Ricoh reveals paper-bright colour e-paper
Hue well done?
Here's a snap of Ricoh's colour e-paper, which, the company claims, is two-and-a-half times brighter than anyone else's colour e-paper.
There's not much colour e-paper out there at the moment, you may have noticed, so Ricoh's boast is a mite hollow.
It also reckons its offering has "about four" times as wide a colour gamut as competing technologies.
The Ricoh e-paper has a reflectivity - essentially how 'white' the display looks - of 70 per cent, the company said. That compares to 80 per cent for a sheet of white photocopier paper, or 45 per cent for monochrome e-paper of the kind found in today's e-book readers.
E-paper screens rely entirely on light incident on the panel for their illumination, the light bouncing back of the rear of the display and out through the coloured pixels. Ricoh said it had increased the panel's reflectivity by compressing and combining the colour filter layers, and sticking a reflective base to the stack.
Ricoh's approach to colour e-paper differs from others in that it uses cyan, yellow and magenta as its primary colours rather than the more commonplace red, green and blue.
All good stuff, but alas no word from Ricoh on when we may see its panel in kit you can buy. ®
COMMENTS
"Ricoh's boast is a mite hollow."
No it isn't. If other techs exist and this beats them then that's progress and the developer has every right to boast.
Woah, you mean colour E-paper wasn't CMY before?
Glory be, those guys with the RGB one are superlative idiots.
When was the last time you saw an RGB printer? Colouring a surface *does not work that way*.
I hereby claim the idea of "CMYK" E-paper.
I also claim CcMmYyK (Light and dark of each secondary colour) and any combination thereof which would give different gamuts at various price points.
This is now my idea, and I release it for free because I want every e-paper manufacturer to use it, unencumbered by stupid patent trolls trying to claim the bleeding obvious.
The word you're looking for...
...is 'ubiquitous'.
That is all.
Subtractive vs Additive
LCDs are clear or Black. So don't work in three layers of CYM. Hence they have to have additive dots side by side. Each dot has to block entirely cyan (leaving red), magenta (leaving green) and yellow (leaving blue) wasting at least 2/3rds of the backlight. Real LED displays (like fill a wall) are Red, Green and Blue LED dots. AMOLED are really yellow or UV/Violet (with phosphor to get white), Most have LCD style RGB filters.
To use CYM you need a display that each element is coloured or transparent. The mono eInk in kindle etc uses tiny balls that are black on one pair of faces and white on the other, so they have to to use RGB filter additive side by side for colour which makes them VERY dim.
They must be using a liquid dye type display, each cell is empty (clear) or filled with cyan, yellow or magenta liquid. Parallax is an issue unless the cells are very much thinner than they are wide and high. OTH each cell can be 3x bigger than the RGB additive technique. Or twice as big for additive RGB arranged
RG
GB
for 2 x2 subpixel instead of older 3 x1 RGB stripes.
Can you say Contrast Ratio..
Its white is whiter than white, but is its black white too?
All well and good boasting about its reflectivity.. but how about the opposite??
