| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a short-arc type discharge lamp which is lightweight and has high heat radiation with regard to enlargement of an electrode accompanying enlarged power of a discharge lamp and can easily be manufactured and is hardly blackened and has longer lifetime. <P>SOLUTION: In the short-arc type discharge lamp which is vertically lighted up at input power of 10 KW or more and input current of 100 A or more at the time of lighting-up, a positive electrode 1 is provided with an approximately truncated cone-shaped or spherical dome-shaped point section 2 having a flat surface 5 at the pointed head opposite to a negative electrode 8, a columnar body section 3 having the maximum diameter surface 6 continued to the point section 2, and an approximately truncated cone-shaped rear end 4 gradually reducing its diameter from a rear side of the body section 3 continued to the body section 3. When current density on the maximum diameter surface 6 of the body section 3 is 0.2 A or below per 1 mm<SP>2</SP>and the shortest distance from an inner peripheral surface of a light-emitting tube to an outer peripheral surface at a rear end of the positive electrode is X1 (mm) and the shortest distance from an inner peripheral surface of a bulb at the center line of the light-emitting tube to the outer peripheral surface of the positive electrode is X0 (mm), relationship of X1 and X0 is set up to be 0.8≤X1/X0. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
