LSR Developments in LEDs for Automotive and Street Lighting

LSR’s resistance to UV light and high temperatures allow direct contact to LED, while low injection pressure allows overmolding of sensitive parts.

 

The materials feature in our upcoming June issue discusses the latest developments in LED lighting materials and how savvy material suppliers have been adapting to this rapidly evolving technology. Since I could not fit everything I wanted to into the article, I’m taking the opportunity here to share some of the interesting things that didn’t make the cut in three blog installments.

 

The first two involve case studies: this one on Momentives’s clear LSR lens and optics developments, and the next one on PolyOne’s ThermaTech thermally conductive compounds in LED heat sink applications. A third will highlight new materials for the LED lighting sector from Trinseo and Wacker.

 

Momentive Performance Materials Inc., Waterford, N.Y., is among the leading suppliers of LSR that have seen the potential for their materials to play a major role in the ever-expanding LED lighting sector where applications now range from interior and exterior illumination; automotive and transportation lighting; backlighting for TVs, computers, phone displays; and signs and billboards.

 

The two case studies below exemplify Momentive’s advances in automotive and street lighting as relayed by HeeSeok Hwang, senior global project manager. As Hwang summed it up, “The typical properties of ultra-clear LSRs enable totally new functions for LED applications. LSR’s UV-light and high-temperature resistance allow direct contact to LED; low viscosities and low injection pressures allow overmolding of mechanically sensitive inserts; and the LSR-injection process enables ultra-precision shaping of microstructures. Taking this and thinking toward the future, Momentive has taken an additional step to improve the efficiency of lighting technology through LSR.”

 

 

• Automotive Lighting:

Together with partners in the industry and supported by national means of Germany’s major research organization Deutsche Forschungsgemeinschaft, a team of Momentive LSR specialists has started to work on a new injection molding process to overmold a LED chip with Momentive’s Silopren LSR7080HP LSR. The objective is to combine primary and secondary optics in one component to reduce assembly, improve efficiency, and to downsize the complete lighting component. The project involves analysis of optical performance, molding precision, and the bond strength between the LED board and the LSR as well as long-term properties.

 

The molding of microstructures on the surface of the LSR lens will be also be tested. Momentive is working with Germany’s Hella, a producer of automotive headlamps and lighting equipment, the IKV institute of plastic technologies; and Austria’s Elmet, a manufacturer of high-precision LSR molds and injection molding equipment. To date, it has been demonstrated that the overmolding process can work without the use of any bonding agent, correspond to the simulation, and not show any optical defects. Endurance tests of the combined primary and secondary optics are ongoing and promising.

 

• Street Lighting: 

Momentive’s next-generation Ultra Clear Silopren LSR grade combines Ultra Clear LSR technology with a specialty polymer technology, enabling luminaires to be equipped with high flame retardance above UL 94 flame class rating for V-1. Momentive has been working with global experts in the lighting industry such as Italy’s Khatod Optoelectronic, a leading manufacturer of optical solutions. “This application is very technical and Khatod was searching for a material able to comply with the various optical, mechanical, and molding process requirements needed for the realization of unique, high-performance optics,” said Dieter Wrobel, corporate fellow at Momentive. After and in-depth analysis and numerous laboratory tests, Khatod determined that Momentive’s Ultra Clear Silopren LSR 7000 series was an ideal match for this applications.

 

Khatod recently used Momentive ultra-clear LSR in SIO3 silicone lenses. There lenses are said to represent a breakthrough in LED lighting technology and are the world’s first range of free-form lenses made of LSR which are optimized for the most popular HB (high-brightness) and COB (chip-on-board) LEDs. “Khatod is a real innovator in the LED lighting industry. Our SIO3 lenses boast cutting-edge engineering and exclusive cold runner-based LSR injection molding process specially customized by Khatod for optical silicone processing. This innovative construction process preserves and enhances the typical characteristics of silicone and makes the lenses excellent for any application in LED lighting requiring excellent lighting performance as well as a robust long life, safe and reliable service,” said Giuseppe Vast, president of Khatod. Khatod’s  new SIO3 silicone lenses recently won the LED Magazine’s SSL Enabling Technologies Sapphire Award, which highlighted the most inspirational and innovative products in the LED marketplace. 

 

Read Part II, Plastic Heat Sinks for LEDs “Shine” for Two Lighting Component Manufacturers

 

Read Part III of Lilli's LED Series—LSRs, PPs and PCs for LED Lighting

 

Search LSRs in PT’s Materials Database.