Detailed explanation of the internal structure of LED light-emitting diode

LED Lamp (led lamp) is mainly composed of five materials: bracket, silver glue, wafer, gold wire and epoxy resin.

First, the bracket:

1), the role of the bracket: for conduction and support
2) The composition of the bracket: The bracket is formed by electroplating of the bracket material, and is composed of five layers of material, copper, nickel, copper and silver from inside to outside.
3), the type of bracket: with a cup holder for concentrating type, flat head bracket for a large angle astigmatism type Lamp.
A, 2002 cup / flat head: This kind of bracket generally does not require high angle and brightness, and its Pin length is about 10mm shorter than other brackets. Pin spacing is 2.28mm
B, 2003 cup / flat head: generally used to make a φ5 or more Lamp, the exposed pin length is +29mm, -27mm. The pin pitch is 2.54 mm.
C, 2004 cup / flat head: used to do the φ3 or so of the Lamp, Pin length and spacing with the 2003 bracket.
D, 2004LD/DD: used to make blue, white, pure green, purple Lamp, can be welded double line, the cup is deep.
E, 2006: Both poles are flat-head type, used for flashing Lamp, solid IC, welding multiple lines.
F, 2009: used to make a two-color Lamp, two wafers can be fixed in the cup, and three pin feet control the polarity.
G, 2009-8/3009: used to make a three-color Lamp, three chips in the cup, four pin feet.

Second, silver glue

The role of silver glue: the role of fixing the wafer and conducting electricity.
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%.
Use of silver glue: refrigerate, need to be thawed and fully stirred before use. After the silver glue is left for a long time, the silver powder will precipitate. If it is not stirred evenly, it will affect the performance of the silver glue.

Third, the chip (Chip):

Light-emitting diode and LED chip structure
1), the role of the wafer: the wafer is the main component of the LED Lamp, is a luminescent semiconductor material.
2) Composition of the wafer: The wafer is made of gallium phosphide (GaP), gallium aluminum arsenide (GaAlAs) or gallium arsenide (GaAs), gallium nitride (GaN), etc., and its internal structure has unidirectional conductivity.
3), the structure of the wafer:
Solder single-wire positive (P/N structure) wafer, two-wire wafer. Wafer size unit: mil
The pads of the wafer are typically gold pads or aluminum pads. The shape of the pad is circular, square, cross, and the like.
4), the color of the wafer:
The color of the luminescence of the wafer depends on the wavelength. The classification of common visible light is roughly: dark red (700 nm), deep red (640-660 nm), red (615-635 nm), amber (600-610 nm), yellow (580-595 nm). Yellow-green (565-575 nm), pure green (500-540 nm), blue (450-480 nm), purple (380-430 nm).
White light and pink light are a mixture of light effects. The most common is a mixture of blue + yellow phosphor and blue + red phosphor.
5), the main technical parameters of the wafer:
A, volt-ampere characteristics of the wafer:
B. Forward Voltage (VF): A voltage applied across the wafer to cause the wafer to conduct. This voltage is related to the wafer itself and the test current. If the VF is too large, the wafer will be broken down.
C. Forward current (IF): The forward conduction current generated by the wafer after a certain voltage is applied. The size of the IF is related to the magnitude of the forward voltage. The operating current of the wafer is around 10-20 mA.
D. Reverse Voltage (VR): The reverse voltage applied to the wafer.
E. Reverse current (IR): refers to a leakage current generated by the wafer after a reverse voltage is applied. The smaller the current, the better. Because the current is large, the wafer is easily reversed.
F, brightness (IV): refers to the brightness of the light source. Unit conversion: 1cd=1000mcd
G. Wavelength: reflects the luminescent color of the wafer. Wafers of different wavelengths have different illuminating colors. Unit: nm
H, light: is a kind of electromagnetic wave. Electromagnetic waves having a wavelength of 0.1 mm to 10 nm are called light.
Light can be divided into: wavelength greater than 0.1mm is called radio wave; 760nm-0.1nm is called infrared light; 380nm-760nm is called visible light; 10nm-380nm is called ultraviolet light; and wavelength less than 10nm is X-ray light.

Fourth, the gold line:

The role of the gold wire: connect the wafer PAD (pad) to the bracket and make it conductive.
The purity of the gold wire is 99.99% Au; the elongation is 2-6%, and the size of the gold wire is 0.9 mil, 1.0 mil, 1.1 mil, and the like.
5. Epoxy resin:
The role of epoxy resin: to protect the internal structure of the Lamp, can slightly change the color, brightness and angle of the Lamp; shape the Lamp.
The encapsulating resin comprises four parts: A glue (main agent), B glue (hardener), DP (diffusion agent), and CP (colorant). Its main components are epoxy resin (Epoxy Resin), acid anhydride (anhydride), high light diffusing filler (Light diffusion) and thermal stability dye (dye).

Six, the mold:

The mold strip is a mold for forming a Lamp, and generally has a circular shape, a square shape, a tower shape, and the like. The depth of the stent is determined by the height of the card. The mold strips should be stored in a clean and below room temperature environment, otherwise it will affect the appearance of the product.