| 摘要 |
PROBLEM TO BE SOLVED: To efficiently absorb heat by making it possible to surely absorb the heat quantity from a resistor and preventing the transfer of heat energy to light emitting elements. SOLUTION: The light emitting elements 62, 63, 64 are arranged along one end on the short side on a substrate 59 and the resistor 90 is arranged at the other end on the short side. A heat sink 92 is stuck to the rear surface side of this substrate 59 and plays the role of absorbing the heat generated from the resistor 90 and releasing the heat. This heat sink is stuck only to the rear surface corresponding to the position where the resistor 90 is mounted. Namely, the heat sink is not stuck to the rear surface corresponding to the positions where the light emitting elements 62, 63, 64 are mounted. The reason thereof lies in that there is a large difference between the calorific value of the resistor 90 and the calorific value of the light emitting elements 62, 62, 64 and that the heat absorbed from the resistor 90 is released reversedly to the light emitting elements 62, 63, 64. |
