ELECTRODE FOR A SHORT-ARC HIGH PRESSURE LAMP
An electrode for a short-arc high-pressure discharge device is disclosed. The electrode includes a body made from a thoriated tungsten material. The body forms a tip at one end. A coating layer covers a part of the thoriated tungsten material so that an area around the tip is not covered by the coating layer.
1 . A discharge lamp comprising:
an anode; and
a cathode,
wherein said cathode includes a thoriated tungsten material and said cathode having a layer covering a part of the thoriated tungsten material, and
wherein a tip area of said cathode is not covered by the layer and wherein the layer has a thickness in the range of 70 to 130 um.
2 . The discharge lamp according to claim 1 , wherein the layer is tungsten.
3 . The discharge lamp according to claim 2 , wherein said cathode includes an additional carbide layer over the layer.
4 . The discharge lamp according to claim 1 , wherein the layer is a metal with a high melting point.
5 . (canceled)
6 . (canceled)
7 . The discharge lamp according to claim 1 , wherein the tip area covers an area at least 2 mm below a tip of said cathode.
8 . The discharge lamp according to claim 1 , wherein the tip area covers an area starting 2-5 mm below a tip of said cathode.
9 . The discharge lamp according to claim 1 , wherein the discharge device is a short-arc high-pressure lamp.
10 - 15 . (canceled)