Dongli Dow Corning New Silicone for White LED Package and Lens

Dongli Dow Corning presented its new silicone product and development for light emitting diode (LED) packages and lenses at "InterOpto`06" held in Meguro-Mitsubishi, Japan from July 12th to 14th, 2006. Products. As the output power of white LEDs continues to increase, shorter wavelength light transmittance and better thermal resistance silicones will increasingly be used for packaging materials and lenses. Because LED manufacturers have different requirements for the hardness, viscosity, and refractive index of silicone resins, the company is actively expanding its product lineup.

The new silicone products and developments exhibited at the exhibition included common ordinary refractive index 1.41, three common types for LED packaging, four kinds of encapsulated products with a refractive index of 1.52, and two types of lens molding products. The three products with a refractive index of 1.41 are the new product "OE6336" with a hardness of 60 to 70 degrees after hardening, 1.46 Pa?s before hardening, and the new product "EG6301" with the same hardness and viscosity of 3.4 Pa?s. The "OE6340" is a development product that has a hardness of 40 degrees and is softened into a gel. The OE6336 and EG6301 with different viscosities were used for the packaging of white LEDs and the color temperature was changed by changing the number of dispersed fluorescent particles in the packaging material. The gel-like OE6340 is mainly for customers who pay special attention to the peeling of the encapsulating material.

The four types of products with a refractive index of 1.52 and packaging include the development product "OE6665" with a hardness of 65 degrees; the new product "JCR6175" with a hardness of 50 degrees and the development product "OE6520" and the "penetration degree" with a softness of 50mm/10 colloidal development product "OE6450". When these high refractive index silicones are used as the encapsulating material, the encapsulating material and the LED chip have similar refractive indexes, so that the light emitted from the LED chips is projected to more chips. Overseas LED manufacturers have more orders. Compared with the marketed JCR6175, the development product OE6520 with a hardness of 50 degrees has improved adhesion and controlled volume change after hardening. Colloidal OE6450 is used in combination with high hardness silicone resin. For example, OLEDs are covered with OE6450 near the LED chip, and the outside is covered with a hard silicone.

The two types of lens molding products include the development product "OE4705" with higher viscosity and easier molding than the original Toray Dow Corning "SR7010" and the development product "OE6665" with the hardness of 65 degrees. The OE6665 is suspended on a printed circuit board on which LED chips have been packaged for simultaneous chip packaging and lens forming (Figure 3). Due to the adhesiveness equivalent to the packaging purpose, it can be used to fix the LED chip. Another reason is that the shading will become convex. This "overmolding" method is a manufacturing technology that fixes a plurality of white LEDs on a printed circuit at a low cost, and the chance of adoption in the future is expected to increase.

Source: Technology Online