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The United Nations regulations have made a series of necessary and detailed regulations on the various technical parameters of the light source for car headlights to ensure the safe operation of lighting and signal light devices after replacing the light source. In addition to regulations that describe the general technical requirements for the use of light sources for signal lights and headlight devices, there are also other specific regulations that describe the provisions and related modifications for replaceable LED light sources for front fog lights, adaptive headlights, and various headlight systems. Therefore, using replaceable standardized light sources has many advantages. Compared with other light sources, standardized LED light sources have very detailed specifications including thermal, photometric, colorimetric and other parameters, which will greatly simplify the design work of headlights. Therefore, this article introduces the current situation of simplifying regulations on light sources. The content is divided into four parts:
United Nations regulations on light sources
There are three main regulations regarding light sources, each targeting three different light source technologies:
Regulation No. 37: Incandescent lamps emitting light through thermal radiation
Regulation No. 99: Gas discharge light sources
Regulation No. 128: LED light sources
When gas discharge light sources were used in the field of automotive lighting, Regulation No. 99 was specifically formulated, taking into account the special performance of gas discharge light sources different from incandescent lamps. At the same time, in order to ensure color rendering, a requirement was put forward for the minimum red component of radiated light. The luminous area of a gas discharge light source is not as obvious as that of a thermal radiation light source, so a specific description of the curvature and diffusion of the arc is also necessary.
The introduction of LED light source technology requires additional corresponding regulations. Unlike other light sources, the photometric and colorimetric performance of LEDs mainly depends on the temperature of the crystal, and the variation of light output with applied voltage is completely different from that of thermal radiation light sources. The luminous characteristics of different LED arrangements are different, and the characteristics of the luminous area and the distribution of light intensity need to be classified and explained.
All three regulations ensure the safe operation of lighting and signal light devices after replacing the corresponding light sources.
Simplification of light source regulations by regulations
In order to alleviate the administrative burden caused by regulatory amendments, regulatory authorities hope to reduce the number of lighting regulations.
The ideal goal is to have a regulation that includes all types of lighting devices, aiming to be as technically neutral as possible, with a performance oriented perspective to ensure technological innovation, and without the need to modify existing regulations during technological innovation.
For light sources, it is not practical to simplify all regulations into one regulation due to the complexity of the types and performance mentioned above. But experts have found a way to reduce changes in regulations regarding light sources while promoting technological innovation. In the past, a significant portion of regulatory amendments were limited to the introduction of new light source categories, as product specifications for different types of light sources only included specific parameters for a certain category and did not focus on how to adapt to regulations for other categories.
The new method shrinks the three light source regulations into three parts: management regulations, technical requirements, and testing. The definition of types and categories of light sources has become a part of it, simplifying the process of proposing and introducing new categories in existing technologies.
Regulation No. 128 on LED light sources for headlight systems
Currently, Regulation No. 128 on LED light sources does not include provisions for the application of headlights. The regulations regarding front fog lights and headlights do not provide provisions for the use of LED light sources.
Generally speaking, when a light source is used for headlight function, it needs to meet stricter thermodynamic conditions, larger luminous flux, and stricter geometric constraints compared to a signal lamp. Therefore, experts are further increasing the definition and requirements of LED light sources in Regulation 128 to ensure safe replacement of light sources, even for low beams with the highest beam requirements, to balance maximum visibility and minimum glare as much as possible.
The introduction of thermodynamic classification and thermal stability testing at the maximum allowable temperature can support the optimal performance of headlights under practical application conditions. The selection of light sources with different thermodynamic levels can be used for different applications, such as motorcycle headlights and vehicle front fog lights with lower thermal boundary conditions, and multifunctional vehicle headlights near internal combustion engines with higher thermal boundary loads.
The specific regulations for the contrast and uniformity of the light source emission area can help the headlight design have smaller glare levels and more obvious cutoff lines. Therefore, regulations specify the minimum contrast of LED light sources used for low beam headlights (generally greater than halogen lamps).
The requirement for uniformity reduces the difference in brightness between crystal elements in the emitting area, avoiding the influence of some black spots between crystal elements. In short, the beam quality after replacing the light source will not decrease.
Finally, strict limitations on the color difference of light sources observed from different angles can avoid interference with road users.
The advantages of replaceable light sources
Applying standardized LED light sources in automotive lighting can reduce the complexity of customized headlights and taillights. Based on the experience of integrating thermal radiation light sources and gas discharge light sources, standardized light sources can provide suppliers with greater choice space, promote market development and performance improvement, and bring a more stable, reliable, and competitive supply chain that does not completely rely on technological development. Unlike non standardized and non replaceable light sources or light source modules, the use of replaceable light sources simplifies the design of automotive lighting manufacturers and enables cost-effective replacement of damaged components.
The detailed regulations on all safety related technical parameters ultimately simplify the quality inspection and approval process of vehicle taillights and headlights, while non replaceable light sources or light source modules require additional technical tests for each new model.
That is to say, the use of replaceable light sources and standardized light sources can make more simplified performance oriented vehicle lighting regulations more practical and feasible. |
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