| 摘要 |
PURPOSE:To improve the quality of a projected picture by forming the angle made by the faceplate and side face of a conductive material on the optical axis side that constitutes a porous mask on the outer surface of a faceplate, so that the rate of a shielding angle can be reduced. CONSTITUTION:A phosphor screen 24 and a metal pack layer 25 are formed on the inner surface of the faceplate 211 of a projection type cathode-ray tube. Simultaneously with this, the adhesion of dirt caused by the charging of the faceplate 211 is prevented and temperature rise is controlled by mounting a glass cover 30 and a frame 27 in which a mesh or lattice type porous mask consisting of conductive materials is formed integratedly on the outer surface of the faceplate. In this case, for the conductive material 281 of the porous mask 28, the angle beta made by the side face of said material 28, on its optical axis side and the faceplate 211 is selected so that the rate of a shielding angle can be reduced. As a result, when a picture is projected on a screen, the optical ununiformity caused by the conductive material 281 can be removed and the good picture can be obtained. |
