Dual paraboloid reflector technology development and the commercialization for projection display

Abstract

One major issue in microdisplay-based projection television has always been the need for more light. Without sufficient amount of light, the screen gain is usually the final parameter that is adjusted to produce acceptable on-axis brightness. As a result, one major disadvantage of rear projection television (RPTV) is narrow viewing angle when compared with other display technologies. Traditional reflector systems, including elliptical and parabolic reflectors, perform well in most cases, but are inefficient for smaller etendue values corresponding to smaller image panels. The common remedy is to make lamps with shorter and shorter arcs to increase the coupling efficiency, but the corresponding lifetime of the lamps are reduced and most of the time, these short arc lamps can only operate at low power, thus limiting the total output of the illuminating system. The Dual Paraboloid reflector (DPR) technology allows the use of higher power lamps while maintaining long life, thus allows wider viewing angles to be achieved. In addition, low power lamps when used with the DPR system allows such a long life operation that lamp replacement is not needed, allowing the RPTV to compete effectively with LCDTV and PDP systems. These advantages are also applicable to front projectors with long life lamps that lower ownership costs.