Patent ID: 6593692
Filing Date: 2003-07-15
Classification: H01J

Abstract:
A high pressure discharge lamp, comprising:an arc tube having sealing parts at both ends thereof and a discharge space formed in the arc tube; two electrodes extending respectively from the sealing parts into the discharge space, so as to face each other with a predetermined distance â€œDeâ€  therebetween, each electrode being composed of an electrode rod and a coil wound around an end of the electrode rod; and mercury being filled in the discharge space in such a manner that a mercury vapor pressure therein in a steady lighting state is in the range of 15 MPa to 35 MPa inclusive; wherein the distance â€œDeâ€  is in the range of 0.5 mm to 1.5 mm inclusive, a tip of each electrode has been formed into a semi-sphere by fusing the electrode rod and the coil, and a thickness â€œdeâ€  and a diameter â€œ&phgr;eâ€  of the semi-sphere are each in a range predetermined in correspondence with a power input of the high pressure discharge lamp.