Sharp shows image-retaining LCD
Cut the power, still see a picture
Boffins at Sharp have come up with an LCD that continues to show a picture when the power's pulled.
Demo'ing the technology in Japan this week, Sharp showed off black-and-white and colour versions of the panel, in a range of sizes running from 1.7in to 14.1in.
Unfortunately, the company didn't say how it has brought e-paper like image retention to LCD. Electronic ink displays use charge particles to produce the picture. When the power is cut, the particles retain their alignment within each pixel. Since it's that alignment which determines whether the pixel is black, grey or clear, the image is maintained.
LCDs, by contrast, require a continuous voltage for the liquid crystal to maintain the polarisation, which governs whether a given pixel is 'on' or not.
A Sharp spokesman admitted that the power consumption required to 'save' the image is large, Japanese newspaper Nikkei reports.
He also confirmed the system uses "some materials that are not usually seen in LCDs", though that doesn't prevent the company from punching out panels using its older LCD production lines.
COMMENTS
@Dave
I think I also remember a system before the advent of cheap projectors that let you detach the lid of the laptop, remove the back of the panel and sit it on an old fashioned OHP and project onto a screen that way.
Maybe someone should bring back the screen-with-no-back idea and sell it as environmentally friendly... the greenies would love it, sales would surge on a tide of green nonsense
Who needs a backlight?
I'm sure in the past I've seen LCD tech that has the option to not use a backlight, but instead open the back of the panel to sunlight and use that instead
@Iain
It's not magic. The front button only cuts off power to the backlight, not the entire panel :P
Fully disfunctional....
"has anybody ever seen a fully functional screen but with a broken or otherwise 'off' CCFL?"
No, I've never seen anything "FULLY FUNCTIONAL" that has any part of it not work. I'm pretty sure that means it isn't fully functional.
Anyhow, if someone could invent better backlight technology and do away with it *properly* without any negative side effects, and improve black depth that's be great. I'm not sure I need the image once the screen is off.
Capacitors?
So, the panel requires a burst of energy to "save" the image but no more thereafter to preserve it. Methinks a capacitor is being charged somewhere and is being used to power a relatively classic LCD albeit maybe with reduced power consumption.
