E Ink unveils Kaleido 4 color e-paper display with wider color range

E Ink, the company that develops e-paper displays for e-readers and writing tablets, has announced Kaleido 4, the latest version of its color e-paper technology. It promises a wider range of colors and faster screen refresh, long a weak point of e-paper. Because E Ink panels are used by e-reader makers such as Amazon, Kobo and Boox, the change could shape the next generation of devices.

What the upgrades promise

According to E Ink, Kaleido 4 "doubles the color gamut volume", allowing the display to show more than 40,000 colors. White reflectance and contrast have also been increased. The company says the faster refresh allows video playback at 18 frames per second. That is low next to the 120Hz OLED screens in many smartphones, but it is meaningful for e-paper, which typically refreshes slowly.

E Ink says the refresh gains come from adding an oxide backplate to the display stack. Amazon has said it made a similar modification to the Kaleido screens in its original Kindle Colorsoft.

Kaleido versus Gallery

Kaleido displays place a color filter over the black and white pigments that move to form text and images on a traditional e-paper panel. Older Kaleido 3 screens are known for somewhat fuzzy text, which is why some manufacturers choose Gallery 3, another E Ink color technology. Gallery uses colored pigments, giving richer images and text but refreshing more slowly.

First device

For now, Kaleido 4 is officially used in just one product: the M10 C II e-paper tablet from Hanvon Technology, available only in China. It also has a redesigned front light and micro-etched glass meant to feel more like paper when writing. How big the improvement is compared with earlier Kaleido displays will only become clear in side-by-side testing.