Iterative Learning Control in a Mass Product : Light on Demand in DLP projection systems

The ultra high pressure (UHP) lamp has become the preferred light source for (DLP) projection systems. The application of UHP lamps in rear and front projection systems sets new and more stringent requirements on the quality of the light generated by these lamps. Deviations of the lamp current from the desired current profile translate to unwanted variations of the light output of the lamp, which may lead to annoying color effects in the projected image. To be able to meet the stringent requirements on the current variations, a new iterative learning control (ILC) approach to lamp current control problem has been designed and implemented in the lamp driver. The design, implementation and excellent performance are described in this paper.