Patent ID: 7282861

Claim:
A light source device, comprising: at least one bulb; a discharge medium, containing a rare gas, sealed inside said at least one bulb; a first electrode inside said at least one bulb; a second electrode outside said at least one bulb; and a holder for holding said second electrode such that said second electrode opposes said at least one bulb across a space so as to be spaced from said at least one bulb by a predetermined distance, wherein the predetermined distance is greater than a shortest distance defined by the following equation, X1L = V EO - ɛ ⁢ ⁢ 1 ɛ ⁢ ⁢ 2 × X2 , ⁢ with X 1 L being the shortest distance, E0 being a dielectric breakdown field of atmospheric gas, V being an input voltage, ∈1 being a dielectric constant of the space, ∈2 being a dielectric constant of a wall of said at least one bulb, and X 2 being a thickness of the wall of said at least one bulb.