LED screen backlight module performance test system

Abstract

The present application relates to LED display test technical field, specifically to a kind of LED screen backlight module performance test system, comprising: receiving the model identification code of module to be measured, and the initial driving current is applied by calling corresponding standard optical parameter set.By light sensing probe array, actual light signal under different current driving is collected, and it is converted into digital optical measurement value set containing multiple sampling point brightness and color coordinate value.Brightness measurement value and target brightness value are compared point by point, and brightness consistency deviation matrix is generated;Color coordinate measurement value is judged with target range, and color coordinate qualified identification list is generated.According to deviation matrix, actual brightness uniformity value is calculated, and it is compared with standard threshold value.If actual brightness uniformity value meets the standard and the color coordinates of all sampling points are qualified, then module qualified determination instruction is generated.The system realizes the automatic, high-precision comprehensive evaluation of the brightness spatial uniformity and chroma consistency of backlight module.

Description

Technical Field

[0001] The present invention relates to the technical field of LED display testing, and particularly to a performance testing system for the backlight module of an LED screen. Background Technique

[0002] In the existing performance testing of the backlight module of an LED screen, the commonly used method is to measure the optical parameters of the central area of the module or a few specified points. The testing process usually conducts the brightness test and the color coordinate test as independent links. In the brightness test link, the existing technology often only calculates the average brightness value of the entire module or several sampling points and compares it with the target value. In the color coordinate test link, usually only checks whether the color coordinate values of one or several points meet the specifications, or calculates the average value of the color coordinates of all sampling points to determine whether the color deviates.

[0003] The existing testing scheme cannot accurately quantify the discrete distribution of the brightness of each point within the entire light-emitting plane of the backlight module. Relying only on the average value or the data of a few points, it is difficult to truly reflect whether there are local bright spots or dark areas on the screen, resulting in inaccurate evaluation of the key indicator of brightness uniformity. At the same time, separating and independently judging the brightness and color coordinates has loopholes in the judgment logic. There may be situations where the brightness of the module is uniform but the color of some areas is significantly deviated, or the overall color is qualified but the brightness distribution is extremely uneven, and the existing method may still determine it as a qualified product.

[0004] A testing scheme is needed that can accurately evaluate the consistency of the brightness distribution on the entire light-emitting surface of the backlight module, rather than relying only on a few points or the average value. At the same time, a judgment logic needs to be established, requiring that the color of each detected point in the entire area of the module is accurate, and its brightness uniformity must also meet the standard. Both conditions must be met simultaneously to finally determine it as qualified. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies existing in the prior art and propose a performance testing system for the backlight module of an LED screen.

[0006] To achieve the above purpose, the present invention adopts the following technical scheme: A performance testing system for the backlight module of an LED screen, comprising:

[0007] A parameter retrieval module, which receives the model identification code of the待测LED屏背光模组 (to-be-tested LED screen backlight module), retrieves the standard optical parameter set corresponding to it, including the target brightness value, the target color coordinate range, and the standard brightness uniformity threshold, and applies a preset initial drive current;

[0008] The photoelectric data acquisition module collects the actual light signals generated by the backlight module of the LED screen under test under different preset current levels through a photosensitive probe array, and converts the actual light signals into a set of digital optical measurement values ​​containing brightness and color coordinate measurements of multiple sampling points.

[0009] The brightness difference analysis module compares the brightness measurement values ​​in the set of digital optical measurement values ​​with the target brightness value point by point, and calculates and generates a brightness consistency deviation matrix.

[0010] The color coordinate judgment module performs a range conformity judgment between the color coordinate measurement values ​​in the set of digital optical measurement values ​​and the target color coordinate range, and generates a list of color coordinate qualified identifiers.

[0011] The uniformity assessment module calculates the actual brightness uniformity value based on the brightness consistency deviation matrix and compares the actual brightness uniformity value with the standard brightness uniformity threshold.

[0012] If the actual brightness uniformity value is less than or equal to the standard brightness uniformity threshold, and the color coordinate qualification indicator list shows that the color coordinate measurement values ​​of all sampling points are within the target color coordinate range, then the backlight module qualification instruction is generated.

[0013] As a further aspect of the present invention, the step of retrieving a standard optical parameter set corresponding to the target brightness value, target color coordinate range, and standard brightness uniformity threshold, and applying a preset initial driving current, includes:

[0014] Receive the model identification code of the LED screen backlight module under test, and retrieve the standard optical parameter set corresponding to the model identification code from the preset database. The standard optical parameter set includes the target brightness value, the target color coordinate range, and the standard brightness uniformity threshold.

[0015] The backlight module of the LED screen under test is lit up, and a preset initial drive current is applied through a programmable constant current source.

[0016] As a further aspect of the present invention, the step of acquiring the actual light signal generated by the LED screen backlight module under different preset current levels through a photosensitive probe array includes:

[0017] The programmable constant current source is controlled to output current according to a preset current sequence, the preset current sequence including at least five arithmetic current points from the minimum rated current to the maximum rated current.

[0018] After the LED screen backlight module under test is stably driven for a preset stabilization time at each of the equal differential current points, the photosensitive probe array is started for synchronous measurement.

[0019] Each probe in the photosensitive probe array corresponds to a preset sampling area of ​​the light-emitting surface of the backlight module of the LED screen under test, and collects the spectral energy distribution data of the preset sampling area.

[0020] The spectral energy distribution data is input into the spectral calculation unit bound to the probe to calculate the brightness measurement value and color coordinate measurement value of the corresponding preset sampling area;

[0021] Record the brightness measurement value and color coordinate measurement value of all preset sampling areas at each of the equal current points, and store them indexed according to the coordinates of the current point and the sampling area.

[0022] As a further aspect of the present invention, the calculation of the brightness consistency deviation matrix includes:

[0023] For each of the equal-differential current points, read the brightness measurement values ​​of all preset sampling areas under the equal-differential current points;

[0024] Calculate the arithmetic mean of the brightness measurements of all preset sampling areas under the equal current point, and use it as the global reference brightness of the equal current point;

[0025] For each preset sampling area under the equal current point, calculate the percentage difference between the brightness measurement value of the preset sampling area and the global reference brightness, and use it as the relative brightness deviation value of the preset sampling area;

[0026] The relative brightness deviation values ​​calculated for all preset sampling areas at each of the equal current points are arranged in a two-dimensional matrix form corresponding to the coordinates of the sampling areas to generate the brightness consistency deviation matrix.

[0027] As a further aspect of the present invention, the generation of the color coordinate qualified identifier list includes:

[0028] The target color coordinate range corresponding to the model identification code of the LED screen backlight module under test is obtained from the preset database. The target color coordinate range includes the boundary coordinates of a predetermined shape on the chromaticity diagram.

[0029] Read the color coordinate measurement value corresponding to each sampling point in the set of digital optical measurement values;

[0030] For each sampling point, determine whether its color coordinate measurement value is located within a predetermined shape area enclosed by the boundary coordinates;

[0031] If the color coordinate measurement value is located within the predetermined shape area, a color coordinate qualification mark for the sampling point is generated;

[0032] If the color coordinate measurement value is outside the predetermined shape area, a color coordinate non-compliance mark is generated for the sampling point;

[0033] Summarize the qualified and unqualified labels of all sampling points to generate a list of qualified labels for the color coordinates. The list includes the sampling point number and the corresponding label status.

[0034] As a further aspect of the present invention, the calculation of the actual brightness uniformity value includes:

[0035] From the brightness consistency deviation matrix, select the relative brightness deviation value of each preset sampling area under the standard test current point, where the standard test current point is a specified value in the preset current sequence;

[0036] Find the maximum positive value and the minimum negative value among the relative brightness deviation values ​​of all preset sampling areas under the standard test current point, where the maximum positive value is the largest positive value among all relative brightness deviation values ​​and the minimum negative value is the smallest negative value among all relative brightness deviation values.

[0037] Calculate the sum of the absolute values ​​of the maximum positive value and the minimum negative value, and take half of the sum of the absolute values ​​as the actual brightness uniformity value of the LED screen backlight module under test.

[0038] As a further aspect of the present invention, it also includes steps for aging process monitoring and performance degradation assessment:

[0039] After completing the initial optical performance test and generating a backlight module qualification determination command, the backlight module of the LED screen under test is controlled to enter the preset aging test mode.

[0040] In the preset aging test mode, the programmable constant current source is controlled to output a periodically fluctuating accelerated aging drive current, and the total aging duration is recorded.

[0041] At the predetermined aging monitoring node, the accelerated aging driving current is interrupted, the initial driving current is restored, and the optical signal of the LED screen backlight module under test is collected again through the photosensitive probe array to generate optical measurement values ​​after aging.

[0042] The aging optical measurement values ​​are compared with the set of digital optical measurement values ​​obtained during the initial test under the same driving current to calculate the brightness retention rate and color coordinate drift.

[0043] The long-term reliability level of the LED screen backlight module under test is evaluated based on the brightness maintenance rate and color coordinate drift.

[0044] As a further aspect of the present invention, the step of comparing the optical measurement values ​​after aging with the set of digital optical measurement values ​​obtained during the initial test under the same driving current, and calculating the brightness retention rate and color coordinate shift, includes:

[0045] Extract the initial brightness measurement set and the initial color coordinate measurement set of all preset sampling areas under the initial driving current from the set of digital optical measurement values;

[0046] From the optical measurement values ​​after aging, extract the set of brightness measurement values ​​and the set of chromaticity measurement values ​​of all corresponding preset sampling areas under the same initial driving current;

[0047] For each preset sampling area, the ratio of its aging brightness measurement value to its initial brightness measurement value is calculated to obtain the point brightness maintenance rate of the preset sampling area;

[0048] Calculate the average point brightness maintenance rate of all preset sampling areas as the overall brightness maintenance rate of the LED screen backlight module under test;

[0049] For each preset sampling area, the Euclidean distance between its aged color coordinate measurement value and its initial color coordinate measurement value on the chromaticity diagram is calculated to obtain the color coordinate point drift of the preset sampling area.

[0050] Find the maximum value among the color coordinate point drifts of all sampling areas, and take it as the maximum color coordinate drift of the LED screen backlight module under test.

[0051] As a further aspect of the present invention, it also includes:

[0052] If the parameter generation module determines that the backlight module of the LED screen under test is qualified, it further analyzes the data distribution of the brightness consistency deviation matrix.

[0053] The regions in the brightness consistency deviation matrix where the relative brightness deviation value is consistently positive and exceeds the slight deviation threshold are identified and marked as overbrightness compensation regions.

[0054] The regions in the brightness consistency deviation matrix where the relative brightness deviation value is consistently negative and below the slight deviation threshold are identified and marked as underbrightness compensation regions.

[0055] Based on the specific values ​​of the relative brightness deviation of each sampling point in the overbrightness compensation area and the underbrightness compensation area, the corresponding current gain coefficient or current attenuation coefficient is calculated.

[0056] The coordinate information of the compensation area is associated with the corresponding current gain coefficient or current attenuation coefficient to generate a partition brightness compensation lookup table for the display driver chip to use.

[0057] As a further aspect of the present invention, it also includes:

[0058] The color gamut tracing module obtains the specific color coordinate measurement value of the corresponding sampling point when there is a color coordinate unqualified identifier in the color coordinate qualified identifier list;

[0059] The specific color coordinate measurement value is projected onto a chromaticity map containing the target color coordinate range, and its offset direction and offset distance from the center point of the target color coordinate range are calculated;

[0060] Based on the LED bead arrangement diagram of the LED screen backlight module under test, determine the position of the physical LED bead or LED bead group corresponding to the sampling point that emits the specific color coordinate measurement value;

[0061] Retrieve batch information and supplier information of the LEDs corresponding to the positions of the physical LEDs or LED groups;

[0062] Generate an analysis report that includes the coordinates of the non-conforming points, the direction and distance of the color coordinate deviation, and the corresponding traceability information of the LED beads.

[0063] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0064] After acquiring data from multiple sampling points using a photosensitive probe array, the brightness measurement value of each point is compared point-by-point with a unified target brightness value, and a brightness consistency deviation matrix is ​​calculated. This matrix can quantitatively characterize the discrete distribution of brightness values ​​at each point within the entire emitting plane, directly reflecting the degree of inconsistency in brightness across spatial dimensions. This replaces the traditional evaluation method that relies solely on measurements from a few points or the overall average value, deepening the evaluation of backlight module brightness uniformity from judging "brightness level" to a precise measurement of "brightness distribution state."

[0065] The color coordinate measurements at each sampling point are independently assessed for range compliance, generating a list of qualified color coordinate indicators encompassing the results for all points. The final qualification instruction mandates that both "all sampling point color coordinates are qualified" and "actual brightness uniformity calculated based on full-point brightness data meets the standard" must be met simultaneously. This scheme elevates the standard for color accuracy from overall or sampled compliance to requiring compliance at every point across the entire area, and couples this with the brightness spatial uniformity index. This forms a more stringent and comprehensive spatial consistency evaluation criterion for the optical performance of the backlight module. Attached Figure Description

[0066] Figure 1 This is a timing diagram of the LED screen backlight module performance testing system described in this invention;

[0067] Figure 2Flowchart for generating the brightness consistency deviation matrix;

[0068] Figure 3 A heatmap showing the relative brightness deviation of LED backlight modules;

[0069] Figure 4 Radar chart showing the aging test performance of LED backlight modules;

[0070] Figure 5 The graph shows the relative brightness deviation in different regions as a function of driving current. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0072] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the 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, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0073] See Figure 1The parameter retrieval module receives the model identification code of the LED screen backlight module under test. Based on this code, the module retrieves a set of standard optical parameters from a pre-set database. This set explicitly includes the target brightness value, target color coordinate range, and standard brightness uniformity threshold. Simultaneously, the system controls a programmable constant current source to apply a preset initial drive current to the LED screen backlight module under test to illuminate it. The photoelectric data acquisition module activates its photosensitive probe array. As the programmable constant current source outputs different levels of drive current according to a preset current sequence, the array simultaneously acquires the actual light signals from each preset sampling area of ​​the emitting surface of the module under test. These light signals are then converted into a set of digital optical measurement values ​​containing the brightness and color coordinate measurements of each sampling point. The brightness difference analysis module then processes this set of digital optical measurement values, comparing the brightness measurements with the target brightness value point by point, and calculating a brightness consistency deviation matrix reflecting the brightness differences at each point. The color coordinate judgment module works in parallel. It compares each color coordinate measurement value in the digital optical measurement value set with the target color coordinate range retrieved from the database to determine whether each measurement value falls within the predetermined range, and generates a color coordinate pass / fail flag list indicating the pass / fail status of each sampling point. The uniformity evaluation module calculates an actual brightness uniformity value characterizing the brightness uniformity of the entire emitting surface based on the brightness consistency deviation matrix generated by the brightness difference analysis module, and compares this calculated value with the standard brightness uniformity threshold pre-stored in the standard optical parameter set. The pass / fail judgment module combines the output results of the uniformity evaluation module and the color coordinate judgment module to make a judgment. The system will only generate a backlight module pass / fail instruction if and only if the calculated actual brightness uniformity value is less than or equal to the standard brightness uniformity threshold, and the color coordinate pass / fail flag list confirms that the color coordinate measurement values ​​of all sampling points are within the target color coordinate range.

[0074] In one embodiment of the present invention, the parameter retrieval module receives the model identification code of the LED screen backlight module under test, such as a QR code or serial number string. The model identification code can be "BLU-75A-2024-Q1". The parameter retrieval module retrieves the standard optical parameter set corresponding to the model identification code "BLU-75A-2024-Q1" from a preset database through a query interface. The standard optical parameter set is stored in the form of a data structure, including the target brightness value "1000 nits", the target color coordinate range "x:[0.310,0.320],y:[0.330,0.340]" and the standard brightness uniformity threshold "85%". While acquiring the standard optical parameter set, the system sends an instruction to the programmable constant current source. The programmable constant current source then applies a preset initial driving current to the LED screen backlight module under test. The value of the initial driving current is 100 mA, which is used to light up the LED screen backlight module under test.

[0075] In some embodiments, the photoelectric data acquisition module is activated after the parameter retrieval module completes its operation. The photoelectric data acquisition module controls the programmable constant current source to output current according to a preset current sequence. This preset current sequence includes five equal-gradient current points from the minimum rated current to the maximum rated current. For example, if the minimum rated current is 80 mA and the maximum rated current is 120 mA, the five equal-gradient current points are 80 mA, 90 mA, 100 mA, 110 mA, and 120 mA, respectively. After the LED backlight module under test is stably driven at each equal-gradient current point for a preset stabilization time (set to 300 milliseconds), the system activates the photosensitive probe array for synchronous measurement. The photosensitive probe array consists of 64 independent spectral probes. Each probe in the array corresponds to a preset sampling area on the emitting surface of the LED backlight module under test. For example, probe number P01 corresponds to the first grid area in the upper left corner of the emitting surface. Each probe collects spectral energy distribution data for its corresponding preset sampling area during measurement. This spectral energy distribution data is a light intensity distribution curve within a wavelength range of 380 nm to 780 nm.

[0076] In practical implementation, the system inputs the spectral energy distribution data collected by each probe into the spectral calculation unit bound to the probe. Each spectral calculation unit runs the same calculation program, which performs calculations based on the CIE standard colorimetric observer function and photometric function, involving integral operations. The spectral calculation unit calculates the input spectral energy distribution data to obtain the luminance measurement value and color coordinate measurement value of the corresponding preset sampling area. The unit of luminance measurement value is nits, and the color coordinate measurement value is expressed in (x,y) coordinate pairs. The system records the luminance measurement value and color coordinate measurement value calculated at each equal current point for all preset sampling areas according to a preset data structure. The data structure adopts a multi-dimensional array form. The first dimension index represents the current point number, and the second and third dimension indices represent the two-dimensional matrix coordinates of the sampling area. The elements stored in the array are tuples containing luminance and color coordinate values. The system stores the recorded set of digital optical measurement values ​​according to the current point and sampling area coordinates. The index storage is written into a database table in non-volatile memory. The primary key of the database table is composed of the current point number and the area coordinates.

[0077] Optionally, the number of equal differential current points in the preset current sequence is not limited to five; it can be set to seven or nine equal differential current points depending on the test accuracy requirements. Optionally, the arrangement of the photosensitive probe array matches the shape of the light-emitting surface of the LED backlight module under test. For a rectangular light-emitting surface, the probes are arranged in a rectangular array; for a circular light-emitting surface, the probes are arranged in a concentric ring.

[0078] It is understandable that the spectral calculation unit calculates the brightness measurement value. The process follows the formula below:

[0079] in: Represents the brightness measurement value. This represents the maximum spectral luminous efficacy, with a value of 683 lumens per watt. Represents the CIE standard photometric observer spectral luminous efficiency function. The integral interval represents the spectral energy distribution data received by the spectral calculation unit. The wavelengths represent the range from 380 nm to 780 nm. The process by which the spectral calculation unit calculates the chromatic coordinate measurements (x, y) is also based on the spectral energy distribution data. Matching function with CIE standard colors , , The tristimulus values ​​X, Y, and Z are obtained through integral calculation and then normalized.

[0080] See Figure 2 In one embodiment of the present invention, the brightness difference analysis module performs analysis for each equal-difference current point. The brightness difference analysis module reads the brightness measurement values ​​of all preset sampling areas under the equal-difference current point "100 mA" from the stored set of digital optical measurement values. For example, it reads a list containing 64 brightness measurement values, where the values ​​in the list may be [998, 1001, 995, ..., 1005], all in nits. The brightness difference analysis module calculates the arithmetic mean of the brightness measurement values ​​of all preset sampling areas under the equal-difference current point "100 mA". The arithmetic mean is calculated by summing the values ​​and dividing by the number of sampling areas, 64. The calculated result "1000.5 nits" is used as the global reference brightness of the equal-difference current point "100 mA". For each preset sampling area at the equal-difference current point "100 mA", the brightness difference analysis module calculates the percentage difference between the measured brightness value of the preset sampling area and the global reference brightness "1000.5 nits". The calculation process is (measured brightness value at sampling point - global reference brightness) / global reference brightness * 100%. The calculation result is used as the relative brightness deviation value of the preset sampling area, which is expressed as a percentage. A positive value represents that the brightness is higher than the global reference brightness, and a negative value represents that the brightness is lower than the global reference brightness. The brightness difference analysis module arranges the relative brightness deviation values ​​calculated for all preset sampling areas at each equal-difference current point in a two-dimensional matrix form corresponding to the sampling area coordinates to generate a brightness consistency deviation matrix. The brightness consistency deviation matrix is ​​a three-dimensional data structure. The first dimension index corresponds to the five equal-difference current points, and the second and third dimension indices correspond to the 8x8 sampling area grid coordinates. Each element in the matrix stores the percentage value of the relative brightness deviation at the corresponding position under the corresponding current.

[0081] In some embodiments, the color coordinate determination module retrieves the target color coordinate range corresponding to the model identification code "BLU-75A-2024-Q1" of the LED backlight module under test from a preset database. The target color coordinate range includes the boundary coordinates of a predetermined shape on the chromaticity diagram. The predetermined shape is a quadrilateral, and the boundary coordinates are the coordinates (x1, y1), (x2, y2), (x3, y3), and (x4, y4) of the four vertices on the CIE1931 chromaticity diagram. The color coordinate determination module reads the color coordinate measurement value corresponding to each sampling point in the digital optical measurement value set, which stores the (x, y) coordinate values ​​of each sampling point at each current point. For each sampling point, the color coordinate determination module determines whether its color coordinate measurement value is located within the predetermined shape area enclosed by the boundary coordinates. The determination algorithm uses either the ray method or the polygon inclusion algorithm. If the color coordinate measurement value is located within the predetermined shape area, a color coordinate qualification mark is generated for the sampling point, and the mark status is recorded as "PASS". If the color coordinate measurement value is outside the predetermined shape area, a color coordinate failure flag is generated for the sampling point, and the flag status is recorded as "FAIL". The color coordinate judgment module summarizes the pass and fail flags of all sampling points and generates a color coordinate pass flag list, which includes the sampling point number and the corresponding flag status.

[0082] In practical implementation, the generation of the brightness consistency deviation matrix covers all preset current points. For each current value in the arithmetic current point sequence [80, 90, 100, 110, 120] mA, the brightness difference analysis module independently performs a global reference brightness calculation and a calculation of the relative brightness deviation value of each sampling point. The brightness consistency deviation matrix allows observation of the trend of brightness deviation as the driving current changes. The generation of the color coordinate qualified identifier list also independently judges the measured value of each sampling point under each current point. Therefore, the length of the color coordinate qualified identifier list is equal to the number of sampling points multiplied by the number of current points. When the color coordinate judgment module performs inclusion judgment, the boundary coordinates of the target color coordinate range form a convex polygon region. The judgment algorithm calculates the cross product sign of the vector formed by the color coordinate point to be measured and each side of the polygon to determine the inclusion relationship of the point.

[0083] Optionally, the global reference brightness can be calculated using a weighted average instead of a simple arithmetic average, and the weighting coefficients can be set according to the importance of the sampling area's position on the luminous surface. Optionally, the predetermined shape of the target color coordinate range is not limited to a quadrilateral; it can also be an ellipse or an irregular polygon, with the number and definition of the boundary coordinates adjusted accordingly.

[0084] It is understandable that the relative brightness deviation value of the preset sampling area is... The calculation follows the formula:

[0085] in: This represents the relative brightness deviation of the preset sampling area located in the i-th row and j-th column at the k-th arithmetic current point, expressed as a percentage. The value represents the brightness measurement of the preset sampling area located in the i-th row and j-th column at the k-th arithmetic current point read from the set of digital optical measurements, in nits; The value represents the arithmetic mean of the brightness measurements of all preset sampling areas at the k-th equal-difference current point calculated by the brightness difference analysis module, i.e., the global reference brightness, in nits; the subscripts i and j traverse the row and column indices of all sampling areas, and the subscript k traverses all equal-difference current points.

[0086] It is understandable that the process of the color coordinate judgment module generating the list of qualified color coordinate identifiers is a batch, automated logical judgment process. The color coordinate judgment module traverses each color coordinate record in the digital optical measurement value set, compares it with the fixed target color coordinate range boundary, and outputs a Boolean logic result. The generation of the list of qualified color coordinate identifiers does not rely on manual intervention; its judgment criteria are entirely based on the target color coordinate range boundary coordinates retrieved from a preset database.

[0087] In one embodiment of the present invention, the uniformity evaluation module selects the relative brightness deviation values ​​of each preset sampling area under the standard test current point from the brightness consistency deviation matrix. The standard test current point is a specified value in a preset current sequence. For example, the preset current sequence is [80, 90, 100, 110, 120] mA, and the standard test current point is specified as 100 mA. The uniformity evaluation module extracts all elements in the brightness consistency deviation matrix that index the current point 100 mA. These elements constitute a two-dimensional matrix. Each element in the matrix represents the relative brightness deviation value of a specific sampling area of ​​the light-emitting surface under a driving current of 100 mA. The uniformity evaluation module identifies the maximum positive and minimum negative values ​​among the relative brightness deviations of all preset sampling areas at the standard test current point of "100 mA". The search process traverses the entire two-dimensional matrix corresponding to that current point, comparing the magnitude of each relative brightness deviation value. The maximum positive value is the largest positive value among all relative brightness deviations, for example, "+2.5%" found in the matrix elements. The minimum negative value is the smallest negative value among all relative brightness deviations, for example, "-1.8%" found in the matrix elements. The minimum negative value refers to the smallest negative number. The uniformity evaluation module calculates the sum of the absolute values ​​of the maximum positive and minimum negative values. This sum is obtained by taking the absolute values ​​of the maximum positive and minimum negative values ​​and adding them together. Half of this sum is taken as the actual brightness uniformity value of the LED screen backlight module under test. The actual brightness uniformity value is calculated as 4.3% divided by 2, which equals 2.15%. The actual brightness uniformity value is a single percentage value used to quantify the brightness consistency of the emitting surface.

[0088] In some embodiments, the standard test current point is specified based on the typical operating conditions of the LED backlight module under test. These typical operating conditions are recorded in a preset database and associated with the model identification code. When the uniformity evaluation module performs the search for the maximum positive value and the minimum negative value, the zero and positive values ​​in the relative brightness deviation matrix are compared for the maximum positive value, and the zero and negative values ​​are compared for the minimum negative value. The calculated actual brightness uniformity value reflects the degree of brightness difference between the brightest and darkest areas of the emitting surface; the smaller the actual brightness uniformity value, the better the brightness uniformity. After calculating the actual brightness uniformity value, the uniformity evaluation module compares the actual brightness uniformity value with the standard brightness uniformity threshold retrieved from the standard optical parameter set. The comparison operation determines whether the actual brightness uniformity value is less than or equal to the standard brightness uniformity threshold.

[0089] In practice, the process of finding the maximum positive value and the minimum negative value is a numerical comparison, without considering the specific physical location of these two values ​​on the emitting surface. The uniformity evaluation module's operation on the brightness consistency deviation matrix is ​​limited to a single current point dimension, i.e., the standard test current point dimension. The calculation formula for the actual brightness uniformity value is symmetrical, and the formula simultaneously considers the combined effects of positive and negative deviations. The standard brightness uniformity threshold is a preset value, such as 85%. This threshold represents the maximum allowable range of brightness difference. An actual brightness uniformity value of 2.15% means that the brightness uniformity is better than the standard threshold of 85%.

[0090] Optionally, the standard test current point may not be preset as the median value of an arithmetic sequence, but may be set as the rated current or maximum operating current according to the specifications of the LED backlight module under test. Optionally, the reference used when calculating the actual brightness uniformity value may not be the maximum positive value and the minimum negative value, but rather the standard deviation of the entire deviation matrix; however, the current implementation uses half of the sum of absolute values ​​for calculation.

[0091] It's understandable that the actual brightness uniformity value... The calculation follows the formula:

[0092] in: The actual brightness uniformity value of the LED screen backlight module under test, calculated by the uniformity evaluation module, is expressed as a percentage. The value represented by the maximum positive value found by the uniformity evaluation module among the relative brightness deviations corresponding to the standard test current points, expressed as a percentage. It is a real number that is greater than or equal to zero; The smallest negative value, expressed as a percentage, is found by the uniformity assessment module among the relative brightness deviations corresponding to the standard test current points. It is a real number less than or equal to zero; sign Indicates to and Take the absolute values ​​separately. The denominator 2 in the formula represents the average of the sum of the absolute values ​​to obtain the half-width value that characterizes the overall brightness difference.

[0093] As can be understood, the uniformity evaluation module's calculation process is a deterministic numerical processing flow. The input to the uniformity evaluation module is the luminance consistency deviation matrix and the specified standard test current point index. The output of the uniformity evaluation module is a single actual luminance uniformity value. The comparison result between the actual luminance uniformity value and the standard luminance uniformity threshold is a Boolean logic value. This comparison result is passed to the subsequent pass / fail judgment module to generate the final judgment instruction. The uniformity evaluation module does not change the data in the luminance consistency deviation matrix; it only reads and processes the data.

[0094] See Figure 3 This is a heatmap showing the relative brightness deviation of an LED backlight module. This heatmap is the direct basis for generating the zoned brightness compensation lookup table. By identifying persistently overbright and underbright areas, the corresponding current gain / attenuation coefficients can be calculated to drive the chip for precise brightness compensation, thereby improving the overall display effect. Simultaneously, it provides fundamental data for color gamut traceability. When color coordinates are unqualified, this map can be used to pinpoint the specific physical LED chip location for quality traceability. During the R&D phase, comparing heatmaps from different processes and different LED chip batches can evaluate the effectiveness of process improvements and accelerate product iteration. In aging tests, heatmaps at different stages can be generated to visually display the decay trend of brightness uniformity and assess the long-term reliability of the product.

[0095] In one embodiment of the present invention, after completing the initial optical performance test and generating a backlight module qualification determination command, the system controls the LED screen backlight module under test to enter a preset aging test mode. In the preset aging test mode, the system controls a programmable constant current source to output a periodically fluctuating accelerated aging drive current. The waveform of the accelerated aging drive current is a square wave, with a peak current of 150 mA, a valley current of 50 mA, and a frequency of 1 Hz. The system records the total aging duration, which can be 100 hours or 500 hours. At predetermined aging monitoring nodes, such as the 24th, 120th, and 500th hours after the start of aging, the system interrupts the accelerated aging drive current and restores the initial drive current, which is 100 mA. The system then uses a photosensitive probe array to re-acquire the light signal of the LED screen backlight module under test, generating post-aging optical measurement values. The system compares the post-aging optical measurement values ​​with the set of digital optical measurement values ​​obtained during the initial test under the same drive current to calculate the brightness maintenance rate and color coordinate drift. The system evaluates the long-term reliability level of the LED screen backlight module under test based on the brightness maintenance rate and color coordinate drift. The long-term reliability level can be divided into five levels from "L1" to "L5".

[0096] In some embodiments, the system extracts from the digital optical measurement value set an initial luminance measurement value set and an initial chromaticity coordinate measurement value set for all preset sampling areas under an initial drive current of "100 mA". The initial luminance measurement value set is a list containing 64 luminance values, and the initial chromaticity coordinate measurement value set is a list containing 64 (x,y) coordinate pairs. From the aged optical measurement values, the system extracts from the aged luminance measurement value set and the aged chromaticity coordinate measurement value set for all corresponding preset sampling areas under the same initial drive current of "100 mA". The aged luminance measurement value set is also a list containing 64 luminance values, and the aged chromaticity coordinate measurement value set is a list containing 64 (x,y) coordinate pairs. For each preset sampling area, the system calculates the ratio of its post-aging brightness measurement to its initial brightness measurement to obtain the point brightness maintenance rate of the preset sampling area. For example, for sampling area (1,1), the initial brightness measurement is 1000 nits, and the post-aging brightness measurement is 980 nits, then the point brightness maintenance rate is 980 / 1000 = 0.98 or 98%. The system calculates the average point brightness maintenance rate of all preset sampling areas as the overall brightness maintenance rate of the LED screen backlight module under test. The average value is calculated using an arithmetic mean. For each preset sampling area, the system calculates the Euclidean distance between its post-aging color coordinate measurement and its initial color coordinate measurement on the chromaticity diagram to obtain the color coordinate point drift of the preset sampling area. The chromaticity diagram uses the CIE1931 (x,y) coordinate system. The system finds the maximum value of the color coordinate point drift among all sampling areas as the maximum color coordinate drift of the LED screen backlight module under test.

[0097] In practice, the calculation of brightness maintenance rate and color coordinate drift is performed in parallel. The system calculates the point brightness maintenance rate and color coordinate drift for each sampling area separately. The overall brightness maintenance rate reflects the average level of overall brightness decay of the backlight module after aging, while the maximum color coordinate drift reflects the most severe color deviation after aging. The acquisition process of optical measurement values ​​after aging is consistent with the process of the photoelectric data transfer module during initial testing, but only data at the standard test current point is collected. The long-term reliability level is determined by comparing the calculated overall brightness maintenance rate and maximum color coordinate drift with a preset level threshold table. The level threshold table defines the lower limit of brightness maintenance rate and the upper limit of color coordinate drift corresponding to different reliability levels.

[0098] Optionally, the duration of the aging test mode can be adjusted according to product specifications, and the preset aging monitoring nodes can be increased or decreased. Optionally, the waveform of the accelerated aging drive current is not limited to a square wave; it can also be a sine wave or a pulse wave with a higher peak current to simulate different stress conditions, see Table 1.

[0099] Table 1: Example Table of Aging Monitoring Node Data

[0100] Sampling area initial brightness Brightness after aging Point brightness maintenance rate Initial color coordinates (x, y) Color coordinates (x, y) after aging Color coordinate point drift A1 1002 985 0.983 (0.315,0.335) (0.316,0.336) 0.0014 A2 995 978 0.983 (0.314,0.334) (0.315,0.335) 0.0014 B1 1008 990 0.982 (0.316,0.336) (0.318,0.337) 0.0022 B2 1001 982 0.981 (0.315,0.335) (0.317,0.336) 0.0022

[0101] It is understandable that the color coordinate point drift in the preset sampling area is... The calculation follows the formula:

[0102] in: The color coordinate point drift of the preset sampling area in the i-th row and j-th column is a dimensionless distance value. and The x and y components of the aged chromatic coordinate measurement value of the preset sampling area in the i-th row and j-th column are extracted from the aged optical measurement value. and These represent the x and y components of the initial chromaticity coordinate measurements of the preset sampling region in the i-th row and j-th column, extracted from the set of digital optical measurements. The formula calculates the straight-line distance between two points on the CIE 1931 chromaticity diagram, used to quantify the magnitude of chromaticity coordinate changes.

[0103] It is understandable that the system performs a precise point-to-point matching between the aged optical measurements and the initial optical measurements; the initial and aged data for each sampling area are correlated through a unique area coordinate index. Overall brightness retention rate. The calculation involves taking the brightness maintenance rate of all points. The arithmetic mean, i.e. Where N is the total number of sampling regions. Maximum color coordinate drift. It is all The maximum value within. Long-term reliability level assessment is based on overall brightness maintenance rate. and maximum color coordinate drift Jointly determined, for example, Level L1 requirements and .

[0104] See Figure 4This is a radar chart showing the aging test performance of an LED backlight module, serving as the core visual output of the aging process monitoring and performance degradation assessment module. As aging time increases, the polygon area of ​​the radar chart continuously shrinks, indicating a linear decline in overall performance. After 500 hours of aging, performance across all dimensions shows a significant decrease, particularly in color coordinate drift and uniformity. By fitting performance data at different time points, the effective lifespan and long-term reliability level of the module can be predicted. For the dimension with the most significant degradation, improvements in LED chip materials and packaging processes can be traced back. Based on the performance after 500 hours of aging, product quality can be graded to guide selection for different application scenarios. Integrating multi-dimensional performance indicators into a single chart visually demonstrates the impact of aging on overall performance, avoiding the limitations of evaluating a single indicator.

[0105] In one embodiment of the present invention, after determining that the backlight module of the LED screen under test is qualified, the parameter generation module further analyzes the data distribution of the brightness consistency deviation matrix. The parameter generation module identifies areas in the brightness consistency deviation matrix where the relative brightness deviation value is consistently positive and exceeds the slight deviation threshold, marking them as overbrightness compensation areas. The slight deviation threshold is a preset percentage value, such as +0.5%. A consistently positive relative brightness deviation value means that the deviation value in this area is positive at multiple test current points. The parameter generation module identifies areas in the brightness consistency deviation matrix where the relative brightness deviation value is consistently negative and below the slight deviation threshold, marking them as underbrightness compensation areas. Below the slight deviation threshold means the value is less than -0.5%. Based on the specific values ​​of the relative brightness deviation values ​​at each sampling point in the overbrightness compensation area and the underbrightness compensation area, the parameter generation module calculates the corresponding current gain coefficient or current attenuation coefficient. The parameter generation module associates the coordinate information of the compensation area with the corresponding current gain coefficient or current attenuation coefficient to generate a partitioned brightness compensation lookup table for the display driver chip to use. The data structure of the partitioned brightness compensation lookup table includes a region coordinate index and a compensation coefficient.

[0106] In some embodiments, when a color coordinate non-compliance identifier exists in the color coordinate qualification identifier list, the color gamut traceability module obtains the specific color coordinate measurement value of the corresponding sampling point. The color gamut traceability module projects the specific color coordinate measurement value onto a chromaticity diagram containing the target color coordinate range, and calculates the offset direction and distance between the specific color coordinate measurement value and the center point of the target color coordinate range. The color gamut traceability module, in conjunction with the LED bead layout drawing of the backlight module under test, determines the location of the physical LED or LED bead group corresponding to the sampling point that emitted the specific color coordinate measurement value. The LED bead layout drawing defines the number or coordinates of the physical LEDs covered by each sampling area. The color gamut traceability module retrieves the batch information and supplier information of the LEDs corresponding to the location of the physical LED or LED bead group. The batch information and supplier information are stored in the material management database and associated with the unique code of the LED. The color gamut traceability module generates an analysis report containing the coordinates of the non-compliance point, the direction and distance of the color coordinate deviation, and the corresponding LED traceability information.

[0107] In practical implementation, the parameter generation module analyzes the brightness consistency deviation matrix based on data pattern recognition at multiple current points. For example, if the relative brightness deviation values ​​of a region at five current points (80, 90, 100, 110, and 120 mA) are [+0.8%, +0.9%, +1.0%, +1.1%, +1.2%], this region is identified as an overbrightness compensation area. The calculation of the current gain coefficient or current attenuation coefficient is based on the ratio between the target brightness and the average brightness of the region. For example, for an overbrightness compensation area, it is desirable to reduce the driving current to make its brightness approach the global reference brightness; therefore, a current attenuation coefficient less than 1 is calculated. The format of the partitioned brightness compensation lookup table can be a text file or a binary file, containing row numbers, column numbers, and corresponding compensation coefficient values. The color gamut tracing module calculates the offset direction by calculating the vector direction from the center point of the target color coordinate range to the specific color coordinate measurement value; the offset distance is the magnitude of this vector. The LED layout drawing divides the emitting surface into a grid corresponding to the sampling area of ​​the photosensitive probe array, with each grid containing one or more physical LEDs. The analysis report is output in a structured document format, including tables and diagrams, to guide problem localization in the production process.

[0108] Optionally, the slight deviation threshold can be set with different absolute values ​​for overbrightness and underbrightness. Optionally, the zone brightness compensation lookup table can include not only coordinates and coefficients, but also the current range or brightness range for which compensation is effective.

[0109] It is understandable that the parameter generation module calculates the current attenuation coefficient for a sampling point in the overbrightness compensation area. The process follows the formula below:

[0110] in: The representative parameter generation module calculates the current attenuation coefficient for the sampling point located in the i-th row and j-th column, which is a real number between 0 and 1; This represents the target brightness value obtained from a standard set of optical parameters, measured in nits. The average brightness measurement value, in nits, is obtained by the parameter generation module from the sampling point located in the i-th row and j-th column under multiple test current points. The formula is based on the principle that brightness and current have an approximately linear relationship within a certain range, and the brightness is indirectly adjusted by adjusting the current ratio.

[0111] The process of generating the analysis report by the color gamut traceability module is understandable; it involves information integration and correlation. The module locates the index of the non-compliant identifier from the list of qualified color coordinate identifiers, retrieves the corresponding specific color coordinate measurement value from the digital optical measurement value set, obtains the center point coordinates of the target color coordinate range from the preset database, maps the sampling area to the physical LEDs from the LED layout drawing file, and queries the batch and supplier of the LEDs from the material management database. The analysis report links optical measurement anomalies with specific physical materials and production batch information, providing a reverse tracing path from test results to the production source. The generation of the partitioned brightness compensation lookup table utilizes the systematic deviation information in the brightness consistency deviation matrix, aiming to improve display uniformity through subsequent fine-tuning of the drive current.

[0112] See Figure 5 This is a line graph showing the relative brightness deviation of different areas as a function of drive current, providing a visual representation of the brightness consistency deviation matrix. Transforming the abstract brightness consistency deviation matrix into an intuitive line graph clearly demonstrates the deviation characteristics and current sensitivity of different areas. It serves as the direct data source for generating the zoned brightness compensation lookup table. By identifying overly bright / underbright areas, precise regional brightness adjustment can be achieved, significantly improving display uniformity. Analyzing areas with drastic deviation fluctuations (such as G1) allows for tracing back to production issues, optimizing LED selection, arrangement, and packaging processes, thus improving product consistency from the source. Covering the full operating current range from 80mA to 120mA ensures that performance under different operating conditions is verified, avoiding the limitations of evaluating a single current point.

[0113] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A performance testing system for LED screen backlight modules, characterized in that, The system includes: The parameter retrieval module receives the model identification code of the LED screen backlight module under test, retrieves the standard optical parameter set corresponding to it, which includes the target brightness value, target color coordinate range and standard brightness uniformity threshold, and applies a preset initial driving current. The photoelectric data acquisition module collects the actual light signals generated by the backlight module of the LED screen under test under different preset current levels through a photosensitive probe array, and converts the actual light signals into a set of digital optical measurement values ​​containing brightness and color coordinate measurements of multiple sampling points. The brightness difference analysis module compares the brightness measurement values ​​in the set of digital optical measurement values ​​with the target brightness value point by point, and calculates and generates a brightness consistency deviation matrix. The color coordinate judgment module performs a range conformity judgment between the color coordinate measurement values ​​in the set of digital optical measurement values ​​and the target color coordinate range, and generates a list of color coordinate qualified identifiers. The uniformity assessment module calculates the actual brightness uniformity value based on the brightness consistency deviation matrix and compares the actual brightness uniformity value with the standard brightness uniformity threshold. If the actual brightness uniformity value is less than or equal to the standard brightness uniformity threshold, and the color coordinate qualification indicator list shows that the color coordinate measurement values ​​of all sampling points are within the target color coordinate range, then the backlight module qualification instruction is generated. The process of retrieving a set of standard optical parameters, including the target brightness value, target color coordinate range, and standard brightness uniformity threshold, and applying a preset initial driving current, includes: Receive the model identification code of the LED screen backlight module under test, and retrieve the standard optical parameter set corresponding to the model identification code from the preset database. The standard optical parameter set includes the target brightness value, the target color coordinate range, and the standard brightness uniformity threshold. The backlight module of the LED screen under test is lit up, and a preset initial drive current is applied through a programmable constant current source; The programmable constant current source is controlled to output current according to a preset current sequence, the preset current sequence including at least five arithmetic current points from the minimum rated current to the maximum rated current. Each probe in the photosensitive probe array corresponds to a preset sampling area of ​​the light-emitting surface of the backlight module of the LED screen under test. The calculation of the brightness consistency deviation matrix includes: For each of the equal-differential current points, read the brightness measurement values ​​of all preset sampling areas under the equal-differential current points; Calculate the arithmetic mean of the brightness measurements of all preset sampling areas under the equal current point, and use it as the global reference brightness of the equal current point; For each preset sampling area under the equal current point, calculate the percentage difference between the brightness measurement value of the preset sampling area and the global reference brightness, and use it as the relative brightness deviation value of the preset sampling area; The relative brightness deviation values ​​calculated for all preset sampling areas at each of the equal current points are arranged in a two-dimensional matrix form corresponding to the coordinates of the sampling areas to generate the brightness consistency deviation matrix.

2. The LED screen backlight module performance testing system according to claim 1, characterized in that, The process of acquiring the actual light signals generated by the LED screen backlight module under different preset current levels through a photosensitive probe array includes: After the LED screen backlight module under test is stably driven for a preset stabilization time at each of the equal differential current points, the photosensitive probe array is started for synchronous measurement. Collect spectral energy distribution data of the preset sampling area; The spectral energy distribution data is input into the spectral calculation unit bound to the probe to calculate the brightness measurement value and color coordinate measurement value of the corresponding preset sampling area; Record the brightness measurement value and color coordinate measurement value of all preset sampling areas at each of the equal current points, and store them indexed according to the coordinates of the current point and the sampling area.

3. The LED screen backlight module performance testing system according to claim 2, characterized in that, The generated list of qualified color coordinate identifiers includes: The target color coordinate range corresponding to the model identification code of the LED screen backlight module under test is obtained from the preset database. The target color coordinate range includes the boundary coordinates of a predetermined shape on the chromaticity diagram. Read the color coordinate measurement value corresponding to each sampling point in the set of digital optical measurement values; For each sampling point, determine whether its color coordinate measurement value is located within a predetermined shape area enclosed by the boundary coordinates; If the color coordinate measurement value is located within the predetermined shape area, a color coordinate qualification mark for the sampling point is generated; If the color coordinate measurement value is outside the predetermined shape area, a color coordinate non-compliance mark is generated for the sampling point; Summarize the qualified and unqualified labels of all sampling points to generate a list of qualified labels for the color coordinates. The list includes the sampling point number and the corresponding label status.

4. The LED screen backlight module performance testing system according to claim 3, characterized in that, The calculation yields the actual brightness uniformity value, including: From the brightness consistency deviation matrix, select the relative brightness deviation value of each preset sampling area under the standard test current point, where the standard test current point is a specified value in the preset current sequence; Find the maximum positive value and the minimum negative value among the relative brightness deviation values ​​of all preset sampling areas under the standard test current point, where the maximum positive value is the largest positive value among all relative brightness deviation values ​​and the minimum negative value is the smallest negative value among all relative brightness deviation values. Calculate the sum of the absolute values ​​of the maximum positive value and the minimum negative value, and take half of the sum of the absolute values ​​as the actual brightness uniformity value of the LED screen backlight module under test.

5. The LED screen backlight module performance testing system according to claim 4, characterized in that, It also includes steps for aging process monitoring and performance degradation assessment: After completing the initial optical performance test and generating a backlight module qualification determination command, the backlight module of the LED screen under test is controlled to enter the preset aging test mode. In the preset aging test mode, the programmable constant current source is controlled to output a periodically fluctuating accelerated aging drive current, and the total aging duration is recorded. At the predetermined aging monitoring node, the accelerated aging driving current is interrupted, the initial driving current is restored, and the optical signal of the LED screen backlight module under test is collected again through the photosensitive probe array to generate optical measurement values ​​after aging. The aging optical measurement values ​​are compared with the set of digital optical measurement values ​​obtained during the initial test under the same driving current to calculate the brightness retention rate and color coordinate drift. The long-term reliability level of the LED screen backlight module under test is evaluated based on the brightness maintenance rate and color coordinate drift.

6. The LED screen backlight module performance testing system according to claim 5, characterized in that, The step of comparing the aged optical measurement values ​​with the set of digital optical measurement values ​​obtained during the initial test under the same driving current, and calculating the brightness retention rate and color coordinate shift, includes: Extract the initial brightness measurement set and the initial color coordinate measurement set of all preset sampling areas under the initial driving current from the set of digital optical measurement values; From the optical measurement values ​​after aging, extract the set of brightness measurement values ​​and the set of chromaticity measurement values ​​of all corresponding preset sampling areas under the same initial driving current; For each preset sampling area, the ratio of its aging brightness measurement value to its initial brightness measurement value is calculated to obtain the point brightness maintenance rate of the preset sampling area; Calculate the average point brightness maintenance rate of all preset sampling areas as the overall brightness maintenance rate of the LED screen backlight module under test; For each preset sampling area, the Euclidean distance between its aged color coordinate measurement value and its initial color coordinate measurement value on the chromaticity diagram is calculated to obtain the color coordinate point drift of the preset sampling area. Find the maximum value among the color coordinate point drifts of all sampling areas, and take it as the maximum color coordinate drift of the LED screen backlight module under test.

7. The LED screen backlight module performance testing system according to claim 6, characterized in that, Also includes: If the parameter generation module determines that the backlight module of the LED screen under test is qualified, it further analyzes the data distribution of the brightness consistency deviation matrix. The regions in the brightness consistency deviation matrix where the relative brightness deviation value is consistently positive and exceeds the slight deviation threshold are identified and marked as overbrightness compensation regions. The regions in the brightness consistency deviation matrix where the relative brightness deviation value is consistently negative and below the slight deviation threshold are identified and marked as underbrightness compensation regions. Based on the specific values ​​of the relative brightness deviation of each sampling point in the overbrightness compensation area and the underbrightness compensation area, the corresponding current gain coefficient or current attenuation coefficient is calculated. The coordinate information of the compensation area is associated with the corresponding current gain coefficient or current attenuation coefficient to generate a partition brightness compensation lookup table for the display driver chip to use.

8. The LED screen backlight module performance testing system according to claim 7, characterized in that, Also includes: The color gamut tracing module obtains the specific color coordinate measurement value of the corresponding sampling point when there is a color coordinate unqualified identifier in the color coordinate qualified identifier list; The specific color coordinate measurement value is projected onto a chromaticity map containing the target color coordinate range, and its offset direction and offset distance from the center point of the target color coordinate range are calculated; Based on the LED bead arrangement diagram of the LED screen backlight module under test, determine the position of the physical LED bead or LED bead group corresponding to the sampling point that emits the specific color coordinate measurement value; Retrieve batch information and supplier information of the LEDs corresponding to the positions of the physical LEDs or LED groups; Generate an analysis report that includes the coordinates of the non-conforming points, the direction and distance of the color coordinate deviation, and the corresponding traceability information of the LED beads.

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