Search Results

1 In 2008 the first full LED (LED = Light Emitting Diode) headlamp will arrive to the worlds markets, providing all lighting functions with semiconductor based light emitting devices, LED. The first Full LED headlamp differs in style and technology from other headlamps. Target was to find a face that fulfils the demands of the stylists and also gives the possibility to be assembled, to fulfill customer specs and legal requirements. Fulfilling this, the development showed various intermediate steps. As LED is still a evolving technology, mature and fixed technical solutions were and are not always existing. So technical solutions had to be developed under the constraints of new technology and regarding the existing mechanical and electrical environment in the car.

After about one decade HID headlamps are available on all major market areas. Since the design and manufacturing possibilities have changed in that period, the current light performance will be reviewed in the paper. The market penetration in the three major markets shows obvious differences. The penetration related to car platforms and classes will be discussed. It will be shown that HID headlamps have different penetration level in US, Japan and Europe. Additionally, the future styling development will be evaluated by the technical possiblities given today using reflector/projector type and additional illuminated areas. A future styling trend will be estimated for the three different markets. The future application of HID headlamps in adaptive lighting systems will be analyzed.

The goal of the investigations was to find out if there is a correlation between the luminance distribution on the lens surface of projection type headlamps (e.g. maximum luminance) and the average subjective glare rating (discomfort glare) of subjects under night time traffic conditions. The luminance distributions of different projection type systems are measured with a luminance measurement system and compared concerning their characteristics. For the validation a glare rating experiment has been carried out with a standard type glare source of different size and luminance peaks similar to projection lens luminances. It was found out that for glare peaks up to a diameter of α = 2′ (observation angle) the candle power of the glare source is the proper parameter to calculate the subjective glare effect. For larger sizes of the glare sources there is a dependency to the diameter of the glare source for the glare effect.

In recent years the efficiency of Light Emitting Diodes (LEDs) has increased rapidly. Using red, amber or white LEDs for exterior automobile rear lighting is already state of the art and offers new styling possibilities. Since up to 70 lm / Watt and 150 lm / LED for white LEDs are predicted, they become interesting for headlamp functions like low and high beam. Therefore new styles and technical solutions are feasible. Nevertheless, creating a full LED headlamp is still challenging. New high efficient optical design methods to create front signal functions like daytime running light or turn indicator weather with medium bright LEDs (1 lm to 10 lm per LED) or with high bright LEDs (30 lm to 100 lm per LED) will be discussed. A space optimized full LED headlamp, which fulfills the regulations but consume much less space compared to halogen headlamps will be presented.

The characteristics of the semiconductor based Light Emitting Diodes (LEDs) is completely different to the characteristics of traditional light source used in automotive exterior front lighting systems. The characteristics include not only optical items, but also electrical, mechanical and temperature issues. These characteristics make new approaches in the field of automotive headlamp development necessary. Due to the designer's wishes, the LEDs must be mounted on a 3-dimensional surface with small tolerances to the associated optics. High power LEDs create a lot of heat, so that they have to be assembled with a cooling device. The generated heat should be used for defogging and deicing of the outer lens of the headlamp. Electrical drivers are needed to keep the current through the LED constant. All new technical challenges will lead to more stylistic freedom