| 摘要 |
PROBLEM TO BE SOLVED: To provide a light source device for accurately measuring a light output in a simple configuration.SOLUTION: A light source device 1 having a light guide rod 30 as a light guide member that receives light of a discharge lamp 4 being a light source, and outputs it, and controlling the quantity of the light incident on the light guide rod 30 in accordance with a light output. A transparent plate 13 with half mirror is disposed between the discharge lamp 4 and the light guide rod 30 at an inclined angle relative to an optical axis of the discharge lamp 4, so that a part of the incident light propagating inside toward an end surface 48. A light amount sensor 50 is provided on the end surface 48 to detect light 49 propagating to the end surface 48 of the transparent plate 13 with half mirror. The light output is detected on the basis of the amount of the propagating light 49. |
