Two innovative silicone products successfully developed by Wacker Chemical Group. These two silicone encapsulation materials, named LUMISIL740 and LUMISIL770, can be cured into highly transparent silicone elastomers and can withstand extremely high operating temperatures and strong light radiation without yellowing or embrittlement. They are especially suitable for High-efficiency LED packaging has been recognized by the market and continues to sell well.
(Jiangxi New Materials Co., Ltd.)
LUMISIL 740 and LUMISIL 770, two new LED packages The materials are all two-component formulas that can be cross-linked through a platinum catalyzed addition reaction at room temperature. The vulcanized rubber can reach the typical refractive index of polydimethylsiloxane of 1.41, which is a “normal refractive index” package. Material (Normal Refractive Index Encapsulant). They can effectively protect LED-sensitive semiconductor chips from environmental influences and can also be used as carriers for fluorescent dyes to change the color of LED light in a targeted manner.
What is special about LUMISIL740 and LUMISIL770 is their ability to withstand high temperatures, light and temperature changes extremely well. An aging test can confirm here: the test sample made of LUMISIL740 did not show yellowing or embrittlement after being stored at a temperature of 245 degrees Celsius for 500 hours. Even after 1,000 hours, the vulcanized rubber had almost no change. . LUMISIL740 has proven to be particularly resistant to the combined stresses of temperature and light. In the temperature change test from above zero 125 degrees Celsius to minus 45 degrees Celsius, both packaging materials withstood more than 1,000 test cycles, and therefore were able to well balance the thermal tension caused by different thermal expansions of the materials used in LEDs. .
These new silicones have good durability and are especially suitable for packaging LEDs that heat up quickly and emit intense light. The main difference between these two products is the hardness of their vulcanized rubber. LUMISIL740 can be cross-linked into materials with a hardness of Shore A50, and LUMISIL770 is slightly harder, up to Shore A70. The overall performance of LUMISIL740 is specifically tailored for the packaging of multi-chip LEDs; these LEDs have no housing and are densely mounted directly on the circuit board in chip-on-board (COB) technology. LUMISIL770 is an ideal material for single-chip LED packaging.
The viscosity of both encapsulating materials allows them to be applied without difficulty via the dispensing process. The self-adhesive formulations of LUMISIL740 and LUMISIL770 enable the products to self-adhere to semiconductor chips and common reflective film and housing substrates without the need for pretreatment.
