Signaling the end of a patent battle lasting for almost three years, Korea’s Intellectual Property Tribunal (IPT) rejected an attempt to invalidate Dow Corning patent 10-976075. The patent is among Dow Corning’s rich intellectual property (IP) portfolio covering the company’s proprietary high refractive index (RI) phenyl-based optical silicone technology, which offers numerous high-value benefits to LED devices. These benefits include improved light output, excellent mechanical protection of LED components and enduring gas barrier properties for enhanced reliability. Handed down by the IPT on August 9, the decision in favor of Dow Corning significantly strengthens its intellectual property position for the technology in Korea, as well as in other key global LED manufacturing centers, including the U.S., Japan, Taiwan, China, Malaysia and Europe.

“Dow Corning is clearly delighted and very encouraged by the IPT’s decision,” said Gregg Zank, SVP and CTO, Dow Corning. “As a global innovator, collaboration partner and leader in high RI optical silicones, we are committed not only to ground-breaking development of high-performance LED materials, but also to rigorously defending the high-value intellectual property that protects our products and the competitive advantage in quality and reliability that we share with our customers in today’s fast-growing LED market.” 

Dow Corning originally developed its phenyl-based silicone encapsulants in Japan over a decade ago, and filed for patent protection in Japanand elsewhere. The materials’ high RI has since helped them set the standard for optical LED silicone materials. The patent was granted for this technology in multiple countries, including Japan, Korea, the U.S., E.U., Taiwan, Malaysia and China. Korean Patent 10-976075was granted in 2010.

As LEDs increasingly occupy greater share of the general lighting market, Dow Corning – a global innovator in silicones, silicon-based technology and innovation – expects adoption of high RI optical materials like its phenyl-based silicones to be a key driver of future LED market growth. 

“Higher refractive index is more than a technical abstraction. It is a strategic market advantage for LED manufacturers worldwide,” said Eric Peeters, VP, Dow Corning Electronics and Lighting Solutions. “Our patented materials deliver RI as high as 1.54, compared to 1.41 for competitive methyl-based silicone chemistries. While seemingly small, that difference can translate into about 7 percent more light output. Achieving a comparable improvement from an LED chip would require significant investment.”

In addition to higher RI, Dow Corning’s broad portfolio of phenyl silicone packaging materials delivers photo and thermal stability suitable for many middle and high-power general lighting applications, including chip-on-board LED architecture. Compared to methyl technology, phenyl-based silicone encapsulants generally offer a comparatively stronger gas barrier, which helps protect key LED components such as silver electrodes and phosphor against moisture deterioration and sulfur corrosion. LED electrodes double as reflective elements, and phosphor is a key element of light conversion. So, enhanced gas barrier protection helps maintain both the performance and reliability of LED output. 

Over the past decade, the high efficiency and reliability afforded by Dow Corning’s phenyl silicones has helped establish the company as today’s recognized market and technology leader in optical encapsulants for high-performance LED applications. Virtually all of the company’s optical encapsulants fall under the recently upheld patent or its associated IP portfolio. So, LED manufacturers can be confident they are designing with high-performance encapsulant materials backed by strong international patent protection.