Solid-state sources for general lighting have gained much interest worldwide, but many technological hurdles have yet to be overcome, according to the “Advancements in Solid State Lighting” report by Frost & Sullivan of Palo Alto, Calif.Analyst Kasthuri Jagadeesan noted that government initiatives are driving research and development of solid-state lighting but that more development is needed to increase efficiency and to manage thermal issues. Lighting manufacturers are studying the best uses for LEDs and then designing the fixtures for the applications. But Jagadeesan maintains that the best red and amber AlInGa LEDs offer only 40- to 50-percent electrical-to-optical efficiencies, whereas the best UV, blue, green and white InGaN LEDs achieve only 30- to 35-percent conversion efficiencies. She indicated that this capability must improve, as must the lumen output for LED-based white lighting, before LEDs can be successfully introduced into the mainstream market.Fueling the growth in high-brightness LEDs is the technology competition among LED manufacturers as well as the cross-licensing agreements between major producers in Japan, the US and Europe. As a result, new materials, production techniques and research into phosphors will drive the development of more efficient LEDs, which will happen in tandem with solid-state lighting entering the general illumination market. LEDs will begin as replacements for halogen sources, and by 2020 they will be substitutes for incandescent and fluorescent ones. The report contends that high-intensity discharge sources will be the last to be replaced by LEDs. Organic LEDs (OLEDs) also are described, and many challenges are noted for both active- and passive-matrix OLEDs. The technology — organic vapor phase deposition — is described, with companies such as Universal Display Corp. of Ewing, N.J., and Aixtron AG of Aachen, Germany, mentioned as innovators in this process. Yet the technological hurdles are directing research toward small-molecule and polymer-based OLEDs. The future for OLEDs, the report states, is in cost-effective mass production using roll-to-roll manufacturing techniques. Part of the “Technical Insights” series, the report on solid-state lighting was released in September 2007 and has been updated continually to provide a technology overview and outlook for the market between 2007 and 2015. It includes ongoing technology analysis and industry trends, based on interviews with developers, researchers, engineers, analysts and others in the market.