As shown in FIG. 1D, in the present embodiment, the top layer 420a of the LED sections 402, 404 has the largest diameter (or maximum thickness) in the radial direction of the LED filament and the diameter of the top layer 420a is gradually reduced from the LED sections 402, 404 to the conductive section 430, and a portion of the conductor 430a (for example, the intermediate portion) is not covered by the top layer 420a. The base layer 420b, whether in the LED sections 402, 404 or in the conductive section 430, has substantially the same width, thickness or diameter in the radial direction of the LED filament. In the present embodiment, the number of LED chips 442 in each of the LED sections 402, 404 may be different. For example, some LED sections 402, 404 have only one LED chip 442, and some LED sections 402, 404 have two or more LED chips 442. In addition to the number of the LED chip 442 designing in each LED section 402, 402 is different, the types of the LED chip 442 may also be different. It is acceptable as well that the number of the LED chip 442 designing in each LED section 402, 402 is consistent, and the types of the LED chip 442 is different.
