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Automotive lamps are essentially the optical transform devices. A light intensity angular distribution from a given light source (filament, HID arc, LED, etc.) is transformed to a desired new light intensity angular distribution namely beam pattern by means of an optical system such as a reflector or lens optics, or a projector module system. There are fundamentally five types of optical transformations occurring in a headlamp optical design: A). Light intensity angular distribution transforms from a light source to a beam pattern that is another fashion of angular distribution via a reflector-optics device. This transform device, sometimes, is referred to as the free-form reflector design; B). Light intensity angular distribution from a light source is transformed to a spatial distribution on a focal plane of an ellipsoidal (or similar) reflector; C).

The studies for headlamp optical design using current available and future projected white LEDs have been conducted. With desires of high performance and compact packaging sizes for both high and low beam headlamps, using LED light sources is a great challenge for the headlamp design optical engineers for light collecting efficiency, beam pattern compression and optical accuracy. Although total lumen flux produced by the LEDs may be comparable to the exiting light sources, e.g., incandescent bulbs, the optical and mechanical characteristics of LEDs may limit the headlamp applications. The paper identifies the etendue concerns and limitations for automotive headlamps when using LED light sources. It provides a guideline for considerations of using LEDs for automotive headlamp applications.

This paper discusses methodologies for the optical design of a High Intensity Discharge (HID) light source reflector optic low beam head lamp which meets visual optical aim (VOA) requirements. Methods of optimizing the gradient of the sharp cut-off required for visual aiming are presented. A merit function with conditional equations is introduced to optimize the design to maximize the gradient, maximize the hot spot, and control glare light. Design results are shown both before and after the design has been optimized.

Utilization of new technologies, such as LEDs, light guides, and electro-luminesence (EL), in courtesy lighting offers promising opportunities in styling, packaging, and functionality. Although these lamps are not as strictly regulated as other automotive lighting, considerable investigation is required to meet the desired styling and performance. In this paper we present the results of a study on running board lighting. This investigation was used to guide development of external courtesy lighting, where direct light, reflected light, contrast, and directionality are all design considerations.

A method of evaluating the uniformity of an illumination pattern of an automotive head lamp on a road surface is presented. The most critical area where the beam pattern uniformity can be identified is the high intensity region. In this area three parameters are used to evaluate beam pattern uniformity, correlation set, contrast level and relative intensity factor gradient. In a low intensity region of the illumination pattern, the same principle can be applied.

The use of Free-Form Reflector (FFR) technology allows the enhancement of performance in fog lamp design, especially where the figure of merit for performance is the sharpness of the cutoff line. However, traditional fog lamp bulbs with transverse filament orientations may not be the most desirable light source to take advantage of FFR technology. Axial filament orientations can have advantages over transverse filament orientations in the design of FFR fog lamps. Also, as front fog lamps have increasingly higher photometric performance levels, they exhibit an increased sensitivity to lamp misaiming and other detrimental lighting conditions. This paper will discuss high performance fog lamp design strategies using FFR technology and proper usage of front fog lamps.