Light emitting diodes (LEDs) have superior characteristics such as low power consumption, high-energy conversion efficiency, long lifespan, and no mercury pollution, thereby taking the advantage over incandescent lights. However, the conventional LED has a deficiency in its capability of heat dissipation, thus the incandescent light cannot be totally replaced by the conventional LED yet.
For example, a heat sink is usually used for transferring heat energy away from a conventional LED lamp. However, the heat sink alone is not sufficient to remove enough heat energy generated from the LEDs. Thus, developers constantly try to improve the heat dissipating efficiency of the heat dissipating device in order to cool the LEDs. For example, the heat dissipating efficiency of the heat dissipating device can be improved by using the principle of phase-change heat dissipation.
However, even though the heat dissipating efficiency of the heat dissipating device is able to be improved according to the principle of phase-change heat dissipation, but once the heat dissipating device, which is placed upside down, is unable to exert phase-change heat dissipation because gas tends to rise up, thereby restricting how the lamp including the phase-change heat dissipating device is installed and illuminated. That is, the lamp which is exclusively designed for illuminating downward to the ground is not adapted for illuminating upward, leftward or rightward. Therefore, developers try to solve the problem that the position of the lamp with the phase-change heat dissipating device is restricted.