Fuji Xerox Co Ltd unveiled a prototype of a color electronic paper compliant with an optical writing system at the International Display Workshops (IDW), which is open from Dec 5 to 7, 2007.
Its high brightness, high contrast, color strength and rewriting speed met with a public response. And a large crowd of people were incessantly flooding in to take a look at the prototype.
The electronic paper is made with reflective color liquid crystals that were developed by utilizing the selective reflection effect of cholesteric liquid crystals. Three layers (red, green and blue) are laminated to enable full-color display.
The display layers have a PDLC (polymer-dispersed liquid crystal) structure that disperses and retains cholesteric liquid crystals in a matrix of gelatin. Each of the three display layers is controlled by the optical writing system with organic photoreceptors.
The integrating sphere reflectance (white) of the electronic paper is 27.4%, and the contrast ratio (the ratio of white color reflectance to black color reflectance) is 6.4. The display is A6 size (105 × 148mm). It is as thin as 0.4mm and can be bent. It weighs 10.4g. For the future, the company plans to develop an A4 size display.
Fuji Xerox also prototyped an A5 size optical writing device that can write on two A6 size electronic papers. The device is equipped with an LCD panel for laptop computers and green and red LED arrays.
When I watched a video of the electronic paper being written, it looked like that the rewriting time is very short and less than one second. The display has a memory function and can be dealt as a paper after being removed from the writing device.