We propose an innovative vehicle headlight design based on a highly efficient LED light pipe system. In the system, light rays are emitted from multiple high-power LEDs in front of a total internal reflection (TIR) lens. After passing through the TIR lens, the rays are divided into two beams by a prism splitter, and each beam is guided to each headlamp by a light pipe. We propose the system because it uses fewer LEDs but provides enough lumens and reduces the number of TIR lenses required. Detailed analysis of the system is given, and the simulation results show that the headlamp produces a legal Economic Commission for Europe (ECE) lowbeam pattern, with a total optical efficiency up to 40.2%, when four LED (Lumileds-K2) sources are used.
The major factors of an illuminative environment are a high rendering index and uniformity. The natural light illumination system (NLIS) is used to guide sunlight for indoor illumination. The NLIS consists of three subsystems: collecting, transmitting, and emitting. Nowadays, a variety of light emitters are available for different illuminative environments. This paper proposes a linear microstructure to diffuse parallel light for indoor illumination. To increase uniformity and promote the illuminative area, the light emitter includes two microstructures for the distribution of light. Finally, the proposed light emitter gives illuminance uniformity and efficiency of 0.55% and 74.18%, respectively.
Presently, energy conservation and carbon dioxide emission reduction have become increasingly important because of global warming. Using solar energy, which is considered as one of the most important renewable energy sources, does not only decrease the consumption of fossil fuels, but also slows down the pace of global warming. For indoor illumination, our team has developed a technique called "Natural Light Illumination." Instead of using solar cells, our system directly guides sunlight into the interior of a structure. However, the efficiency of the light-collecting module is still low. To address this problem, we propose a new lightcollecting module based on a prism array structure with high efficiency. We use optical simulation tools to design and simulate the efficiency of the module, which is found to be 57%. This value is higher than that of the original concentrator (i.e., 11%).
this paper presents a novel reflecting freeform surface component which adopts both artificial light and natural light as input, which component is a part of the NLIS (Natural Light Illumination System). The use of reflective elements significantly reduces the thickness of the structure; avoid high cost and installation restrictions. By this design, the illumination has 80.1% of uniformity and 83.82% of efficiency.
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