[LINK] LED display screens

[stephen at melbpc.org.au]

Fancy using a window as a computer monitor?


LED display technology gets a twist

Thu Aug 20, 2009 3:48pm EDT  By Julie Steenhuysen
http://www.reuters.com/article/scienceNews/idUSTRE57J5IM20090820


CHICAGO (Reuters) - U.S. researchers said on Thursday they have found a 
way to make large-scale flexible display screens that can be stretched to 
fit the contours of a bus, yet are transparent enough so riders can see 
out windows.

The thin, light screens might be used to make brake light indicators that 
follow the contours of a car, or health monitors or imaging devices that 
wrap around a patient like a blanket, said John Rogers of the University 
of Illinois at Urbana-Champaign, whose study appears in the journal 
Science.

He said the large display screens combine the scale and durability of 
light-emitting diodes, or LED technology, used to make flat, lighted 
billboards, with the flexibility of screens made using organic -- carbon-
containing -- materials.

Rogers said current technology using inorganic materials produces chunky 
individual LED lights that need to be arranged piecemeal with a robotic 
arm. 

Screens made using organic materials can be sprayed or painted onto a 
film surface, but they are not as bright or durable, he said.

To solve this challenge, researchers built their LEDs on a thin layer of 
film, later dissolved by a chemical and then affixed tiny plastic tabs on 
two corners to ensure the LEDs did not wash away in the chemical bath.

The team used a special stamping technology to deposit and assemble the 
inorganic LEDs onto glass, plastic or rubber surfaces. 

The system works much like a rubber stamp and ink pad, using the LEDs as 
ink.

"The new approach can lift large numbers of small, thin LEDs from the 
wafer in one step, and then print them onto a substrate in another step," 
Rogers said.

The LEDs can be interconnected and wired with a conventional process used 
to wire computer chips, he added. And because LEDs can be placed far 
apart and still provide enough light, the panels and displays can be 
nearly transparent.

"We can put them on a strip of plastic and make brake lights," said 
Rogers, who noted that the project was initially funded in part by Ford 
Motor Co, which was looking for a way to make brake lights that can 
follow the contour of a car.

The National Science Foundation and the U.S. Department of Energy also 
funded the project.

(Editing by Maggie Fox and Paul Simao)

--

Cheers,
Stephen