| 摘要 |
[PROBLEM TO BE SOLVED] To provide a bulb-type lamp that can achieve improvement in the heat dissipation properties and size/weight reduction simultaneously, and that can lighten thermal load on a lighting circuit. [SOLUTION] A bulb-type lamp 1 is composed of: an LED module 3 including LEDs; a cylindrically-shaped case 7, to one end of which a base member 15 is attached and which allows dissipation of heat therefrom, the heat being generated by the LEDs emitting light; a mount member 5, on which the LED module 3 is mounted, which closes the other end of the case 7, and allows conduction of the heat to the case 7; a lighting circuit 11 that, upon receiving power via the base member 15, causes the LEDs to emit light; and a circuit holder 13 positioned inside the case 7, with the lighting circuit 11 disposed inside the circuit holder 13. The air space exists between the circuit holder 13 and the case7, and between the circuit holder 13 and the mount member 5. Hence, the lighting circuit 11 is isolated from the air space due to the presence of the circuit holder 13. In the bulb-type lamp 1, a fraction S1/S2 satisfies a relationship 0.5 ‰¤ S1/S2, where S1 denotes an area of a portion of the mount member 5 that is in contact with the case 7, and S2 denotes an area of a portion of the mount member 5 that is in contact with a substrate 17 of the LED module 3. |
