New breakthrough on full color video electronic paper display in China

The latest accomplishments in color video electronic paper displays jointly developed and manufactured by South China Normal University (SCNU) and Shenzhen Guohua Optoelectronics Ltd., under the leadership of Professor Guofu Zhou and Professor Alex Henzen, are demonstrated. The accomplishments are based on the team's research and development on the leading key technologies on color video electronic paper displays.

The research team has succeeded in producing the first reflective electronic display, capable of displaying full motion video while displaying print-quality color images, maintaining good visibility under all lighting conditions.

The display is based on the electrowetting display principle, and significant steps were taken improving the technology by implementing a new, 5.8 inch TFT active matrix panel with very high transmission, a new display driver capable of addressing the reflective panel with 18 bits color signals, and using a revolutionary display architecture based on layered switching of the base colors used in color-print on paper (cyan, magenta and yellow).

According to Professor Zhou, this is the first time the world can see a full color movie, showing realistic colors on a reflective display. This record breaking performance is also due to the dyes used by the color layers, which are also products of the SCNU team.

Professor Alex Henzen, a core member of the SCNU team and technical leader on e-paper, used a new 5.8 inch e-paper display to demonstrate a tablet computer prototype. Professor Alex Henzen said, "This reflective, sunlight readable display will revolutionize the e-reader and tablet market, dropping display energy requirements by several orders of magnitude and providing days of continuous color video on a single battery charge, and finally being able to enjoy reading tablets in bright sunlight.

Significant improvement possibilities for outdoor billboards, based on electrowetting color video e-paper: high contrast, low power, high color gamut.

Since the team has demonstrated color and monochrome e-paper outdoor billboard components to potential customers two years ago, they have been continuously improving this e-paper technology and application. The most important modification is the pixel structure. Based on a new process and the technology mentioned in the above section, the team had significantly optimized the structure in both size and shape, which increased the display pixel aperture to more than 80%, and the contrast ratio to over 10:1. It makes the display more colorful and brighter. What's more, a dye synthesis team has optimized the dye formula, which improved contrast and color gamut to a level comparable to magazine color print (SWOP) and TV display (sRGB).

The team will exhibit four new prototypes: Two reflective color display panels, with variation in the way the light is reflected, and two monochrome reflective panels, one of which approaching the brightness of paper, with some angle dependence, while the other reaches 40% reflectance maintaining a fully diffuse image. All prototypes are fully video capable and deliver 6 bits grey or 18 bit color, respectively.

"The e-reader market has waited for a color video e-paper display for many years. This is a huge, demanding market, for education and outdoor application. The high demand for online learning during the epidemic this year highlights the need for reflective color video display technology in the future", stated Professor Zhou, "Our display technology perfectly matches the full features these devices require. We are going to release our first application product in the summer of 2021." The team tends to spin out the industrialization of this technology in 2021.