LED potting compound is an auxiliary material for LED packaging. It has high refractive index and high light transmittance. It can protect the LED chip and increase the luminous flux of the LED. It has small viscosity and easy defoaming. It is suitable for potting and molding, so that the LED has Better durability and reliability.
The role of LED potting
In the process of using LED, the loss of photon generated by radiation recombination mainly includes three aspects: 1. The internal structure defect of the chip and the absorption of the material; 2. The reflection of the photon at the exit interface due to the difference in refractive index Loss; 3, and total reflection loss due to the incident angle greater than the critical angle of total reflection.
Therefore, a lot of light cannot be emitted from the chip to the outside. By coating a surface of the chip with a relatively high refractive index silica gel between the chip and the air, the loss of photons at the interface is effectively reduced, and the light extraction efficiency is improved. In addition, the role of silica gel also includes mechanical protection of the chip, stress release, and as a light guide structure to enhance heat dissipation to reduce the junction temperature of the chip and improve LED performance. In order to improve the reliability of LED packaging, silica gel also has low moisture absorption, low stress and aging resistance. Currently used potting compounds include epoxy resin and silica gel. Studies have shown that increasing the refractive index of silica gel can effectively reduce the photon loss caused by the physical barrier of refractive index and improve the external quantum efficiency, but the performance of silica gel is greatly affected by the ambient temperature. As the temperature increases, the thermal stress inside the silica gel increases, causing the refractive index of the silica gel to decrease, thereby affecting the LED light efficiency and light intensity distribution. However, the comprehensive performance of silica gel is significantly better than that of epoxy resin, and it is widely used in high-power LED packaging .
LED potting glue is classified by function
1. Mechanical protection to improve reliability;
2. Strengthen heat dissipation to reduce the junction temperature of the chip and improve the performance of the LED;
3. Optical control, improve light extraction efficiency, optimize beam distribution
LED potting glue is classified after curing
This series of products are classified according to the state after curing: gel type, rubber type, and resin type. The viscosity and hardness can be adjusted according to the use.
LED potting application
In the process of using LED, the loss of photon generated by radiation recombination mainly includes three aspects: internal structural defects of the chip and absorption of materials; reflection loss of photons at the exit interface due to refractive index difference; The total reflection loss caused by the incident angle being greater than the critical angle of total reflection. Therefore, a lot of light cannot be emitted from the chip to the outside. By coating a surface of the chip with a relatively high refractive index transparent layer - LED silica gel , since the adhesive layer is between the chip and the air, the loss of photons at the interface is effectively reduced, and the light extraction efficiency is improved. In addition, the potting function also includes mechanical protection of the chip, stress release, and as a light guide structure. Therefore, it is required to have high light transmittance, high refractive index, good thermal stability, good fluidity, and easy spraying. In order to improve the reliability of the LED package, the potting compound is also required to have low hygroscopicity, low stress, and aging resistance. Currently used potting compounds include epoxy resin and silica gel. Because of its high light transmittance, large refractive index, good thermal stability, low stress and low hygroscopicity, silica gel is superior to epoxy resin and is widely used in high-power LED packaging, but the cost is high. Studies have shown that increasing the refractive index of silica gel can effectively reduce the photon loss caused by the physical barrier of refractive index and improve the external quantum efficiency, but the performance of silica gel is greatly affected by the ambient temperature. As the temperature increases, the thermal stress inside the silica gel increases, causing the refractive index of the silica gel to decrease, thereby affecting the LED light efficiency and light intensity distribution.
Brushed Dc Motor,Dc Brushed Motor,Brushed Rc Motors,High Torque Brushed Dc Motor
Changzhou Sherry International Trading Co., Ltd. , https://www.sherry-motor.com