The principle of surface mount LED emission: The terminal voltage of the PN junction forms a certain potential barrier. When a forward bias voltage is applied, the potential barrier drops, and the majority carriers in the P and N regions diffuse towards each other. Due to the much higher electron mobility than hole mobility, a large number of electrons will diffuse into the P region, forming an injection of minority carriers into the P region. These electrons recombine with holes on the valence band, and the energy obtained during the recombination is released in the form of light energy. This is the principle of PN junction luminescence.

It is believed that LED packaging is of great significance for the quality of surface mount LEDs

1、 The necessity of LED packaging

The LED chip is just a small solid, and its two electrodes can only be seen under a microscope. It only emits light after being exposed to current. In terms of manufacturing process, in addition to stopping the welding of the two electrodes of the LED chip to lead out the positive and negative electrodes, maintenance of the LED chip and the two electrodes also needs to be stopped.
  

2、 The role of LED packaging

Developing packaging technologies with low thermal resistance, excellent optical properties, and high reliability is a necessary path for the industrialization of new LED applications and markets LED technology is mostly developed and evolved based on semiconductor discrete device packaging technology. The function of sealing the chip of a regular light-emitting diode inside a package is to maintain the chip and complete electrical interconnection.

3、 Selection of LED packaging methods

The photons emitted from the PN junction of LED are non directional, meaning they have the same probability of being emitted in all directions, so not all light generated by the chip can be emitted. The amount of light that can be emitted depends on the quality of semiconductor data, chip structure, geometric shape, internal packaging information, and packaging information.