HP's bendy plastic e-paper display on the way
Ribbony prototype tested
Bendy plastic displays might actually arrive in a year or two - HP has developed a prototype of a flexible display screen with Arizona State University's Flexible Display Center.
Flexible displays could be pulled out from a PDA-like device to provide a viewing area larger than the device itself. They could also be used as a form of paper, signage, or as displays stretched between supports for a meeting and then rolled away and packed up.
Making them is difficult because the flexible material obviously moves, meaning it deforms, and this makes it excessively difficult to add precisely aligned display components to it and ensure they stay aligned and don't become unstuck.
The HP display is crafted like a tape ribbon but in wider rolls. Roll-based manufacture is cheaper than sheet-by-sheet manufacture. A flexible plastic substrate is the starting point. This is flexible Polyethylene Naphthalate (PEN) from DuPont Teijin Films. HP then layers a thin film transistor array on this using a self-aligning imprint technology (SAIL) method. HP says it produces perfect alignment irrespective of any process-induced distortions in the substrate.
Then E Ink’s Vizplex imaging film is integrated to produce an actively addressed display. This is a bi-stable electrophoretic imaging material and it enables images to persist without applied voltage - it uses reflected light for viewing - and so lowers electricity usage.
The flexible display is monochrome and the same E-Ink material is used in Amazon's Kindle reader as a form of e-paper. In that device it has 4 grey-scales and the screen is basically light grey with darker grey text. It suffers from a lack of contrast compared to desktop, notebook and smartphone display screens. E-Ink does have a Vizplex film with 8 grey-scale levels, but not colour.
Amazon's Kindle
An HP statement says: "Mass production of such [flexible] displays can enable production of notebook computers, smart phones and other electronic devices at much lower costs since the display is one of the more costly components."
This is not really true as the HP bendy screen is a four- or eight-greyscale monochrome display lacking in contrast compared to the bright colourful screens we are all used too and few people would buy an HP notebook if it had such a crap screen.
The monochrome flexible display technology is amazing but limited. The holy grail here is a flexible, colour display with notebook screen brightness and resolution. That is still a long, long way off. ®
COMMENTS
Why do people say signage..
...when they mean signs? It really annoys me.
Practical uses for Colour ePaper
How many of us have been to a conference, or worse, had to stand at a conference stand. You know the bendy pre-printed screen that sits behind you... suddenly this could be an extremely large presentation display.
Let's not forget that there are other applications that just eBooks out there for this tech!
Moreover...
...it will be delivered in a box approximately the size of the Edmonton Incinerator.
Color
Since the base material is white/light grey (unlike black CRTs/LCDs), it would make sense to use a CMYK color scheme, as most printing processes do. Might require a hardware converter for everything that expects to use an RGB display. While it would cut the total pixel count by a factor of 4, I expect they'll continue to bring the pixel size down. Used to be you couldn't get bigger than 640x480 on a CRT; now it's two, three, maybe four times that in both dimensions.
Once they get to 256 colors, 72 ppi, and a refresh rate above 40Hz, they've got a marketable product. At 800x600 resolution, it'll be about the size of a letter/A4 sheet, with the quality of a regular printout. Great for reading books/newspapers, probably good enough for most office work (email, text documents, spreadsheets, etc.). I wonder if they can lay a multi-touch sensor on top of it...
The big thing to worry about is the limit of its flexibility. What happens when someone tries to fold it in half?
The real holy grail
"The holy grail here is a flexible, colour display with notebook screen brightness and resolution"
Nope. Almost every book in any library has monochrome text. None of the books in the library are backlit. Most of the books have a printed resolution less than any modern LCD. LCDs don't work in bright light.
We're talking about e-paper here, not a flexible LCD replacement. We're almost there. Tell the boffins to get on with it!
