Abstract: A high-pressure discharge lamp which includes a translucent ceramic discharge vessel having a swollen portion defining a discharge space and a pair of cylindrical portions formed in and communicating with the swollen portion and extending from the swollen portion in the opposite directions with each other. The high-pressure discharge lamp also includes metal tubes each having a outer diameter D and fit with its one end on the cylindrical portion, a pair of fusible metal plugs each plugged in the outer end of the metal tube, the fusible metal plug sealing the discharge vessel by being fused to the inner surface of the metal tube for a specified height T from the outer end of the metal plug, a pair of electrode systems each supported its one end to the fusible metal plug and facing the interior of swollen portion with its other end, and ionizing filling filled in the discharge vessel The ratio T/D of the height T concerning the fusible metal plug and the diameter D satisfies the following equation 0.

Abstract: A high pressure discharge lamp includes a light-transmissive ceramic discharge vessel with an envelope having a maximum outer diameter D1 and open ends, a metal pipe having one end, i.e., a top end fused in the open end of the light-transmissive ceramic discharge vessel and the other end, i.e., a base end protruding from the light-transmissive ceramic discharge vessel, a pair of electrodes each having one end, i.e., a base end connectively supported on the base end of the metal pipe and the other end, i.e., a top end extending within the light-transmissive ceramic discharge vessel, and a discharge agent which is filled in the light-transmissive ceramic discharge vessel, wherein it is also characterized by that the high pressure discharge lamp has an overall length L1, and the overall length L1 and the maximum outer diameter of D1 satisfies a following equation. 1.5≦L1/D1≦4.

Abstract: The invention provide a high-pressure discharge lamp comprising a translucent ceramic discharge vessel having a swollen portion defining a discharge space and a pair of cylindrical portions formed in communicating with the swollen portion and extending from the swollen portion in the opposite directions with each other, metal tubes each having a outer diameter D and fit with its one end on the cylindrical portion, a pair of fusible metal plugs each plugged in the outer end of the metal tube, the fusible metal plug sealing the discharge vessel by being fused to the inner surface of the metal tube for a specified height T from the outer end of the metal plug, a pair of electrode systems each supported its one end to the fusible metal plug and facing the interior of swollen portion with its other end, and ionizing filling filled in the discharge vessel, wherein the ratio T/D of the height T concerning the fusible metal plug and the diameter D satisfies the following equation.

Abstract: A high pressure discharge lamp includes a light-transmissive ceramic discharge vessel with an envelope having a maximum outer diameter D1 and open ends, a metal pipe having one end, i.e., a top end fused in the open end of the light-transmissive ceramic discharge vessel and the other end, i.e., a base end protruding from the light-transmissive ceramic discharge vessel, a pair of electrodes each having one end, i.e., a base end connectively supported on the base end of the metal pipe and the other end, i.e., a top end extending within the light-transmissive ceramic discharge vessel, and a discharge agent which is filled in the light-transmissive ceramic discharge vessel, wherein it is also characterized by that the high pressure discharge lamp has an overall length L1, and the overall length L1 and the maximum outer diameter of D1 satisfies a following equation.