Posted: By Ken Werner 03.12.21
E Ink launched the first generation of its Kaleido color eReader display in Q2 2020. Conceptually, the Kaleido was not unlike previous E Ink color eReader displays. That is, it was an active-matrix monochrome ePaper display with a color filter array (CFA) to provide the color.
The problem with the previous versions was that the reflectivity and contrast ratio of the underlying monochrome display, while capable of providing a very favorable reading experience, could not provide a sufficiently bright display after the optical losses of the CFA. The colors were muddy, the color gamut was small, and these displays did not remain on the market for long.
With the first-generation Kaleido, E Ink reduced the optical losses in the CFA by printing the filter directly on the imaging film instead of on a separate glass substrate. It produced the same 16 levels of grayscale and 4096 colors as its predecessors, but those colors were brighter in an equivalent ambient. (Remember, these are reflective displays.) E Ink says the new display also uses a faster electrophoretic for quicker updates, animation, and videos.
|The color filter array of the Kaleido Plus is printed directly on the electrophoretic ink layer. (Source: E Ink)|
The Kaleido Plus is a significant improvement over its immediate processor. The CFA is made with a new printing pattern, and it is closer to the electrophoretic ink layer, which produces brighter colors and better text rendering, says E Ink. The color gamut is improved by a factor of three when the front light is on because refinements in the front light reduce light scattering, which creates more saturated images. Other improvements are reduced graininess, ghosting, and flashing.
|The Kaleido Plus offers significant improvements in contrast and gamut with the front light off compared to its predecessor, but the increase in color gamut with the front light on is dramatic. (Source: E Ink)|
The Kaleido Plus is available as a 7.8-inch display, up from the first generation's 6 inches. Resolution is 468 × 624 color pixels. The resolution of the underlying monochrome display is 1404 × 1876.
E Ink CEO Johnson Lee said that with the new product E Ink is "bringing a new level of color saturation to our color devices, and we look forward to Kaleido Plus being adopted in the eTextbook market in the future. We are proud to have the support of our leading customers, PocketBook (InkPad Color) and Onyx (BOOX Nova3 Color), for this launch.”
|The improved gamut with front light on is dramatic. What appeared as rust and gray are actually red and blue. (Source: E Ink)|
Evgenii Zaitsev, Chief Sales and Marketing Officer of PocketBook, said, “There is more and more eContent with illustrations which require color, like comics and books for children, non-fiction and periodicals. We see a growing demand for color E Ink eReaders and we will do our best to satisfy customer’s needs.” E Ink said Kaleido Pluss is geared toward applications that require the reading of charts, graphs, maps, photos, comics, and advertising.
Ken Werner is Principal of Nutmeg Consultants, specializing in the display industry, manufacturing, technology, and applications, including mobile devices, automotive, and television. He consults for attorneys, investment analysts, and companies re-positioning themselves within the display industry or using displays in their products. He is the 2017 recipient of the Society for Information Display's Lewis and Beatrice Winner Award. You can reach him at firstname.lastname@example.org or www.nutmegconsultants.com.