Sony Corp developed a 13.3-inch flexible color electronic paper (e-paper) device and announced it at the 49th SID International Symposium, Seminar & Exhibition (SID 2011), the world’s largest academic conference on display technologies.
After making the announcement, the company exhibited the e-paper device in the author’s interview, gathering a large crowd of people. And many researchers highly evaluated the image quality of the device.
This time, Sony realized a thickness of 150μm or less and a weight of 20g or less by using a plastic substrate. The e-paper device has a 13% color gamut on NTSC standards, a reflectance of 10% and a contrast ratio higher than 100,000:1.
Its pixel consists of red, green, blue and white sub-pixels, and the pixel count is 800 x 1,200. The sub-pixel measures 169μm x 169μm. The resolution and gradation of the screen are 75ppi and 16, respectively.
The high color gamut and reflectance were achieved partly because it became possible to attach a TFT substrate to E Ink Corp’s front plate with high precision (0.35μm), Sony said. Because of the high precision, the company succeeded in reducing the margin between sub-pixels and increasing the aperture ratio of pixels to ensure the high color gamut and reflectance.
To enhance the precision in combining the TFT substrate and the front plate, Sony used a glass substrate that can be easily handled even with existing manufacturing equipment as a substrate for supporting purpose.
The e-paper device is manufactured as follows. Adhesive is applied to the glass substrate, and a plastic substrate is attached to it. Then, amorphous TFTs are formed on it with a low-temperature process (180°C or lower). Lastly, the plastic substrate is removed from the glass substrate.
Source: techon
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