Bimetal/resistor switch and ceramic bridge assembly for metal halide lamps

摘要

A high pressure lamp assembly having an improved structure for supporting the discharge tube while providing an opening bi-metallic switch for electrically disconnecting the auxiliary electrode. Metallic frames are disposed at the upper and lower ends of the discharge lamp to provide at least partial support to the discharge tube. A non-conductive bridge assembly is connected between the lead through of the auxiliary electrode and a conductive rod extending from the stem. The non-conductive bridge provides at least partial mechanical support to the discharge tube. Connected across the non-conductive bridge is the starting resistor and bi-metallic switch element. When the bi-metallic element is unheated, it provides electrical connection through the starting resistor to the auxiliary electrode. When heated by the heat from the discharge tube, the bi-metallic switch moves out of engagement with the ceramic bridge and thus breaks the electrical connection to the auxiliary electrode.