JPS6424342A - Shadow mask type color cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain a high quality image with no color unevenness by composing the surface layer at the electron gun side of a shadow mask with an adiabatic layer, and an electron beam reflection layer made of mainly a specific heavy metal, attached over the adiabatic layer. CONSTITUTION:An adiabatic layer 3 formed on the surface of a shadow mask at the electron gun side is composed of a thin film of a ceramics or the like, and an electron beam reflection layer 8 attached on the adiabatic layer 3 is made of mainly a heavy metal of the atomic number 70 or higher such as bismuth oxide, for example, and formed in the thickness responding to the weight 0.05 to 1mg/cm<2>. As a result, about 60% of the electron beams which cannot pass through permeating holes 7 being cut off by the shadow mask, of the electron beams emitted from the electron gun, is reflected through a reflection layer 8 to the electron gun side and scattered. The majority of the remaining electron beams are converted to the thermal energy in the reflection layer 8, the heat delivered to the shadow mask 6 is reduced at the diabatic layer 3, and the rise of the temperature of the shadow mask is suppressed. In such a way, the quality of the image can be improved.