Abstract: The invention relates to a high-pressure sodium discharge lamp intended to be operated in conjunction with an external starter or with an internal starter without a glow discharge. The lamp has an outer bulb which is provided with a lamp cap and encloses an evacuated space in which a discharge vessel is arranged. According to the invention, the space enclosed by the outer bulb further accommodates a closed holder, whose wall mainly comprises glass-forming constituents and which contains at least helium. Thus, it is achieved that the lamp has a strongly reduced increase in lamp voltage during the life.

Abstract: The invention relates to a high-pressure discharge lamp provided with a discharge vessel having a ceramic wall and a ceramic end plug which is arranged therein by means of sintering in a sunken position and in which a current-supply member of a main electrode is arranged in a gas-tight manner by means of a sealing ceramic connection. Outside the discharge space enclosed by the discharge vessel, a ceramic filling piece is arranged, which adjoins with a capillary intermediate space the wall of the discharge vessel, the end plug and the current-supply member. The capillary intermediate space is filled substantially entirely with sealing ceramic. With this construction of the vessel end, the sintered joint between the wall of the discharge vessel and the end plug is completely covered by sealing ceramic and the sealing ceramic is prevented from extending into the discharge space.

Abstract: The invention relates to a high-pressure discharge lamp comprising a discharge vessel enclosing a discharge space and provided with two main electrodes. Each of the main electrodes is connected to a lead-through element which is enclosed with an intermediate space by a closing part and is connected thereto in a gas-tight manner by means of a sealing joint. According to the invention, the lead-through element is provided with a protuberance reaching as far as the closing part and being present around the whole periphery of the lead-through element. In this manner, a screening of the sealing joint from the discharge space is obtained.

Abstract: A electric gas discharge lamp having a tubular ceramic discharge vessel which is provided at one end with a ceramic end plug which extends axially outside the end of the discharge vessel. The outside diameter of the projecting portion of the end plug being not more than 90% of the outside diameter of the discharge vessel.