Quote:
Originally Posted by LDBoblo
I don't think any reflective technology gives close to "true" white. EWD like Liquavista expects to get above 50% white reflectance (some claims state 60%), EPD like E-Ink stands around 40% (SiPix's flexible-backed MicroCup stuff mentioned 33% reflectance). Some technologies like electrofluidic and electrochromic are [at least theoretically] capable of above 80% (pretty white). For what it's worth, Mirasol's white papers suggest they are capable of around 50% white reflectance, compared to 60% for the Wall Street Journal (print version, obviously). Bear in mind that white reflectance can be measured in different ways, so the numbers are not always completely comparable.
White reflectance will certainly improve overall readability in diverse light conditions, but black reflectance is also important to consider. Without a solid black state, even good white reflectance will look washed out.
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I have to say, LDBoblo seems to know his stuff. I just read
an article that said basically the exact same thing he just said.
The article mentioned that the Mirasol screen had a reflectivity of 50% with a contrast ratio of 8:1, whereas the Wall Street Journal's reflectivity was 60% with a contrast ratio of 4:1 (higher contrast ratios are better). The article also mentioned the technology used to create the mirasol screen (IMOD) has produced reflectivity greater than 60% with a 15:1 contrast ratio. BTW, a sheet of white paper measures between 70-90% reflectivity.
The article also explains why producing grays is difficult for IMOD devices-- basically a color is either on or off so you need to work at the subpixel level to get a color in between. There are two ways to get grays (spatial and temporal dithering) and one costs more while the other uses more power.