Whether silicone rubber material is suitable for LED packaging

In the 21st century, where the global energy shortage and the environment are worrying, LED has achieved unprecedented opportunities in the field of lighting because of its energy-saving and environmentally friendly characteristics. A Light Emitting Diode (LED) is a semiconductor light-emitting device that converts electrical energy into light energy and is a solid-state light source. Compared with traditional incandescent lamps, LED light sources have unparalleled advantages such as high brightness, long life, power saving, pollution-free, flexible and impact resistance. According to the study, if 55% of incandescent lamps and fluorescent lamps are replaced by LEDs in the United States, they can save $35 billion in electricity bills and 755 million tons of carbon dioxide emissions each year. The replacement of 100% of incandescent lamps in Japan into LEDs can reduce the power generation of one or two nuclear power plants and save more than 1 billion liters of crude oil per year. LED lights, with their significant advantages, will inevitably lead to a new lighting revolution in the history of human lighting following incandescent and fluorescent lamps.

In recent years, with the rapid development of LED chip technology and the maturity of related drive circuits, high-power white LEDs have not only become the darling of architectural lighting, but also increasingly toward home lighting. However, some problems in the LED packaging technology have restricted the further development of LED in the field of lighting. Its energy saving advantages such as high brightness, long life, and power saving cannot be truly realized. The basic task of the package is to connect the outer leads to the electrodes of the LED chip and improve the illuminance while protecting the LED chip from external environmental interference. The most difficult point of today's packaging technology is the poor heat dissipation of the package material and the poor luminosity. The temperature of the packaging material comes from the heat generated by the operation of the LED chip, and the heat released by the phosphor radiation is emitted. The key to improving the luminosity lies in the selection and application of the packaging material and the phosphor. Due to the good thermal stability and optical characteristics of silicone rubber, today's major international LED manufacturers mainly use two-component transparent silicone rubber as the packaging material. However, the thermal stability of silicone rubber is good, but the thermal conductivity is poor. After working for a period of time, most of the heat accumulated in the silicone rubber material is difficult to dissipate, resulting in rapid aging of the material. So far, many reports on the failure of LED lighting products have been related to the aging of silicone rubber materials. It is precisely because of the aging mechanism of silicone rubber that the relationship between molecular structure and optical characteristics is not well understood. The major international LED lighting companies are still unable to accurately predict the life of LEDs in their product descriptions, delaying LED products. The real popularity of use.

Another problem with silicone rubber used as an LED packaging material is that since the silicone rubber and the LED chip are significantly different in mechanical characteristics, the internal high temperature causes it to peel off from the LED chip and ultimately affect the luminosity. Dr. Cai published in the internationally renowned microfluidic journal Microfluidic and Nanofluidic, Cost Control and Reliable Adhesion Methods for Microfluidic Devices of Various Substrates Made of Silicone Rubber. And reliable sealing method for PDMS (PolyDiMethylSiloxane) ba sed microfluidic devices with various substrates" proposes a solution to this problem. He studied the polymerization of silicone rubber and analyzed which molecules were added to have a significant effect on the polymerization of silicone rubber. At the same time, through the verification of mechanical tests and electronic industry standard aging test, Dr. Cai summarized and developed a silicone-based material that can be widely used in various substrates to withstand high temperature, acid, alkali and other harsh conditions. Adhesive formulation. The adhesive can be adhered to various substrates by simple spraying or spin coating. The thickness of 10-20 nm ensures a very strong chemical adhesion between the silicone rubber and the chip substrate. Since the adhesive itself is also a silicone material that does not affect the optical characteristics of the silicone rubber, it is very suitable for LED packaging.

In the middle and lower reaches of the LED industry chain, packaging is an important link between the industry and the market. LED packaging involves knowledge of the fields of light, heat, electricity, polymer materials, etc. It is a comprehensive and complex subject, and it is also an urgent problem to be solved in the popular application of LED lighting. The silicone rubber material used for packaging has always been the main factor affecting the quality and life of LED. Only through in-depth understanding and analysis can it solve the problem of LED packaging better. We believe that with the unremitting efforts of materials scientists and LED researchers, LED lighting will shine and contribute to human energy conservation and emission reduction in the true sense.

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