Slashdot Mirror
DIY Electronic Paper Display
An anonymous reader writes "LinuxDevices.com has an article about a development kit for prototyping device displays based on electronic paper technology. The kit includes a 170dpi, 6-inch (diagonal) SVGA (800 x 600) EPD (electronic paper display) module supporting four shades of gray, and a small computer module that runs the display. EPDs provide bright, high-contrast, thin, lightweight displays that remain legible under 'any lighting condition' -- much like newsprint. Once an image has been 'printed,' no power is needed to hold it."
At the moment, I wouldn't rush out to build this. What I am doing, is waiting for somebody in the community to make it, break it, fiddle with it and make it better and higher res. I'd really like to see contributions to E-Ink and the other digital paper methods come from the online community, and I'd really like to see myself using this technology too.
What comes to my mind is placing the paper in an 'in' tray and having it have the next item of business printed onto it.
I'll subscribe to Slashdot when I see a month without a dupe, a typo, or an article the "editors" didn't read.
I don't know about anyone else, but I've been looking for a dev kit like this forever. Even just as an E-Reader (what the dev kit is preconfigured for) the possibilities are tremendous!
I'm a bit annoyed that it's taken 30 years since Xerox first developed the idea, but at least it's here now. Just imagine if this technology catches on. No more need for paperback books (you can keep all the latest on your pocket reader), technical books can finally be portable now that page graphics can be shown in detail, and eye strain will reduce considerably as your eyes can lock onto something that's actually there rather than simulated by a beam of light.
Javascript + Nintendo DSi = DSiCade
To expand:
1. Hi-Res Palm Pilots are 300x300 whereas this first-gen dev kit is 800x600.
2. In theory, eInk has all the contrast of paper. In practice it often has a slightly grey background, but still plenty of contrast in comparison to computer screens.
3. This effectively means that the processor can be put in a wait state or possibly turned off when the screen isn't being updated. For ebook readers, watches, and personal organizers, there's even the possibility of using something REALLY low power like a PIC since you're only updating the screen on very rare occasions.
Javascript + Nintendo DSi = DSiCade
I have used the LibriE electronic book mentioned in the article, which is available in Japan. I felt that it was an adequate replacement for a book, with an easily readable screen. Changing the page had some delay, but on the other hand so does changing the page of a real book. I imagine that the target audience of this are people wishing to read books on crowded Tokyo trains. Since less space is required this could be a good book replacement, after the cost comes down a bit. Biggest problem for their target group surely must be reading newspapers on the train, since they require a lot of space to open. It would be nice to see them provide newspapers for easy download to these devices.
This is the PDA every linux user (or maybe just me) has ever wanted. High rez, low power consuption, nice size, simple CPU. Open API. Who cares if it only has 4 levels of gray, that's all you need if your planning on doing work.
And these people think they need to sell it as a dev kit? It's a product already, just give it a shell.
On the other hand... $3000? Is that Canadian money?
I would rather be ashes than dust!
I've seen figures of around 0.5-1.0 seconds per pixel full addressing for these type of displays. :)
o ws_electronic_paper_potential_052301.html
Whilst not quick enough for movies (as you point out), would be perfectly acceptable for virtual paper
heres a link to an article mentioning the 1second refresh
http://www.trnmag.com/Stories/052301/Prototype_sh
"In addition, although the transistors allow a switching speed of about 2.5 milliseconds, the total time for an image to change smoothly is about one second; typical LCD's pixels are refreshed 70 times a second. "Currently the electronic ink, and not the transistors, limit the speed,"
liqbase
As usual, Slashdot manages to link to a vaguely interesting article and be completely incorrect and misleading in the title and summary.
This is *not* intended to be built by you, the hobbyist -- it is no "DIY" kit.
This is intended for people like Sony who want to be selling products based on this in a year or so. For them, $3k is more than reasonable, and not particularly out of line with the dev kits for many more mundane systems.
What is cool about this from the Slashdot reader's standpoint is that:
(a) It runs Linux. Linux is becoming dominant in the embedded world. Why not? It's flexible, there are no licensing fees, it's quite powerful, it's very well tested, and there is a huge pool of application developers available to hire from when you need to write your apps. The only drawback over a custom OS is memory usage -- but, hell, memory is getting cheaper every day, and for a high-end embedded device, it's not a big chunk of the cost.
(b) With any luck, it means that companies will start shipping e-paper products within two years or so. The last crop of "ebook readers" pretty much failed, which I think is too bad -- too expensive, and people didn't like the DRM. Perhaps the lower battery requirements of e-paper will make it feasible.
(c) The display drivers are open source. The concept of making drivers open source, the idea that it's valuable to avoid being stuck with hardware in your product that has NDA requirements, may be spreading. Maybe not. It still makes me hopeful.
Any program relying on (nontrivial) preemptive multithreading will be buggy.
The point is that reading text in notepad or from a pdf file should NOT require my laptop to be plugging along, wasting precious battery life on ubiquitous yet completely unimportant colors and movement. It's text. E-paper will open up a VAST new range of functionality, AND people seem to be forgetting that it is viewable from all angles, can (eventually) be rolled or scrolled up when not in use, and (perhaps most importantly) combats the horrible eyestrain that comes from attempting to read a full-text novel on an lcd screen. This is basically solid-state text, a book that's only one page long yet contains all the works of Tolstoy. Haven't you been lusting for this forever? Its the future, people! How long before these things are equipped with Wi-Fi, and can download the day's New York Times automatically and without the environmental and industrial cost of millions of wasted sheets of paper? How long before you're checking your email in a format that's actually READABLE at small screen sizes? How long before e-paper ASCII porn becomes the bee's knees? :P
Also, its important to note that in those other towering industrial countries (ahem, you know, OUTSIDE of the US, where we got so much of our tech to begin with), small one-application devices are MUCH more common than full-out computers for the user-on-the-go. Considering that our cell phones can do basically anything BUT display readable text, having a device that can fill that gap is beautiful. And speaking of cell phones, I'd gladly go to a monochrome e-paper display for a phone that would last me 50hrs on a charged battery...while you're clapping all 'special-needs' at your 16-kajillion color screen for the first 5 hours of the road trip, I'll be functional till we're back home. All of this goes to combat the rediculous bass-ackwards element of high-end technology - that the simple things are many times as difficult and power-consuming as the complex.
We look at technology right now in terms of best and brightest. But e-paper is a tremendous step towards what technology WILL be - an integrated, scalable, and subtle extension of our biological lives. I have NO doubt that we've got a humanistic renaissance coming up in a few years here, and we'll look back on widescreen displays and "gotta-have-it" superficial devices in the same way we shake our heads at the oily, pastelled veneer of the 80's. When technology TRULY becomes a part of our lives, when function overtakes form, wasting timeenergymoney so that we can watch Scary Movie between classes is going to seem pretty sophomoric, yes?
Sigh.
Quoted "constrast ratio" for active screens is not the same as the actual viewed contrast ratio of the LCD. That's the contrast ratio of the emitted white sections over the emitted black sections. But that's not what the eye sees, because it sees "emitted+reflected". The true contrast ratio of an active LCD varies with lighting conditions. It can be very very high in dark rooms (100:1, 500:1, etc.), but will be very very low in any sort of lit room. Outside, it'll probably be near 1:1 - i.e., unviewable. Much lower than that 100:1, 500:1. More like 4:1, or lower, in normal viewing conditions.
The contrast ratio of an E-ink display is about 10:1. Moreover, the E-ink display has about a 40% reflectance (as opposed to a 4% reflectance for LCDs), which means it's much brighter too.
CRTs have the same problem. They quote a 3000:1 contrast ratio, but the black and white sections have virtually the same reflectivity, which means that that contrast ratio only applies when the light in the room is much less than the light emitted from the CRT.
If you want to compare passive and active displays, you have to do it equally. In the same viewing conditions. Most people I know don't work inside pitch black offices.
and simple lambertian demands limit the reflectivity of the white areas (its no mirror, you know?)
E-ink displays are slightly less white state reflective than newsprint, but not much (40% compared to 60%). They have a much, much higher reflectivity than LCD displays - about 10 times higher (LCDs are 4%). With that high reflectivity, it doesn't take a lot of light for an E-ink display to have a much higher contrast ratio than an active LCD.