| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrict the blackening phenomenon of an arc tube inner wall and the shaking of arc, thereby improving an illuminance maintenance rate. <P>SOLUTION: In a short arc type discharge lamp having an anode placed above a cathode on an axis line passing through the centers of the cathode and the anode which are both placed in the perpendicular direction when lighted, assuming that the maximum outside diameter of an arc tube sealing body is Dm, that the planar position passing through the maximum outside diameter of the arc tube sealing body is a reference position Ym, that the distance from the reference position Ym, along the axis line passing through the centers of the cathode and the anode, to the tip of the anode is X1, that the distance from the reference position Ym, along the axis line passing through the centers of the cathode and the anode, to a point where the bottom of the electrode core rod of the cathode is exposed at an end face fronting on the electrode tip of an electrode core rod support material is X2, and that the radius of curvature of a curved surface forming an expanded part of the arc tube sealing body in a cross section along the axis line passing through the centers of the cathode and the anode of the arc tube sealing body is R, the relationships 0.69≤(Dm/R)<1.24 and 0<(X1/X2)≤0.271 hold. <P>COPYRIGHT: (C)2012,JPO&INPIT |
