| 摘要 |
PURPOSE:To obtain a good contrast of a picture and to decrease an amount of electron beam by specifying to a given value light transmittance of a bulb front wall of a picture tube. CONSTITUTION:A front wall 1 having a phosphor film 2, of a bulb of a picture tube comprising glass is formed by specifying its light transmittance to a range of 17-20%. A ratio of an emission 5 from a light spot 4 formed on a phosphor film 2 by collision of an electron beam to reflection lights 7, 8 of an external light 6 arrived on the front wall 1 forms a contrast. The contrast is improved by making the light transmittance of the front wall appropriate to obtain a picture which does not tax syes, and a high resolution by reducing an amount of electron beam. |
