| 摘要 |
PROBLEM TO BE SOLVED: To reduce a failure rate by prolonging the life of a cooling fan while maintaining excellent heat exhausting performance.SOLUTION: A control part 21 controls to set a current value of an output current Io as a specified value A1 and rotate a cooling fan 12 at a specified rotation number in a case where a signal instructing a first lighting state is inputted, and controls to lower the current value of the output current Io below the specified value A1 and make the rotation number of the cooling fan 12 lower than the specified rotation number in a case where a signal instructing a second lighting state is inputted. Thus, in addition to reduction of a heat exhausting amount from a light source 15 associated with light reducing, the rotation number of the cooling fan 12 is reduced. Therefore, life-prolongation of the cooling fan 12 is achieved while maintaining excellent heat exhausting performance. |
