| 摘要 |
PROBLEM TO BE SOLVED: To prevent a life of a light source from being reduced while keeping lights emitted from a lighting system almost constant. SOLUTION: A light source circuit 140 has a light source for emitting lights by a current. An illuminance detection circuit 150 has an illuminance sensor for receiving the lights and measuring an amount of the received lights. A power source circuit 160 supplies the current to the light source circuit 140. A control circuit 300 (control part) controls the current supplied to the light source circuit 140 by the power source circuit 160, so that the amount of the lights measured by the illuminance sensor approaches a predetermined light quantity within a range such that the current supplied to the light source circuit 140 by the power source circuit 160 does not exceed a maximum rating value of the light source circuit 140. COPYRIGHT: (C)2012,JPO&INPIT |
