| 摘要 |
<p>PURPOSE:To improve the fidelity of color reproducibility by correcting the green primary color x,y chromaticity coordinates of an NTSC standard by the wavelength selection characteristic of dichroic coating, and in the case of a high definition television signal, inserting a dichroic filter into the optical system of the projection lens of a green monochromatic light emission and projection tube so as to reduce deviation from the green primary color x,y chromaticity coordinates. CONSTITUTION:The dichroic coating of the short wavelength passing characteristic of cut-off wavelength lambda1 is applied to the projection lens 2 of the green monochromatic light emission and projection tube 1. Further, the dichroic filter 3 of the long wavelength passing characteristic of the cut-off wavelength lambda2 is fitted to the tip part of the projection lens 2 of the projection tube 1 in freely attachable and detachable construction. This filter 3 is changed from a position f1 at the time of the input of the high definition television signal to the position f2 in the case of the input of an NTSC signal. Then, the green primary color x,y coordinates CNTS of the NTSC standard is corrected by the wavelength selectivity of the lens 2, and in the case of the high definition television signal, the dichroic filter is inserted into the optical system of the projection lens 2 so as to reduce the deviation from the green primary color chromaticity coordinates.</p> |
