New Display Device Claims 'Newspaper Quality'

Nov 19, 2008
Takuya Otani, Nikkei Electronics
A comparison between the new display device and a newspaper is shown on the left. On the right are a reflective LCD panel and electronic paper (from Funai's promotional materials).
A comparison between the new display device and a newspaper is shown on the left. On the right are a reflective LCD panel and electronic paper (from Funai's promotional materials).
[Click to enlarge image]
Structure and drive principle of Funai's new display device
Structure and drive principle of Funai's new display device
[Click to enlarge image]

Funai Electric Advanced Applied Technology Research Institute Inc developed a new reflective display device that the company claims has display properties "equivalent to those of newspaper."

The technology used in the new device clearly differs from those used for the existing reflective display devices such as electronic paper and reflective LCD panels, the company said.

The display device is a so-called electrochromic display (ECD), which utilizes the phenomenon that the color of a material is reversibly changed by electric pressure. Funai used leuco dye, which colors when electrically activated.

The device has a structure in which a solution containing the dye is sandwiched with an electrode sheet that drives the device and a transparent electrode (ITO) for the display surface. The distance between the electrodes is 50μm.

This time, Funai found that there is an electrical nonlinearity between the dye and the electrodes. Based on this nonlinearity, the company developed a method to separately drive each pixel, thereby enabling high-speed drive control without the use of TFT. Specifically, the display generates a color in 0.1ms. This is the competitive edge over the existing electronic paper, the company said.

In addition, the device has a contrast ratio of approximately 8:1 and a reflectivity of about 80%. These display properties are the advantage over reflective LCD panels, according to the company.

Funai is aiming to commercialize the new display device by the end of fiscal 2009 in collaboration with its partner companies. Though the prototype can only display black-and-white images, the company intends to promote the development toward a multi-color display in preparation for a wider variety of applications.