The e-reader industry is stuck with 300 PPI screens or below. The Amazon Kindle Paperwhite, Kobo Clara HD and Barnes and Noble Nook Glowlight 3 are some examples of six inch ebook readers that have the highest resolution screen that is currently available. Large screen devices such as the Remarkable, Onyx Boox Note or Sony Digital Paper generally have 227 PPI screens, so text does not look as crisp. There are a few new e-paper technologies that are ready for primetime and 2019 might be the year where we break the 300 PPI barrier.
In 2017 Japan Displays unveiled a new 600 PPI display that will allow future e-readers to have double the resolution of existing models. The Amazon Kindle Paperwhite, Voyage, and Oasis have 300 PPI with a resolution of 1440 x 1080 pixels.
E Ink Holdings and Japan Displays formed a partnership in 2016 ar and the two sides have been working on this 600 PPI screen for the past two years. Japan Display says that the WXGA or full HD displays are just as sharp as the screens used for high-end smartphones.
“Our strong partnership with E Ink allows us to strategically broaden our business into new markets beyond LCDs,” said Kazuhiro Ogawa, vice president at JDI. “E Ink’s low-power, highly-readable e-paper technology presents an exciting opportunity for JDI to expand the development of e-paper displays with built-in LTPS backplanes, opening the doors to new opportunities not only for both companies, but more importantly for our innovative customers.”
Meanwhile, Plastic Logic developed a new e-paper display early 2018 that has a massive 155% increase in resolution and now supports 500 PPI. This impressive, industry-leading improvement has been achieved solely through advances in Plastic Logic’s transistor matrix backplane on a 10.8 inch E Ink screen. Prior to this technology breakthrough Plastic Logic’s most advanced commercially available display was 196 PPI on a 4.7 inch screen.
Plastic Logic’s 500 PPI displays makes written text much sharper which is an advantage for Chinese and Japanese where detail has previously been lost due to resolution limitations. Another use case benefiting from the improved display density would be applications where accurate lines and measurements are critical, such as e-paper rulers, portable mapping or CAD drawings.
The President of E Ink Johnson Lee told Good e-Reader that “As our partners have demonstrated, E Ink is compatible with very high resolution backplanes. These backplanes cannot only make the display even more paper-like in terms of resolution for text and images, but they can also be lower power using an LTPS backplane. We partner with Japan Display Inc (JDI) because they make one of the best LTPS TFTs in the world. Plastic Logic, the technology that originated from the labs of Cambridge University, makes one of the best organic TFTs in the world. As a display provider, we offer our customers a range of configurations in terms of resolution, backplane technology and power consumption. We cannot comment on our customers’ product plans, but could see a benefit to a higher resolution display as eNote devices for work and school become more common.”
In order for 500 to 600 PPI screens to work on e-readers the screens would draw more power and would require faster processors and larger batteries. The Freescale/NXP IMX.7 dual core processor would be ideal and the Amazon Kindle Oasis 2 is the only device that has used it in a commercial product.
Michael Kozlowski is the Editor in Chief of Good e-Reader. He has been writing about audiobooks and e-readers for the past ten years. His articles have been picked up by major and local news sources and websites such as the CNET, Engadget, Huffington Post and Verge.