LED five main raw materials are: chip, stent, silver glue, gold wire, epoxy resin
The composition of the wafer: by the gold pad, p pole, n-Pole, Pn Junction, back gold layer composition (double pad wafer without back gold layer). The wafer is composed of a P-layer semiconductor element, and the n-layer semiconductor element is rearranged by the electronic movement of the PN binding. It is this change that allows the wafer to be in a relatively stable state. When the wafer is applied to a positive electrode by a certain voltage, the hole in the positive p area will flow to n, and the electrons in N region will move relative to the P region of cavities. At the same time as the electrons and holes move relative to each other, the electron holes pair together to excite the photons and produce light energy. Main classification, Surface luminous type: Most of the light emitted from the wafer surface. Five-sided luminous type: surface, side have more light emitting according to the luminous color points, red, orange, yellow, yellow, green, pure green, standard green, blue and green, blue.
Bracket Structure 1 layer is iron, 2 layer copper plating (good conductivity, heat dissipation fast), 3 layer nickel plating (oxidation resistance), 4 layer silver plated (good reflective, easy to weld line)
Silver Gum (due to the variety, we according to H20E for example)
Also called white gum, milky white, conductive adhesion (baking temperature: 100°c/1.5H) Silver powder (conductive, heat dissipation, fixed wafer) + Epoxy resin (cured silver powder) + diluent (easy to stir). Storage conditions: Silver gum manufacturers generally will be silver -40°c storage, the application of the unit will generally silver glue to -5°c storage. Single agent for 25°C/1 years (dry, ventilated place), mixing agent 25°c/72 hours (but on-line operation due to other factors of "temperature and humidity, ventilation conditions", in order to ensure the quality of the product of the general use of mixed agent time of 4 hours)
Baking conditions: 150°C/1.5H
Stirring condition: Stir evenly in one direction for 15 minutes
Gold wire (for example, φ1.0mil)
The gold wire used by the LED has φ1.0mil, φ1.2mil, the material of gold wire, the material of the gold wire of LED is generally 99.9%, the use of gold wire
The use of its gold content is soft, easy to deformation and good conductivity, heat dissipation characteristics, so that the chip and the stent between the formation of a circuit.
Epoxy resin (take EP400 as an example)
Composition: A, b Two groups of agents:
A glue: Is the main agent, by epoxy resin + defoamer + heat-resistant agent + thinner
B: is a curing agent, by acid-intoxicated + off-mold agent + promoter
Conditions of Use:
Mix ratio: a/b=100/100 (weight ratio)
Mixed viscosity: 500-700cps/30°c
Time of gelation: 120°c*12 minutes or 110°c*18 minutes
Conditions of use: room temperature 25°c about 6 hours. According to the production line, we will use the conditions for 2 hours.
Hardening Condition: Initial hardening 110°c-140°c 25-40 minutes