| 摘要 |
PROBLEM TO BE SOLVED: To improve the heat radiation properties of a light-emitting device.SOLUTION: A light-emitting device has a light-emitting unit 20 which is hollow and conical shaped. The light-emitting unit 20 has a luminous plane on a conical-shaped side face. The inside of the light-emitting unit 20 (internal space) is hollow. The light-emitting device further has openings 41, 42, 43 for letting the internal space and the external space of the light-emitting unit 20 communicate with each other. The light-emitting unit 20 is formed in shape of, for example, a frustum of cone, with a center axis extending in the vertical direction, in which the openings 41, 42, 43 are disposed in the top section and/or the bottom section of the frustum of cone. |
