摘要:
A high pressure discharge lamp (10) with a thermally improved anode (18), as well as a method of making such a lamp, are disclosed. The lamp includes a refractory arc tube (12) with a hermetically sealed arc chamber (14), a fill in the arc chamber for facilitating light generation, and an anode (18) and a cathode (16) extending into the hermetically sealed arc chamber (14) and being spaced apart from each other. The anode (18) comprises a shank of refractory metal (20), a cylindrically shaped refractory metal sleeve (318b) on a portion of the shank (20), and an end proximally facing the cathode (16). The anode (18) end comprises a substantially solid mass of refractory metal, and is integrally joined to both the shank (20) and the metal sleeve (318b) to facilitate heat flow from the anode (18) end to the shank (20) and sleeve (312b). The anode (18) end preferably is generally shaped as a hemisphere facing the cathode (16). The fill may comprise mercury, metal halide, and xenon at a relatively high fill pressure. The anode (18) may be formed by, first, providing a refractory metal shank (20), and placing a refractory metal sleeve (318b), e.g., one or more layers of a helically wound refractory metal wire, along a portion of the shank (20), to form a sleeve-shank combination. A portion of the sleeve-shank combination, facing downwards, is then heated sufficiently to cause metal from the sleeve-shank combination to ball up and form an anode end that integrally joins both the shank (20) and the metal sleeve (318b). The heating is preferably sufficient to cause the anode (18) end to ball up into a generally hemispherical shape.