Luminous intensity compensation method for testing the optical performance of lighting fixtures

Abstract

The present invention discloses a luminous intensity compensation method for testing the optical performance of lighting fixtures, which includes step S1 of acquiring reference test data data1 of an accepted lighting fixture, step S2 of acquiring actual test data data2 of the lighting fixture under test, step S3 of fitting and comparing the reference test data data1 and the actual test data data2 to obtain an initial data position that best matches the actual test data data2 in the reference test data data1, step S4 of performing position compensation on the initial data position to obtain a final data position, and step S5 of determining a final luminous intensity value of the lighting fixture under test based on the final data position. The present invention not only shortens testing time, improves production line testing efficiency, and meets production requirements, but also reduces the impact of heat accumulation on measurement results, thereby improving the accuracy of the measurement results.

Description

[Technical Field]

[0001] The present invention relates to the technical field of luminaire testing, and in particular to a luminous intensity compensation method for luminaire optical performance testing. [Background technology]

[0002] Automotive lights illuminate vehicles while driving at night and also serve as a warning signal for various driving situations. Automotive lights are generally divided into headlights, taillights, turn signals, fog lights, etc. Before a vehicle's lights are shipped, their performance (e.g., optical performance, sealing performance, etc.) must be inspected. Regulations require that the luminous intensity data be stable before a legal measurement can be made. However, the thermal stability time of a lighting fixture typically requires 30 minutes after it is turned on, significantly lengthening the test time and impacting the efficiency of the inspection process. In particular, multiple change inspections are required during the design verification phase, and as the number of items increases, automotive lighting companies' inspection equipment is unable to meet the inspection requirements.

[0003] In addition, according to the testing procedure, before testing the optical performance of a vehicle light, stress relief by high-temperature baking and electrical property testing are performed. For example, after high-temperature baking, heat accumulates inside the vehicle light. If the optical performance test of the lighting fixture is performed directly at this time, the heat accumulation will affect the test accuracy. Alternatively, the lighting fixture must first be placed in another working position to dissipate heat and cool down, which requires an additional cooling device (e.g., a fan), which not only occupies the testing time but also increases costs. For example, when testing the electrical performance, the lighting fixture must be turned on for 20 seconds. Even after turning on, heat accumulates inside the vehicle light, affecting the accuracy of subsequent light intensity detection. Therefore, there is a need for a new testing method that can reduce the impact of heat accumulation on the testing results and improve the testing efficiency. Summary of the Invention [Problem to be solved by the invention]

[0004] The technical problem that the present invention aims to solve is to provide a luminous intensity compensation method for lighting fixture optical performance testing, which not only can shorten the test time, improve the testing efficiency of the production line, and meet production requirements, but also can improve the impact of heat accumulation on the measurement results and improve the accuracy of the measurement results, in order to solve the technical problem of heat accumulation affecting the lighting fixture light intensity test. [Means for solving the problem]

[0005] The technical means used in the present invention to solve this technical problem are: Step S1: acquiring reference test data data1 of a passing lighting fixture; step S2 of acquiring actual test data data2 of the lighting fixture under test; The reference test data data1 and the actual test data data2 are fitted together. G Step S3: obtaining the initial data position of the actual test data data2 that best matches the reference test data data1; Step S4: performing position compensation on the initial data position to obtain a final data position; and step S5 of determining a final luminous intensity value for the lighting fixture under test based on the final data position; The step S1 of acquiring the reference test data data1 of the passed lighting fixtures specifically includes the following steps: continuously measuring the reference luminous intensity data of the passed lighting fixture until it reaches a stable state, to obtain a reference luminous intensity decay change curve of the passed lighting fixture; performing a normalization process on the reference luminous intensity decay curve to calculate reference gradient data for each data point on the reference luminous intensity decay curve; and setting the reference gradient data as the reference test data data1.

[0006] Furthermore, step S2 of obtaining the actual test data data2 of the test lighting fixture specifically includes: continuously measuring the test lighting fixture to obtain a set of actual luminous intensity data, performing normalization processing on the actual luminous intensity data, and calculating the actual gradient data of each data point in the actual luminous intensity data; using the actual gradient data as the actual test data data2.

[0007] Furthermore, the continuous measurement time t1 for continuously measuring the qualified lighting fixture until it stabilizes is at least 30 minutes, the measurement interval Δt1 is less than 1 second, the continuous measurement time t2 of the test lighting fixture is at least 20 seconds, and the measurement interval Δt2 is the same as the measurement interval Δt1 of the qualified lighting fixture.

[0008] Furthermore, the step of performing normalization processing on the reference luminous intensity attenuation change curve: removing the obtained first reference luminous intensity data

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[0009] Furthermore, in step S3, the calculation formula for the initial data position is as follows: Index = arg min(ΔG , , m , , , M , , , , , , , , , compen , M , , , , , , , , , , ,

[0011] , ) Here, Index represents the time position in the reference light intensity attenuation change curve, and ΔG p represents the sum of the squares of the differences between the gradient data change sequence G [L1 / 2] ~G L1 of the actual light intensity data and the reference gradient data sequence of the corresponding length located at the p position in the reference light intensity data. The range of the value of p is 1 ≤ p < L1 - L2 + 1, and L2 represents the total sum of the actual light intensity data.

[0010] Furthermore, the calculation formula for ΔG p is as follows:

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[0012] Furthermore, the final data position Index compen After obtaining the above, the actual final luminosity value at time T is calculated as follows:

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[0013] The beneficial effects of the present invention include the introduction of a luminous intensity decay gradient into the luminous intensity compensation method for testing the optical performance of lighting fixtures of the present invention, which finds the most appropriate measurement time point by matching the decay gradient of a small portion of the lighting fixture under test with the reference decay rate of a qualified lighting fixture, and then calculates the luminous intensity value of the lighting fixture under test when it is stable or the luminous intensity value at another time based on the most appropriate measurement time point, thereby shortening the test time, improving the testing efficiency of the production line, and meeting production requirements. Meanwhile, it also reduces the impact of heat accumulation on the measurement results, improving the accuracy of the measurement results, and eliminating the need to provide an additional work station for cooling and dissipating heat from the lighting fixture, further saving costs. [Brief explanation of the drawings]

[0014] The invention will now be further described with reference to the figures and examples.

[0015] [Figure 1] 4 is a flowchart of a luminous intensity compensation method for lighting fixture optical performance testing of the present invention. [Figure 2] 10 is a graph showing the luminous intensity decay curves of different lighting fixtures of the present invention; [Figure 3] 3A-3C are schematic diagrams of different positions of the light emitting beam of the lighting fixture of the present invention; [Figure 4] 1 is a graph showing luminous intensity decay curves at different positions of the same lighting fixture of the present invention; [Figure 5] 10 is a luminous intensity decay curve of the same lamp of the present invention after baking and after not baking. [Figure 6] 10 shows the luminous intensity decay curves of the same lighting fixture of the present invention when it is turned on for 5 minutes and when it is not turned on. [Figure 7] 1 is a graph showing the luminous intensity decay curves of different lighting fixtures of the present invention in general situations; [Figure 8] 1 is a schematic diagram showing the matching of actual gradient data (short line segments) and reference gradient data (long curves) according to the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will now be described in more detail with reference to the drawings, which are all simplified schematic diagrams and merely serve to explain the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0017] In describing the present invention, it should be understood that orientations or positional relationships indicated by terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "up," "down," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like, are based on the drawings and are intended solely to facilitate and simplify the description of the present invention, and should not be construed as limiting the present invention, as they do not expressly or imply that the devices or elements described necessarily have, are configured, or operate in a particular orientation. Furthermore, features qualified as "first" or "second" may expressly or implicitly include one such feature or more such features. In describing the present invention, unless otherwise specified, "plurality" means two or more than two.

[0018] In the description of the present invention, it should be understood that unless otherwise clearly defined or limited, the terms "attach," "couple," and "connect" should be understood in a broad sense, for example, to mean fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected, directly connected, or indirectly connected via an intermediate medium, or to allow the interiors of two elements to communicate with each other. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0019] As shown in FIG. 1, the luminous intensity compensation method for lighting fixture optical performance testing of the present invention includes: Step S1: acquiring reference test data data1 of a passing lighting fixture; step S2 of acquiring actual test data data2 of the lighting fixture under test; Fitting the reference test data data1 and the actual test data data2 G Step S3: obtaining the most matching initial data position of the actual test data data2 in the reference test data data1 by comparing the actual test data data2 with the reference test data data1; Step S4: performing position compensation on the initial data position to obtain a final data position; and step S5 of determining a ratio between the actual test data data2 and the reference test data data1 based on the final data position, and obtaining a final luminous intensity value of the lighting fixture under test based on the ratio.

[0020] In other words, the present invention compares and matches the actual test data with the reference test data to find the best match position of the actual test data in the reference test data, and then converts the final luminous intensity value of the tested lighting fixture when stabilized based on the ratio. In this way, the influence of heat buildup in the lighting fixture on the measurement results can be mitigated, while the detection efficiency can be significantly improved.

[0021] Specifically, step S1 of acquiring reference test data data1 for a qualified lighting fixture includes the steps of continuously measuring the reference luminous intensity data of the qualified lighting fixture until it reaches a stable state to obtain a reference luminous intensity decay curve for the qualified lighting fixture, normalizing the reference luminous intensity decay curve to calculate reference slope data for each data point on the reference luminous intensity decay curve, and using the reference slope data as reference test data data1. It should be noted that the measurement time t1 for continuously measuring a qualified lighting fixture until it reaches a stable state is at least 30 minutes, the measurement interval Δt1 is less than 1 second, and the basis for determining whether it has reached a stable state is that the luminous intensity value changes by less than 3% within 15 minutes. Generally, a stable state can be reached after 30 minutes of lighting, and the measurement interval can be 0.5 seconds. A reference luminous intensity decay curve (i.e., a curve showing the change in the reference luminous intensity data over time) can be plotted based on the acquired reference luminous intensity data. As the lighting time of a lighting fixture increases, the luminous intensity data of the lighting fixture gradually decays until it stabilizes. The steady-state luminous intensity data is used to determine whether the optical performance of the lighting fixture meets regulatory requirements. A normalization process is performed on each data point on the reference luminous intensity decay curve to facilitate subsequent analysis. After normalization, the reference slope data for each data point on the reference luminous intensity decay curve is calculated, i.e., the change trend of the reference luminous intensity decay curve can be obtained.

[0022] Specifically, step S2 of acquiring actual test data data2 for the lighting fixture under test specifically includes the steps of continuously measuring the lighting fixture under test to acquire a set of actual luminous intensity data, normalizing the actual luminous intensity data, calculating actual gradient data for each data point in the actual luminous intensity data, and using the actual gradient data as actual test data data2. It should be noted that the continuous measurement time t2 of the lighting fixture under test is at least 20 seconds, and the measurement interval Δt2 is the same as the measurement interval Δt1 of the passed lighting fixture, e.g., 0.5 seconds. The continuous measurement time of the lighting fixture under test is much shorter than that of the passed lighting fixture. One actual luminous intensity data can be acquired for each luminous intensity measurement. Assuming that the lighting fixture under test is measured for a total of 30 seconds at 0.5-second intervals, a total of 60 actual luminous intensity data can be acquired, and a short luminous intensity decay curve can be constructed based on these 60 actual luminous intensity data. For convenience of analysis, the actual luminous intensity data is also normalized and the actual gradient data is calculated.

[0023] In other words, in this embodiment, the data of the passed lighting fixture is used as the comparison data, and the actual data of the lighting fixture under test is compared with the comparison data to obtain the luminous intensity value of the lighting fixture under test when it is stabilized. This not only saves testing time and improves testing efficiency, but also reduces the impact of heat accumulation caused by other processes on the test results, thereby improving the accuracy of the test results.

[0024] Specifically, the step of normalizing the reference luminous intensity decay curve is performed by:

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[0025] It should be noted that the photometric data is obtained by the sensor. Generally, the sensor performs integral measurement. Since the lighting fixture does not light up during the integral time of the previous part and lights up completely during the integral time of the latter part, the first obtained data may be relatively small. Therefore, when performing data processing, the first obtained photometric data is removed. In this embodiment, when performing normalization processing on the reference photometric data and the actual photometric data, the first obtained data is removed respectively. For the continuous measurement of qualified lighting fixtures, a total of L1 reference photometric data

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[0026] After obtaining the reference gradient data and the actual gradient data, the least squares method is used for fitting to find the part that most matches the actual gradient data in the reference gradient data, thereby finding the optimal data position (shown in Figure 8). The calculation formula for the initial data position is Index = arg min(ΔG p ), where Index represents the time position in the reference photometric attenuation change curve, and ΔG p represents the sum of the squares of the differences between the gradient data change sequence G [L1 / 2] ~G L1 of the actual photometric data and the reference gradient data sequence of the corresponding length located at the p position in the reference photometric data. The value range of p is 1 ≤ p < L1 - L2 + 1. The calculation formula for ΔG p is

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[0027] In other words, when obtaining a stable luminous intensity value of the lighting fixture under test, the present invention does not require the full 30 minutes of measurement time. After obtaining some data (for example, measuring for 30 seconds), it can be compared with the reference data to find the time position where the light attenuation is most consistent, and then converted using a formula to obtain a stable luminous intensity value or a luminous intensity value at another time. This not only significantly reduces the measurement time, improves detection efficiency, and reduces costs, but also reduces the impact of heat accumulation on the test results and improves the accuracy of the test results.

[0028] Then, experimental data prove the feasibility of the method.

[0029] Figure 2 shows the luminous intensity decay curves at point (0,0) for four rear fog lights of the same type. The continuous detection time was 30 minutes, the measurement interval was 0.5 seconds, and a total of 3,600 data points were acquired. The first luminous intensity data point was removed and normalized, resulting in four luminous intensity decay curves. The abscissa represents the test time, and the ordinate represents the normalized data. As can be seen from the figure, the luminous intensity decay curves for the same type of rear fog lights show almost the same change trend, with the normalized data gradually decreasing over the test time and eventually stabilizing. Therefore, it is feasible to use the test data from approved lighting fixtures as the reference data.

[0030] Figure 4 shows the luminous intensity decay curves for the same lighting fixture at different positions. The beam emitted by the lighting fixture is generally conical, with the center of the beam at (0,0). By offsetting the beam 5° up, down, left, and right from the center of the beam (as shown in Figure 3), four other positions are obtained: (0,5), (0,-5), (5,0), and (-5,0). The luminous intensity decay curves for the same lighting fixture were measured at each of these five positions. The test device was placed 1.2 meters in front of the center of the lighting fixture, and the measurement data was normalized to obtain five luminous intensity decay curves. As can be seen from the figure, the luminous intensity decay curves measured at different positions for the same lighting fixture are almost the same.

[0031] Figure 5 shows the luminous intensity decay curves of a backup fog light measured directly after 30 minutes of high-temperature baking in an oven. The black curve represents the decay curve after high-temperature baking, while the gray curve represents the decay curve at room temperature without baking. Figure 6 shows the decay curves of a luminous intensity measurement performed after the lighting fixture was turned on for 5 minutes before testing. The black curve represents the decay curve measured after 5 minutes of lighting, while the gray curve represents the decay curve at room temperature without early lighting. As can be seen from Figures 5 and 6, the lighting fixture with heat accumulation exhibits a rapid decay in light intensity for the first 8 seconds, followed by a sudden slowdown in the decay rate. This indicates that heat accumulation has a significant impact on lighting fixture luminous intensity measurements and significantly affects the accuracy of the test results. Figure 7 shows the decay curves of different lighting fixtures (four curves) when turned on for 50 seconds at room temperature (no heat accumulation). As can be seen from Figure 7, the decay curves of the different lighting fixtures differ slightly when no heat accumulation occurs.

[0032] Test data from one acceptable backup fog light at position (0,0) was selected as the reference data, and three identical backup fog lights, A, B, and C, were selected to verify the effectiveness of this method. Using the conventional test method and the test method of the present invention, the three backup fog lights, A, B, and C, were tested at positions (0,0), (0,5), and (5,0), respectively, and the light intensity of the lighting fixtures was recorded. The test results are shown in Tables 1 to 3. As can be seen from the results in the three tables, the conventional method cannot compensate for errors caused by heat accumulation. When the lighting fixture is turned on for a long time or baked at a high temperature in an oven for a certain period of time, the measurement accuracy is significantly affected, with a maximum error of -17%. However, after using the compensation method of the present invention, the maximum error is -2.8%. This clearly shows that the present invention can significantly improve measurement accuracy and reduce measurement errors when heat accumulates in the lighting fixture.

[0033] [Table 1]

[0034] [Table 2]

[0035] [Table 3]

[0036] In summary, the luminous intensity compensation method for testing the optical performance of lighting fixtures of the present invention incorporates a luminous intensity decay gradient, and matches the decay gradient of a small portion of the lighting fixture under test with the reference decay rate of a qualified lighting fixture to find the most appropriate measurement time point. Then, based on the most appropriate measurement time point, the luminous intensity value of the lighting fixture under test when it stabilizes or at another time is calculated. This shortens the test time, improves the testing efficiency of the production line, and meets production requirements. Meanwhile, it also reduces the impact of heat accumulation on the measurement results, improving the accuracy of the measurement results. It also eliminates the need for separate work stations for cooling and dissipating the lighting fixture, further saving costs. This method can quickly and easily determine the optical performance of the tool during the design verification phase and meets the accuracy requirements for tool optical performance detection.

[0037] The above preferred embodiments of the present invention are given as examples, and it is understood that those skilled in the art may make various changes and modifications based on the above description without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content of the specification, but should be determined by the claims.

Claims

1. Step S1: acquiring reference test data data1 of a passing lighting fixture; Step S2 of acquiring actual test data data2 of the lighting fixture under test; Step S3: fitting and comparing the reference test data (data1) and the actual test data (data2) to obtain the initial data position of the actual test data (data2) that best matches the reference test data (data1); Step S4: performing position compensation on the initial data position to obtain a final data position; and step S5 of determining a final luminous intensity value for the lighting fixture under test based on the final data position; Specifically, step S1 of acquiring reference test data DATA1 of the approved lighting fixtures includes the following steps: continuously measuring the reference luminous intensity data of the passed lighting fixture until it reaches a stable state, to obtain a reference luminous intensity decay change curve of the passed lighting fixture; performing a normalization process on the reference luminous intensity decay curve to calculate reference gradient data for each data point on the reference luminous intensity decay curve; and setting the reference gradient data as the reference test data data1.

2. Specifically, step S2 of acquiring actual test data data2 of the lighting fixture under test includes the following steps: continuously measuring the lighting fixture under test to obtain a set of actual luminous intensity data, performing a normalization process on the actual luminous intensity data, and calculating actual gradient data for each data point in the actual luminous intensity data; 2. The method of claim 1, further comprising the step of: setting the actual gradient data as the actual test data data2.

3. The measurement time t is measured continuously until the acceptable lighting fixture is stabilized. １ is at least 30 minutes, and the measurement interval Δt １ is less than 1 second, and the continuous measurement time t ２ is at least 20 seconds, and the measurement interval Δt ２ is the measurement interval Δt of the approved lighting fixture １ 3. The method for compensating for luminosity according to claim 2, wherein:

4. The step of performing normalization on the reference luminous intensity decay change curve includes: The first reference magnitude data obtained [Equation 35] Remove the remaining reference luminosity data [Equation 36] performing a normalization process on the normalization formula: [Equation 37] represents normalized data, n is a positive integer, and 1<n≦L １ and L １ represents the data sum of the reference luminous intensity data, that is, the sum L １ - obtaining one normalized data; Calculating reference gradient data for the normalized data, the calculation formula being: [Equation 38] represents the N-th reference gradient data calculated for the normalized reference data, and 1≦N<L １ 3. The method of claim 2, further comprising the step of:

5. In step S3, the calculation formula for the initial data position is as follows: I think=ndex=arg men(ΔG) ｐ ) where Index represents the time position in the reference luminous intensity decay curve, and ΔG ｐ However, the gradient data change sequence of the actual luminous intensity data G ［Ｌ１／２］ ~G Ｌ１ and the sum of squares of the differences between the reference gradient data sequence of the corresponding length located at position p in the reference luminous intensity data, where p is in the range of 1≦p<L １ -L ２ +1 and L ２ 5. The method of claim 4, wherein: represents a data sum of the actual luminous intensity data.

6. ΔG ｐ The calculation formula is as follows: [Number 39] Here, G Ｍ represents the actual gradient data, and [ ] represents the rounding process. [Equation 40] represents the p+M−1th reference gradient data calculated for the normalized data, where G Ｍ The expression is [Equation 41] where 1≦M<L ２ and [0.001] is the actual luminosity data E ｍ represents the normalized data of [Equation 43] where m is a positive integer and 1<m≦L ２ 6. The light intensity compensation method according to claim 5, wherein:

7. In step S4, the formula for performing position compensation on the initial data position is as follows: Index ｃｏｍｐｅｎ =Index+[a×e ｂ（Δｓ－ｃ） ] Here, a, b, and c are all constants, and Δs represents a variable introduced in luminous intensity compensation, and its expression is as follows: [Equation 44] 7. The luminous intensity compensation method according to claim 6, wherein: represents the Index+mth reference luminous intensity data.

8. Said final data position Index ｃｏｍｐｅｎ After obtaining the above equation, the actual final luminosity value at time T is calculated as follows: [Equation 45] Here, E Ｔ represents the actual luminous intensity value measured at time T of the luminaire under test; [Equation 46] represents the reference luminous intensity data of the approved lighting fixture at time T, [Equation 47] The final data position index of the passed lighting fixture ｃｏｍｐｅｎ represents the reference luminous intensity data at E ｌａｓｔ 8. The luminous intensity compensation method according to claim 7, wherein ∇ represents the actual luminous intensity data obtained in the final measurement in the continuous measurement of the lighting fixture under test.

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