| 摘要 |
PURPOSE:To secure such a lamp as being small in a sealing part caliber and inexpensively small size for a product as well as excellent in lighting efficiency, by situating a nearly one a half length part of a light emitting tube and another nearly one a half length part where its other end opens, at an almost symmetrical position in relation to a lamp lengthwise axis at a part surrounding an electrode for the light emitting tube. CONSTITUTION:In order to make W and H dimensions of a light emitting tube 3 and its discharge length yet longer, a nearly one a half part 32 following a part 31 and another nearly one a half part 33 having an opening 34 both are made to take such a form as being bent in both directions so as to situate them at a symmetrical position with each other in relation to a lamp lengthwise axis O of the part 31 surrounding an electrode 51 airtightly. One more light emitting tube 3' is made to be entirely the same form. With this constitution, although each of electrodes 51 and 51' is set up at the central part of the lamp lengthwise axis using a flare 2, W and H dimensions can be made to be yet smaller while making each length of these light emitting tubes 3 and 3', determining a practically effective discharge passage, large as compared with a simple U-shaped one. What is more, an opening caliber before sealing an envelope 1 also can be made smaller. |
