The five major raw materials of LED are: chip, bracket, silver glue, zhidao gold wire, epoxy resin.

1. The composition of the wafer: it consists of a gold pad, P pole, N pole, PN junction, and a back gold layer (the double pad wafer has no back gold layer). The wafer is composed of P-layer semiconductor elements and N-layer semiconductor elements rearranged and combined by electron movement.

2. The structure of the bracket is 1 layer of iron, 2 layers of copper plating (good conductivity, fast heat dissipation), 3 layers of nickel plating (anti-oxidation), and 4 layers of silver plating (good reflectivity, easy to solder wires).

3. Silver glue, because there are many types, take H20E as an example, also known as white glue, milky white, conductive adhesion (baking temperature: 100 ° C / 1.5H) silver powder (conductive, heat dissipation, fixed chip) + Epoxy resin (cured silver powder) + thinner (easy to stir).

4. Gold wire, the gold wire used for LED is φ1.0mil, φ1.2mil, the material of the gold wire, the material of the gold wire for LED is generally 99.9% gold. The deformation, good conductivity, and good heat dissipation characteristics allow a closed circuit to be formed between the chip and the holder.

5. Two parts of epoxy resin, A and B:

A glue: it is the main agent, which consists of epoxy resin + defoamer + heat resistance agent + thinner.

Agent B: It is a curing agent, which consists of acid, mold release agent and accelerator.