Fig. 1. Test points for low beam in ECE R112 regulation.
Fig. 3. Optical structure of a vehicle headlamp.
Fig. 8. Comparison between spectrums: (a) LED source spectrum, (b) Projected beam spectrum on cut-off line.
Fig. 9. Effects of difference and balance of the exit ray angle with wavelength.
Fig. 10. Exit ray angles with wavelength at various tilted angles of aspheric lens surface.
Fig. 11. Changes of ray bending by tilted surface of an aspheric lens.
Fig. 12. Layouts of headlamp: (a) Conventional single lens of plano-convex, (b) New single lens of tilted plano-convex.
Fig. 13. Measurement positions of cut-off line quality.
Fig. 14. Simulation results for color aberration induced by each aspheric lens: (a) Conventional lens of plano-convex, (b) New lens of tilted plano-convex.
Fig. 15. Positions having intensity more than 200 cd are marked as black dot points in CIE 1931 chromaticity diagram. Among them, color aberrations exist at the points outside the white light zone: (a) Conventional headlamp with plano-convex lens, (b) New headlamp with tilted plano-convex lens.
Fig. 16. Comparison of color aberrations on cut-off line at various projected distances: (a) Conventional headlamp with plano-convex lens, (b) New headlamp with tilted plano-convex lens.
Fig. 2. Various type headlamps: (a) Reflector type, (b) Projector type.
Fig. 5. Layout for evaluation of color aberration in a headlamp.
Fig. 6. (a) Layout of a headlamp with PC aspheric lens, (b) Exit ray angles with wavelength at exit pupil.
Fig. 7. (a) Headlamp beam pattern, (b) Color aberration on cut-off line.
Fig. 4. Color aberration on cut-off line, induced by upper and lower sections of the lens.
Table 1. Required intensity of ECE R112 regulation at several test points
Table 2. Differences and balances of the exit ray angles at various tilted angles of aspheric lens surface (in degree)
Table 3. Comparison of the angular positions having color aberrations between two headlamps
Table 4. Simulated results in comparison with the requirements of the ECE R112 regulation
References
- United Nations Economic Commission for Europe vehicle regulations, ECE Regulation No. 112-Rev. 3 (2013).
- M. Sivak, M. J. Flammagan, B. Schoettle, and G. Adachi, "Chromatic aberrations near the cutoff of low-beam headlamps," Report No. UMTRI-2004-6 (2004).
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- R. Melikov, Master's Thesis, Koc University, Istanbul (2016), p. 25.