公开(公告)号：EP1435642A4

公开(公告)日：2007-04-11

申请号：EP02801537

申请日：2002-10-11

Applicant: NGK INSULATORS LTD

Inventor： MIYAZAWA SUGIO

IPC: H01J9/24 ,  H01J61/33 ,  H01J17/16 ,  H01J61/30 ,  H01J61/52 ,  H01J61/82

CPC classification number: H01J61/30 ,  H01J9/247 ,  H01J61/302 ,  H01J61/33 ,  H01J61/523 ,  H01J61/827

Abstract: A ceramic discharge tube 1A for a high-pressure discharge lamp having ionized luminous substance and starting gas filled in the inside space thereof, comprising a tubular center luminous part 2A and a pair of tubular end parts 3 projected from both sides of the center luminous part 2A, wherein the maximum wall thickness 1 of the end parts 3 is 0.5 to 0.9 times the maximum wall thickness t of the center luminous part 2A, whereby the luminous efficiency of the high-pressure discharge lamp can be increased.