DIAMONDS can make the screens of laptop computers glow as brightly as the
monitor on a desktop, according to researchers at the electronics giant
Motorola. Screens using carbon films with some of the properties of diamonds are
sharper, brighter, and have a better viewing angle than the liquid crystal
displays of laptops鈥攁nd they could be on the market by the end the
decade.
Bulky desktop monitors and laptops use entirely different technologies. In
monitors, an electron gun at the back fires electrons at a phosphor screen. One
reason for their size is the need for the gun to scan the screen. Laptops use
LCDs which, instead of glowing, selectively block and filter light from a lamp
behind the screen. The displays are dim and cannot be seen from every angle.
The solution to this problem could be devices called cold cathodes, which
emit electrons at a low voltage鈥攁nd could illuminated a phosphor screen.
Several companies have tried using tiny pyramid-shaped pins of molybdenum to
inject electrons, but the tips do not last.
Advertisement
Jim Jaskie, an engineering physicist at Motorola in Arizona, has found that
carbon is much better at throwing electrons at the screen. 鈥淭he crystalline
structure of graphite and diamond are very close, but they have bizarrely
different electrical properties,鈥� he says. 鈥淕raphite is a good conductor, but
with diamond, an electron would rather leave the crystal.鈥�
A thin film of carbon, if deposited correctly, has some of the
characteristics of each. If a small current is applied to the carbon film,
electrons flow through the graphite-like part and jump out of the diamond
sections to illuminate a phosphor screen. 鈥淚t鈥檚 still exceedingly poorly
understood,鈥� says Jaskie. 鈥淏ut we鈥檙e very excited about carbon. We think it鈥檚
the future.鈥�
Michael Siegal, an engineer with Sandia National Laboratories in Albuquerque
agrees. 鈥淭here鈥檚 a lot they don鈥檛 know,鈥� he says. 鈥淭hey don鈥檛 understand the
mechanism, but they have done some remarkable things鈥攁nd they have
demonstrated superb properties.鈥�
Unlike the pin-based cathodes, the carbon sheets are flat, cheap and durable.
According to Jaskie, carbon-based laptops could soon be on the market. 鈥淭hey鈥檙e
pretty close. I would think about two years,鈥� he says.