LED lamp having enhanced waterproofing

An LED lamp comprising:

• a heat sink comprising a base;
• a plurality of LED modules each comprising a printed circuit board thermally attached to a bottom surface of the base of the heat sink and a plurality of LEDs mounted on the printed circuit board;
• an envelope disposed on the base of the heat sink, comprising an annular frame, the frame defining a receiving groove surrounding the LED modules, the receiving groove stepped to have an upper portion and a lower portion further recessed downwardly from a bottom of the upper portion;
• and
• an annular waterproof gasket received in the receiving groove and sandwiched between the base of the heat sink and the envelope, the waterproof gasket comprising a main body and an engaging portion protruding downwardly from a bottom of the main body;
• wherein the main body of the waterproof gasket is received in the upper portion of the receiving groove and the engaging portion of the waterproof gasket is received in the lower portion of the receiving groove.