| 摘要 |
PURPOSE:To make a lamp suitable for the lighting of a unified six-feet billboard by forming it in a straight tube type with a tube length of 1,650+ or -30mm., a tube outer diameter of 29-35mm. and filled with inactive argon gas with a gas seal pressure of 1.7-3.7 Torr. CONSTITUTION:When a tube outer diameter is made smaller than 29mm. the start voltage of a lamp is increased to make the lighting difficult, and on the contrary when the tube outer diameter exceeds 35mm. the light flux is reduced and also the efficiency is largely lowered. A tube filled with argon is capable of stable lighting even at a low temperature of -10 deg.C and the light flux rise time after the start is also short. When the seal pressure is less than 1.7 Torr the consumption of an emitter material becomes excessive and the lamp life is made extremely short, and when the pressure exceeds 2.7 Torr the tube is not lighted unless applied with a high lamp voltage, thereby a special lighting circuit must be designed and it is disadvantageous for a practical use, and the light flux is reduced and the efficiency is lowered. |
