Light emitting diode

A light emitting diode (LED), comprising:

• two or more single chips electrically connected in series,
• wherein each of the single chips comprises
• a substrate;
• and
• a plurality of serial arrays having a plurality of light emitting cells connected in series on the substrate, wherein,
• first connecting connectors are configured to connect at least two of the plurality of the light emitting cells in series, and second connectors are configured to connect the at least two of the plurality of the light emitting cells to at least two other light emitting cells of the plurality of the light emitting cells in parallel to operate in response to a reverse voltage, wherein an overvoltage is prevented from being applied to the plurality of light emitting cells,
• each of the light emitting cells comprises a lower semiconductor layer, an upper semiconductor layer, an active layer interposed between the lower semiconductor layer and the upper semiconductor layer, and an upper electrode layer formed on the upper semiconductor layer, wherein the upper electrode layer is formed with transparent characteristic material and the upper electrode layer is directly in ohmic contact with the upper semiconductor layer to lower contact resistance, and a buffer layer is interposed between the lower semiconductor layer and the substrate to reduce mismatch between the substrate and the lower semiconductor layer, wherein an upper electrode pad and a lower electrode pad are respectively disposed at the corners of the upper electrode layer and the lower semiconductor layer being diagonally opposite to each other, and upper electrode pads and lower electrode pads of four immediately adjacent light emitting cells are connected by a “” shaped connector and are disposed in a symmetrical pattern, and
• the upper electrode layer is directly formed between the upper electrode pad and the upper semiconductor layer.