Polymer 'muscles' add colour to visual displays

[metadigital]

New Scientist is reporting that in the not-so-distant future computer monitors, and televisions may utilize a color changing polymer that responds to a current instead of existing techniques. From the article: "Aschwanden and colleagues built arrays of 10 pixels, each 80 micrometers across. The pixels consist of a piece of polymer covered with ridges tipped with gold. When white light is shone at the polymer from one side it reflects out of the screen and is also split into different wavelengths by this 'diffraction grating'. However, a slit above the polymer ensures that only one wavelength of light escapes, giving the pixel its color. The pieces of polymer also contract in response to current, like simple muscles. As they do so, the fan of light-waves is moved, changing the color that is fed through the slits above and out of the screen. Cutting the current causes the muscle to return to its original state."

 

Polymer 'muscles' add colour to visual displays

Television screens and computer displays capable of producing a wider range of visible colours could someday be built incorporating tiny sections of electrically-activated polymer. This polymer contracts and relaxes, like a muscle, in response to a current.

 

Researchers at the Swiss Federal Institute of Technology have made prototype display pixels that change colour as an underlying polymer is activated. This lets different wavelengths of light escape from the screen and means the display can generate the full spectrum of colours within white light.

 

Existing screens cannot produce every colour that is visible to the human eye. This is because their pixels make different colours by varying the brightness of red, green and blue elements. This can only produce a limited range.

 

True blue

"Some blues, for example, are beyond usual screens," researcher Manuel Aschwanden told New Scientist. "If you compare pictures of the sky or sea with the actual scene you can see the colours are not the same as reality." Similarly, many shades of green are also beyond electronic displays, he says.

 

Aschwanden and colleagues built arrays of 10 pixels, each 80 micrometres across. The pixels consist of a piece of polymer covered with ridges tipped with gold. When white light is shone at the polymer from one side it reflects out of the screen and is also split into different wavelengths by this "diffraction grating".

 

However, a slit above the polymer ensures that only one wavelength of light escapes, giving the pixel its colour. The pieces of polymer also contract in response to current, like simple muscles. As they do so, the fan of light-waves is moved, changing the colour that is fed through the slits above and out of the screen. Cutting the current causes the muscle to return to its original state.

 

Full spectrum

"We are working on pixels that mix the output of three tuneable gratings to produce the full range of colour humans can see," explains Aschwanden. This would be necessary because some colours, like browns, are not part of the spectrum that makes up white light.

 

The researchers also hope to reduce the amount of power needed to operate the displays. "At first it was necessary to apply around 1000 volts to tune the grating as required," Aschwanden says. "We've recently got it down to around 300 volts, which is low enough for commercial applications."

 

Journal reference: Optics Letters (vol 31 p 2610)

 

Sounds like a similar process to Liquid Crystals.

[Bokishi]

I want one!

[Nartwak]

Heh, I was reading up on synthetic muscle polymers a few years ago. I didn't expect them to take this turn though. ^_^

[Fenghuang]

Where's the totally sweet and awesome robots and cybernetic limb upgrades?