E-ink drawing pad closer to paper

Paper has some advantages over electronic drawing tablets. There's feedback in the form of friction, and the high-contrast surface is easy on the eyes.

Researchers from Philips Emerging Display Technologies, Limburgs University Center in the Netherlands, Androme NV in Belgium, and E Ink Corporation have combined an electronic ink display with a touch panel input device to produce a electronic drawing tablet that comes closer to paper.

The device could eventually be used for freehand computer input, including cartoon drawing and adding annotation to documents, according to the researchers.

The device uses E Ink's electronic ink, which consists of tiny capsules filled with clear fluid, positively-charged white pigment chips, and negatively-charged black pigment chips. A negative voltage causes the white chips to move to the top of the capsules and the black chips to move to the bottom. A positive voltage reverses the positions.

The researchers laminated this microcapsule layer onto an electromagnetic input panel, and added a paper-like top layer.

They improved the ink's slow response time by having the system initially ignore gray-level accuracy. An update that takes into account gray-level accuracy takes about one second. Electronic ink is capable of going from white to black in just under a third of a second, however, and achieving a 10 percent change in brightness in 50 milliseconds, which is bright enough for visual feedback.

The researchers are working to further increase the update speed. They presented the work at the Society for Information Display (SIDS) International Symposium 2004 in Seattle, Washington, May 23 to 28.