Discharge lamp having heat reflecting shields surrounding its electrodes

Claim 1

IN COMBINATION WITH A HIGH-PRESSURE ARC-DISCHARGE DEVICE COMPRISING, AN ELONGATED LIGHT-TRANSMITTING REFRACTORY ARC TUBE HAVING A MAIN BODY OF GENERALLY UNIFORM DIAMETER AND CLOSED AT EACH END BY A SEAL, SAID ARC TUBE ENCLOSING A PREDETERMINED CHARGE OF SELECTED DISCHARGE-SUSTAINING SUBSTANCE WHICH IS REQUIRED TO BE MAINTAINED AT A HIGH TEMPERATURE FOR PROPER OPERATION OF SAID DEVICE, ELECTRODES OPERATIVELY DISPOSED WITHIN SAID ARC TUBE PROXIMATE EACH END THEREOF AND ELECTRICALLY CONNECTING TO LEAD-IN CONDUCTORS SEALED THROUGH SAID ARC TUBE SEALS, A LIGHT-TRANSMITTING OUTER ENVELOPE ENCLOSING SAID ARC TUBE, ARC TUBE SUPPORT MEANS WITHIN SAID OUTER ENVELOPE FOR ENGAGING AND SUPPORTING SAID ARC TUBE PROXIMATE THE END SEALS THEREOF, AND ADDITIONAL LEAD-IN CONNECTIONS ELECTRICALLY CONNECTED TO SAID ARC TUBE LEAD-IN CONDUCTORS AND SEALED THROUGH SAID OUTER ENVELOPE FOR ELECTRICALLY ENERGIZING SAID ARC TUBE, THE IMPROVEMENT WHICH COMPRISES: (A) A REFRACTORY METALLIC RETAINING END CAP OVER EACH CLOSED END OF SAID ARC TUBE, EACH SAID METALLIC END CAP EXTENDING FROM AN ARC TUBE END AND ALONG THE ARC TUBE BODY A DISTANCE SUFFICIENT TO OVERLAP SUBSTANTIALLY ALL PORTIONS OF THE SAID ELECTRODE WHICH IS POSITIONED PROXIMATE THE SAME END OF SAID ARC TUBE TO ENTRAP HEAT GENERATED PROCIMATE EACH SAID ELECTRODE DURING OPERATION OF SAID DEVICE, EACH SAID METALLIC END CAP COMPRISING A FIRST PORTION HAVING A GENERALLY RING-LIKE CONFIGURATION AND ENCIRCLING A PORTION OF THE BODY OF SAID ARC TUBE AND A SECOND PORTION FORMED AS A SERIES OF ADJACENT GENERALLY TRAPEZOIDAL-SHAPED MEMBERS CONNECTED AT THEIR BASES TO SAID RING-LIKE FIRST PORTION AND BENT PROXIMATE THEIR BASES TO GENERALLY CONFORM TO AND COVER OVER AN END OF SAID ARC TUBE; AND (B) A REFRACTORY FIBROUS MATERIAL MAT TIGHTLY PACKED BETWEEN EACH SAID END CAP AND THOSE PORTIONS OF SAID ARC TUBE WHICH ARE COVERED BY SAID END CAPS, AND EACH SAID REFRACTORY MAT BEING NON-GAS-EMITTING, INERT AND NON-REACTIVE WITH RESPECT TO SAID ARC TUBE AND SAID METALLIC END CAPS AT THE OPERATING TEMPERATURES OF SAID ARC TUBE; WHEREBY DURING OPERATION OF SAID DEVICE EACH END PORTION OF SAID ARC TUBE COMPRISES AN EFFECTIVE HEAT TRAP TO INHIBIT CONDENSATION OF DISCHARGE-SUSTAINING FILLING AT THE END PORTIONS OF SAID ARC TUBE.