OLED Origins

Oct. 9, 2008
Believe it or not, OLEDs extend back to the early 1950s. Researchers at the Université de Nancy in France produced electroluminescence in organic materials by applying a high-voltage ac potential to crystalline thin films of acridine orange and q

Believe it or not, OLEDs extend back to the early 1950s. Researchers at the Université de Nancy in France produced electroluminescence in organic materials by applying a high-voltage ac potential to crystalline thin films of acridine orange and quinacrine. Dow Chemical Co. followed in the 1960s by developing ac-driven electroluminescent cells using doped anthracene. Other researchers added further contributions.

It’s generally acknowledged that the Kodak Company was the first to discover the diode OLED in the late 1970s, when it was observed that organic materials can glow in response to electrical currents. Kodak scientist Ching Tang then discovered that sending an electrical current through a carbon compound caused the compound to glow. Both Tang and StevenVan Slyke continued the research, and in 1987, they reported on OLED materials that became the foundation of today’s OLED technology.

Since then, Kodak has set industry benchmarks with patented discoveries in OLED technology. Third-generation OLEDs from Kodak and others have been demonstrated as vibrant full-color displays that far exceed the color gamut of the other leading display technology, LCDs, by as much as 20%.

In the last few years, OLED advances have come fast and furious. For instance, Cambridge Display Technology (CDT) pioneered the development of light-emitting polymers (P-OLEDs) and their use in a wide range of electronic display products used for information management, communications, and entertainment. P-OLEDs are part of the family of OLEDs—thin, lightweight, and power-efficient devices that emit light when an electric current flows.

Another OLED contribution from CDT is its development of light-emitting blue polymers with lifetimes of 25,000 hours from an initial luminance of 400 cd/m2, which is equivalent to 400,000 hours from 10 cd/ m2. This milestone further enhances the company’s polymer P-OLEDs, since the production of video-capable OLED displays requires a full range of red, green, and blue colors with long lifetimes and good efficiency.

Other major OLED manufacturers like Universal Display Corp. and Novaled GmbH have reported OLED advances in terms of light output levels and better efficiencies. Dupont Co. is also a leading contributor to OLED materials and process technologies. Osram Opto Semiconductors and Siemens are investigating OLEDs as well.

Japanese companies like Sony and Matsushita and Korea’s Samsung have become extremely intrigued with the use of OLEDs for consumer electronic products. Many prototypes of such products have emerged, and there are plans to mass-produce them, though it remains unclear when this will happen.

About the Author

Roger Allan

Roger Allan is an electronics journalism veteran, and served as Electronic Design's Executive Editor for 15 of those years. He has covered just about every technology beat from semiconductors, components, packaging and power devices, to communications, test and measurement, automotive electronics, robotics, medical electronics, military electronics, robotics, and industrial electronics. His specialties include MEMS and nanoelectronics technologies. He is a contributor to the McGraw Hill Annual Encyclopedia of Science and Technology. He is also a Life Senior Member of the IEEE and holds a BSEE from New York University's School of Engineering and Science. Roger has worked for major electronics magazines besides Electronic Design, including the IEEE Spectrum, Electronics, EDN, Electronic Products, and the British New Scientist. He also has working experience in the electronics industry as a design engineer in filters, power supplies and control systems.

After his retirement from Electronic Design Magazine, He has been extensively contributing articles for Penton’s Electronic Design, Power Electronics Technology, Energy Efficiency and Technology (EE&T) and Microwaves RF Magazine, covering all of the aforementioned electronics segments as well as energy efficiency, harvesting and related technologies. He has also contributed articles to other electronics technology magazines worldwide.

He is a “jack of all trades and a master in leading-edge technologies” like MEMS, nanolectronics, autonomous vehicles, artificial intelligence, military electronics, biometrics, implantable medical devices, and energy harvesting and related technologies.

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