Display unit LED voltage measuring method and device

Abstract

The invention discloses a display unit LED voltage measuring method and device, and the method comprises the steps: inputting a constant current to an LED power supply pin of a display unit; a driving chip of the display unit is controlled to adjust the input current value of the LED power supply pin, so that the LED lamp beads generate illumination intensity; collecting the illumination intensity value of the current LED lamp bead, and carrying out an optimization test on the illumination intensity value of the LED lamp bead and a preset illumination intensity value; and measuring the voltage value of the LED power supply pin of the display unit. According to the technical scheme, by means of the ingenious photoelectric linkage feedback control principle, the barrier of an electrical test black box caused by advanced integrated packaging is successfully avoided, the LED display panel designed through the method meets the requirement for the display effect, power consumption is effectively reduced, and the purpose of saving energy is achieved.

Description

Technical Field

[0001] This invention relates to the technical field of LED display testing, and specifically to a method and apparatus for measuring the voltage of an LED display unit. Background Technology

[0002] The future trend of LED displays is towards high brightness and energy efficiency. LED displays are typically assembled from multiple display units, each generally employing innovative packaging solutions, such as AM (Active Matrix) and MIP (Micro LED Integrated Package) technologies. This not only reduces yield pressure and cost but also produces superior display quality, such as independent pixel control, achieving extremely high contrast, HDR effects, and color performance.

[0003] The integrated circuit (IC) and LED driver package of this type of display unit typically exposes the pins for the IC signal, IC power supply, and LED power supply. Existing testing equipment and methods, during electrical and optical testing, only measure the optical characteristics and LED current of the LED, and do not have the capability to measure the LED voltage.

[0004] To obtain the LED voltage, the common practice is to estimate the LED's voltage across the drive current using the LED datasheet, and then estimate the voltage of the IC switching losses and the power supply IR drop losses to obtain the LED drive voltage. This estimation method is not accurate. The obtained LED voltage either has a large margin, resulting in wasted LED power consumption, or a small margin, leading to the risk of color distortion in distant LEDs. Summary of the Invention

[0005] The main objective of this invention is to provide a method and apparatus for measuring the voltage of an LED display unit, aiming to solve the technical problem mentioned in the background art that the method of estimating the LED voltage cannot accurately obtain the voltage of the LED when it is displaying normally, resulting in either wasted power consumption or color deviation in the LED display screen designed in this way.

[0006] To achieve the above objectives, the present invention provides a method for measuring the LED voltage of a display unit, used to perform voltage testing on a display unit encapsulated with a driver chip and LED beads, the measurement method comprising: A constant current is input to the LED power supply pin of the display unit; The driver chip controlling the display unit adjusts the input current value of the LED power supply pin, so that the LED beads generate light intensity; Collect the current illuminance value of the LED lamp bead, and perform an optimization test between the illuminance value of the LED lamp bead and the preset illuminance value; Measure the voltage value of the LED power supply pin of the display unit.

[0007] Furthermore, the LED bead is a full-color mixed-color integrated LED bead with at least three colors. Before the step of controlling the driver chip of the display unit to adjust the input current value of the LED bead, the measurement method also includes setting the LED bead to a single-color display mode.

[0008] Furthermore, when the LED bead displays a first single color, the measured voltage value is the voltage value of the first color; when the LED bead displays a second single color, the measured voltage value is the voltage value of the second color; when the LED bead displays a third single color, the measured voltage value is the voltage value of the third color; and the final voltage value is the maximum value of the voltage values ​​of the first color, the second color, and the third color.

[0009] Furthermore, the preset light intensity value is the test result value of the LED lamp bead in a conventional optical testing process.

[0010] Furthermore, the method for optimizing the illuminance value of the LED lamp bead against a preset illuminance value is as follows: S11: Record the illuminance value of the current LED bead; S12: Calculate the value obtained by dividing the illuminance value of the LED lamp bead by the preset illuminance value; S13: Determine whether the value meets the preset threshold; If the condition is not met, adjust the input current value of the LED power supply pin and proceed to step S11. If the conditions are met, the optimization test stops.

[0011] Furthermore, the method for adjusting the input current value of the LED power supply pin is as follows: The correspondence between several constant current source settings and color LED current settings is collected in advance; Based on the aforementioned correspondence, the input current value of the LED power supply pin is adjusted to the current setting value to reduce the number of adjustments required.

[0012] Furthermore, the method for optimizing the illuminance value of the LED lamp bead against a preset illuminance value is as follows: S21: Record the illuminance value of the current LED bead; S22: Calculate the relative error between the current illuminance value of the LED lamp bead and the preset illuminance value; S23: Determine whether the relative error meets the preset conditions. If the conditions are met, stop the optimization test; if the conditions are not met, proceed to step S24. S24: Calculate the next current value using a proportional-integral control algorithm, and adjust the input current value of the LED power supply pin according to the current value, then jump to step S21.

[0013] Furthermore, the proportional-integral control algorithm is as follows: next current value = current current value + Ki × relative error, where Ki is a pre-set control parameter.

[0014] This invention also proposes a display unit LED voltage measuring device for performing voltage testing on a display unit that encapsulates a driver chip and LED beads, comprising: A constant current source module is used to input a constant current to the LED power supply pin of the display unit; The optical measurement module is used to collect the illuminance value of the current LED beads; A voltage detection module is connected to the LED power supply pin of the display unit and is used to measure the voltage value of the LED power supply pin of the display unit. The control module is used to control the driver chip of the display unit to adjust the input current value of the LED power supply pin so that the LED beads generate light intensity; and to perform optimization tests on the light intensity value of the LED beads and the preset light intensity value.

[0015] Furthermore, it also includes a current detection module, which is used to measure the current value of the display unit in order to adjust the input current value of the LED power supply pin in conjunction with the driver chip of the display unit.

[0016] In the technical solution of this invention, the "photoelectric linkage feedback control" principle is cleverly used to successfully bypass the "black box of electrical testing" obstacle brought about by advanced integrated packaging, and to convert the internal LED operating voltage, which cannot be directly measured, into the external voltage of the system that can be measured and controlled with high precision.

[0017] Specifically, this involves operating the LED in a constant current source state, continuously adjusting the current value to ensure the LED's light intensity falls within the normal range (pre-obtained during conventional LED optical testing), and measuring and recording the LED voltage at this point to obtain the optimal display voltage for the LED. Furthermore, the optimal voltage for each of the LED's RGB colors can be measured using the same method, thus selecting the best voltage value. This method ensures that the obtained LED voltage value is neither excessive nor insufficient, achieving a balanced state. If this method is used to test the voltage of an entire batch of LEDs, and the LED with the highest voltage is selected as the reference voltage for LED power supply, combined with the voltage drop of the PCB layout traces, the LED power supply voltage can be set. By adjusting the DC-DC output voltage settings for the LED power supply of this batch of display units during LED board fabrication, the LED display panel can ultimately meet display effect requirements while effectively reducing power consumption, achieving energy saving. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the external pins of the display unit; Figure 2 This is a flowchart of a display unit LED voltage measurement method according to an embodiment of the present invention; Figure 3 This is a flowchart of a display unit LED voltage measurement method according to another embodiment of the present invention; Figure 4 This is a flowchart of a method for performing optimization testing according to an embodiment of the present invention; Figure 5 This is a flowchart of a method for performing optimization testing according to another embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a display unit LED voltage measuring device according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a display unit LED voltage measuring device according to another embodiment of the present invention.

[0020] 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

[0021] Before describing the specific implementation methods, it is necessary to analyze the technical difficulties addressed by this invention in more detail. This invention stems from LED display technology, particularly the fact that each display unit or module constituting the display screen employs advanced integrated packaging technology, and a key "black box" testing bottleneck encountered in the process of moving towards high brightness and energy efficiency.

[0022] Taking AM MIP technology as an example, it integrates a micro-LED chip with a custom-designed CMOS driver IC into a single package, realizing the vision of "one package, one smart pixel." This structure brings revolutionary advantages, such as pixel-level independent control, achieving extremely high contrast, HDR effects, and color accuracy; it also boasts high reliability, with extremely short internal wiring, strong anti-interference capabilities, and high physical reliability. Furthermore, it reduces system complexity, simplifies PCB motherboard design, and facilitates the implementation of micro-pitch displays.

[0023] However, this high degree of integration creates a "testing black box." Traditional testing methods for discrete devices fail here. For discrete LEDs, the anode and cathode are directly exposed, and test probes can be easily connected in parallel across the device to directly measure its forward voltage drop (Vf) while applying a constant drive current (If). This Vf is the LED's most critical electrical parameter and the absolute basis for driver circuit design. But within the display unit package, the LED's cathode is directly connected to the output node of the driver IC's internal current source; this node is not independently led out to the package pins. Figure 1 As shown, the only externally accessible pins are system function pins, such as VDD (powering the driver IC logic), VLED (powering the LED chip), DL (data input), DR (data output), and GND (ground). When we measure the voltage between VLED and GND, what we measure is: The voltage drop across the internal trace from the VLED pin to the LED anode, plus the LED chip's own Vf, the on-state voltage drop (Vds_sat) of the MOSFET inside the driver IC, and the voltage drop across the internal trace from the current source to GND constitute an indivisible series total voltage drop. The Vds_sat of the driver IC is not a fixed value; it is significantly affected by semiconductor process variations, ambient temperature, and its operating region (saturation or linear region).

[0024] Since direct measurement is not possible, the industry currently generally adopts the "estimation design method," which is: Design voltage (V_design) = Typical / maximum Vf value from LED datasheet + Estimated voltage drop of IC driver + Estimated IR drop within PCB and package.

[0025] This approach is essentially a game against uncertainty, leading to two contradictory systemic risks: On the one hand, conservative design leads to wasted power consumption, thus becoming an enemy of energy saving. To prevent insufficient brightness or color cast under worst-case scenarios (such as LEDs with high Vf, increased Vds_sat at high temperatures, and maximum IR drop in far-end pixels), designers significantly increase the voltage margin. In this case, the excess voltage will all be converted into heat loss on the driver IC. For displays with millions or even hundreds of millions of pixels, this wasted power consumption is extremely considerable, directly contradicting the industry's trend towards energy saving.

[0026] On the other hand, aggressive design leads to uneven display and color cast, thus becoming an enemy of image quality. Compromising voltage margin in pursuit of high efficiency causes the effective operating voltage of the pixel furthest from the power supply (far-end pixel) to drop below the critical point when the drive current is high. At this point, the current source of the driver IC exits the constant current saturation region and enters the linear region, unable to maintain the preset constant current. The decrease in current leads to reduced brightness. Because the Vf characteristics of RGB LEDs are different (usually the Vf of blue and green LEDs is higher than that of red), the effect of current changes on the brightness of the three colors is non-linear. This directly causes color spots (color cast) on white images, severely damaging display uniformity and image quality.

[0027] Therefore, the voltage measurement method of this technical solution will break the "test black box" of this structure and invent an indirect but accurate measurement method to directly obtain the actual operating voltage required by each display unit under "normal working state", providing a unique and true data basis for precise and low-power power system design.

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1: This embodiment details the complete process for measuring the characteristic operating voltage of a single display unit.

[0030] like Figure 2 As shown, a method for measuring the LED voltage of a display unit is used to perform voltage testing on a display unit that encapsulates a driver chip and LED beads. The measurement method includes: S1: Input a constant current to the LED power supply pin of the display unit; S2: Control the driver chip of the display unit to adjust the input current value of the LED power supply pin so that the LED can generate light intensity, that is, at least ensure that the LED can light up normally but the light intensity is likely to be lower than the target value (preset light intensity). S3: Collect the current illuminance value of the LED lamp bead, and perform an optimization test between the illuminance value of the LED lamp bead and the preset illuminance value; S4: Measure the voltage value of the LED power supply pin of the display unit.

[0031] This embodiment uses an AM MIP packaged display unit as an example. This display unit is a full-color integrated model, internally integrating at least red (R), green (G), and blue (B) LED chips and corresponding driver ICs. Measurements were performed in a constant temperature (25°C ± 0.5°C) darkroom environment. Figure 3 As shown.

[0032] Step 101: System Initialization and Preset Data Recording. Start the measurement system, including a constant current source, illuminance meter, digital multimeter (DMM), and main control computer. The system performs self-test and warm-up, acquiring the optical data measured in the previous testing process by scanning the QR code, tag code, or reading its unique code from other management systems on the display unit under test. This data includes at least: the illuminance L_std_R, L_std_G, and L_std_B of the package for red, green, and blue light respectively, under a standard test current I_std (e.g., 5.0mA for red, green, and blue light), i.e., the preset illuminance. The preset illuminance value is the test result value of the LED bead in the conventional optical testing process. This optical data can be used as important parameters in subsequent testing steps.

[0033] Step S102: Install the device under test (DUT) and establish electrical connections. Precisely mount the DUT package into the precision test socket of the temperature control test fixture, ensuring reliable pin contact. Connect the positive and negative terminals of the constant current source to the VLED power supply pin and GND pin of the package, respectively. Connect the voltage measurement terminal in parallel to the VLED and GND pins. Connect the signal input pins (e.g., DL) of the package to the digital I / O card of the host computer via a data cable.

[0034] Step S103: Configure the driver IC and set it to monochrome test mode. The main control computer sends a sequence of commands to the driver IC inside the display unit package via the communication protocol. First, the driver IC is reset. Then, it is configured to "static display mode" and "analog current dimming mode," and the PWM dimming function is turned off to eliminate interference from the modulation frequency on the optical measurement. For the upcoming red channel measurement, a command is sent to set the current drive values ​​of the green and blue channels to zero, leaving only the red channel adjustable.

[0035] Step S104: Start the constant current source and begin the red channel closed-loop optimization test. Set the constant current source to output a stable current (e.g., 50mA) higher than the expected total operating current to provide basic power to the test circuit. Then, perform the optimization test as follows: Figure 4 As shown: Step S21: Perform optical measurement and record the current illuminance value of the LED bead, i.e., the current intensity of the analog current generated by the driver IC to drive the red LED to emit light. At this time, the illuminance meter collects the light signal and obtains the current illuminance value of the red light L_meas_R(0).

[0036] Step S22: The central control computer calculates the relative error e_R(n) between the current illuminance value of the LED lamp bead and the preset illuminance value. The relative error is calculated as follows: e_R(0) = (L_std_R-L_meas_R(0)) / L_std_R, where L_std_R is the target illuminance, which was recorded in step 101.

[0037] Step S23: Determine whether the relative error meets a preset condition. If the condition is met, stop the optimization test. For example, the preset condition can be |e_R(0)|≤m. In this embodiment, m is set to 0.005, i.e. 0.5%. When |e_R(0)|≤0.5%, stop the optimization test. If |e_R(0)|>0.5%, proceed to step S24.

[0038] Step S24: Calculate the next current value using a proportional-integral control algorithm, and adjust the input current value of the LED power supply pin according to the current value, then jump to step S21.

[0039] The proportional-integral control algorithm is as follows: the next current value I_std(n) = the current current value I_std(n-1) + Ki × the relative error |e_R(n-1)|, where Ki is a pre-set control parameter and n represents the number of iterations. The first iteration integral term is e_R(0). Steps S22 to S24 are repeated until the preset condition is met, which in this embodiment is |e_R(n)| ≤ 0.5%.

[0040] Step S105: Measure the voltage value of the LED power supply pin of the display unit. When the optical measurement value meets the preset conditions, the main control computer immediately sends a rising edge trigger signal to the DMM via the hardware trigger line. After receiving the trigger signal, the DMM samples the voltage value of the VLED pin to GND with the highest accuracy and speed, records it as V_meas_R, and returns it to the main control computer through the communication interface. This voltage value V_meas_R is the minimum input voltage (at 25°C) required by the system to make the red LED of the display unit reach its standard illuminance L_std_R.

[0041] Step S106: Repeat the measurement of the green and blue channels. After completing the red channel measurement, the main control computer sends a command to close the red channel and open the green channel, repeating steps S103 to S105 to measure the balance point voltage V_meas_G of the green channel. Subsequently, the green channel is closed, the blue channel is opened, and the process is repeated to measure the balance point voltage V_meas_B of the blue channel. After each channel switch, the system waits 50ms to ensure electrical and optical stability. When the LED displays the first single color, the measured voltage value is the voltage value of the first color; when the LED displays the second single color, the measured voltage value is the voltage value of the second color; when the LED displays the third single color, the measured voltage value is the voltage value of the third color.

[0042] Step S107: Calculate the characteristic operating voltage of the display unit. Because for a full-color package, its external power supply voltage must simultaneously meet the demanding requirements of the three color channels. Therefore, the final voltage value is the maximum of the first, second, and third color voltage values. That is, the characteristic operating voltage (V_char) of this package is the maximum value of the three channel voltages. V_char = MAX(V_meas_R, V_meas_G, V_meas_B) The main control computer binds V_char with the unique code of the display unit, stores it in the database, and can output a label to be attached to the product for subsequent classification and power supply design.

[0043] If display modules are assembled in batches, batch testing and power supply voltage determination are performed according to the method of this invention to ultimately determine the voltage of the display screen. The specific method is as follows: Perform steps S101 to S107 above on all display units (e.g., N=10,000 units) in the production batch to obtain a dataset containing N V_char values. Analyze this dataset and find the maximum value V_batch_max = MAX(V_char_1,V_char_2, ..., V_char_N).

[0044] The display module design engineers, based on V_batch_max and the accurately simulated voltage drop ΔV_pcb of the PCB-level power network under the worst operating conditions (e.g., 0.18V), and considering a very small design safety margin δ (e.g., 0.02V), ultimately determined the LED power supply voltage setting for this batch of modules. V_supply_setting = V_batch_max + ΔV_pcb + δ Therefore, this method completely replaces the rough estimation that relies on typical values ​​in the specifications and empirical coefficients, and achieves precise customization and design of the power supply voltage.

[0045] Example 2: This embodiment provides a simplified process that is more suitable for high-speed testing on production lines. Its core lies in using the "light intensity ratio method" for rapid determination and utilizing a pre-stored lookup table to accelerate current adjustment.

[0046] The method for optimizing the illuminance value of the LED beads against a preset illuminance value is as follows: Beforehand, the correspondence between several constant current source settings and color LED current settings is collected. Before performing voltage measurements, a certain number of display units of the same model are sampled for detailed current-light intensity characteristic calibration. That is, under multiple discrete current code values ​​C_i, the corresponding light intensity L_i is measured. A "current value-relative light intensity" lookup table (LUT) for this model is established and stored in the test system.

[0047] S11: Perform optical measurements and record the current illuminance value of the LED beads; S12: Calculate the value obtained by dividing the illuminance value of the LED lamp bead by the preset illuminance value; S13: Determine whether the value meets the preset threshold; If the condition is not met, adjust the input current value of the LED power supply pin and proceed to step S11. If the conditions are met, the optimization test stops.

[0048] The method for adjusting the input current value of the LED power supply pin is as follows: Based on the correspondence of the aforementioned "current value-relative light intensity" lookup table (LUT), the input current value of the LED power supply pin is adjusted to the current setting value to reduce the number of adjustments. This is a method for performing fast single-channel optimization.

[0049] For a specific color channel (e.g., red) of the display unit under test, the system loads its I_std_R. After the test begins: Based on I_std_R and the pre-stored LUT, a current code value C_est that makes the light intensity close to I_std_R is obtained by directly looking up the table and sent as the initial value to the driver IC.

[0050] The optical measurement module quickly acquires the current light intensity I_meas. It then calculates the ratio Ratio = I_meas / I_std_R.

[0051] A preset threshold range is established, for example, [0.995, 1.005]. If the ratio falls within this range, voltage measurement is triggered immediately. If the ratio > 1.005, it indicates that the current is too high, and the system lowers the current code value by a preset step size; if the ratio < 0.995, the current code value is increased. This adjustment can employ a strategy of rapid approximation with large steps and fine adjustment with small steps.

[0052] With the assistance of LUTs, the threshold range can usually be reached within 1-3 adjustments, greatly improving the testing speed.

[0053] Record the voltage value at which equilibrium is reached. After completing the RGB three-channel test, take the maximum value as V_char. The batch processing method is the same as in Example 1.

[0054] Example 3: The present invention also provides a measuring apparatus for implementing the above-described method. Please refer to [link / reference]. Figure 6 .

[0055] A display unit LED voltage measuring device is used to perform voltage testing on a display unit that encapsulates a driver chip and LED beads, comprising: The constant current source module is used to input a constant current to the LED power supply pins of the display unit. Specifically, it provides a stable, low-ripple DC current to the VLED and GND pins of the display unit under test. This module has programmable control functionality and accepts switching commands from the control module.

[0056] An optical measurement module is used to acquire the illuminance value of the currently described LED beads. It includes an integrating sphere (or standard optical fixture) and a high-precision fast spectroradiometer (or calibrated photometric probe). It is used for non-contact acquisition of the light signal emitted by the display unit and converts it into a digital signal of luminous flux or illuminance. This module must be installed in a fixed location to ensure consistent measurement conditions.

[0057] A voltage detection module is connected to the LED power supply pin of the display unit to measure the voltage value of the LED power supply pin. Specifically, a high-precision digital multimeter or voltage acquisition card can be used, with its input terminals connected to the VLED and GND pins of the display unit via a Kelvin four-wire connection for accurate voltage measurement. This module supports external hardware-triggered sampling.

[0058] The control module, the core of the entire device, can be an industrial control computer or a controller integrating a high-performance MCU. It controls the driver chip of the display unit to adjust the input current value of the LED power supply pin, thereby enabling the LED beads to generate light intensity; and it is used to perform optimization tests on the light intensity value of the LED beads against a preset light intensity value. It includes: Communication unit: Used for digital communication with the driver IC of the display unit to send configuration and adjustment commands.

[0059] Data acquisition and processing unit: Receives data from the optical measurement module and the current detection module, executes the closed-loop control algorithm, calculates the error, and generates new current adjustment commands.

[0060] Logic control and triggering unit: coordinates the working timing of each module. When the optical measurement data meets the preset threshold conditions, this unit immediately sends a hardware trigger signal to the voltage detection module and records the returned voltage value.

[0061] Data storage and interface unit: Stores a preset "standard optical fingerprint" database and measurement results, and provides a human-machine interface (HMI) and an interface for transmitting data to the upper-level MES system.

[0062] like Figure 7 As shown, the device also includes a current detection module, which measures the current value of the display unit to adjust the input current value of the LED power supply pin in conjunction with the driver chip of the display unit. Specifically, the current detection module is connected in series in the constant current source output circuit to monitor the total circuit current in real time and to verify the system's operating status.

[0063] In addition, it includes a temperature-controlled test fixture for precisely fixing the display unit under test, and can control the test environment temperature at a set value (such as 25°C) through a built-in cooling system to eliminate the influence of temperature fluctuations on the measurement results.

[0064] The working process of the device has been explained in the foregoing method embodiments and will not be repeated here. This integrated device enables fully automatic, high-precision, and rapid measurement of the LED voltage of the display unit.

[0065] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. A method for measuring the LED voltage of a display unit, used to perform voltage testing on a display unit encapsulated with a driver chip and LED beads, characterized in that, The measurement method includes: A constant current is input to the LED power supply pin of the display unit; The driver chip controlling the display unit adjusts the input current value of the LED power supply pin, so that the LED beads generate light intensity; Collect the current illuminance value of the LED lamp bead, and perform an optimization test between the illuminance value of the LED lamp bead and the preset illuminance value; Measure the voltage value of the LED power supply pin of the display unit.

2. The voltage measurement method as described in claim 1, characterized in that, The LED bead is a full-color mixed-color integrated LED bead with at least three colors. Before the step of controlling the driver chip of the display unit to adjust the input current value of the LED bead, the measurement method also includes setting the LED bead to a single-color display mode.

3. The voltage measurement method as described in claim 2, characterized in that, When the LED displays a first single color, the voltage value is measured as the voltage value of the first color; when the LED displays a second single color, the voltage value is measured as the voltage value of the second color; when the LED displays a third single color, the voltage value is measured as the voltage value of the third color; the final voltage value is the maximum value of the voltage values ​​of the first, second, and third colors.

4. The voltage measurement method as described in claim 1, characterized in that, The preset light intensity value is the test result value of the LED lamp bead in the conventional optical testing process.

5. The voltage measurement method as described in claim 4, characterized in that, The method for optimizing the illuminance value of the LED lamp bead against a preset illuminance value is as follows: S11: Record the illuminance value of the current LED bead; S12: Calculate the value obtained by dividing the illuminance value of the LED lamp bead by the preset illuminance value; S13: Determine whether the value meets the preset threshold; If the condition is not met, adjust the input current value of the LED power supply pin and proceed to step S11. If the conditions are met, the optimization test stops.

6. The voltage measurement method as described in claim 5, characterized in that, The method for adjusting the input current value of the LED power supply pin is as follows: The correspondence between several constant current source settings and color LED current settings is collected in advance; Based on the aforementioned correspondence, the input current value of the LED power supply pin is adjusted to the current setting value to reduce the number of adjustments required.

7. The voltage measurement method as described in claim 4, characterized in that, The method for optimizing the illuminance value of the LED lamp bead against a preset illuminance value is as follows: S21: Record the illuminance value of the current LED bead; S22: Calculate the relative error between the current illuminance value of the LED lamp bead and the preset illuminance value; S23: Determine whether the relative error meets the preset conditions. If the conditions are met, stop the optimization test; if the conditions are not met, proceed to step S24. S24: Calculate the next current value using a proportional-integral control algorithm, and adjust the input current value of the LED power supply pin according to the current value, then jump to step S21.

8. The voltage measurement method as described in claim 7, characterized in that, The proportional-integral control algorithm is as follows: next current value = current current value + Ki × relative error, where Ki is a pre-set control parameter.

9. A display unit LED voltage measuring device, used for voltage testing of a display unit encapsulated with a driver chip and LED beads, characterized in that, include: A constant current source module is used to input a constant current to the LED power supply pin of the display unit; The optical measurement module is used to collect the illuminance value of the current LED beads; A voltage detection module is connected to the LED power supply pin of the display unit and is used to measure the voltage value of the LED power supply pin of the display unit. The control module is used to control the driver chip of the display unit to adjust the input current value of the LED power supply pin so that the LED beads generate light intensity; It is used to perform an optimization test on the illuminance value of the LED beads and the preset illuminance value.

10. The voltage measuring device as described in claim 9, characterized in that, It also includes a current detection module, which is used to measure the current value of the display unit in order to adjust the input current value of the LED power supply pin in conjunction with the driver chip of the display unit.

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