TCL has unveiled its latest form of display technology as part of its IFA Special Edition 2020 presentation. NXTPAPER is an alternative to e-ink that, as its maker claims, "repurposes natural light" to prevent eye-strain while still producing a convincing range of colors. These panels are also touted to improve on contrast, power-efficiency and thickness compared to more conventional screen materials.
https://www.notebookcheck.net/TCL-launches-NXTPAPER-a-new-rival-to-e-ink-rated-for-improved-color-contrast-and-eye-safety.492189.0.html
Reflective and trans-reflective displays have been around for ages. One great strength is the readability in sunlight without the need to overpower the sun, using its immense power instead. Usually, colours would suffer but that's of little consequence in many scenarios.