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Fuji Xerox e-Paper Showcased

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Last week, one of the biggest e-paper conferences, SID, was held in Boston. Fuji Xerox had their line of e-paper technology on display at the event, one that the company claims is far better with its color display qualities. Fuji Xerox revealed this has been achieved by removing the color filter, which has resulted in a more vibrant display.

The technology that is used in this e-paper is that each color has been set a different threshold. The color particles to be drawn would be different as the charge that is applied would differ depending on the threshold set for that color. The drawing takes place on the back of the display board. However, Fuji has stated it is still in early stages with the e-paper technology. The prototype uses two colors, while plans are afoot to use three colors in the full color e-paper. The prototype is a 5 inch screen with a resolution of 600 x 800 pixels. The resolution can be considered to be a bit low for mass production.

Fuji is not alone in the race, as there are other companies that are experimenting with this type of working principle. The Mirasol display from Qualcomm is one. However, while e-paper can be extremely frugal in their energy requirements, the cost factor is proving to be the main hurdle for the progress of this technology. Compared to LCD and AMOLED based screens, this form of e-paper has turned out to be very costly. Another deficiency with the Mirasol screens is that they lag in color brightness.

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  • Uli

    Awsome!
    Finally a completely new approach for filterless color epaper. The advantage of filterless technologies is the much higher color saturation and brightness. You can get an idea of this benefit when you compare the first snapshots of Fuji’s prototype (http://nkbp.jp/JS0UEj) with products using filters like E-Ink Triton, Mirasol or first generation Liquavista. It really comes close to dye printed on a white paper! I am so excited about Fuji’s new color e-paper because it follows an approach that is pretty different from the other filterless approach I know (second generation Liquavista and Ricoh). Instead of arranging multiple layers of controllable color elements on top of each other, it uses up and down moving pigment particles. Looking at the photograph in this goodereader article, I assume that the key behind this approach is a hysteresis in the particle movement when the pixel voltage is varied. (Just having three different voltage thresholds for the particle movement would not be sufficient, as you would only be able to produce four different colour states like white, cyan, magenta+cyan, magenta+cyan+yellow. Exploiting the hysteresis of the particle movement, you can generate multiple different color states for a certain voltage, depending on the direction in which you approach this voltage (charging or discharging the capacitor of the pixel). If the positions and widths of the three hystereses are chosen smartly, you can produce all seven possible combinations of cyan, magenta and yellow plus white -> eight different color states.) If this assumption is correct, then some advantages and disadvantages of the technology can be deduced:

    positive:
    – filterless -> high color saturation, high brightness
    – perhaps even better than the other filterless approach, beacuse you have less transparent layers on top of each other and thus less reflection losses
    – using very small dye particles the achievable screen resolution just depends on the capacitor array and its controlling hardware. (Liquavista for example has to manufacture very complex microscopic dye cells which can be a huge drawback.)
    – power consumption is likely to be as low as b/w e-ink.
    – compatible with flexible screen materials

    negative:
    – low framerate, because particle movement takes time and produces heat
    – unavoidable page turn flickering (and therfore no video capability), because setting a certain color state requires a certain voltage sweep through other color states.
    – very low number of displayable colors (c, y, m, c+y, c+m, y+m, c+y+m) because the share of each of the three dye components cannot be controlled to any desired percentage. It’s just on/off for each color component. (Liquavista allows an independent stepless control of all three color components. Of course, the addition of a grayscale LCD layer on top of the Fuji screen will improve the color impression as the pixel brightness will be controllable. But this won’t enable the display of color nuances like orange or blue-green. This disadvantage could possibly be compensated by a very high screen resolution.)

    Well, maybe my assuptions are wrong, and the Fuji epaper works differently. Anyways, I am excited about the color epaper products we can expect to appear in the next couple of years!