| 摘要 |
PURPOSE:To obtain the titled device of excellent efficiency having filament electrodes whereby the series resistance becomes the minimum value by specifying the relation of the width, height and pitch of said electrode. CONSTITUTION:It is contrived that the ratio of the width of a filament electrode 7 to its height is in the range of 1:5-1:1.5 and that the aperture rate on the first plane and the pitches of a plurality of said electrodes 7 are in the range between the curve AB and the curve CD. In this case, when the height is made to exceed 150% of the width, a photoetching process performed at the time of forming said electrode becomes difficult, when the height is made less than 50% of the width, the series resistance becomes large. In other words, values in the range between the curve AB and the curve CD give the best series resistance minimum value. |
