DVN was given a first sneak preview first of the world’s first goniophotometric system for assessing and characterising the performance of lights as installed on vehicles. It was at LMT in Berlin, where an extensive red-brick factory complex dating from the 1900s—one of Osram’s very first lamp factories, is LMT’s headquarters and the premises of an inconspicuous warehouse. Upon entering the warehouse, once one’s eyes adjust to the darkness comes the wow effect: An ultra high-tech light testing hall under darkroom conditions, at least 8 m high and 35 m long; a BMW 3 series placed on rotating-table, 6m in diameter with built-in road spurs, at a height of about one metre. In the corner there’s a mock-up vehicle with fixing points for many headlamps and 4 wheels which do not touch the ground. In the far distance a measuring screen covers the entire wall—the only reflective surface in the hall; at the right edge of the screen towers a linear axis thicker than an I-beam, at least 8 metres high.
A carriage mounted to the oversize I-beam moves slowly up and down, making that distinctive LMT goniophotometer sound.
During our visit LMT’s top specialists were finalising a new goniophotometric test stand to measure the light intensity distribution of headlamps as installed on the vehicle. This is a completely new principle of measurement for vehicle lighting. LMT have branded the system VELAS®, short for Vehicle Lighting Assessment System. One is reminded of the Spanish “Vela” which means “candle”, candela being the SI unit for photometry related measurements.
Taking a closer look, the rotating table is in fact a precision goniometer able to handle even the largest of vehicles. Light distributions projected onto the screen by the vehicle are photo-stitched in a rapid fashion with the help of a Technoteam luminance camera, or scanned directly at 25 metres by an LMT photometer head mounted to the carriage of the 8m vertical axis. The exact position of car and headlamps on the turn table is crucial and is measured precisely before the lighting tests can start. The mock-up near the entrance is the “dummy” or reference vehicle used as a calibration system for both cars and headlamps. The lab enables headlamp performance assessment based on the CIE TC4-45 or any other such specification.
Overall, the system is an impressive piece of technology in service to the push for performance-based standards for vehicle-integrated lighting systems, and it is further evidence of the rapid pace of innovation we continue to witness in the vehicle lighting industry. We look eagerly forward to a presentation of the complete system at one of the next DVN Workshops.