Fabrication technique may lead to commercial electrowetting displays

One very different entry in the race to create a commercially viable flexible display is the electrowetting display, in which each pixel contains a drop of colored oil that is moved electrically to different locations within the pixel cell.

Aug 1st, 2007

One very different entry in the race to create a commercially viable flexible display is the electrowetting display, in which each pixel contains a drop of colored oil that is moved electrically to different locations within the pixel cell. Such displays can have high visibility and be flexed or rolled. One hurdle to the potential wide use of these displays is the fabrication process, in which a tiny oil drop of precise size must be metered into each pixel by a microsyringe-a showstopper for mass production.

Now, researchers at the University of Cincinnati (Cincinnati, OH) and the Industrial Technology Research Institute (Hsin Chu, Taiwan) have developed a “self-assembly” process that can fill all pixels precisely at the same time with no manual metering required. The display substrate (containing a pixel grid) is lowered onto an oil film floating on water; the oil first wets the pixels, then the water separates the oil from all but the grid sidewalls, resulting in precise metering of volume. The display is then sealed with a top substrate. In one example, pixels 50 × 150 µm in size were filled; switching speed of the finished pixels was less than 10 ms. Contact Jason Heikenfeld at heikenjc@email.us.edu.

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