Referring to FIGS. 11 and 12, the projection of the circular extension electrode and the circular contact electrode on the forming surface A constitutes a structure of concentric circles. Thus, when the LED chip is soldered to the driving circuit, the solder is located at the center of the concentric circles, which ensures a large area of contact between the driving circuit and the circular extension electrode, and between the circular extension electrode and the circular contact electrode, thereby increasing the soldering strength.

It should be noted that, in other exemplary embodiments, the first extension electrode is electrically connected to the first contact electrode, and the second extension electrode is electrically connected to the second contact electrode. The projection of the circular extension electrode and the circular contact electrode on the forming surface A may also be in a structure with intersecting circles, inscribed circles or an inner circular.

In this exemplary embodiment, the first extension electrode 111 and the second extension electrode 121 are made of metal, such as gold, silver or aluminum. The metal can be reflective, thereby improving the light extraction efficiency of the LED chip. In other exemplary embodiments, the first extension electrode and the second extension electrode may also be made of other conductive materials.