Patent ID: 8851683

Claim:
A light source device comprising: a luminous tube including a pair of electrodes for generating light by electric discharging and a bulb for sealing the pair of electrodes, the pair of electrodes arranged to face each other; a reflector that includes a reflection surface for reflecting light emitted from the bulb, the reflection surface formed into a concave surface shape to reflect the light emitted from the bulb, the reflector housing the luminous tube so that the bulb can be located in a center of the reflection surface; an air blowing device for generating a flow of gas to cool the luminous tube; a first flow path for jetting out the gas along an inner surface of the reflector toward a first half part located far from the installation surface of the bulb; a second flow path for jetting out the gas along the inner surface of the reflector toward a second half part located near the installation surface of the bulb; and a movable plate for separating the first flow path and the second flow path from each other to form a part of each flow path, the movable plate adjusting an amount of gas flowing into each flow path to adjust a ratio of an air flow in each flow path, the movable plate gradually narrowing a flow path area in the flow path adjusted to increase the air flow in a jetting-out direction of the gas, wherein the luminous tube includes a sealing part that seals a conductor for supplying power to the pair of electrodes and that extends in an emitting direction of the light reflected by the reflector; the light source device further comprises a third flow path for jetting out the gas that flowed from the air blowing device toward a leading end of the sealing part in the emitting direction of the light; and the third flow path is partially formed by a separation wall for separating the first flow path and the second flow path from each other.