Patent ID: 8203269

Claim:
A high intensity discharge light source comprising: an arc tube having a longitudinal axis and a main central discharge chamber fowled therein; first and second electrodes having inner terminal ends spaced from one another along the longitudinal axis and each electrode extending at least partially into the main central discharge chamber or at least reaching reduced diameter end portions of the main central discharge chamber with its inner terminal end; first and second sub-chambers disposed at opposite, first and second axial ends of the main central discharge chamber, each sub-chamber located entirely axially outward of the inner terminal ends of the electrodes, wherein the main central discharge chamber has a cross-sectional dimension substantially the same as or wider thancross-sectional dimensions of the first and second sub-chambers; a reduced dimensional region adjacent each end of the main central discharge chamber that separates the respective first and second sub-chambers from the main central discharge chamber; and first and second sealing portions at opposite, first and second axial ends of the arc tube.