Advanced UHP lamps for projection systems

TLDR: In this paper, a UHP lamp with a UV-enhancer cavity in the lamp seal and an additional antenna was used to reduce the ignition voltage from 20 kV to 5 kV.

Abstract: Projection systems for large screens have made tremendous progress during the last years, both in terms of performance and size reduction. Improved UHP lamp systems made a major contribution to enable the new generation of projectors. The arc gap is reduced to 1 mm only and allows a high collection efficiency in the projector. At the same time the lamp wattage was increased. In this way, today's projectors can create high-quality XGA pictures with more than 3000 screen lumens using one single 200 W UHP-lamp. Such a projector reaches an efficiency of more than 10 screen lumens per watt electrical input power. The volume of lamp and driver has been reduced by one order of magnitude during the last six years. This was possible by recent progress that has been achieved on the ignition of the lamp. By using a UV-enhancer cavity in the lamp seal and an additional antenna the ignition voltage could be reduced from 20 kV to below 5 kV. This allows more compact drivers and is ideal for miniaturizing projectors. A new optical concept allows for extremely compact reflector systems: A dichroic coating applied to one half of the UHP burner focuses all light into one hemisphere. Additionally 20-30% more light can be collected in systems with high optical demands. Making use of both the reduced ignition voltage and the new optical concept a reduction of the volume of lamp and driver by a factor of 10 has been realized.