| 摘要 |
PURPOSE:To obtain superior light colour and contrast even under the light of the sun in the daylight by constituting a vacuum outer enclosure from the glass having the colour same to or similar to the phspour used on a cathode-ray tube. CONSTITUTION:To a grid 8, the negative potential for a cathode 7 is applied, and to a heater 6, a prescribed value of current is applied. When the cathode 7 is heated, and the voltage of the grid 8 increases close to the potential of the cathode 7, electron beam 10 is irradiated towards a fluorescent surface 2 from the cathode 7. The electron beam 10 forms nonconvegence beam having a fixed spread due to a variety of conditions such as the diameter of the opening 9 of the grid 8, the distance between the grid 8 and the cathode 7, and the voltage of the anode, and is irradiated onto the fluorescent surface 8. A face glass 3a is constituted of the glass having the colour same to or similar to the phosphor used. |
