Patent ID: 8919964

Claim:
A light source device comprising: an arc tube which has a light emission portion including a pair of electrodes internally; a reflection mirror configured to reflect light emitted from the light emission portion; a tubular body disposed in the front side of the reflection mirror in the light emission direction and surrounding the arc tube; a pair of ducts connecting with the tubular body and provided with a first channel and a second channel to guide air; and a channel switching mechanism which allows air to flow through the first channel or the second channel, wherein the light source device is installable in various positions, including a normal position, a ceiling mounted position, an upward projection position, and a downward projection position, wherein the tubular body includes a pair of communicating ports which connect the inside and the outside of the tubular body such that the inside and the outside of the tubular body communicate with each other, and supply airs flowing through the first channel and the second channel toward the light emission portion, and the pair of the communicating ports are disposed on a virtual line passing through the center line of the arc tube and crossing the vertical direction and the horizontal direction, and either one of the pair of communicating ports is positioned diagonally above the center line in each condition of the various positions, as viewed in a direction along the center line.