Maneesh Bahadur

Novel silicone materials for LED packaging

Silicone based materials have attracted considerable attention from Light Emitting Diode (LED) manufacturers for use as encapsulants and lenses for many next generation LED device designs. Silicones can function in several roles that include protective lenses, stress relieving encapsulants, mechanical protection and light path materials. The key attributes of silicones that make them attractive materials for high brightness (HB) LEDs include their high transparency in the UV-visible region, controlled refractive index (RI), stable thermo-mechanical properties, and tuneable hardness from soft gels to hard resins. The high current and high operating temperatures of HB-LEDs present a significant materials challenge for traditional organic materials such as epoxies, acrylics and cyclo olefin copolymers (COC) that lack the thermal and molecular stability needed to provide optical clarity and mechanical performance required for next generation devices. In addition, the retention of optical clarity over the lifetime of the device, which involves long term exposure to high flux in the UV-visible wavelength region, is a critical requirement. Silicones have been demonstrated to provide the required stability. This paper will describe recent silicone materials development efforts directed towards providing LED manufacturers with silicone materials solutions for LED device fabrication. Injection molding of novel silicone resin based materials will be discussed as a surmountable challenge for high throughput LED device manufacturing.

Novel silicone materials for LED packaging and opto-electronics devices

Silicone based materials have attracted considerable attention from Light Emitting Diode (LED) manufacturers. In LEDs, silicones can function in several roles that include optical lenses, stress relieving encapsulants, mechanical protection and light path materials. The key attributes of silicones that make them attractive materials for high brightness (HB) LEDs include their excellent transparency in the UV-visible region, their non-discoloring behavior and their stable thermo-mechanical properties. The first part of this paper/presentation will describe recent silicone materials development efforts directed towards providing LED manufacturers with silicone materials solutions for LED device fabrication. Injection molding of novel silicone resin based materials will be discussed as a viable route for high throughput LED device manufacturing. For other portions of the light spectrum, specifically at telecom wavelengths, the performances of silicone based materials are also verified and this makes them attractive materials for numerous photonics device applications. The second part of this paper/presentation will describe recent demonstrations of siloxane for use as waveguides for datacom and telecom applications. A Variable Optical Attenuator (VOA) utilizing silicone based waveguides (exploiting dn/dT property) and an Optical Backplane built from silicone waveguides and out-of-plane mirrors built on glass and FR-4 substrates are discussed.

Silicone materials for LED packaging

Silicone based materials have attracted considerable attention from light emitting diode (LED) manufacturers for use as encapsulants and lenses for many high brightness LED (HB LED) devices. Currently silicones function in two key roles in HB LED devices, (1) as protective lenses and (2) stress relieving encapsulants for wire bond protection. The key attributes of silicones that make them attractive as light path materials for high brightness HB LEDs include their high transparency in the UV-visible region, controlled refractive index (RI), stable thermo-mechanical properties, and tuneable modulus from soft gels to hard resins. This paper will describe recent developments in moldable silicone hard resin materials. Progress on cavity moldable and liquid injection moldable (LIM) silicone compositions for discreet components is described. Also, an example of liquid injection overmolding is presented.