Quantum leap for flat-screen TVs


11 Dec 2007

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Researchers from both US and Chinese universities have been working on developing an LED (light emitting diode) screen for use in mobile devices and flat-screen TVs that not only consumes less power than traditional LEDs but is also thousands of times brighter and displays truer colours.

The QDLED, or quantum-dot LED, screen works by using nanotechnology that ‘excites’ electrons to emit a particle of light, displaying different colours depending on the size of the quantum dot.

The difference between QDLEDs and OLED (organic LEDs) such as Sony’s new XEL-1 television is that a device using QDLED for its display can run on three or four volts of electricity and will operate for 300 hours without losing brightness.

Andrew Wang, principal scientist of Ocean NanoTech, the firm that developed QDLED, told New Scientist magazine that while the optimum brightness of a high-quality, commercially available LCD monitor is 500 candelas per square metre, QDLEDs have reached 9,000 candelas – a scientific breakthrough considering an average room light is 2,000 candelas.

Researchers at Massachusetts Institute of Technology (MIT) in the US have already been working on this technology since 2002 but have not achieved the brightness level of 9,000 candelas reached by Ocean NanoTech, which has researchers from the Chinese Academy of Sciences working on its project.

However, MIT spin-off QD Vision applied for and received a US patent earlier this year for Stabilized Semiconductor Nanocrystals, which is material used to improve the performance of its QDLED flat screens.

Display technology has changed much in the past few years with the standard being either LCD (liquid crystal display), which uses a fluorescent backlight to shine through liquid crystal molecules, or plasma screens, which generally display better pictures but are heavier and use more power and work when light is emitted from phosphors or chemical compounds sandwiched between two thin layers of glass.

By Marie Boran