Method for operating a vehicle lighting device and vehicle lighting device
By providing differentiated current profiles and intelligent current control for different lamp modules in automotive lighting equipment, the thermal difference problem in solid-state light source temperature management is solved, achieving uniformity and thermal stability of light source performance and reducing power consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- VALEO VISION SA
- Filing Date
- 2021-11-22
- Publication Date
- 2026-06-26
AI Technical Summary
In existing automotive lighting equipment, it is difficult to effectively manage the thermal differences between modules while maintaining the uniformity of light source performance, resulting in performance degradation and excessive derating.
By providing differentiated current profiles for different lamp modules in automotive lighting equipment, extending the derating time of high-temperature modules, optimizing current control using machine learning and ridge regression algorithms, and combining temperature and time conditions for intelligent management.
This approach achieves the goal of maintaining luminous flux uniformity while extending the overall derating time of lighting equipment, improving the thermal stability and performance of the light source, and reducing power consumption.
Smart Images
Figure CN116584153B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automotive lighting equipment, and more specifically, to temperature control of light sources included in these devices. Background Technology
[0002] Automakers are increasingly using digital lighting equipment in their mid-to-high-end products.
[0003] These digital lighting devices typically include solid-state light sources, whose operation is largely dependent on temperature.
[0004] Temperature control in these components is a highly sensitive aspect and is typically implemented through derating, which means reducing the current supplied to the light source, thereby correspondingly reducing the output flux and operating temperature. This necessitates that the light source's performance be significantly larger (in size) to cope with these overheating issues, thus allowing for reduced operating values while maintaining acceptable levels.
[0005] It is difficult to maintain optimal headlight performance under all driving conditions. Often, one lighting module heats up faster than others, thus negatively impacting the remaining modules due to the high internal temperature of the HL. This phenomenon is not optimal because when one lamp module is dated, other modules are also affected to ensure acceptable uniformity, even though they have not yet reached the derating threshold. Summary of the Invention
[0006] This problem has been assumed until now, but therefore a solution is provided.
[0007] This invention provides an alternative solution for managing the temperature of the light source of an automotive lighting device using a method and an automotive lighting device according to the invention. Preferred embodiments of the invention are defined in the dependent claims.
[0008] Unless otherwise defined, all terms used herein (including technical and scientific terms) should be interpreted as those commonly used in the field. It should be further understood that general terms should also be interpreted as those commonly used in the relevant field, rather than idealized or overly formal, unless explicitly defined herein.
[0009] In this text, the term “including” and its derivatives (such as “contains”, etc.) should not be construed as having an exclusionary meaning; that is, these terms should not be interpreted as excluding the possibility that the content described and defined may include other elements, steps, etc.
[0010] In a first aspect, the present invention provides a method for operating an automotive lighting device, the automotive lighting device comprising at least a first lamp module and a second lamp module, each lamp module comprising a solid-state light source, the method comprising the following steps:
[0011] - Provide a first preliminary current profile to feed the first lamp module, the first preliminary current profile having a first average flux value;
[0012] - Estimate the first initial derating time associated with the first initial current curve;
[0013] - Provide a second preliminary current profile to feed the second lamp module, the second preliminary current profile having a second flux average value;
[0014] - Estimate the second initial derating time associated with the second initial current curve, which is longer than the first initial derating time;
[0015] - Feeding a first current profile to the first lamp module, the first current profile providing a flux average value that is 0.96 times lower than the first flux average value; and
[0016] - A second current curve is fed to the second lamp module, which provides a flux average that is 1.04 times higher than the second flux average.
[0017] The fact that the calculated second preliminary derating time is higher than the first preliminary derating time means that the two lamp modules calculate the preliminary derating time, and the first lamp module is the lamp module with the lower derating time, while the second lamp module is the lamp module with the higher derating time.
[0018] In existing technologies, the initial derating time of the first module jeopardizes the performance of the entire lighting system because it causes the second lighting module to drate, even though the second module does not require derating. However, in the method of this invention, the derating time of the second lamp module is shorter than the second initial derating time, thereby increasing the derating time of the first lamp module. Therefore, the overall derating time is extended, resulting in good performance over a longer period of time while maintaining flux uniformity.
[0019] The large variation in the height of the current curve can compensate for differences in the derating time of the lamp modules. This method is particularly advantageous when the differences between the estimated derating times are significant.
[0020] In some specific embodiments, the first current curve and the second current curve include a current value starting from a first current value and increasing the current value when a predetermined condition is met.
[0021] In this way, the first and second current curves are optimized to provide the minimum required current at each moment, and have the ability to increase the current when needed.
[0022] In some specific embodiments, the step of obtaining the first current value is performed using a machine learning algorithm that obtains information from vehicle sensors.
[0023] Machine learning algorithms acquire information from different sensors in the vehicle and are trained and tested under different conditions to obtain the maximum derating time for less favorable lamp modules.
[0024] This machine learning algorithm can be located in the cloud or embedded in the vehicle's control unit.
[0025] In some specific embodiments, the vehicle sensors include at least some of temperature sensors, vehicle speed sensors, geolocation sensors, and radar or lidar sensors.
[0026] In some specific embodiments, the predetermined condition includes the fact that the measured luminous flux value drops below the corresponding flux threshold.
[0027] Luminous flux is an important parameter, but it is not the only parameter that provides information about the operation of lighting equipment. By controlling the current value through luminous flux, the overall acceptable operation of the lighting modules is ensured.
[0028] In some specific embodiments, the method further includes the step of obtaining the temperature of the light source, wherein the predetermined condition includes the fact that the temperature of the light source reaches a predetermined value.
[0029] A different but compatible way to control the current is through temperature, which can provide indirect data on luminous flux.
[0030] In some specific embodiments, the predetermined condition includes the fact that a time limit has been reached.
[0031] Another method for controlling the current is to estimate the temperature evolution over time using only a timer. In these cases, no data measurement is required, and the current increases automatically. This can be done once a time pattern has been firmly established.
[0032] In some specific embodiments, the step of increasing the current value includes increasing the current value from a first value to a second value, the second value being greater than the first value but less than 1.1 times the first value, specifically less than 1.05 times the first value, and specifically less than 1.03 times the first value.
[0033] In these examples, the current can be increased within a small range so that the current value (and temperature) remains as low as possible while providing acceptable performance.
[0034] In some specific embodiments, the method further includes the step of recording a sequence of current value increments under predetermined conditions.
[0035] This sequence could be useful if a time-based model is used to avoid continuous temperature measurements.
[0036] In some specific embodiments, the first lamp module is a low beam module, and the second lamp module is a high beam module. This has some synergistic effect because the low beam module and the high beam module sometimes operate simultaneously.
[0037] In some specific embodiments, the steps of the method are applied to at least 10% of the light source of the corresponding lamp module.
[0038] Gradual increases in current can be applied simultaneously to a large number of light sources, for example, all light sources providing a predetermined function. Therefore, energy efficiency and uniform performance can be applied to a wide range of components.
[0039] In some specific embodiments, the method further includes the step of obtaining the temperature of the light source, and triggering the remaining steps of the method when the temperature of the light source reaches a predetermined value.
[0040] The system does not need to continuously monitor temperature and derating time. Establishing a temperature threshold helps the system relax more and reduces power consumption.
[0041] In some specific embodiments, the first current profile provides a flux average value that is 0.94 times lower than the first flux average value, and more particularly, provides a flux average value that is 0.91 times lower than the first flux average value. Conversely, the second current profile provides a flux average value that is 1.06 times higher than the second flux average value, and more particularly, provides a flux average value that is 1.09 times higher than the first flux average value.
[0042] Using these values, which in some cases may compromise the uniformity of the projected light pattern, surprisingly good derating time results were obtained. In some cases, thermal stability can be achieved.
[0043] In some specific embodiments, an artificial intelligence algorithm is used to perform the estimation of a first preliminary depreciation time and / or a second preliminary depreciation time, the AI algorithm having been previously trained on a training dataset. In some specific embodiments, the AI algorithm includes a question tree structure with questions, such that the answer to the question provides a final score, which is converted into a depreciation time value.
[0044] These methods use a training dataset, which is a set of experimental data with different parameters, such as temperature measurements (from thermistors installed around the lighting equipment, external temperature, estimated temperature, etc.), vehicle speed, road conditions, weather, day / night, other active lighting functions, thermal control parameters (LED dimming, derating of other modules, fan speed), and physical headlight parameters. These values are correlated with experimentally known values of derating time. The control unit is taught to use the provided parameters to accurately estimate the derating time, ensuring that the estimate of the actual derating time is as accurate as possible when faced with real-world conditions.
[0045] In some specific embodiments, the artificial intelligence algorithm includes the ridge regression algorithm.
[0046] The use of ridge regression is advantageous because the data used in this method exhibits multicollinearity: there is a direct correlation between the behavior of some parameters used in the method, such as the activated lighting function, duration, and temperature measurements of each module. Furthermore, the heat in one lamp module directly affects the temperature evolution of other lamp modules. In some cases, lighting patterns are constructed using different modules, so the derating of the lighting function depends on the derating time of different modules. When multicollinearity occurs, least squares estimates are unbiased, but their variance is large, which can introduce very high estimation (prediction) errors. Ridge regression allows for the addition of a degree of bias to the regression estimates, which reduces the standard error.
[0047] In some specific embodiments, the steps of feeding the first current curve to the first lamp module and feeding the second current curve to the second lamp module are not performed simultaneously. Instead, the feeding of the first current curve is performed first, and then the feeding of the second current curve is performed after a certain time interval.
[0048] This helps to achieve a better derating time because the operation of increasing the current is delayed until it is necessary.
[0049] In a second aspect, the present invention provides an automotive lighting device, comprising:
[0050] - First lamp module, which includes multiple solid-state light sources;
[0051] - A second lamp module, which includes multiple solid-state light sources; and
[0052] - A control element for performing the steps of the method according to the first aspect of the invention.
[0053] The term "solid-state" refers to the light emitted by solid-state electroluminescent materials, which use semiconductors to convert electricity into light. Compared to incandescent bulbs, solid-state lighting produces visible light with less heat generation and less energy dissipation. The typically small mass of solid-state electronic lighting devices provides greater shock and vibration resistance compared to fragile glass tubes / bulbs and thin filaments. They also eliminate filament evaporation, potentially increasing the lifespan of the lighting device. Some examples of these types of lighting involve using semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), or polymer light-emitting diodes (PLEDs) as the light source, rather than an electric filament, plasma, or gas.
[0054] This lighting equipment provides a useful function for effectively managing the performance of the light source.
[0055] In some specific embodiments, the automotive lighting device also includes a thermistor for measuring the temperature of the solid-state light source. Attached Figure Description
[0056] [ Figure 1 A general perspective view of an automotive lighting device according to the present invention is shown;
[0057] [ Figure 2 The diagram illustrates the standard operation of two lamp modules of a lighting device when the method according to the invention is not applied.
[0058] [ Figure 3 The diagram illustrates the evolution of the flux-temperature curves for the first and second modules when operated according to the method according to the invention.
[0059] [ Figure 4 [This shows the result of...] Figure 3 The effect of temperature over time produced by the method described in the paper.
[0060] [ Figure 5 This illustrates a specific example of how to train and test a system.
[0061] The following reference numerals are used in these figures:
[0062] 1 First Light Module
[0063] 2 Second Light Module
[0064] 3LED
[0065] 4. Control Components
[0066] 5. Thermistor
[0067] 6 Temperature threshold
[0068] 7 Temperature trigger value
[0069] 10 Lighting equipment
[0070] 11 First Preliminary Curve of Module 1
[0071] 11' Curve of the invention of the first module
[0072] 12. First Preliminary Curve of Module Two
[0073] The curve of the invention of the second module 12'
[0074] 13 First Preliminary Current Curve
[0075] 14 First modified current curve
[0076] 21. First Preliminary Derating Temperature of Module 1
[0077] Derating time of the invention of the 21' first lamp module
[0078] 22 The second preliminary derating temperature of the second module
[0079] Derating time of the invention of the 22' second lamp module
[0080] 23 Second Preliminary Current Curve
[0081] 24 Second Modified Current Curve
[0082] 100 Auto Detailed Implementation
[0083] Example embodiments are described in sufficient detail to enable those skilled in the art to implement and realize the systems and processes described herein. It is important to understand that embodiments may be provided in many alternative forms and should not be construed as limited to the examples described herein.
[0084] Therefore, while embodiments may be modified in various ways and take various alternative forms, specific embodiments are shown in the accompanying drawings and described in detail below as examples. There is no intention to limit oneself to the particular forms disclosed. Rather, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included.
[0085] Figure 1 A general perspective view of an automotive lighting device according to the present invention is shown.
[0086] This lighting device 10 is installed in the vehicle 100 and includes:
[0087] - First light module 1, which includes multiple LEDs 3;
[0088] - Second light module 2, which includes multiple LEDs 3;
[0089] -Control element 4;
[0090] - Multiple thermistors 5, which are used to measure the temperature in different parts of the first lamp module and the second lamp module.
[0091] Each lamp module is a high-resolution module with a resolution greater than 2000 pixels. However, there are no restrictions on the technology used to produce the projection modules.
[0092] A first example of this matrix configuration includes a monolithic source. This monolithic source comprises a matrix of monolithic electroluminescent elements arranged in multiple columns and multiple rows. In the monolithic matrix, the electroluminescent elements can be grown from a common substrate and can be selectively activated individually or in subsets via electrical connections. The substrate can be made primarily of semiconductor material. The substrate can include one or more other materials, such as non-semiconductors (metals and insulators). Thus, each electroluminescent element / group can form a light pixel and therefore emit light when its(one) material(s) is powered. This monolithic matrix configuration allows for the selectively activated arrangement of pixels that are very close to each other, compared to conventional light-emitting diodes intended to be soldered onto a printed circuit board. The monolithic matrix can include electroluminescent elements whose principal height dimension, measured perpendicular to the common substrate, is substantially equal to 1 micrometer.
[0093] The monolithic matrix is coupled to a control center to control the generation and / or projection of pixelated beams via the matrix arrangement. The control center is thus able to individually control the light emission of each pixel in the matrix arrangement.
[0094] Alternatively, the matrix arrangement may include a main light source coupled to the mirror matrix. Thus, the pixelated light source is formed by a combination of at least one main light source (formed by at least one light-emitting diode) and an array of optoelectronic elements, such as a micromirror matrix, also abbreviated as DMD, meaning "digital micromirror device," which guides the light from the primary light source to the projection optics by reflecting it. Where appropriate, auxiliary optics may collect the light from at least one light source for focusing and guiding it onto the surface of the micromirror array.
[0095] Each micromirror can pivot between two fixed positions: a first position where light is reflected towards the projection optics, and a second position where light is reflected in a direction different from the projection optics. For all micromirrors, these two fixed positions are oriented in the same manner and, relative to the reference plane supporting the micromirror matrix, form the characteristic angle of the matrix of micromirrors as defined in its specification. Such angles are typically less than 20° and can be approximately 12°. Thus, each micromirror that reflects a portion of the light beam incident on the micromirror matrix forms the base emitter of the pixelated light source. The actuation and control of changing the position of the mirrors to selectively activate this base emitter to emit or not emit the base beam are controlled by a control center.
[0096] In various embodiments, the matrix arrangement may include a scanning laser system in which a laser source emits a laser beam toward a scanning element configured to probe a surface of a wavelength converter with the laser beam. An image of this surface is captured by projection optics.
[0097] The scanning element can be probed at a sufficiently high speed so that the human eye will not perceive any displacement in the projected image.
[0098] Synchronous control of the laser source illumination and the scanning motion of the beam enables the generation of a matrix of base emitters that can be selectively activated at the surface of the wavelength converter element. The scanning device can be a moving micromirror that scans the surface of the wavelength converter element by reflecting the laser beam. The micromirrors mentioned as scanning devices are, for example, of the MEMS (Micro-Electro-Mechanical Systems) type. However, the invention is not limited to this type of scanning device, and other types of scanning devices can be used, such as a series of mirrors arranged on a rotating element, the rotation of which causes the laser beam to scan the propagation / transmission surface.
[0099] In another variation, the light source can be complex and includes at least one segment of a lamp element (e.g., a light-emitting diode) and a surface portion of a monolithic light source.
[0100] Because a large number of light sources are located very close to each other, thermal control is crucial to ensuring good performance and efficiency.
[0101] Figure 2 A schematic diagram of the standard operation of two lamp modules of a lighting device when the method according to the invention is not applied is shown.
[0102] According to the graph, the first lamp module follows the first curve 11, and its temperature increases over time. When the first initial derating time 21 is reached, the first lamp module reaches the maximum temperature threshold 6 and needs to be dated to avoid damage.
[0103] Similarly, if installed alone, the second lamp module will follow the second curve 12, with its temperature increasing over time. When the second initial derating time 22 is reached, the second lamp module will have reached the maximum temperature threshold 6 and will need to be dated to avoid damage. In fact, since the second lamp module is installed alongside the first lamp module, which has a lower derating time, the second lamp module will need to be dated at the first initial derating time, which occurs before the second initial derating time, to ensure beam uniformity and comply with the rule that the high beam module cannot be used without operating the low beam module.
[0104] Figure 3 The evolution of the flux-temperature curves of the first and second modules is shown when operated according to the method according to the invention.
[0105] The first module follows the initial current curve 13, but when the predetermined temperature 7 is reached in the first lamp module, the method of the present invention is triggered, and the first initial derating time is estimated. Figure 5 The text describes specific examples of such estimations.
[0106] Furthermore, the second module follows the initial current curve 23, and when the method is triggered, the second initial derating time is estimated in the same way.
[0107] In real-world scenarios, modules with a longer initial depreciation time will be considered as second-lamp modules.
[0108] When the method is triggered, the current curve of the first lamp module is switched to current curve 14, which provides a flux average value that is 0.9 times the flux average value of the first lamp module before the method is triggered. Then, the current curve of the second lamp module is switched to current curve 24, which provides a flux average value that is 1.1 times the flux average value of the second lamp module before the method is triggered.
[0109] In some cases, the current curve in the first module is reduced first, and then the current curve in the second module is increased when the total flux of the optical pattern reaches a low threshold as specified. In this case, even the derating time is improved.
[0110] These changes negatively impact the uniformity of the final light pattern, but they are implemented to maintain the total luminous flux, which is thus preserved. This significant current reduction greatly increases the derating time of the second module, sometimes achieving thermal stability.
[0111] In this figure, it can be observed that the current curve does not represent a constant current value, but rather exhibits minute variations. A reference value is chosen, and then the intensity may be slightly increased to maintain the average flux value that satisfies the conditions described above.
[0112] Figure 4 It shows the result of Figure 3 The effect of temperature over time produced by the method described in the paper.
[0113] The figure shows the temperature of the two lamp modules over time. The upper part of the figure shows the evolution of the first lamp module. If no decision is made, such as... Figure 2 As shown, the first curve 11 will provide the first depreciation time 21, and the second curve 12 will provide the depreciation time 22.
[0114] However, due to the decision to increase and decrease the average flux in the lighting modules, the first module does not follow the first curve 11, but follows the modified curve 11', and the second module does not follow the second curve 12, but follows the modified curve 12'. The first module does not reach the temperature threshold 6 at the first derating time 21, but reaches the temperature threshold 6 at the modified derating time 21', and the second module does not reach the temperature threshold 6 at the second derating time 22, but reaches the temperature threshold 6 at the modified derating time 22'. Since the derating time of the global function is lower between the first and second derating times, the first derating time, which is always lower than the second derating time, will determine the derating time of the lighting function. Since it has been improved from the first derating time 21 to the modified derating time 21', the derating time of the global lighting function has been improved.
[0115] Figure 5 This illustrates a specific example of how to train and test the system. Different examples with different training datasets are provided. Each example includes a typical driving session in which various parameters are measured over time: temperature measurements (from thermistors installed around the lighting equipment, outside temperature, estimated temperature, etc.), vehicle speed, road conditions, weather, day / night, other active lighting functions, thermal control parameters (LED dimming, derating of other modules, fan speed), and physical headlight parameters. Each of these datasets is associated with known experimental values of derating time. These values are fed into the system, and the control unit estimates the derating time. The estimated derating time is compared to the experimental values to calculate the error.
[0116] Therefore, each training dataset is associated with an error value. Then, due to the multicollinearity of the different values and parameters, a ridge regression algorithm is used to create a supervision rule, which feeds information to the control unit to improve the derating time estimation.
Claims
1. A method for operating an automotive lighting device (10), the automotive lighting device comprising at least a first lamp module (1) and a second lamp module (2), each of the lamp modules comprising a solid-state light source (3), the method comprising the following steps: - Provide a first preliminary current curve (11) to feed the first lamp module (1), the first preliminary current curve (11) having a first flux average value; - Estimate the first initial derating time (21) associated with the first initial current curve (11); - A second preliminary current curve (12) is provided to feed the second lamp module (2), the second preliminary current curve (12) having a second flux average value; - Estimate the second preliminary derating time (22) associated with the second preliminary current curve, the second preliminary derating time (22) being longer than the first preliminary derating time (21); - Feeding a first current curve (11') to the first lamp module (1), the first current curve providing a flux average value that is 0.96 times lower than the first flux average value; and - A second current curve (12') is fed to the second lamp module (2), the second current curve providing a flux average value that is 1.04 times higher than the second flux average value. The first current curve (11') and the second current curve (12') include a current value starting from a first current value and increasing the current value when a predetermined condition is met.
2. The method according to claim 1, wherein, The step of obtaining the first current value is performed using a machine learning algorithm that obtains information from vehicle sensors.
3. The method according to any one of claims 1-2, further comprising the step of obtaining the temperature of the light source, wherein, The predetermined condition includes the fact that the temperature of the light source reaches a predetermined value.
4. The method according to any one of claims 1-2, wherein, The first current curve (11') provides a flux average that is 0.94 times lower than the first flux average.
5. The method according to any one of claims 1-2, wherein, The second current curve (12') provides a flux average that is 1.06 times higher than the second flux average.
6. The method according to any one of claims 1-2, wherein, An artificial intelligence algorithm is used to perform the estimation of the first preliminary depreciation time and / or the second preliminary depreciation time, the artificial intelligence algorithm having been previously trained with a training dataset.
7. The method according to claim 6, wherein, The artificial intelligence algorithm mentioned includes the ridge regression algorithm.
8. The method according to any one of claims 1-2, wherein, The steps of feeding the first current curve (11') to the first lamp module (1) and feeding the second current curve (12') to the second lamp module (2) are not performed simultaneously. Instead, the feeding of the first current curve is performed first, and then the feeding of the second current curve is performed after a certain time interval.
9. The method according to any one of claims 1-2, wherein, The first lamp module is a low beam module, and the second lamp module is a high beam module.
10. The method according to any one of claims 1-2, wherein, The steps of the method are applied to at least 10% of the light source of the corresponding lamp module.
11. The method according to claim 4, wherein, The first current curve (11') provides a flux average that is 0.91 times lower than the first flux average.
12. The method according to claim 5, wherein, The second current curve (12') provides a flux average that is 1.09 times higher than the second flux average.
13. An automotive lighting device, comprising: - First lamp module (1), the first lamp module includes multiple solid-state light sources (3); - Second lamp module (2), the second lamp module includes multiple solid-state light sources (3); and - Control element (4), said control element being used to perform the steps of the method according to any one of claims 1-12.
14. The automotive lighting device according to claim 13 further includes a thermistor (5) for measuring the temperature of the solid-state light source.