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Proceedings Paper

On the relative efficiency of projection systems with tri-axial ellipsoidal reflectors
Author(s): G. Kloos
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Paper Abstract

Efficiency considerations have direct implications on the performance of a projection headlamp and on its implementation into a car. Therefore, an attempt was made to work out a theoretical basis to gain a better understanding of the underlying parameter dependencies that determine the efficiency of a projection system. Designing a modern headlamp, it seems indispensable to use numerical algorithms to obtain the final design. The reason why this analytical study on the parameter dependence of the relative efficiency has been undertaken is that it provides some insight into the structure of the multidimensional solution space of this multi-parameter problem and gives a straightforward guideline to identify optimum solutions. Another motivation stems from the fact that understanding the influence of systems parameters is of key importance for the design of adaptive illumination systems. The method of analysis combines geometrical considerations, analytical ray tracing and calculus to find an expression for a system consisting of an open tri-axial ellipsoidal reflector and a projection lens. The new integral expression allows, for example, to study the influence of the transversal anisotropy of the tri-axial reflector on the relative efficiency of the system. In addition, the effect of mechanical boundary conditions imposed on the reflector of low symmetry and/or the lens can be considered in detail. From the theoretical point of view, it is advantageous that the integral expression, which has been found, is useful to elucidate the underlying scaling laws.

Paper Details

Date Published: 21 April 2006
PDF: 10 pages
Proc. SPIE 6198, Photonics in the Automobile II, 61980H (21 April 2006); doi: 10.1117/12.662735
Show Author Affiliations
G. Kloos, Hella KGaA Hueck and Co. (Germany)

Published in SPIE Proceedings Vol. 6198:
Photonics in the Automobile II
Patrick P. Meyrueis; Thomas P. Pearsall, Editor(s)

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