| 摘要 |
PROBLEM TO BE SOLVED: To restrain the temperature rise of a lighting circuit by satisfying a specific relationship between the capacity ratio of the capacity of a case part to the capacity of a light emitting part and the rated electricity consumption per unit capacity, and thermally optimizing the sizes of the light emitting part and the case part. SOLUTION: The capacity of a case 31 is set to a relative large value in comparison with the capacity of a light emitting part LP. That is, when the capacity of the light emitting part LP is taken as VL and the capacity of the case 31 is taken as VC, the capacity ratio, VL/VC is set <1.0. Therefore, the temperature rise of a lighting circuit OC falls in the allowable range, and thermal damage of not only a semiconductor device but also circuit parts can be avoided in the practical range. By setting the rated electricity consumption P/VL (W/cc) per unit capacity of the light emitting part LP >=0.35, and restraining the temperature rise of the lighting circuit OC, thermal damage of the circuit parts, miniaturized with high output, can be prevented. |
