| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light emitting device improved so as to increase maximum optical output under a high voltage AC power source. <P>SOLUTION: The light emitting device includes a thermally conductive substrate 110, such as a SiC substrate, having a thermal conductivity higher than that of a sapphire substrate. A plurality of light emitting cells 100-1 to 100-n are connected in series on the upper part of the thermally conductive substrate. Meanwhile, a semi-insulating buffer layer 120 is interposed between the thermally conductive substrate and the light emitting cells. For example, the semi-insulating buffer layer may be AlN or semi-insulating GaN. By employing the thermally conductive substrate having the thermal conductivity higher than that of a conventional sapphire substrate, a heat-dissipating performance is enhanced as compared with the conventional sapphire substrate, thereby increasing the maximum light output of the light emitting device driven under the high voltage AC power source. In addition, by employing the semi-insulating buffer layer, increase of a leakage current through the thermally conductive substrate, the leakage current through a substrate, and the leakage current between the light emitting cells are prevented. <P>COPYRIGHT: (C)2012,JPO&INPIT |
