| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a light-emitting tube capable of realizing long lifetime and realizing further high luminance. <P>SOLUTION: This light-emitting tube 20 is equipped with a tubular bulb part 30, and a pair of sealing parts 40, 50 extending to both sides of the tubular bulb part 30. The intermediate position of a pair of electrodes 42, 45 in a cross-sectional face of the tubular bulb part 30; the light-emitting tube 20 is cut in the vertical virtual flat face including a light axis is set as a point P; a position to become the lowest side with respect gravity in the inner face of the tubular bulb part 30 is set as a point A; a position that is to serve as the uppermost side with respect to gravity in the inner face of the tubular bulb part 30 is set as a point B; a position that serves as the lowest side with respect to gravity in the outer face of the tubular bulb part 30 is set as a point C; a position that serves as the uppermost side with respect to gravity in the outer face of the tubular bulb part 30 is set as a point D; a distance from the point P to the point A is set to L<SB>A</SB>; the distance from the point P to the point B is set to L<SB>B</SB>; the distance from the point P to the point C is set to L<SB>C</SB>; and if the distance from the point P to the point D is L<SB>D</SB>, relations L<SB>A</SB><L<SB>B</SB>and (L<SB>C</SB>-L<SB>A</SB>)>(L<SB>D</SB>-L<SB>B</SB>) are satisfied. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
