Fujitsu's FLEPia screens, which were already available a year ago, do work another way, using three layers to reflect one colour each:
Pushing light through all those layers makes for a dull screen
That's great, but the light loses a lot of brightness going through all those layers, and having to refresh each layer separately makes pushes the latency up to eight seconds (yes: in full-colour mode the FLEPia screen can take eight seconds to redraw).
Which brings us to Mirasol: Qualcomm's technology which in the last year has moved from a concept, to prototypes, to production, with a device announcement from an unnamed partner promised at CES in January. Mirasol uses the same sub-pixel technique as E-Ink, but instead of black beads in white goo it changes the distance between a mirrored plate and colour filter to trap light of the wrong wavelength:
This is a blue pixel, obviously
So instead of being reliant on the reflectivity of the white goo, as the Triton screen is, Mirasol is as bright as the mirrored surface underneath is reflective. Not only that, but because it moves plates up and down, rather than shifting beads suspended in goo, it has a much higher refresh rate that enables it to comfortably show video while still consuming a fraction of the power used by a traditional screen.
We've seen a Mirasol screen in action, several times, and it's bloody impressive; but with the prototype more than a year old it's not clear why we don't already have Mirasol displays yet.
Qualcomm hasn't explained, though it has started manufacturing 5.7-inch screens, presumably at the behest of that unnamed partner. 5.7-inches isn't going to give the iPad any cause for concern, and if the technology is as scalable as Qualcomm keeps telling us it is (ideal for Tvs, and all sorts, we're told) then why start with such a small size?
It seems likely the problem is price, which may trump contrast and refresh rate as the most important factor affecting colour electronic ink. Improvements in LCD technology, and better batteries, are pushing electronic ink aside in tablets, and starting to push into electronic book readers too.
The promise of a screen that consumes no power and when idle, and has no flicker, is attractive, but making users pay for it is another matter entirely. So if you want colour in your e-book then you'll have to pay for it, or just buy a LCD tablet and read in the dark instead. ®
Multi-colour e-ink to splash down in six months?
Why colour screens on readers?
Once the resolutions are improved, I could really see this e-ink being used to make great digital photoframes. I've never wanted one of the current generation LCD screen photo frames because of their bright LCD screen and the fact that they need a powersource.
A device that doesn't produce light will look more like a traditional photoframe and if it doesn't require a power source will mean they can be hung pretty much anywhere, yet it could be updated with a different photo if the owner fancies a change.
Cost is a major factor for a colour dedicated ebook reader.
Most of the average book is black and white. I'm not going to pay a premium just to see the front cover in colour.
I can't even see any compelling need to upgrade from my Cybook to a Pearl screen.
Color is important...
Ok, so you look at the people who have e-readers.
Those that want a portable way of carrying a couple of novels as they ride the train to and from work, and those computer geeks that want to be able to carry a bunch of manuals in .pdf as well as e-books.
Then there's power points as .pdf which many are in color. Diagrams in color.
Sure there's gray scale. (I've done enough B&W photography to be comfortable) But color makes life easier.
What I'm looking at is the next gen iPad to see if it has the ~300 dpi display, and seeing 300+ color dpi i e-ink.
I think if you can get the resolution high enough and the refresh fast enough, e-ink is very viable.
Also I'd love to see e-ink on different substrates.
Color is nice
But they were talking about using this stuff in newspapers back when they first announced it, so where the fsck are the ebook readers that look like actual books? The ability to flip amongst several pages is still a pretty big advantage for dead wood.