SBIR Phase I: Substrate-Guided Holographic Diffuser As Efficient Backlighting Solution For LCDs And LED-Lighting Applications

This Small Business Innovation Research (SBIR) Phase I project aims to design and fabricate a novel Substrate-Guided Holographic Diffuser (SGHD) for liquid crystal display (LCD) backlights and for light-emitting diode (LED) lighting. There is a substantial need to reduce the power consumption of backlit LCDs, while making them more affordable to consumers. Finding new techniques and materials both to reduce substantially the number of optical components in LCD backlights and make them more efficient and bright requires application of new scientific approaches. Holographic diffusers give a substantial brightness enhancement in a given direction provided the incident light input is in normal direction with respect to its surface. To date, the necessity to have incident light at a normal angle has prevented the widespread use of holographic diffusers in the LCD backlighting industry, because one or two additional optical films are needed to direct the light from LEDs towards the holographic diffuser. This Phase I effort will result in eliminating the need for one-two additional collimating optical films, and will provide a thin one-component bright LCD backlight with a controlled output angular distribution. The increased efficiency will reduce the power consumption. The broader impact/commercial potential of this project includes development of highly efficient and thin LED lighting panels for architectural, street, and similar lighting designs. Building a model of polychromatic light propagation and diffraction on SGHD will provide a basis for modeling and understanding of light propagation in a number of confined geometries: e.g., in thin waveguides for integrated optics and, in biological tissues. The commercial impact of the SGHD project includes development of more efficient and more cost effective LCD backlights aimed for mobile phones, and potentially for larger size displays, such as LCDs in notebook computers and in desktop monitors. The SGHD provides more compact illumination light patches for LED lighting. At the same time, SGHD should prove to be more power efficient than current solutions. Other applications of SGHD will include lighting components for medical, scientific, and industrial instrumentation. The success of this project will benefit society by reducing the cost and power consumption of LCD backlighting. The market sectors impacted will include LED lighting, color displays.