A sulfur plasma lamp has a lamp envelope of transparent or translucent glass or ceramic material. At least two silicon carbide electrodes are hermetically sealed with the lamp envelope and in contact with an interior of the lamp envelope. A quantity of sulfur within the interior of the lamp envelope is sufficient to create a sulfur plasma upon excitation. A buffer gas within the interior of the lamp envelope enables initial discharge and heating of the interior of the lamp envelope to excite the sulfur into a plasma state. More than two electrodes may be provided, and an electrical potential is created between different pairs of the electrodes at different times, thereby inducing stirring of the plasma upon excitation of the material into a plasma state.

A DC gas discharge lamp includes an anode and a cathode having a first cathode segment, which forms the surface of the cathode at least in a region of the cathode which faces the anode and has an arc attachment region, within which an arc burning between the cathode and the anode attaches during lamp operation as intended. The first cathode segment consists of tungsten with at least one emitter material for reducing the work function of electrons from the cathode. The cathode is embodied in a manner free of thorium. The at least one emitter material has a melting point of less than 3200 K. At least one part of the surface of the cathode outside the arc attachment region is formed by a diffusion barrier for the at least one emitter material.

The present invention relates to a high-intensity discharge lamp (1) comprising a discharge vessel (2) enclosing a filling in a discharge chamber (3), and a pair of electrode rods (4, 5) being formed of a material which is free of thorium and protruding from opposite sides into the discharge chamber (3). The diameter ED of the electrode rods (4, 5) in the discharge chamber (3) N satisfies the formula (I), wherein W represents the value of the nominal lamp power in mW and Ed represents the value of the distance of the electrode rods (4, 5) in the discharge chamber (3) in mm, and wherein the nominal lamp power W is between 20 W and 50 W. With the above formula, high-intensity discharge lamps can be easily designed with different nominal powers and/or 10 electrode distances without time consuming experiments in order to achieve an optimum performance.

[00001]$\begin{array}{cc}\mathrm{ED}{\mathrm{ED}}_0=\sqrt{.Math..Math.W/\left[1+\frac{\mathrm{Ed}-3}{3.Math..Math.\mathrm{Ed}}\right]}.Math.m-10.Math.m,& \left(I\right)\end{array}$

A light source, with electrodes of alternating polarity attached to a substrate in an excimer ultraviolet (UV) lamp, for generating a plasma discharge between each of the electrodes. The shape of the substrate can shape and control the plasma discharge to reduce exposure of materials susceptible to attack by the halogens. The electrodes can be located such that the plasma discharge occurs in a region where it produces less contact of the halogens with the vulnerable areas of the lamp enclosure. The materials, such as the electrodes, substrate, and envelope, can be selected to withstand corrosive materials. In another embodiment, a plurality of sealed tubes, at least some of which contain an excimer gas are positioned between two electrodes.

A high-temperature component made of a refractory metal or a refractory metal alloy, includes a coating for increasing thermal emissivity. The coating is formed substantially of tungsten and rhenium, i.e. of at least 55 wt. % rhenium and at least 10 wt. % tungsten, and has a Re3W phase of at least 35 wt. %. A process for producing a high-temperature component having a coating for increasing thermal emissivity, is also provided.

A discharge lamp includes an emitter other than thorium, which is added to a cathode in a luminous tube. Early depletion of the emitter due to excessive vaporization of the emitter from the cathode is prevented, while achieving stable lighting even at the start-up of the lighting. A main body part (31) of the cathode (3) is made from a high-melting-point metal material that contains no thorium, and a front end part (32) thereof is made from a high-melting-point metal material that contains an emitter (other than thorium). A sintered compact (34), which contains an emitter (other than thorium) at a concentration higher than the emitter contained in the front end part (32), is buried in a sealed space (33) that is formed within the main body part (31) and/or the front end part (32). The sintered compact (34) abuts against the front end part (32).

A DC gas discharge lamp includes an anode and a cathode having a first cathode segment, which forms the surface of the cathode at least in a region of the cathode which faces the anode and has an arc attachment region, within which an arc burning between the cathode and the anode attaches during lamp operation as intended. The first cathode segment consists of tungsten with at least one emitter material for reducing the work function of electrons from the cathode. The cathode is embodied in a manner free of thorium. The at least one emitter material has a melting point of less than 3200 K. At least one part of the surface of the cathode outside the arc attachment region is formed by a diffusion barrier for the at least one emitter material.

A discharge lamp includes a luminous tube and a pair of electrodes. At least one of the pair of electrodes includes a core material, a coil section in which a metal wire is wound on the core material in three or more layers, a distal end portion made of a conductor and provided, with respect to the coil section, at an end portion of the core material on a side where the other electrode is disposed, and a rear end portion made of a conductor and provided on the opposite side of the distal end portion with respect to the coil section. The rear end portion includes a first diameter section having a first diameter and a second diameter section having a second diameter smaller than the first diameter and present in a position farther from the coil section than the first diameter section.

A discharge lamp includes a cathode in a luminous tube, and an emitter, other than thorium, is added to the cathode. The emitter is prevented from being excessively vaporized from the cathode and depleted soon. Smooth lighting is enabled even at start-up. A main body part (31) of the cathode (3) is made from a metallic material having a high melting point and containing no thorium. A front end (32) is made from a metallic material having a high melting point and containing an emitter (excepting thorium). Inside a sealed space (33) formed in the main body part (31) and/or the front end part (32) is received a sintered compact (34) containing an emitter (excepting thorium) that is higher in concentration than the emitter contained in the front end part (32).

Sulfur arc lamp includes an arc chamber that has a cathode and an anode both made of refractory metals that include pure tungsten, pure molybdenum, tungsten alloy, molybdenum alloy or a composite in which tungsten is at least 90%, or a composite in which molybdenum is at least 90%; a plasma initiation gas filling the plasma chamber; power supply configured to switch on and off electric arc discharge between the cathode and anode; second chamber connected to the arc chamber for releasing sulfur vapor into the plasma arc chamber, thereby creating a sulfur-containing plasma gas when the discharge occurs, and configured to selectively remove the sulfur vapor from the sulfur-containing plasma gas when the discharge occurs, wherein the second chamber is configured to reduce a concentration of the sulfur vapor in the arc chamber below 10.sup.13 molecules per cm.sup.3 before the electric arc discharge is off.