In particular, for the first contact electrode 106, the first contact electrode 106 extends through the active layer 102 and the second semiconductor layer 103. Accordingly, the first contact electrode 106 is generally an electrode having a small cross section, which can reduce the influence of the first contact electrode 106 on the LED illumination area. In this exemplary embodiment, by providing the first extension electrode 111 electrically connected to the first contact electrode 106, the increase in the area of the first extension electrode 111 does not affect the LED illumination area. Therefore, by increasing the area of the first extension electrode 111, the soldering area of the first extension electrode 111 and the driving circuit can be increased, thereby improving the soldering strength of the first contact electrode 106 and the driving circuit.

It should be noted that, in other exemplary embodiments, the projected areas of the first extension electrode and the second extension electrode may be equal to or slightly smaller than the projected areas of the first contact electrode and the second contact electrode. Because a plurality of concave spots are formed in the first extension electrode and the second extension electrode, the sidewalls of the plurality of concave spots can still function to increase the soldering area, thereby increasing the soldering strength.