Structure of the LED lamp beads

LED lamp beads are mainly composed of table lamps, silver glue, wafers, gold wires and epoxy resin.

I. LED lamp holder

1. The role of the bracket: conductivity and support

2. Composition of the bracket: The material of the bracket is formed by electroplating, and consists of five layers of material, copper, nickel, copper and silver from inside to outside.

3. Types of table lamps: cup-shaped table lamps are concentrated type, flat-headed table lamps are large-angle astigmatism type II, LED and other cast silver glue

1. The role of silver glue: fixing the wafer and conducting electricity.

2. The main components of silver glue: silver powder accounts for 75%-80%, EPOXY (EPOXY resin) accounts for 10%-15%, and additives account for 5%-10%.

3. Use of silver glue: Refrigerate, thaw and stir well before use. Because the silver gel is kept for a long time, the silver powder will precipitate. If the stirring is uneven, the service performance of silver glue will be affected. 

WeChat official account: Shenzhen LED Chamber of Commerce

3. LED bead wafer

1. The role of the wafer: The wafer is the main component material of LED Lamp and is a luminescent semiconductor material.

2. Wafer composition: The wafer is composed of gallium phosphide (GaP), gallium aluminum arsenide (GaAlAs), gallium arsenide (GaAs), gallium nitride (GaN) and other materials, and its internal structure has unidirectional conductivity.

3. Wafer structure: Single-wire bipolar (P/N structure) wafer soldering, double-wire wafer. Size unit of wafer: wheat, and the pad of wafer is usually gold pad or aluminum pad. Its pad shapes are round, square, cross and so on.

4. Light color of wafer:

The luminescent color of the wafer depends on the wavelength. The common visible light classification is dark red (700nm), deep red (640-660nm), red (615-635nm), amber (600-610nm), yellow (580-595nm), yellow-green (565-575nm), pure green (500-540nm), blue (450-480nm) and purple (380-430nm).

White and pink are a mixture of light. The most common is a mixture of blue + yellow phosphor and blue + red phosphor.

5. Main technical parameters of 5. LED commercial chip:

A, the bolt characteristic diagram of the wafer;

B. Forward voltage (VF): The voltage applied across the wafer to make the wafer pass forward. This voltage is related to the wafer itself and the test current. If the VF is too large, the chip will be punctured.

C. Forward current (IF): It is the forward current generated after a certain voltage is applied to the wafer. The magnitude of IF is related to the magnitude of the forward voltage. The working current of the wafer is about 10-20mA.

D. Reverse Voltage (VR): The reverse voltage applied to the wafer.

E, reverse current (IR): refers to the leakage current generated after applying reverse voltage to the wafer. The smaller the current, the better. Because the current easily causes the wash chip to break down in reverse. WeChat official account: Shenzhen LED Chamber of Commerce

F, Brightness (IV): Indicates the brightness of the light source. Unit conversion: 1cd=1000mcd

G. Wavelength: Reflects the luminous color of the wafer. Different wavelengths of wafers have different luminous colors. Unit: nm

Fourth, LED bead gold wire

The role of gold wire: Connect the wafer PAD (PAD) with the bracket so that it can pass through.

The purity of gold wire is 99.99% Au. The elongation is 2-6%, and the gold wire sizes are 0.9 mil, 1.0 mil, 1.1 mil, etc.

5. LED bead epoxy resin

Function of epoxy resin: It can protect the internal structure of Lamp and change the luminous color, brightness and angle of Lamp slightly; Create a Lamp shape.

Packaging resin is composed of A glue (main agent), B glue (curing agent), DP (diffusion agent) and CP (colorant). The main components are Epoxy Resin (Epoxy Resin), Anhydride (Anhydride), high gloss diffusive filler (Light diffusion) and thermal stability dye (dye).