| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light source device which can collect light with high efficiency by a light collecting type reflecting mirror, and can form good parallel light by a parallel light type reflecting mirror. <P>SOLUTION: The light source device includes: an ultrahigh pressure discharge lamp having a pair of electrodes oppositely arranged on tip ends of electrode core wires of which base end parts are embedded in sealed parts; and a concave reflecting mirror arranged so that an optical axis corresponds to a tube axis of an arc tube, in a light-emitting part of the arc tube. An inner surface of the light-emitting part is formed of a first concave curved surface on a front side of the concave reflecting mirror and a second concave curved surface on a rear side of the concave reflecting mirror. A boundary of them are positioned on the rear side of the concave reflecting mirror from a center of the light-emitting part. The first concave curved surface and second concave curved surface have curvatures which increase as closer to the electrode core. In an optional cross section along the tube axis, the first concave curved surface is formed along a curved ling of Y=log<SB>A</SB>X-αX<SP>2</SP>, and the second concave curved surface is formed along a curved line of Y=log<SB>B</SB>X-βX<SP>2</SP>, and 1<A<B, and 0.001≤α< β≤0.1 are satisfied. <P>COPYRIGHT: (C)2011,JPO&INPIT |
