Future TVs may wed carbon nanotubes, LCDs

[Slimy]

Samsung is experimenting with ways to drop the cost and increase the performance of LCD TVs by adding carbon nanotubes. The Samsung Advanced Institute of Technology, the laboratory arm of the South Korean industrial giant, has come up with a 15-inch prototype LCD (liquid-crystal display) screen that employs an array of carbon nanotubes. The nanotubes replace more-conventional light sources, such as bulbs or light-emitting diodes, to illuminate images on the screen, said Jin Taek Han, a senior researcher at the lab.

The prototype essentially represents the marriage of two separate avenues of TV technology and could help dramatically lower the cost of LCD TVs in the future. Samsung has already been experimenting with carbon nanotube TVs called field-emitter displays, or FEDs. In such TVs, thousands of nanotubes shoot electrons onto a phosphorescent screen to illuminate images. Carbon nanotubes are hollow molecules of intricately arranged carbon atoms that that have fairly remarkable properties. They conduct electricity better than metal, are stronger than steel and can emit light.

These nanotube TVs are actually similar in concept to traditional CRT (cathode-ray tube) TVs, and advocates claim that they will provide better resolution and picture quality than LCD TVs or plasma TVs. Toshiba and Canon will bring out a similar nanotube set known as SED TV late next year. (SED stands for surface-conduction electron-emitter display.) SED TVs, however, require new production lines. This mean higher prices, at least initially. Some analysts have also said that SED TVs may have a hard time competing in the market because prices on LCD TVs and plasma TVs are dropping so quickly.

By combining carbon nanotubes with LCDs, Samsung could leverage its expertise in LCDs. The company is the largest maker of LCD panels in the world. Nanotubes could also help cut LCD costs. Current light sources are costly and have to be carefully placed in a TV. The backlight on a 37-inch LCD currently represents 38 percent of the device's cost, and 50 percent of the cost for a 40-inch LCD, Han said. Companies are trying to reduce the cost of the light source by switching to LEDs and experimenting with lasers as a light source. Carbon nanotubes could work out even cheaper, as it may be possible to grow them in a substrate, the material on which a circuit is created.

"We think carbon nanotubes have a strength in cost," Han said. Additionally, the nanotubes could lower energy consumption and improve picture quality, he said. It takes a traditional LCD 15 milliseconds to render a picture. It takes the LCD with carbon nanotubes as a backlight just four milliseconds to do so. Samsung's goal is to create an LCD with a carbon backlight that lasts 30,000 hours and puts out 60 to 70 lumens per watt, about the same as for a traditional tube TV.

Han added that the work is in the initial stages. For all of their unusual properties, carbon nanotubes remain difficult to mass-manufacture. Tubes grown in the same batch will have different electrical properties, for instance. The Samsung lab, which has an annual budget of $300 million and employs about 1,000 researchers, is also looking into how the properties of nanotubes can be enhanced or controlled with different dopants--elements added to a semiconductor to modify its electrical conductivity. And in the end, these types of screens might be best suited for small formats, such as cell phone screens.

Carbon will also face stiff competition from LED TVs. Several manufacturers, such as Lumileds, are working to reduce the cost of LEDs, which are semiconductors that function as high-powered lamps. Samsung is further ahead on nanotube-based FED TVs. The work on those sets has been transferred from the company's lab to Samsung Display, which will try to figure out if FED TVs can be economically mass-manufactured. The LCD with the carbon backlight, though, is still inside the Samsung lab.

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