In the existing LED lamp strips, hotspot phenomenon may occur due to nonuniform light mixing: as shown in FIG. 1, the light emission angle of LED 101 is less than 180 degrees; an area 102 where dark areas overlap may be generated between two adjacent LEDs 101, 101′, and the luminance of this area would be distinctly lower than an area 103 that can be irradiated by LED light, thereby resulting in alternate bright spots and dark spots.