An LED light guide plate photoelectric integrated test system

Abstract

The present invention relates to the field of light guide detection technology, specifically to an integrated photoelectric testing system for LED light guide plates, including a comprehensive uniformity module that obtains and processes a laser point uniformity index, a comprehensive illumination uniformity index, and a side light leakage index to obtain a comprehensive uniformity index for measuring the comprehensive uniformity of a laser dotted light guide plate; a light transmittance index module that calculates a light transmittance index to measure the light transmittance performance of a light guide plate; an electro-optical conversion index module that calculates an electro-optical conversion index to measure the light transmittance efficiency of a light guide plate; a stability evaluation module that calculates a stability index to measure the stability of a light guide plate during operation; a comprehensive index module that obtains and processes a comprehensive uniformity index, a light transmittance index, an electro-optical conversion index, and a stability index to obtain a quality index, and a quality grading module that performs quality grading on a laser dotted light guide plate according to the quality index and a preset threshold. The present invention improves the efficiency of quality detection and grading by performing an integrated photoelectric test on a laser dotted light guide plate.

Description

Technical Field

[0001] The invention relates to the technical field of light guide detection, in particular to a photoelectric integrated testing system for an LED light guide plate. Background Art

[0002] Laser dotted light guide plate is a light guide plate that uses laser engraving technology to form a precise array of tiny scattering dots on the surface or inside of the light guide plate to achieve uniform scattering and light guiding. This type of light guide plate is widely used in high-end displays, LCD TVs, advertising light boxes and other fields. LED, also known as light emitting diode, is a semiconductor device that can convert electrical energy into light energy. Due to its high efficiency, long life and good durability, LED has widely replaced traditional light sources and become one of the core components of modern lighting and display technology. LED light guide plate is a type of light guide plate, specifically a light guide plate that uses LED as a light source. LED light guide plate distributes the light generated by the LED light source evenly over the entire board surface through the light guide plate, and is used in various display and lighting equipment.

[0003] At the current stage of research, there have been many studies on light uniformity detection, light guiding performance detection, pressure detection, temperature detection and surface defect detection of light guide plates. However, the current tests and inspections are still insufficient in fully reflecting the comprehensive performance of light guide plates, and a large amount of test data needs to be comprehensively analyzed. There is still room for research in the automated generation of comprehensive test reports and quality grading for mass-produced laser-dot light guide plates.

[0004] Therefore, a comprehensive photoelectric testing system for LED light guide plates is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide an LED light guide plate optoelectronic comprehensive testing system, which evaluates the comprehensive uniformity of the light guide plate by analyzing the laser point distribution, comprehensive illumination uniformity and light leakage degree of the side of the light guide plate of the laser dotted light guide plate; evaluates the light transmittance of the light guide plate by a transmittance index module, evaluates the energy efficiency of the light guide plate by an electro-optical conversion index, and examines the stability of the light guide plate under temperature changes by a stability index; and designs quality indicators to facilitate subsequent quality grading of the light guide plate.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An LED light guide plate photoelectric integrated test system, comprising:

[0008] The laser point uniformity module obtains and processes the front image of the laser-dotted light guide plate to obtain a laser point uniformity index.

[0009] Furthermore, the laser point uniformity module obtains and processes the front image of the laser dotted light guide plate to obtain a laser point, and calculates the laser point distribution index according to the center of the laser point. The calculation formula of the laser point distribution index is:

[0010]

[0011] Wherein, l1 represents the laser point distribution index, I represents the number of laser points, J represents the number of adjacent laser points of the i-th laser point, and d ij represents the distance from the center of the i-th laser point to the center of the j-th adjacent laser point, represents the standard distance from the center of the i-th laser point to the center of the j-th adjacent laser point;

[0012] The front image of the laser dotted light guide plate is acquired and processed to obtain the area of ​​the laser dot, and the laser dot area index is calculated according to the area of ​​the laser dot. The calculation formula of the laser dot area index is:

[0013]

[0014] Wherein, l2 represents the laser spot area index, I represents the number of laser spots, s i represents the area of ​​the i-th laser point, represents the standard area of ​​the laser spot;

[0015] The surface image of the laser dotted light guide plate is obtained and grayscaled and denoised to obtain a grayscale image; the grayscale image is segmented to obtain the area of ​​the laser point; the grayscale value in the area is extracted and the average grayscale value of all pixels is calculated, and the laser point depth index is calculated according to the average grayscale value. The calculation formula is:

[0016]

[0017] Wherein, l3 represents the laser point depth index, I represents the number of laser points, K represents the number of pixels in the i-th laser point, Pi ik represents the gray value of the kth pixel in the i-th laser point, Represents the standard gray value of the laser point;

[0018] The laser point distribution index, the laser point area index and the laser point depth index are obtained and processed to obtain the laser point uniformity index. The calculation formula of the laser point uniformity index is:

[0019]

[0020] Wherein, L1 represents the laser point uniformity index, α1 represents the weight coefficient of the laser point distribution index, α2 represents the weight coefficient of the laser point area index, and α3 represents the weight coefficient of the laser point depth index.

[0021] The illumination uniformity module evenly divides the laser dotted light guide plate to obtain divided areas; 2 A test experiment of incident light at different angles is performed, and the light intensity index of each divided area and the comprehensive light uniformity index of the laser-marked light guide plate are calculated.

[0022] Further, the laser dotted light guide plate is divided into N×N uniform parts to obtain N 2 In the nth experiment, the single LED light source is placed directly behind the nth segmented area, and N 2 The test experiment of incident light at different angles; the calculation formula of the light intensity index of the mth segmented area is:

[0023]

[0024] Among them, f m represents the illumination intensity index of the mth segmented area, d mn represents the distance from the geometric center of the mth segmented area to the single LED light source in the nth test experiment, S represents the area of ​​the segmented area, L m (x, y) represents the standard illumination function of the mth segmented area, L mn represents the measured illumination function of the mth segmented area in the nth test experiment, and dxdy represents the double integral;

[0025] The calculation formula of the comprehensive illumination uniformity index of the laser dotted light guide plate is:

[0026]

[0027] Wherein, L2 represents the comprehensive illumination uniformity index.

[0028] The side light leakage degree module is used to calculate the side light leakage degree index.

[0029] Furthermore, the problem of light leakage around the edges of the light guide plate is usually due to imperfections in the design or processing of the light guide plate, causing light to leak out from the edges of the light guide plate instead of being evenly scattered through the surface. This light leakage affects the brightness uniformity and overall optical effect of the light guide plate.

[0030] Furthermore, the side light leakage data of the laser dotted light guide plate is obtained and processed to obtain the side light leakage degree index, wherein the side light leakage data includes luminous flux, side reflectivity of the light guide plate, total circumference of the side of the light guide plate, thickness of the light guide plate and laser dot density; the calculation formula of the side light leakage degree index is:

[0031]

[0032] Wherein, L3 represents the side light leakage index, Φ out Indicates the luminous flux per unit area passing through the light guide plate, Φ in Represents the luminous flux per unit area incident on the light guide plate, R edge represents the reflectivity of the side surface of the light guide plate, C represents the total circumference of the side surface of the light guide plate, h represents the thickness of the light guide plate, and d represents the density of laser dot marking.

[0033] The comprehensive uniformity module is used to obtain the laser point uniformity index, the comprehensive illumination uniformity index and the side light leakage index and process them to obtain a comprehensive uniformity index.

[0034] Furthermore, the laser point uniformity index, the comprehensive illumination uniformity index and the side light leakage index are obtained and processed to obtain the comprehensive uniformity index. The calculation formula of the comprehensive uniformity index is:

[0035]

[0036] Among them, F1 represents the comprehensive uniformity index, ω1 represents the weight coefficient of the laser point uniformity index, ω2 represents the weight coefficient of the comprehensive illumination uniformity index, and ω3 represents the weight coefficient of the side light leakage index.

[0037] The transmittance index module is used to calculate the transmittance index.

[0038] Furthermore, if the transmittance of the light guide plate is too low, the light will not be sufficient, affecting the lighting effect; if the transmittance of the light guide plate is too high, it may cause the light to be not evenly concentrated, thus affecting the lighting effect; therefore, the transmittance of the light guide plate should be moderate to ensure that the light is evenly distributed on the light guide plate, thereby achieving the best lighting effect.

[0039] Furthermore, the light transmittance data of the laser dotted light guide plate is obtained and processed to obtain the light transmittance index, wherein the light transmittance data includes luminous flux, transmittance without dot, material coefficient and laser dot density; the calculation formula of the light transmittance index is:

[0040]

[0041] Wherein, F2 represents the light transmittance index, Φ outIndicates the luminous flux per unit area passing through the light guide plate, Φ in It represents the luminous flux per unit area incident on the light guide plate, τ0 represents the transmittance when there is no dot, e represents the natural base, α represents the material coefficient, and d represents the laser dot density.

[0042] The electro-optical conversion index module is used to calculate the electro-optical conversion index.

[0043] Furthermore, the introduction of the electro-optical conversion index module can effectively evaluate the light efficiency of the LED light guide plate, that is, the light output generated per unit power consumption.

[0044] Furthermore, the light energy data and rated power data of the laser dotted light guide plate are obtained and processed to obtain the electro-optical conversion index, wherein the light energy data includes the number of segmented regions, the area of ​​the segmented regions and the measured illumination function; the electro-optical conversion index is calculated as follows:

[0045]

[0046] Wherein, F3 represents the electro-optical conversion index, N 2 represents the number of segmented regions, L m represents the measured illumination function of the mth segmented area, S represents the area of ​​the segmented area, V represents the rated voltage of the single LED light source, and A represents the rated current of the single LED light source.

[0047] The stability assessment module is used to calculate the stability index.

[0048] Furthermore, the stability evaluation module can help determine the performance of the laser-dot light guide plate under different temperature conditions and analyze whether it can maintain stable optical performance during actual use.

[0049] Further, temperature change data and volume change data are obtained and processed to obtain the stability index of the laser dotted light guide plate, wherein the temperature change data includes the temperature change amount, the initial temperature and the ambient temperature, etc., and the volume change data includes the linear expansion coefficient, etc.; the calculation formula of the stability index is:

[0050]

[0051] Wherein, F4 represents the stability index, β1 represents the weight coefficient of the temperature change, ΔT represents the temperature change of the light guide plate, β2 represents the weight coefficient of the time required for the temperature of the light guide plate to stabilize, τ represents the time constant of the light guide plate, which depends on the material properties and thermal conductivity of the light guide plate, and T final Indicates the final temperature when the light guide plate reaches a stable state, T initial Indicates the initial temperature of the light guide plate, T envrepresents the ambient temperature, β3 represents the weight coefficient of the volume change of the light guide plate, a represents the length of the light guide plate, b represents the width of the light guide plate, d represents the thickness of the light guide plate, and λ represents the linear expansion coefficient of the light guide plate.

[0052] The comprehensive index module obtains and processes the comprehensive uniformity index, the light transmittance index, the electro-optical conversion index and the stability index to obtain a quality index.

[0053] Furthermore, the comprehensive uniformity index, the light transmittance index, the electro-optical conversion index and the stability index are obtained and processed to obtain a comprehensive evaluation index, and the calculation formula of the comprehensive evaluation index is:

[0054] Y=θ1·F1+θ2·F2+θ3·F3+θ4·F4;

[0055] Wherein, Y represents the comprehensive evaluation index, θ1 represents the weight coefficient of the comprehensive uniformity index, θ2 represents the weight coefficient of the light transmittance index, θ3 represents the weight coefficient of the electro-optical conversion index, and θ4 represents the weight coefficient of the stability index;

[0056] The comprehensive evaluation index is obtained, and is mapped to the quality grading interval [Z1, Z2] according to a mapping function to obtain a quality index, where Z1 represents a first quality threshold and Z2 represents a second quality threshold; the calculation formula of the mapping function is:

[0057] W = map(Y);

[0058] Wherein, W represents the quality indicator, and map() represents the mapping function.

[0059] The quality grading module performs quality grading on the laser-dotted light guide plate according to a preset threshold.

[0060] Further, the transmittance index is obtained for the first quality grading. If the transmittance index F2∈[ρ1,ρ2], where ρ1 represents the first preset transmittance index threshold and ρ2 represents the second preset transmittance index threshold, the transmittance performance of the laser dotted light guide plate is qualified, and the second quality grading is performed; if the transmittance index The light transmission performance of the laser-dotted light guide plate is unqualified, and the laser-dotted light guide plate is reprocessed and subjected to the first quality grading;

[0061] The quality index is obtained and a second quality grading of the laser dotted light guide plate is performed according to a preset quality grading threshold.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. The laser point uniformity module evaluates the uniformity of the surface laser point distribution by calculating the cumulative error between the laser point distribution on the surface of the laser-dotted light guide plate and the standard distribution; the illumination uniformity module evaluates the illumination uniformity of the light guide plate through test experiments of incident light at different angles; the side light leakage degree module quantitatively evaluates the light loss on the side of the light guide plate by defining and calculating the side light leakage degree index, which can help identify defects in design or manufacturing; each module separately measures and analyzes the laser point uniformity, comprehensive illumination uniformity and side light leakage degree, and this refined test method improves the accuracy of the test.

[0064] 2. The comprehensive uniformity module combines the data obtained from the laser point uniformity module, the illumination uniformity module and the side light leakage module to generate a comprehensive uniformity index, which can more intuitively reflect the overall uniformity of the light guide plate; the transmittance index is used to evaluate the transmittance of the light guide plate, the electro-optical conversion index evaluates the energy efficiency of the light guide plate, and the stability evaluation examines the stability of the light guide plate under temperature changes. The three aspects cover the main optoelectronic properties of the light guide plate, and conduct a comprehensive and in-depth quality analysis of the light guide plate, providing important feedback data for the subsequent quality grading of the light guide plate.

[0065] 3. The comprehensive index module comprehensively considers multiple key performance indicators of the laser dot light guide plate, such as comprehensive uniformity index, transmittance index, electro-optical conversion index and stability index, and calculates a comprehensive evaluation index using the weight coefficient. This multi-dimensional comprehensive evaluation method avoids the limitations of a single indicator and more accurately reflects the overall performance and quality of the light guide plate. By calculating the comprehensive evaluation index and applying the mapping function, the comprehensive evaluation index is converted into a specific quality grade, which enables a more accurate quality grading of the light guide plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 A schematic diagram of the structure of an LED light guide plate photoelectric integrated testing system provided in Example 1 of the present invention;

[0067] Figure 2 A schematic diagram of the structure of a laser point uniformity module provided in Embodiment 1 of the present invention;

[0068] Figure 3 A schematic diagram of light source positions for different test experiments provided in Example 1 of the present invention;

[0069] Figure 4 This is a schematic diagram of the structure of the quality grading module provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0070] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] Example 1

[0072] In order to ensure that the laser dotted light guide plates it produces can meet high quality standards, a certain light guide plate manufacturer decided to introduce an LED light guide plate photoelectric integrated test system provided by the present invention. The system structure is as follows: Figure 1 The system measures and evaluates multiple performance indicators of the light guide plate through a series of precise test modules, thereby performing effective quality grading.

[0073] The structure of the laser point uniformity module is as follows: Figure 2 As shown, it is used to calculate the laser spot uniformity index.

[0074] Furthermore, the laser point uniformity module obtains and processes the front image of the laser dotted light guide plate to obtain a laser point, and calculates the laser point distribution index according to the center of the laser point. The calculation formula of the laser point distribution index is:

[0075]

[0076] Wherein, l1 represents the laser point distribution index, I represents the number of laser points, J represents the number of adjacent laser points of the i-th laser point, and d ij represents the distance from the center of the i-th laser point to the center of the j-th adjacent laser point, It represents the standard distance from the center of the i-th laser point to the center of the j-th adjacent laser point; the larger the laser point distribution index is, the more uneven the laser point distribution is.

[0077] The front image of the laser dotted light guide plate is acquired and processed to obtain the area of ​​the laser dot, and the laser dot area index is calculated according to the area of ​​the laser dot. The calculation formula of the laser dot area index is:

[0078]

[0079] Wherein, l2 represents the laser spot area index, I represents the number of laser spots, s i represents the area of ​​the i-th laser point, Indicates the standard area of ​​the laser spot; the larger the laser spot area index is, the more uneven the laser spot area is.

[0080] The surface image of the laser dotted light guide plate is obtained and grayscaled and denoised to obtain a grayscale image; the grayscale image is segmented to obtain the area of ​​the laser point; the grayscale value in the area is extracted and the average grayscale value of all pixels is calculated, and the laser point depth index is calculated according to the average grayscale value. The calculation formula is:

[0081]

[0082] Wherein, l3 represents the laser point depth index, I represents the number of laser points, K represents the number of pixels in the i-th laser point, Pi ik represents the gray value of the kth pixel in the i-th laser point, Represents the standard grayscale value of the laser point; the larger the depth index of the laser point, the more uneven the depth.

[0083] The laser point distribution index, the laser point area index and the laser point depth index are obtained and processed to obtain the laser point uniformity index. The calculation formula of the laser point uniformity index is:

[0084]

[0085] Wherein, L1 represents the laser point uniformity index, α1 represents the weight coefficient of the laser point distribution index, α2 represents the weight coefficient of the laser point area index, and α3 represents the weight coefficient of the laser point depth index.

[0086] By analyzing the uniformity of laser points through three aspects: laser point distribution index, laser point area index and laser point depth index, it is possible to detect defects that may exist in the production process, such as dot position offset, inconsistent area size or depth, etc.; the laser point uniformity index is obtained by combining the above three data to comprehensively evaluate the uniformity of the light guide plate, which can subsequently help identify light guide plates that do not meet the standards.

[0087] The illumination uniformity module evenly divides the laser dotted light guide plate to obtain divided areas; 2 A test experiment of incident light at different angles is performed, and the light intensity index of each divided area and the comprehensive light uniformity index of the laser-marked light guide plate are calculated.

[0088] Further, the laser dotted light guide plate is divided into N×N uniform parts to obtain N 2 In the nth experiment, the single LED light source is placed directly behind the nth segmented area, and N 2 The test experiment of incident light at different angles; Figure 3Shown is a schematic diagram of the light source position for incident light at different angles in four test experiments.

[0089] The calculation formula of the illumination intensity index of the mth segmented area is:

[0090]

[0091] Among them, f m represents the illumination intensity index of the mth segmented area, d mn represents the distance from the geometric center of the mth segmented area to the single LED light source in the nth test experiment, S represents the area of ​​the segmented area, L m (x, y) represents the standard illumination function of the mth segmented area, L mn represents the measured illumination function of the mth segmented area in the nth test experiment, and dxdy represents the double integral;

[0092] Furthermore, the standard illumination function refers to the light uniformity of the light guide plate expected during the design of the light guide plate, and the measured illumination function refers to the actual light uniformity of the light guide plate in the segmented area collected in each test experiment.

[0093] The calculation formula of the comprehensive illumination uniformity index of the laser dotted light guide plate is:

[0094]

[0095] Wherein, L2 represents the comprehensive illumination uniformity index; the larger the comprehensive illumination uniformity index is, the more uneven the illumination of the light guide plate is.

[0096] Illumination uniformity is one of the important indicators for measuring the performance of a light guide plate. By dividing the surface of the light guide plate into multiple areas and testing the light intensity at different angles in each area, the uniformity of the light distribution can be accurately evaluated. This helps to detect whether the surface brightness of the entire light guide plate is consistent and accurately identify areas with excessively high or low brightness.

[0097] The side light leakage degree module is used to calculate the side light leakage degree index.

[0098] Furthermore, the problem of light leakage around the edges of the light guide plate is usually due to imperfections in the design or processing of the light guide plate, causing light to leak out from the edges of the light guide plate instead of being evenly scattered through the surface. This light leakage affects the brightness uniformity and overall optical effect of the light guide plate.

[0099] Furthermore, the side light leakage data of the laser dotted light guide plate is obtained and processed to obtain the side light leakage degree index, wherein the side light leakage data includes luminous flux, side reflectivity of the light guide plate, total circumference of the side of the light guide plate, thickness of the light guide plate and laser dot density; the calculation formula of the side light leakage degree index is:

[0100]

[0101] Wherein, L3 represents the side light leakage index, Φ out Indicates the luminous flux per unit area passing through the light guide plate, Φ in Represents the luminous flux per unit area incident on the light guide plate, R edge represents the reflectivity of the side surface of the light guide plate, C represents the total circumference of the side surface of the light guide plate, h represents the thickness of the light guide plate, and d represents the density of laser dot marking.

[0102] By calculating the degree of side light leakage, the main reasons for the side light leakage of the light guide plate, such as the side reflectivity, the thickness of the light guide plate and the laser dot density, can be analyzed, which can help identify the light loss of the laser dotted light guide plate.

[0103] The comprehensive uniformity module is used to obtain the laser point uniformity index, the comprehensive illumination uniformity index and the side light leakage index and process them to obtain a comprehensive uniformity index.

[0104] Furthermore, the laser point uniformity index, the comprehensive illumination uniformity index and the side light leakage index are obtained and processed to obtain the comprehensive uniformity index. The calculation formula of the comprehensive uniformity index is:

[0105]

[0106] Among them, F1 represents the comprehensive uniformity index, ω1 represents the weight coefficient of the laser point uniformity index, ω2 represents the weight coefficient of the comprehensive illumination uniformity index, and ω3 represents the weight coefficient of the side light leakage index.

[0107] Table 1. Comprehensive uniformity index

[0108]

[0109] Table 1 shows the comprehensive uniformity index of five laser-dotted light guide plates. It can be seen that light guide plate D has the best uniformity. The calculation formula of the comprehensive uniformity index combines multiple important indicators together and weights them through weight coefficients to form an overall indicator. This comprehensive evaluation method can fully reflect the optical performance of the light guide plate, avoid the limitations of a single indicator evaluation, improve detection efficiency, and facilitate rapid detection and quality judgment on the production line.

[0110] The transmittance index module is used to calculate the transmittance index.

[0111] Furthermore, if the transmittance of the light guide plate is too low, the light will not be sufficient, affecting the lighting effect; if the transmittance of the light guide plate is too high, it may cause the light to be not evenly concentrated, thus affecting the lighting effect; therefore, the transmittance of the light guide plate should be moderate to ensure that the light is evenly distributed on the light guide plate, thereby achieving the best lighting effect.

[0112] Furthermore, the light transmittance data of the laser dotted light guide plate is obtained and processed to obtain the light transmittance index, wherein the light transmittance data includes luminous flux, transmittance without dot, material coefficient and laser dot density; the calculation formula of the light transmittance index is:

[0113]

[0114] Wherein, F2 represents the light transmittance index, Φ out Indicates the luminous flux per unit area passing through the light guide plate, Φ in It represents the luminous flux per unit area incident on the light guide plate, τ0 represents the transmittance when there is no dot, e represents the natural base, α represents the material coefficient, and d represents the laser dot density.

[0115] The light transmittance index comprehensively considers various factors that affect the light transmittance performance, such as the luminous flux passing through the light guide plate, the incident luminous flux, the transmittance when there is no dot, the material properties and the laser dot density. This quantitative evaluation method can conduct a comprehensive and accurate analysis of the light transmittance performance of the light guide plate.

[0116] The electro-optical conversion index module is used to calculate the electro-optical conversion index.

[0117] Furthermore, the introduction of the electro-optical conversion index module can effectively evaluate the light efficiency of the LED light guide plate, that is, the light output generated per unit power consumption.

[0118] Furthermore, the light energy data and rated power data of the laser dotted light guide plate are obtained and processed to obtain the electro-optical conversion index, wherein the light energy data includes the number of segmented regions, the area of ​​the segmented regions and the measured illumination function; the electro-optical conversion index is calculated as follows:

[0119]

[0120] Wherein, F3 represents the electro-optical conversion index, N 2 represents the number of segmented regions, L m represents the measured illumination function of the mth segmented area, S represents the area of ​​the segmented area, V represents the rated voltage of the single LED light source, and A represents the rated current of the single LED light source.

[0121] The electro-optical conversion index module can effectively evaluate the light efficiency of the laser-dotted light guide plate by calculating the electro-optical conversion index, that is, the light output generated per unit power consumption, which is beneficial to quality control in the production process and subsequent quality grading of the light guide plate.

[0122] The stability assessment module is used to calculate the stability index.

[0123] Furthermore, the stability evaluation module can help determine the performance of the laser-dot light guide plate under different temperature conditions and analyze whether it can maintain stable optical performance during actual use.

[0124] Further, temperature change data and volume change data are obtained and processed to obtain the stability index of the laser dotted light guide plate, wherein the temperature change data includes the temperature change amount, the initial temperature and the ambient temperature, etc., and the volume change data includes the linear expansion coefficient, etc.; the calculation formula of the stability index is:

[0125]

[0126] Wherein, F4 represents the stability index, β1 represents the weight coefficient of temperature change, ΔT=T final -T initial represents the temperature change of the light guide plate, β2 represents the weight coefficient of the temperature stabilization time of the light guide plate, τ represents the time constant of the light guide plate, which depends on the material properties and thermal conductivity of the light guide plate, T final Indicates the final temperature when the light guide plate reaches a stable state, T initial Indicates the initial temperature of the light guide plate, T env represents the ambient temperature, β3 represents the weight coefficient of the volume change of the light guide plate, a represents the length of the light guide plate, b represents the width of the light guide plate, d represents the thickness of the light guide plate, and λ represents the linear expansion coefficient of the light guide plate.

[0127] The stability assessment module can analyze the performance of the light guide under different temperature conditions by calculating the temperature change and the time required for stabilization; by calculating the volume change of the light guide, manufacturers can understand the impact of temperature changes on the size and shape of the light guide.

[0128] The comprehensive index module obtains and processes the comprehensive uniformity index, the light transmittance index, the electro-optical conversion index and the stability index to obtain a quality index.

[0129] Furthermore, the comprehensive uniformity index, the light transmittance index, the electro-optical conversion index and the stability index are obtained and processed to obtain a comprehensive evaluation index, and the calculation formula of the comprehensive evaluation index is:

[0130] Y=θ1·F1+θ2·F2+θ3·F3+θ4·F4;

[0131] Wherein, Y represents the comprehensive evaluation index, θ1 represents the weight coefficient of the comprehensive uniformity index, θ2 represents the weight coefficient of the light transmittance index, θ3 represents the weight coefficient of the electro-optical conversion index, and θ4 represents the weight coefficient of the stability index;

[0132] The comprehensive evaluation index is obtained, and is mapped to the quality grading interval [Z1, Z2] according to a mapping function to obtain a quality index, where Z1 represents a first quality threshold and Z2 represents a second quality threshold; the calculation formula of the mapping function is:

[0133] W = map(Y);

[0134] Wherein, W represents the quality indicator, and map() represents the mapping function.

[0135] The comprehensive evaluation index integrates multiple important test results, including uniformity, transmittance, electro-optical conversion efficiency and stability, providing a comprehensive product quality evaluation and providing a basis for subsequent quality grading.

[0136] The structure of the quality classification module is as follows Figure 4 As shown, the quality of the laser-dotted light guide plate is graded according to a preset threshold.

[0137] Further, the transmittance index is obtained for the first quality grading. If the transmittance index F2∈[ρ1,ρ2], where ρ1 represents the first preset transmittance index threshold and ρ2 represents the second preset transmittance index threshold, the transmittance performance of the laser dotted light guide plate is qualified, and the second quality grading is performed; if the transmittance index The light transmission performance of the laser-dotted light guide plate is unqualified, and the laser-dotted light guide plate is reprocessed and subjected to the first quality grading;

[0138] The quality index is obtained and according to a preset quality grading threshold, the quality grading interval is [0, 1], the second quality grading of the laser dotted light guide plate is performed.

[0139] Table 2 shows the quality grading results of five laser dotted light guide plates. If the quality index ∈ [0.85, 1], the result of the second quality grading is excellent. If the quality index The result of the second quality grading is ordinary. By setting the light transmittance index threshold, it can be ensured that the light transmittance performance of the light guide plate meets the expected standard; for products with unqualified light transmittance performance, they can be repaired and improved through reprocessing and re-quality grading, minimizing the scrap rate and resource waste; the second quality grading according to the preset quality grading threshold can provide clear quality standards and facilitate quality control during the production process.

[0140] Table 2. Quality grading results

[0141] Light guide plate number Transmittance Index First quality classification Quality indicators Second quality classification Light guide plate 1 0.87 qualified 0.89 high quality Light guide plate 2 0.92 Unqualified (reprocessing) 0.84(after processing) ordinary Light guide plate 3 0.84 qualified 0.83 ordinary Light guide plate 4 0.90 qualified 0.91 high quality Light guide plate 5 0.79 Unqualified (reprocessing) 0.81(after processing) ordinary

[0142] The present embodiment provides an LED light guide plate optoelectronic comprehensive testing system, which evaluates the comprehensive uniformity of the light guide plate by analyzing the laser point distribution, illumination uniformity and light leakage degree of the laser-marked light guide plate; evaluates the light transmittance of the light guide plate by a transmittance index module, evaluates the energy efficiency of the light guide plate by an electro-optical conversion index, and examines the stability of the light guide plate under temperature changes by a stability index; and designs quality indicators to facilitate subsequent quality grading of light guide plates and improve the efficiency of light guide plate sorting.

[0143] Example 2

[0144] In a certain light guide plate production factory, an LED light guide plate photoelectric integrated testing system provided by the present invention is used to ensure that the produced light guide plates meet high standards in terms of optical performance, stability and quality. The following is a detailed process of the factory using this system to produce and test the quality of light guide plates.

[0145] The factory first produced a batch of 5,000 laser-dot light guide plates, each with 10,000 laser dots. The production process of the light guide plate includes material selection, laser dotting, cutting and molding. During the production process, the factory pays special attention to the accuracy of the laser dotting, because it directly affects the optical performance of the light guide plate. The front of each light guide plate is designed with laser dots of different densities and distributions. These dots are used to adjust the propagation path of light to achieve a uniform lighting effect.

[0146] The standard spacing of laser points is 2.0mm, the allowable deviation is ±0.1mm, and the standard area of ​​laser points is 0.05mm 2 , the allowable deviation is ±0.002mm 2 . After the light guide plate is made, it enters the laser point uniformity module in the optoelectronic integrated test system. This module obtains and processes the front image of the light guide plate to obtain the distribution, area and depth data of the laser points. By calculating the number of laser points and the distance from the center of each laser point to the center of the adjacent laser point, the laser point distribution index is obtained. This index reflects the uniformity of the laser dot; the area of ​​each laser point is measured and compared with the standard area to calculate the laser point area index. This index is used to evaluate whether the area of ​​the laser dot is consistent; by processing the grayscale image, the grayscale value of each laser point area is obtained, and then the depth index of the laser point is calculated to reflect the depth consistency of the laser dot; through weighted processing of these indicators, the system obtains the final laser point uniformity index. After calculation, the laser point uniformity index of a laser dot light guide plate is 0.956, which meets the production quality.

[0147] The illumination uniformity module is used to evaluate the illumination performance of the light guide plate under incident light at different angles. The light guide plate is evenly divided into several areas. In each experiment, a single LED light source is placed directly behind the divided area and tested multiple times at different angles. The illumination intensity index of each area is calculated, reflecting the illumination uniformity of the area. The system combines the illumination intensity index of all areas to calculate the comprehensive illumination uniformity index of the light guide plate.

[0148] The side light leakage module is used to detect light leakage at the edge of the light guide plate. The system collects data such as the side luminous flux, reflectivity, perimeter, thickness and dot density of the light guide plate, and calculates the side light leakage index through a formula. This index helps the factory understand the defects in the edge design of the light guide plate and make improvements.

[0149] The comprehensive uniformity module is used to obtain the laser point uniformity index, the comprehensive illumination uniformity index and the side light leakage index and process them to obtain a comprehensive uniformity index.

[0150] The light transmittance index module analyzes the light transmittance data of the light guide plate to evaluate its light transmittance performance and ensure that the light can be evenly distributed on the light guide plate.

[0151] The electro-optical conversion index module evaluates the luminous efficiency of the light guide plate. By measuring the relationship between the light output and power consumption of the light guide plate, the electro-optical conversion index is obtained. This indicator is crucial for monitoring and analyzing the energy efficiency of the light guide plate.

[0152] The stability assessment module detects the optical performance and physical changes of the light guide plate under different temperature conditions through temperature change experiments. The system calculates the stability index and analyzes whether the light guide plate can maintain stable performance in actual use.

[0153] Finally, the comprehensive index module of the system weights all the test results to obtain a comprehensive evaluation index. Based on this index, the system obtains the quality index and maps the light guide plate to different quality grading intervals. Table 3 shows the quality index of a group of laser dot light guide plates.

[0154] Table 3. Quality indicators and grading results

[0155] Light guide plate number Quality indicators Second quality classification Light guide plate 001 0.88 high quality Light guide plate 002 0.90 high quality Light guide plate 003 0.87 ordinary Light guide plate 004 0.86 ordinary Light guide plate 005 0.91 high quality Light guide plate 006 0.87 ordinary Light guide plate 007 0.88 high quality Light guide plate 008 0.92 ordinary Light guide plate 009 0.88 high quality Light guide plate 010 0.93 high quality

[0156] On this basis, the quality grading module first performs preliminary grading according to the light transmittance index. After ensuring that the light transmittance performance is qualified, a second grading is performed according to the quality index. The quality grading interval is [0,1]. If the quality index of the light guide plate ∈ [0.88,1], the result of the second quality grading of the light guide plate is high quality. If the quality index The result of the second quality grading of the light guide plate is ordinary. The unqualified light guide plates will be reprocessed to ensure that each light guide plate shipped out of the factory meets the high quality standards.

[0157] After the light guide plates were tested and graded, the light transmittance of the 5,000 laser-dotted light guide plates was 99.85%, the quality rate was 52.37%, and the common rate was 47.48%. The products were put on the market. The factory also continuously improved the production process through customer feedback and used the test system to optimize the design and quality control process of the light guide plates. This series of operations not only improved the market competitiveness of the products, but also provided customers with more efficient and higher-quality lighting solutions.

[0158] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An LED light guide plate photoelectric integrated test system, characterized in that: include: The laser point uniformity module obtains and processes the image of the laser dotted light guide plate to obtain a laser point uniformity index. The calculation formula of the laser point uniformity index is: Wherein, L1 represents the laser point uniformity index, α1 represents the weight coefficient of the laser point distribution index, α2 represents the weight coefficient of the laser point area index, α3 represents the weight coefficient of the laser point depth index; I represents the number of laser points, J represents the number of adjacent laser points of the i-th laser point, d ij represents the distance from the center of the i-th laser point to the center of the j-th adjacent laser point, represents the standard distance from the center of the i-th laser point to the center of the j-th adjacent laser point; s i represents the area of ​​the i-th laser point, represents the standard area of ​​the laser point; K represents the number of pixels in the i-th laser point, Pi ik represents the gray value of the kth pixel in the ith laser point, Represents the standard gray value of the laser point; The illumination uniformity module evenly divides the laser dotted light guide plate to obtain divided areas; conducts test experiments of incident light at different angles, and calculates the illumination intensity index of the divided areas and the comprehensive illumination uniformity index of the laser dotted light guide plate; the calculation formula of the illumination intensity index is: Among them, f m represents the illumination intensity index of the mth segmented area, d mn represents the distance from the geometric center of the mth segmented area to the single LED light source in the nth test experiment, S represents the area of ​​the segmented area, L m (x, y) represents the standard illumination function of the mth segmented area, L mn represents the measured illumination function of the mth segmented area in the nth test experiment, and dxdy represents a double integral; The side light leakage degree module is used to calculate the side light leakage degree index. The calculation formula of the side light leakage degree index is: Wherein, L3 represents the side light leakage index, Φ out Indicates the luminous flux per unit area passing through the light guide plate, Φ in Represents the luminous flux per unit area incident on the light guide plate, R edge represents the reflectivity of the side surface of the light guide plate, C represents the total perimeter of the side surface of the light guide plate, h represents the thickness of the light guide plate, and d represents the density of laser dot; The comprehensive uniformity module obtains and processes the laser point uniformity index, the comprehensive illumination uniformity index and the side light leakage index to obtain a comprehensive uniformity index; The light transmittance index module is used to calculate the light transmittance index. The calculation formula of the light transmittance index is: Wherein, F2 represents the light transmittance index, Φ out Indicates the luminous flux per unit area passing through the light guide plate, Φ in It represents the luminous flux per unit area incident on the light guide plate, τ0 represents the transmittance when there is no dot, e represents the natural base, α represents the material coefficient, and d represents the laser dot density; The electro-optical conversion index module is used to calculate the electro-optical conversion index. The calculation formula of the electro-optical conversion index is: Wherein, F3 represents the electro-optical conversion index, N 2 represents the number of segmented regions, L m represents the measured illumination function of the mth segmented area, S represents the area of ​​the segmented area, V represents the rated voltage of the single LED light source, and A represents the rated current of the single LED light source; The stability evaluation module is used to calculate the stability index, and the calculation formula of the stability index is: Wherein, F4 represents the stability index, β1 represents the weight coefficient of the temperature change, ΔT represents the temperature change of the light guide plate, β2 represents the weight coefficient of the time required for the light guide plate temperature to stabilize, τ represents the time constant, T final Indicates the final temperature when the light guide plate reaches a stable state, T initial Indicates the initial temperature of the light guide plate, T env represents the ambient temperature, β3 represents the weight coefficient of the volume change of the light guide plate, a represents the length of the light guide plate, b represents the width of the light guide plate, d represents the thickness of the light guide plate, and λ represents the linear expansion coefficient of the light guide plate; The comprehensive index module obtains and processes the comprehensive uniformity index, the light transmittance index, the electro-optical conversion index and the stability index to obtain a quality index; The quality grading module performs quality grading on the laser-dotted light guide plate according to a preset threshold.

2. The LED light guide plate photoelectric integrated test system according to claim 1, characterized in that: The laser point uniformity module comprises: Acquire and process the front image of the laser-dotted light guide plate to obtain a laser point, and calculate the laser point distribution index according to the center position of the laser point; Acquire and process the front image of the laser-dotted light guide plate to obtain the area of ​​the laser dot, and calculate the laser dot area index according to the area of ​​the laser dot; Acquire the surface image of the laser-dotted light guide plate and perform grayscale and denoising processing to obtain a grayscale image; segment the grayscale image to obtain the area of ​​the laser point; calculate the average grayscale value of all pixels in the area and further process it to obtain the laser point depth index; The laser point distribution index, the laser point area index and the laser point depth index are acquired and processed to obtain the laser point uniformity index.

3. The LED light guide plate photoelectric integrated test system according to claim 1, characterized in that: The illumination uniformity module comprises: The laser dotted light guide plate is divided into N×N uniform parts to obtain N 2 In the nth experiment, the single LED light source is placed directly behind the nth segmented area, and N 2 The test experiment of incident light at different angles is performed to obtain the light intensity index f of the mth segmented area. m ; The calculation formula of the comprehensive illumination uniformity index of the laser dotted light guide plate is: Wherein, L2 represents the comprehensive illumination uniformity index.

4. The LED light guide plate photoelectric integrated test system according to claim 1, characterized in that: The comprehensive uniformity module includes: The laser point uniformity index, the comprehensive illumination uniformity index and the side light leakage index are obtained and processed to obtain the comprehensive uniformity index. The calculation formula of the comprehensive uniformity index is: Among them, F1 represents the comprehensive uniformity index, ω1 represents the weight coefficient of the laser point uniformity index, ω2 represents the weight coefficient of the comprehensive illumination uniformity index, and ω3 represents the weight coefficient of the side light leakage index.

5. The LED light guide plate photoelectric integrated test system according to claim 1, characterized in that: The comprehensive indicator module includes: The comprehensive uniformity index, the light transmittance index, the electro-optical conversion index and the stability index are obtained and processed to obtain a comprehensive evaluation index, and the calculation formula of the comprehensive evaluation index is: Y=θ1·F1+θ2·F2+θ3·F3+θ4·F4; Wherein, Y represents the comprehensive evaluation index, θ1 represents the weight coefficient of the comprehensive uniformity index, θ2 represents the weight coefficient of the light transmittance index, θ3 represents the weight coefficient of the electro-optical conversion index, and θ4 represents the weight coefficient of the stability index; The comprehensive evaluation index is obtained, and is mapped to the quality grading interval [Z1, Z2] according to a mapping function to obtain a quality index, where Z1 represents a first quality threshold and Z2 represents a second quality threshold; the calculation formula of the mapping function is: W = map(Y); Wherein, W represents the quality indicator, and map() represents the mapping function.

6. The LED light guide plate photoelectric integrated test system according to claim 1, characterized in that: The quality grading module includes: The light transmittance index is obtained for the first quality grading. If the light transmittance index F2∈[ρ1,ρ2], where ρ1 represents the first preset light transmittance index threshold and ρ2 represents the second preset light transmittance index threshold, then the light transmittance performance of the laser dotted light guide plate is qualified; if the light transmittance index If the light transmission performance of the laser dotted light guide plate is unqualified, the laser dotted light guide plate is reprocessed and subjected to the first quality grading; The quality index is obtained and a second quality classification is performed according to a preset quality classification threshold.

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