanced image; performing noise residue detection on the denoised enhanced image to obtain a noise residue rate; comparing the noise residue rate with a preset denoising threshold; and selecting the denoised enhanced images that meet the threshold requirements to obtain a clear spot image. The specific implementation of this step is as follows: in SMD... In the testing process of the 2835 white LED bead, after the calibration spot image is generated, the gray value of each pixel in the image is first analyzed by neighborhood statistics. A 3×3 pixel window is used to slide across the entire image, calculating the gray standard deviation between each central pixel and its eight neighboring pixels. If this standard deviation exceeds a preset fluctuation threshold (e.g., 15 gray levels), the pixel is marked as an anomaly, forming a preliminary noise region marker. Then, all marked noise pixels are partitioned into connected components. A four-neighbor or eight-neighbor algorithm is used to cluster spatially adjacent anomalies into independent regions, identifying multiple discrete noise clusters. For example, in a calibration spot image, an isolated noise cluster with an area of ​​45 pixels in the upper right corner and a thin, striped cluster in the center are identified. Next, based on these noise clusters, the calibration spot image undergoes partitioned noise reduction processing. Median filtering is used to smooth and denoise within the noise clusters, while noise is preserved in non-noise areas. The original pixels are kept unchanged or a light Gaussian filter is applied to avoid loss of detail. After processing, a denoised image is generated. Then, edge pixel enhancement is performed on the denoised image. The Sobel operator is used to extract image gradient information to highlight boundary areas with drastic brightness changes. The gradient map is then weighted and fused with the original image to enhance the contrast and sharpness of the light spot edges, forming a denoised and enhanced image. Next, noise residue detection is performed on the denoised and enhanced image. By calculating the gray-level variance of the image background area (non-luminous area) and the overall image signal-to-noise ratio, the noise residue rate is derived. For example, if the calculated noise residue rate of the current image is 6.8%, this value is compared with the system's preset noise reduction threshold (e.g., ≤7%). If the noise residue rate is lower than or equal to the threshold, the denoised and enhanced image is determined to meet the imaging quality requirements and is selected as a qualified image, ultimately entering the next processing stage as a clear light spot image. If it is higher than the threshold, a second noise reduction process is triggered until the standard is met. For example, in a certain batch of SMD In the testing of 2835 white LED beads, the noise reduction and enhancement image of one bead was found to have a noise residual rate of 7.5%, which exceeded the 7% threshold. The system automatically readjusted the filtering parameters and processed the image again until the noise residual rate dropped to 6.2%, at which point a clear light spot image was generated for subsequent edge contour extraction.

[0083] In a specific embodiment, based on the light spot image, a reverse voltage test is performed on the LED bead to obtain the reverse leakage current value, including:

[0084] The brightness distribution of the light spot image is scanned to obtain light spot brightness data, and the uniformity of the light spot brightness data is analyzed to obtain a brightness distribution map;

[0085] Based on the brightness distribution map, a reverse voltage is applied to the LED beads to obtain reverse current sampling data, and time-domain analysis is performed on the reverse current sampling data to obtain a reverse current curve.

[0086] The steady-state current value is obtained by numerically extracting the current stability interval in the reverse current curve, and the steady-state current value is calibrated and compensated to obtain the reverse leakage current value.

[0087] Specifically, based on the light spot image, a reverse voltage test is performed on the LED chip to obtain the reverse leakage current value. This includes scanning the brightness distribution of the light spot image to obtain light spot brightness data, and performing uniformity analysis on the light spot brightness data to obtain a brightness distribution map; applying a reverse voltage to the LED chip based on the brightness distribution map to obtain reverse current sampling data, and performing time-domain analysis on the reverse current sampling data to obtain a reverse current curve; extracting the current stability interval in the reverse current curve to obtain a steady-state current value, and calibrating and compensating the steady-state current value to obtain the reverse leakage current value. The specific implementation of this step is as follows: in SMD... In the testing process of the 2835 white LED bead, after the light spot image is generated, a brightness distribution scan is first performed on the image. The grayscale value of each pixel in the image is read row by row and column by column and mapped to a relative light intensity value, forming a data matrix containing the pixel coordinates and corresponding brightness values ​​of the entire light spot area, which is the light spot brightness data. Then, a uniformity analysis is performed on the light spot brightness data. The root mean square error method is used to calculate the brightness deviation of the entire luminous area. The central area is set as the reference brightness, and the percentage deviation of the surrounding areas from it is calculated. The analysis results are presented in the form of a heat map, generating a brightness distribution map. This brightness distribution map visually shows whether there are locally dark or overly bright areas in the light spot. For example, if the brightness distribution map of a certain LED bead shows that the brightness in its lower left quadrant is only 65% ​​of the average, it indicates a defect of uneven light emission. Then, based on the information in this brightness distribution map, a reverse voltage test process is triggered. The control system switches the power supply polarity and applies a -5V DC reverse voltage to the electrodes of the LED bead for a duration of 500 milliseconds. Simultaneously, a high-precision sensor is activated. The ampere-level current acquisition module acquires minute current signals flowing through the device at a frequency of 2000 times per second, forming a current sampling sequence that varies with time, which is the reverse current sampling data. Subsequently, time-domain analysis is performed on this reverse current sampling data to plot the waveform curve of the current changing with time, identifying the transition process from the initial current surge to a stable state. The current stability range is determined to be less than ±0.05μA after 300 milliseconds of voltage application. The current values ​​of multiple consecutive sampling points within this range are then extracted and their average value is calculated to obtain the steady-state current value, for example, if the measured value is 0.78μA. This steady-state current value is then calibrated and compensated. The compensation process is based on a pre-calibrated temperature-current offset curve and probe contact resistance compensation coefficient to correct for systematic errors introduced by ambient temperature fluctuations and test fixtures. Finally, the compensated current value is output as the reverse leakage current value, for example, correcting 0.78μA to 0.81μA. This reverse leakage current value is stored in association with the aforementioned brightness distribution map for comprehensive evaluation of the SMD. Does the 2835 white LED bead exhibit photoelectric dual abnormality due to internal defects?

[0088] In a specific embodiment, a reverse voltage is applied to the LED beads based on the brightness distribution map to obtain reverse current sampling data, including:

[0089] The timing control module turns off the light emission of the LED beads to obtain an off state signal, and then performs a stability judgment on the off state signal to obtain an off confirmation result.

[0090] Based on the extinguishing confirmation result, a step-increasing reverse voltage is applied to the LED beads through a voltage switching device to obtain a reverse voltage response signal, and the rising edge of the reverse voltage response signal is detected to obtain the voltage switching time point.

[0091] Based on the voltage switching time point, the reverse current of the LED beads is collected in a timely manner by the synchronous sampling unit to obtain the original current sampling sequence, and the original current sampling sequence is subjected to time-domain filtering to obtain the reverse current sampling data.

[0092] Specifically, based on the brightness distribution map, a reverse voltage is applied to the LED beads to obtain reverse current sampling data. This includes turning off the LED beads' light emission state through a timing control module to obtain an off-state signal, and performing a stability judgment on the off-state signal to obtain an off-state confirmation result. Based on the off-state confirmation result, a step-increasing reverse voltage is applied to the LED beads through a voltage switching device to obtain a reverse voltage response signal, and the rising edge of the reverse voltage response signal is detected to obtain the voltage switching time point. Based on the voltage switching time point, the reverse current of the LED beads is periodically collected by a synchronous sampling unit to obtain an original current sampling sequence, and the original current sampling sequence is time-domain filtered to obtain reverse current sampling data. The specific implementation method of this step is as follows: in SMD After the 2835 white LED bead completes the acquisition of the light spot image and generates the brightness distribution map, the system initiates the reverse voltage test preparation process. First, the timing control module sends a shutdown command to the driver power supply, cutting off the positive working voltage applied to the electrodes of the LED bead, causing the device to stop emitting light. At this time, the light-emitting surface of the LED bead is continuously monitored by an optical detector, and a sequence of background images under no-light conditions is acquired. The average gray value of the images is used as the off-state signal. If the gray value change of three consecutive frames is less than a preset threshold (e.g., ±2 gray levels), the LED bead is determined to be completely off and stable, and the off-state confirmation result is "stable off". If the gray value continues to fluctuate or there is residual light, the process is delayed until the stability requirement is met. Based on the off-state confirmation result, the system activates the voltage switching device, which consists of a relay array and a polarity switching circuit. According to a preset program, starting from 0V, the voltage is applied sequentially to the electrodes of the LED bead. A stepped increasing reverse voltage of -1V, -2V, -3V, -4V to -5V is applied, with each voltage step maintained for 100 milliseconds. During the application process, the voltage feedback signal in the circuit is monitored in real time to form a reverse voltage response signal. The rising edge of this signal is then detected, and a comparator identifies the start time of each voltage transition. For example, when the voltage jumps from -2V to -3V, the timestamp of the zero-crossing point of the rising edge is detected to determine the accurate application time of each voltage step, which is the voltage switching point. Immediately based on this voltage switching point, a synchronous sampling unit is activated. This unit uses the voltage switching point as a time reference and starts sampling at 5000 times per second for 80 milliseconds after each voltage step stabilizes, continuously acquiring 400 raw data points to form a raw current sampling sequence. For example, the raw current sampling sequence acquired at the -5V step shows an initial current of 1.The initial current was 2 μA and gradually stabilized. The original current sampling sequence was then subjected to time-domain filtering using a finite impulse response (FIR) low-pass filter with a cutoff frequency of 1 kHz. This filtered out high-frequency noise and power supply crosstalk, retaining the effective signal in the range of 0.1 Hz to 1 kHz. The resulting smooth and continuous current data stream was used as reverse current sampling data for subsequent generation of reverse current curves and extraction of steady-state current values.

[0093] In a specific embodiment, the quality of the LED chip is evaluated based on the voltage-current curve, the light spot image, and the reverse leakage current value to obtain the quality evaluation result of the LED chip, including:

[0094] Feature parameters are extracted from the voltage-current curve to obtain electrical performance parameters, and luminescence characteristics are analyzed from the spot image to obtain optical performance parameters. Stability analysis is performed on the reverse leakage current value to obtain leakage current stability parameters.

[0095] The electrical performance parameters, optical performance parameters, and leakage current stability parameters are compared with preset electrical performance threshold ranges, optical performance threshold ranges, and leakage current stability threshold ranges, respectively, to obtain a comprehensive comparison result set.

[0096] The quality of the LED beads is evaluated based on the comprehensive comparison result set, and the quality evaluation result of the LED beads is obtained.

[0097] Specifically, based on the voltage-current curve, light spot image, and reverse leakage current value, the quality of the LED chip is evaluated to obtain the quality evaluation result of the LED chip. This includes extracting feature parameters from the voltage-current curve to obtain electrical performance parameters, analyzing the luminous characteristics of the light spot image to obtain optical performance parameters, and performing stability analysis on the reverse leakage current value to obtain leakage current stability parameters. The electrical performance parameters, optical performance parameters, and leakage current stability parameters are compared with preset electrical performance threshold ranges, optical performance threshold ranges, and leakage current stability threshold ranges, respectively, to obtain a comprehensive comparison result set. Based on the comprehensive comparison result set, the quality of the LED chip is evaluated to obtain the quality evaluation result of the LED chip. The specific implementation method of this step is: in SMD... After the 2835 white LED bead completes all testing procedures, the voltage-current curve is first subjected to feature parameter extraction. The algorithm identifies key nodes on the curve, including the forward conduction current at 2.0V, the current value and its fluctuation range at the 3.0V rated operating point, the curve slope change rate, and the turn-on voltage position. These values ​​are archived as electrical performance parameters. For example, a certain LED bead has a current of 19.8mA at 3.0V and a turn-on voltage of 2.1V, both falling within the normal range. Simultaneously, the light spot image is analyzed for luminous characteristics. Image processing algorithms are used to calculate the average grayscale value of the luminous area, the brightness uniformity index (expressed as standard deviation divided by the mean), and whether there are dark spots or bright spots with a pixel area exceeding 5 consecutive pixels. The light spot center offset and edge integrity score are extracted to form a set of light performance parameters. For example, an image analysis result shows a brightness uniformity of 8.3%, no center offset, but an 8-pixel dark area in the lower right corner, which is recorded as an abnormal feature. Next, the reverse leakage current value is analyzed for stability. The system analyzes and combines the time series of reverse current sampling data acquired during the acquisition process to determine whether the current value continuously fluctuates by more than ±0.05μA during the -5V voltage stabilization application phase (300ms to 500ms). If the fluctuation is small, it is considered stable, and the output leakage current stability parameter is marked as "stable." Otherwise, it is marked as "fluctuating." For example, if the measured reverse leakage current value is 0.42μA and the fluctuation is less than 0.03μA in the last 200ms, it is determined to be stable. Subsequently, the electrical performance parameters are compared with a preset electrical performance threshold range, which is set as 19.0mA to 21.0mA at a turn-on voltage of 2.0V to 2.3V and a current of 19.0mA to 21.0mA at 3.0V. If all conditions are met, the comparison result is "qualified"; otherwise, it is "abnormal." At the same time, the optical performance parameters are compared with a preset optical performance threshold range, which requires brightness uniformity ≤10% and no local defects greater than 5 pixels. If these conditions are met, it is "qualified"; otherwise, it is "abnormal." The leakage current stability parameter is also compared with the leakage current stability threshold range, which requires reverse leakage current ≤0.A 5μA current and stable state are considered "qualified" if these conditions are met, otherwise "abnormal". These three comparison results constitute a comprehensive comparison result set. For example, if a certain LED bead has "qualified" electrical performance, "abnormal" optical performance, and "qualified" leakage current, the set would be (qualified, abnormal, qualified). Finally, based on this comprehensive comparison result set, quality assessment logic is executed. The system's built-in judgment rule is: all three "qualified" items are judged as "Grade A"; only one "abnormal" item is judged as "Grade B"; and two or more "abnormal" items are judged as "Grade C" or "scrap". Therefore, the aforementioned LED bead is classified as "Grade B". The final quality assessment result for the LED bead is generated and written to the database for subsequent sorting and shipping control.

[0098] The detection method for LED beads in the embodiments of the present invention has been described above. The detection device for LED beads in the embodiments of the present invention will be described below. Please refer to [link / reference]. Figure 2 One embodiment of the LED bead detection device in this invention includes:

[0099] The first test module 21 is used to perform an energization test on the electrodes of the LED lamp bead to obtain the initial current value of the LED lamp bead;

[0100] The application module 22 is used to apply a stepped voltage to the LED based on the initial current value to obtain a voltage-current curve;

[0101] The detection module 23 is used to detect the light emission of the LED beads corresponding to the rated operating point in the voltage-current curve using an optical detector, and obtain a light spot image.

[0102] The second test module 24 is used to perform a reverse voltage test on the LED beads based on the light spot image to obtain the reverse leakage current value;

[0103] Evaluation module 25 is used to evaluate the quality of the LED beads based on the voltage-current curve, spot image and reverse leakage current value, and obtain the quality evaluation result of the LED beads.

[0104] In this embodiment, the specific implementation of each module in the above device embodiment is described in the above method embodiment, and will not be repeated here.

[0105] like Figure 3 As shown, this embodiment of the invention provides an LED bead detection system, comprising:

[0106] At least one processor;

[0107] At least one memory for storing at least one program;

[0108] When the at least one program is executed by the at least one processor, the at least one processor implements the above-described LED bead detection method.

[0109] It is evident that the content of the above method embodiments is applicable to this system embodiment. The specific functions implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0110] Furthermore, this application also discloses a computer program product or computer program stored in a computer-readable storage medium. A processor of a computer device can read the computer program from the computer-readable storage medium and execute the computer program, causing the computer device to perform the aforementioned LED bead detection method. Similarly, the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0111] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for testing LED beads, characterized in that, Includes the following steps: The electrodes of the LED bead are energized to obtain the initial current value of the LED bead; Based on the initial current value, a stepped voltage is applied to the LED chip to obtain a voltage-current curve; An optical detector is used to detect the light emission of the LED beads corresponding to the rated operating point in the voltage-current curve to obtain a light spot image. Based on the light spot image, the LED bead is subjected to a reverse voltage test to obtain the reverse leakage current value; Based on the voltage-current curve, spot image, and reverse leakage current value, the quality of the LED chip is evaluated to obtain the quality evaluation result of the LED chip. Based on the light spot image, a reverse voltage test is performed on the LED chip to obtain the reverse leakage current value, including: The brightness distribution of the light spot image is scanned to obtain light spot brightness data, and the uniformity of the light spot brightness data is analyzed to obtain a brightness distribution map. The brightness distribution map shows whether there are local areas that are too dark or too bright in the light spot. The reverse voltage test process is triggered based on the information of the brightness distribution map. Based on the brightness distribution map, a reverse voltage is applied to the LED beads to obtain reverse current sampling data, and time-domain analysis is performed on the reverse current sampling data to obtain a reverse current curve. The current stability interval in the reverse current curve is numerically extracted to obtain the steady-state current value. The steady-state current value is then calibrated and compensated to obtain the reverse leakage current value. The reverse leakage current value is stored in association with the brightness distribution map to comprehensively evaluate whether the LED bead has photoelectric dual anomalies caused by internal defects. Based on the brightness distribution map, a reverse voltage is applied to the LED beads to obtain reverse current sampling data, including: The timing control module turns off the light emission of the LED beads to obtain an off state signal, and then performs a stability judgment on the off state signal to obtain an off confirmation result. Based on the extinguishing confirmation result, a step-increasing reverse voltage is applied to the LED beads through a voltage switching device to obtain a reverse voltage response signal, and the rising edge of the reverse voltage response signal is detected to obtain the voltage switching time point. Based on the voltage switching time point, the reverse current of the LED beads is collected in a timely manner by the synchronous sampling unit to obtain the original current sampling sequence, and the original current sampling sequence is subjected to time-domain filtering to obtain the reverse current sampling data.

2. The LED bead detection method according to claim 1, characterized in that, The electrodes of the LED bead are energized to obtain the initial current value of the LED bead, including: The test probes are brought into contact with the positive and negative electrodes of the LED beads by a probe station to apply a preset test voltage, obtain electrode contact signals, and verify the continuity of the electrode contact signals to obtain contact continuity results. Based on the contact continuity results, a preset test voltage is maintained on the LED beads with good contact to obtain real-time current data, and the stable value is extracted from the real-time current data to obtain the initial current value.

3. The LED bead detection method according to claim 1, characterized in that, Based on the initial current value, a stepped voltage is applied to the LED chip to obtain a voltage-current curve, including: Based on the initial current value, the voltage starting point is determined, and an incremental voltage starting from the voltage starting point is applied to the LED beads to obtain multiple sets of voltage-current corresponding data. The voltage-current corresponding data is then filtered for outliers to obtain valid voltage and current data. The effective voltage and current data are continuously recorded to obtain a voltage and current time series sequence, wherein the voltage and current time series sequence includes voltage and current data pairs arranged in chronological order; and data point smoothing processing is performed based on the voltage and current time series sequence to obtain smooth curve data; The smooth curve data is mapped to obtain a voltage-current scatter distribution, wherein the voltage-current scatter distribution includes discrete data points with voltage as the horizontal axis and current as the vertical axis; and a continuous curve is fitted based on the voltage-current scatter distribution to obtain a voltage-current curve.

4. The LED bead detection method according to claim 1, characterized in that, Based on the above, the light spot image is obtained by detecting the light emission of the LED beads corresponding to the rated operating point in the voltage-current curve using an optical detector, including: An optical detector is used to collect the light emitted by LED beads at their rated operating point in the voltage-current curve to obtain raw light signal data. The light signal data is then converted into photoelectric data to obtain an initial light spot image. Based on the initial spot image, a region is cropped to obtain an effective spot region, and the effective spot region is then grayscale calibrated to obtain a calibrated spot image. The calibrated spot image is pixel-sharpened to obtain a clear spot image, and the edge contour of the clear spot image is extracted to obtain a spot image.

5. The method for detecting LED beads according to claim 1, characterized in that, Based on the voltage-current curve, spot image, and reverse leakage current value, the quality of the LED chip is evaluated to obtain the quality evaluation results of the LED chip, including: Feature parameters are extracted from the voltage-current curve to obtain electrical performance parameters, and luminescence characteristics are analyzed from the spot image to obtain optical performance parameters. Stability analysis is performed on the reverse leakage current value to obtain leakage current stability parameters. The electrical performance parameters, optical performance parameters, and leakage current stability parameters are compared with preset electrical performance threshold ranges, optical performance threshold ranges, and leakage current stability threshold ranges, respectively, to obtain a comprehensive comparison result set. The quality of the LED beads is evaluated based on the comprehensive comparison result set, and the quality evaluation result of the LED beads is obtained.

6. A testing device for LED beads, employing the testing method according to any one of claims 1-5, characterized in that, include: The first test module is used to perform an energization test on the electrodes of the LED lamp bead to obtain the initial current value of the LED lamp bead; An application module is used to apply a stepped voltage to the LED based on the initial current value to obtain a voltage-current curve; The detection module is used to detect the light emission of the LED beads corresponding to the rated operating point in the voltage-current curve using an optical detector, and obtain a light spot image. The second test module is used to perform a reverse voltage test on the LED beads based on the light spot image to obtain the reverse leakage current value; The evaluation module is used to evaluate the quality of the LED beads based on the voltage-current curve, the spot image, and the reverse leakage current value, and to obtain the quality evaluation result of the LED beads.

7. A detection system for LED beads, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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