Halogen-Free Radiation-Curable, High Refractive Index Meterials

By Jeffrey Wang, Marcus Hutchins, Kenneth Woo, Chris Matayabas, Tom Konish

There is increasing demand for high refractive index (RI) materials that have high transparency and low birefringence for advanced integrated opti­cal and optoelectronic applications.1-3 Some of the important and well­ known applications include optical disks, diffraction gratings, optical fiber clad coatings, anti-reflection coatings, imaging sensors, light-emitting diodes (LED), and photonic devices such as waveguides and optical switches.4 High refractive index coatings are applied to flat panel displays, such as liquid crystal displays (LCD), as a brightness enhancing film (also known as a prism sheet). Polarizer films used in LCDs also require hard coatings with high RI. High RI coatings may improve the light emission and reception effi­ciency of white LEDs sufficiently to enable them to become the preferred light source of the 21st Century. Anti-reflective films may improve the ap­pearance of LCD and other display devices.

Microlenses in charge-coupled devices (CCDs) made from high RI materials may in­crease the amount of light received for higher sensitiv­ity and higher definition. The creation of thin lenses will also contribute to the development of thinner equipment. Thus, there are many applications for high RI materials.