The present disclosure provides a light emitting device including an LED array including a plurality of LED cells connected in series disposed on a single substrate; wherein each LED cell includes a first edge, a second edge, a third edge, and a fourth edge, and wherein the LED array includes a first LED and a second LED, the first edge of the first LED is adjacent to the third edge of the second LED; a first trench, disposed between the first LED cell and the second LED; and a first conducting metal, disposed on the first trench, the first edge of the first LED and the third edge of the second LED, and electrically connecting the first LED and the second LED in series; wherein the first LED and/or the second LED includes a round corner in a top view.