Patent ID: 8198814

Claim:
A high pressure sodium lamp comprising: an evacuated cover including a base part, a first arc tube and a second arc tube each comprising a first electrode coupled to the base part by a first conductor member and a second electrode coupled to the base part by a second conductor member, the first arc tube and the second arc tube mounted parallel with each other, the second conductor member symmetrically arranged between the first arc tube and the second arc tube and isolated by a shielding member, wherein the shielding member is a cylinder made of ceramic surrounding the second conductor member and having only the second conductor member within the cylinder, and wherein the shielding member is held in place on the second conductor member without the need of additional fittings, wherein the shielding member is arranged for preventing, during operation of the high pressure sodium lamp, the photo electronic stream from the second conductor member to the first arc tube and the second arc tube, and wherein the second conductor member lies in an intermediate plane, the intermediate plane extending between the first arc tube and the second arc tube such that a first line intercepting the second conductor member and a longitudinal center line of the first arc tube forms an angle alpha with the intermediate plane, and a second line intercepting the second conductor member and a longitudinal center line of the second arc tube forms an angle beta with the intermediate plane, wherein the angle alpha corresponds to the angle beta.