PROJECTING UNIT FOR LARGE PICTURE PROJECTION

摘要

Projecting units for large picture projection are known which operate in accordance with the principle of modulation of polarised light. In light valves for picture modulation of the polarised light passing through, the necessary polariser in most cases consists of a polarisation foil, as a result of which only a maximum of 50% of the incident light can be utilised. According to the invention, an interference-type polariser, which provides for almost loss-free polarisation of the incident light, is used as replacement for this polarisation foil. Due to the special design of the interference-type polariser, the necessary volumes of the modules of the interference-type polariser and also of adjacent elements such as mirror, condenser and IR/UV absorption filter are minimised. Due to the special design with IR and UV-transmitting mirror, a large proportion of the thermal radiation is already filtered out at the interference-type polariser.