Patent ID: 6791267
Filing Date: 2004-09-14
Classification: H01J

Abstract:
A high pressure discharge lamp comprising a light emitting vessel made of a semitransparent ceramic material and having a pair of end portions each with an opening formed in said end portion and a light emitting portion, a pair of discharge electrodes, and electrode supporting members each supporting said discharge electrode and fixed to said end portion, wherein said light emitting vessel defines an inner space, an ionizable light emitting substance and a starter gas are filled in said inner space, said electrodes are contained in said inner space, said light emitting portion has a thicker wall portion and a thinner wall portion, and said thinner wall portion has a cross sectional area of not smaller than 35 percent and not larger than 80 percent of that of said thicker wall portion so that said light emitting portion has a brightness center in said thinner wall portion.