Patent ID: 7232241

Claim:
An illumination system comprising: an arc tube including a light-emitting portion that emits light between electrodes and sealing portions that is arranged on both sides of the light-emitting portion; a first reflecting mirror that is arranged on a rear side of the light-emitting portion along a longitudinal direction of the arc tube; and a second reflecting mirror that is arranged on a front side of the light-emitting portion, a diameter D 1 on a reflecting surface of the first reflecting mirror, indicated by an available marginal light emitted to the rear side from the light-emitting portion, being larger than a diameter d 1 of an outer surface of the second reflecting mirror, and the diameter d 1 of the outer surface of the second reflecting mirror being set to a size within the light of the available marginal light reflected by the first reflecting mirror; a reflecting surface of the second reflecting mirror surrounding about half of the front side of the light-emitting portion and the light emitted from a center of the light-emitting portion and incident on the second reflecting mirror and a normal of the second reflecting mirror agree with each other; and the reflecting surface of the second reflecting mirror being formed by face-grinding or press-molding a pipe having an inside diameter larger than the outside diameter of the sealing portion.