and affordable. BTS was created to help manage and serve as a catalyst for positive change in the building sector. As part of this mandate BTS has studied lighting sources and systems over a long period and, through that work and through industry-driven roadmaps, it has helped solid-state lighting emerge as a promising technology and a candidate for accelerated development. Solid-state lighting has already demonstrated its superior energy efficiency and longevity in selected niche applications, and Dr. Ginsberg said that the symposium would help to extend this progress through the exchange of ideas.
He offered a brief history of the solid-state revolution. The first chapter produced the transistor radio in the 1940s and 1950s, bringing worldwide access to information and entertainment. A more recent development was the possibility of replacing cathode-ray television sets and bulky computer monitors with highly efficient, high-quality solid-state flat screens. Even better screens are promised by organic light emitting diodes, or OLEDs, for which prototypes are already available. In both substitutions each solid-state replacement has proven to have higher quality, reliability, and energy efficiency than its predecessor.
Solid-state lighting began with inorganic LEDs that were first known as signal lights, employed for on-off applications in electronic devices and more recently in traffic signals and exit signs. BTS believes that sufficient R&D can overcome technical barriers and move solid-state lighting into the white-light market to compete both with Edison’s incandescent bulbs and with fluorescent technologies. Just a few years ago it was assumed that LEDs would never have such wide application because of their high cost and limited color. While that debate went on, a quiet revolution led to color breakthroughs and the NASDAQ sign in Times Square with its 16.8 million LEDs.
A more recent technology was initially developed by Eastman Kodak and its partners: organic LEDs, or OLEDs, which may eventually replace the computer screen and computer monitors we have today. OLEDs are already being used in mobile phones and car radios. If research continues to be successful, these OLED displays will eventually be incorporated into such building elements as ceiling tile and other home and office applications described earlier by Dr. Kennedy. These systems may also employ frequencies and signals that are invisible to the human eye, enabling our computer and communication networks to run without wires in the office of the future.
In addition to general illumination and the specific uses for LEDs and OLEDs