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Previous work has shown it is possible to automatically optimize both directional pointing of light and its spatial distribution along light guide luminaires using prismatic light extraction elements.
In addition to aiming light in the right direction(s), it is increasingly important that lamps are efficient. This is particularly true for electric vehicles, but it is generally important for reducing carbon emissions throughout automotive lighting. Since lamp test specifications are typically defined in terms of intensity test point requirements, it follows that an efficient design must approximate the overall distribution of the test point pattern. At the same time, a good lamp design should not sacrifice visual appearance for the sake of efficiency.
As illustrated in previous work, when using prismatic extractors, one can point the centroid (average flux weighted direction of rays) in a desired direction(s). However, this does not always result in a high-efficiency system, nor does it guarantee alignment of the peak of the distribution with any specific direction (e.g. the test point pattern’s peak value). In some cases, it may also be desirable to change the appearance of the extractors themselves as viewed by an observer looking back at the lamp.
In this work, we extend our optimization approach for light guide-based automotive lamps to include optimization of efficiency, particularly useful in electric vehicle applications. Specifically, we consider specialized aiming and tailoring of the lamp’s intensity distribution to better match the desired test point pattern; thereby increasing lamp efficiency. At the same time, we also consider visual appearance.
To achieve better efficiency and visual appearance, we consider some different techniques to modify the light distributions. Some examples of ways to modify the distribution are: strategic use of fillets, prism face curvature, sharpness (Bezier) weighting factors, distributed prism aiming, and laser-etched surface texture solutions.
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