LED, a real sense of energy? Silicone rubber is the key

Hubei News Network May 19 power in the global energy shortages, environmental concern of the 21st century , LED with its efficient energy saving features, the lighting has been an unprecedented opportunity. LED light-emitting diode (Light Emitting Diode, abbreviated as LED) is a kind of electrical energy can be converted to a semiconductor light emitting device , are solid state light sources. Compared with traditional incandescent , LED light source with high brightness , long life , energy saving , pollution-free , flexible, impact resistance and other unparalleled advantages . Study reported that 55 percent of the United States if the LED to replace incandescent and fluorescent lamps , the annual electricity savings of $ 35 billion and reduce 755 million tons of carbon dioxide emissions. Japan, 100% of the incandescent LED, can be reduced by 1 ~ 2 nuclear generating capacity , annual savings of more than one billion liters of crude oil consumption. LED lights With significant advantages, will lead history of mankind lighting incandescent , fluorescent and the new lighting revolution .

In recent years , with the rapid development of LED chip technology and associated driver circuits mature , high power white LED architectural lighting not only become the darling , are increasingly moving to household lighting . However , LED packaging technology some of the problems that exist in the field of LED lighting restrict the further development of its high brightness, long life, energy saving and other advantages not truly reflected. Encapsulated basic task is to protect the LED chip from the external environment under the premise of interference , the outer leads connected to the electrodes of the LED chip , and increase luminous efficiency . The primary difficulty packaging technology today is poor heat dissipation and packaging materials and poor luminous efficiency . Packaging materials from the LED chip operating temperature of the heat generated by the radiation emitting phosphor after accumulating the heat released , and the key to improve the luminance and the phosphor is that the choice of packaging materials and applications . Since silicone rubber has good thermal stability and optical characteristics of today's major international LED manufacturers mainly use two-component transparent silicone rubber as a packaging material . However , silicone rubber, heat stability is good, but poor thermal conductivity , LED working for some time , most of the heat accumulated in the distribution of silicone rubber material is difficult , leading to rapid aging material . So far, a lot about the failure of the report of the LED lighting products with the silicone rubber material aging. Precisely because of the aging mechanism of silicone rubber , molecular structure and optical characteristics of the relationship between a thorough enough understanding , major international LED lighting company is also unable to explain their products in the life of the LED to accurately predict the delay of the LED products the truly universal use .

Recently , electronic materials expert Dr. Cai Dengke ( University of Dortmund, Germany ) spectroscopy in the internationally renowned journal " Molecular Structure " (Journal of Molecular Structure) published a detailed description and analysis of a physical and chemical properties of silicone rubber paper, " Raman , in infrared , near-infrared and ultraviolet-visible spectrum of silicone rubber polymer optical waveguide materials characterization "" Raman, mid-infrared, near-infrared and ultraviolet-visible spectroscopy of PDMS silicone rubber for characterization of polymer optical waveguide materials ". Tsai found that carbon-hydrogen bond (CH) of molecular structure is caused by some visible band of silicone rubber in the main heat absorbed . He focuses on the spectrum from the ultraviolet to the infrared silicone rubber molecular structure and the relationship between the optical absorption , a detailed definition of silicone rubber within the visible absorption spectrum , and accurately analyzed and summarized in the visible range of the absorption peak of the absorption strength . Because the current aging of commonly used organic spectroscopy analysis , the researchers concluded can be based on spectral data Tsai , from the molecular structure accurately determine the cause of failure resulting silicone rubber and silicone rubber material fed back to the research company or LED , the corresponding molecules of silicone rubber modified to enhance the reliability of materials and in the application of LED products . This paper summarizes and analyzes data in silicone rubber LED products will solve the problem of aging plays a vital role and groundbreaking contributions.

Silicone rubber for LED packaging materials , another problem is that because the LED chip in silicone rubber and mechanical characteristics significantly different , the internal temperature will cause it to peel off from the LED chip and ultimately affect their own emission rate . Dr. Choi in internationally renowned microfluidic magazine " microfluidics and nano fluid " (Microfluidic and Nanofluidic) published a paper on " silicone rubber composition for various substrates microfluidic devices cost control and reliable adhesion method " "Cost-effective and reliable sealing method for PDMS (PolyDiMethylSiloxane) based microfluidic devices with various substrates " on this issue proposed solutions . He passed on silicone rubber polymerization studies , analysis of what elements would add silicone rubber polymerization significant impact . Meanwhile, mechanical testing and electronic industry standard aging test confirmed by Dr. Cai to summarize and develop a siloxane based materials, can be widely applied to various substrates can be high temperature , acid , alkali and other harsh conditions blocking agent formulations. Such blocking agents , or through a simple spin coating spray to adhesion on various substrates , a thickness of 10 to 20 nm can guarantee the silicone rubber substrate and the chip to form a very strong chemical adhesion. The blocking agent is a silicone material itself does not affect the optical characteristics of silicone rubber , so it is suitable for the LED package .

The LED on the downstream industry chain, packaging is an important connecting link between industry and market . LED package comes to light, heat , electricity , polymer materials and other fields of knowledge , is an integrated complex subject , but also the popularity of LED lighting applications pressing problem . Silicone rubber for packaging materials has been the impact of LED quality and life of the main factors , and only through its in-depth understanding and analysis in order to better address the problem of the LED package . We believe that materials scientists and researchers to the tireless efforts of LED , LED lighting will shine, in the true sense of humanity to contribute to energy conservation .