Patent ID: 8378573
Filing Date: 2013-02-19
Classification: H01J

Abstract:
1. A high pressure discharge lamp comprising: an electric discharge container that includes a light emission section and sealing portions formed at both ends of the light emission section; and a pair of tungsten electrodes, each of the electrodes comprises a base end, an axis portion, a large diameter portion and a tip; wherein the base end is buried in the sealing portion, each of the tips of the pair of electrodes faces each other in the light emission section, and purity of the tungsten is 99.99% or more; wherein the axis portion is smaller than the large diameter portion in diameter, the large diameter portion comprises a concavo-convex structure; and wherein the concavo-convex structure comprises a portion having extending grooves and a portion having no grooves are asymmetrical with respect to the axis of the electrode in the cross sectional view taken in a direction perpendicular to the axis of the electrode; and wherein the portion having extending grooves is extending in an axial direction.