[opendtv] Re.Swiss develop full spectrum colour display technology
- From: "Nick Radlo" <nickradlo@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Mon, 21 Aug 2006 13:53:42 +0000
Does anyone have any more knowledge of this? From the BBC News website...
Nick Radlo
.............................
Artificial muscles light up TVs
By Jonathan Fildes
Science and technology reporter, BBC News
Arrays of thousands of tiny "super prisms" controlled by robotic muscles could
bring real colour to TV screens for the first time, scientists say.
The devices, known as electrically tunable diffraction gratings, have been
built by researchers in Switzerland.
They manipulate light to reproduce the full spectrum of colours on screen,
impossible using existing technology.
The team say the devices could also be used to make computer displays with the
same resolution as high-end LCDs.
"Today's displays can only reproduce a limited range of colours," said Manuel
Aschwanden of the Swiss Federal Institute of Technology in Zurich, and one of
the team behind the work.
"The main advantage of this technology is that it can display all colours."
Existing screen technology, like TV cathode ray tubes, LCDs and plasma screens,
reproduce colours using three lighting elements coloured red, green and blue.
Other colours are created by combining the primary colours. For example, yellow
is created by mixing red and green.
To show complex pictures a display must combine the colours at thousands of
individual points across the screen.
Different types of screen do this in different ways. For example an LCD is
divided into thousands of individual pixels, further divided into three
subpixels coloured red, green, and blue by filters.
Altering the brightness of each coloured subpixel creates a palette of millions
of different shades that can be used to represent most pictures.
Methods like this are unable to reproduce every colour we see in the real
world. This is particularly evident when reproducing images of the sky.
"When you take a picture and download it to your laptop the blues are never the
same as the real sky," said Mr Aschwanden.
Problems like this occur because the three primary colours current displays use
to reproduce on-screen colour are fixed. The green, blue and red a manufacturer
chooses to use in a display determine all the other colours it can reproduce.
The new system is not limited to the three colour system.
Instead, the researchers have developed a flexible approach that uses the full
spectrum of colours visible to the naked eye.
To do this the team have built what they call a diffraction grating, a slotted
grate like a miniature Venetian blind.
Diffraction grates are nothing new. They are already used in projector systems
and fibre optic telecommunications.
However, unlike existing solid grates the new one is made of a flexible
polymer.
The rubbery material is normally used to build artificial muscles for robots as
it contracts if a voltage is applied.
When pure white light from a light emitting diode (LED) hits the grate it is
split into the full spectrum of colours like a rainbow produced by a prism.
By applying different voltages to the artificial muscle the grate expands and
contracts, causing the fan of split light to shift from side to side.
Different colours can then be isolated from the spectrum using a tiny hole
fixed in front of the grate. Adjusting the voltage across the muscle allows
different parts of the colour spectrum to be lined up with the hole.
In a working screen, multiple grates behind each pixel would also allow
composite colours to be mixed, reproducing the full range of colours the human
eye can perceive.
At the moment the team have built a proof-of-concept array of 400 gratings side
by side. Although too small to be useful the miniature display has a high
resolution.
"It is the same density as a high-quality LCD display," Mr Aschwanden told the
BBC news website.
The team are now working on refining their experimental setup and in particular
trying to lower the voltage required to make the system work.
Initial experiments required thousands of volts to flex the muscle, but the
team have now reduced that to 300, making the technology more attractive to
electronics firms.
With more refinement Mr Aschwanden says that the devices could have multiple
uses in microscopes, fibre optic communications as well as high-end colour
screens.
"Tuning or steering light is at the core of all optical systems", he said.
"This offers a cheap, accurate way to do it."
The work was carried out with Professor Andreas Stemmer at the Swiss Federal
Institute of Technology and is published in the US journal Optics Letters.
Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/1/hi/technology/5263108.stm
Published: 2006/08/21 07:49:00 GMT
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