| 摘要 |
<p>PURPOSE:To obtain the filter for a color information display device which does not darken the video on the display surface of the color information display device and improves a contrast ratio by providing a dyestuff layer having plural dyestuffs which are different in light transmission characteristics. CONSTITUTION:The filter 1 for a CRT is disposed on the front surface of a light emitting surface 2a of a cathode ray tube (CRT) 2 of which the three primary colors used for color display are, for example, red, green and blue. The emission peak wavelengths of the three primary colors are about 630nm red, 530nm green and 450nm blue. The light transmission characteristics of the filter 1 for the CRT are such that the light transmittance is high in the emission peak wavelength region of the three primary colors and the light transmittance is low, i.e. the light absorbability is high in the other wavelength regions. Such light transmission characteristics are obtd. by combining the dyestuff having the characteristic 3 of the high light absorbability at about, for example, 590nm wavelength, prescribed a compounded dyestuff of an anthraquinone system and the dyestuff having the characteristic 4 of the high light absorbability at about 480nm wavelength, for example, a compounded dyestuff of an azo system. The darkening of the video on the display surface is prevented in this way and the contrast ratio is improved.</p> |
