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10 April 2014 11:44 am ,
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The Pyrenean ibex, an impressive mountain goat that lived in the central Pyrenees in Spain, went extinct in 2000. But a...
Tight budgets are forcing NASA to consider turning off one or more planetary science projects that have completed their...
Ebola is not a stranger to West Africa—an outbreak in the 1990s killed chimpanzees and sickened one researcher. But the...
In an as-yet-unpublished report, an international panel of geoscientists has concluded that a pair of deadly...
Tropical disease experts tried and failed before to eradicate yaws, a rare disfiguring disease of poor countries. Now,...
Since 2002, researchers have reported that agricultural communities in the hot and humid Pacific Coast of Central...
Balkan endemic kidney disease surfaced in the 1950s and for decades defied attempts to finger the cause. It occurred...
- 10 April 2014 11:44 am , Vol. 344 , #6180
- About Us
Rubbing Out the Rub
4 May 2001 7:00 pm
The liquid crystal displays (LCDs) that light up laptop computers, cell phones, and other accessories of the digital age make up a $21-billion-a-year business. It could become even more profitable, now that researchers have eliminated a cumbersome step in the manufacturing process. The advance could simplify and speed display manufacture.
A typical LCD screen is made up of thousands of tiny cells. In each one, light enters through a polarizing filter at the back of the screen and is twisted 90 degrees by a spiral staircase of stacked liquid crystalline molecules. Then the light exits through a similar filter at the front of the screen that is oriented perpendicular to the first. When an electric voltage reorients the liquid crystal molecules, the light is no longer twisted and can't exit. The pixel goes dark.
To make the liquid crystal molecules in each cell stack up in the staircase-like fashion, displaymakers rub the two plastic layers that sandwich them in perpendicular directions with a velvet roller. This aligns the plastic molecules and causes the liquid crystals near them to line up in the same direction; with the liquid crystals on either side now stacked perpendicular to one another, the ones in between automatically form the staircase.
But this method can damage the transistors on the panel, introduce tiny contaminants onto the screen, and create streaks across it, says Mahesh Samant, a chemist at IBM's Almaden Research Center in San Jose, California. As a result, manufacturers frequently toss out hundreds of damaged screens.
Samant and his IBM colleagues in Yorktown Heights, New York, set out to develop a better method. They tried bombarding various thin surfaces with ions. The technique worked, they report in the 3 May issue of Nature: The ions created tracks in the films that oriented the liquid crystals. Together with colleagues at IBM's display and engineering business units in Japan, they used the new technique to make 15-inch and 22-inch LCD displays that team member James Lacey calls "sharper and crisper" than today's models.
Industry analysts are watching closely. LCD prices have plummeted recently as production soared, and the new process could help LCD makers drop prices even further, says Kimberly Allen of Stanford Resources, a company that analyzes display technology and markets.