LED light emitting diode structure

LED light emitting diode structure

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

1. Bracket:

1), the role of the bracket: used to conduct and support

2). The composition of the bracket: the bracket is formed by the plating of the bracket material, and is composed of five layers of material, copper, nickel, copper and silver from the inside to the outside.

3). Types of brackets: the cup bracket is used as the condensing type, and the flat head bracket is used as the large-angle astigmatism type Lamp.
A. 2002 cup / flat head: This kind of bracket is generally made of materials that do not have high requirements on angle and brightness. Its Pin length is about 10mm shorter than other brackets. Pin pitch is 2.28mm
B. 2003 cup / flat head: generally used to make Lamp above φ5, the exposed pin length is + 29mm, -27mm. The pin pitch is 2.54mm.
C. 2004 cup / flat head: used to make Lamp around φ3. Pin length and spacing are the same as 2003 bracket.
D, 2004LD / DD: used to make blue, white, pure green, purple Lamp, can weld double wire, the cup is deep.
E, 2006: Both poles are flat head type, used for flashing Lamp, solid IC, welding multiple wires.
F, 2009: used to make two-color Lamp, two chips can be fixed in the cup, and three pin feet control the polarity.
G, 2009-8 / 3009: used to make three-color Lamp, three chips can be fixed in the cup, and four pin feet.

Second, silver plastic

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

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

The use of silver glue: refrigerated, it needs to be thawed and fully stirred before use, because the silver powder will precipitate after being left for a long time. If it is not stirred evenly, it will affect the performance of the silver glue.

3. Chip:

Structure composition of LED and LED chip

1). The role of the chip: The chip is the main component of the LED Lamp, and it is a light-emitting semiconductor material.

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

3), the structure of the chip:

Welding single wire positive polarity (P / N structure) wafers, double wire wafers. Wafer size unit: mil

The bonding pad of the chip is generally a gold pad or an aluminum pad. The pad shape is round, square, cross, etc.

4), the luminous color of the chip:

The luminous color of the chip depends on the wavelength, and the common visible light classifications are roughly: 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), purple (380-430nm).

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

5). The main technical parameters of the chip:

A. The volt-ampere characteristic diagram of the chip:
B. Forward voltage (VF): A voltage applied across the wafer to forward the wafer. This voltage has a corresponding relationship with 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 current generated by the chip after a certain voltage is applied. The size of IF is related to the size of forward voltage. The working current of the chip is about 10-20mA.
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 applying a reverse voltage. The smaller this current, the better. Because the current is large, it is easy to cause the wafer to be reversely broken down.
F. Brightness (IV): refers to the brightness of the light source. Unit conversion: 1cd = 1000mcd
G. Wavelength: reflect the luminous color of the wafer. Wafers with different wavelengths have different luminous colors. Unit: nm
H. Light: It is a kind of electromagnetic wave. Electromagnetic waves with a wavelength of 0.1mm-10nm 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; wavelength less than 10nm is X-ray light.

4. Gold thread:

The role of the gold wire: connect the chip PAD (pad) to the bracket and make it conductive.

The purity of the gold wire is 99.99% Au; the elongation is 2-6%. The size of the gold wire is: 0.9 mil, 1.0 mil, 1.1 mil, etc.

5. Epoxy resin:

The role of epoxy resin: protect the internal structure of Lamp, can slightly change the light color, brightness and angle of Lamp; shape Lamp.

The encapsulating resin consists of four parts: A glue (main agent), B glue (hardener), DP (diffusion agent), and CP (colorant). Its main components are epoxy resin (Epoxy Resin), acid anhydrides (acid anhydrous Anhydride), high light diffusive filler (Light diffusion) and thermal stability dye (dye)

6. Molding strip:

The mold strip is a mold formed by Lamp, and generally has a round shape, a square shape, and a tower shape. The depth of the stent is determined by the height of the clamping point of the mold strip. The mold strip should be stored in a clean and below room temperature environment, otherwise it will affect the appearance of the product