High pressure electric discharge lamp and electrode therefor

Claim 1

A high pressure electric discharge lamp comprising: a fused silica arc tube having a press seal at each end thereof; molybdenum ribbons embedded in said press seals; a pair of electrodes disposed within said arc tube, each of said electrodes comprising a tubular body of pressed-and-twice-sintered refractory metal powder having an axial hole therethrough, said axial hole having been of uniform diameter after the first sintering; a refractory metal rod one end of which extends into said axial hole and is secured to the rearward portion of said body and the other end of which is connected to a molybdenum ribbon, said rod being secured in said rearward portion by having been inserted into said hole after the first sintering and then second sintering the rod and tubular body at a higher temperature than the first sintering; an emissive pellet disposed within the central portion of said axial hole and secured therein by means of having been pressed agaiNst the walls of said axial hole and said rod, said pellet being recessed from the forward end of said body and the space in said axial hole between said pellet and said forward end being open.