| 摘要 |
PURPOSE:To remove chromatic aberration on a screen and improve resolution by coloring the front glass of a projection type cathode-ray tube and absorbing the light with the wavelengths other than desired wavelength out of various sorts of the light emitted from a phosphor. CONSTITUTION:The front glass 2' of a projection type cathode-ray tube 1' for green is a colored front glass with the transmission factor which depends on wavelengths shown in the figure. When the projection type cathode-ray tube 1' with such a front glass 2' and a projection type lens are used, green (shown by a dotted line in the figure) has almost the bright distribution shown by a solid line after it passes through the front glass 2'. That is to say, the brightness of the luminous colors that correspond to approximately 480nm, 580nm, and 120nm, respectively is reduced to less than half and, as a result, an image whose apparent chromatic aberration is improved can be obtained on a screen. In addition, the same effect can be obtained if the same means is used also with regard to the front glass of red and blue projection type cathode-ray tubes as required. |
