Colour E-Ink displays are coming exclusively to digital signage applications, a major breakthrough for the technology that started out adorning Kindles and other e-readers.

E-Ink Holdings, the company behind the technology, has revealed a breakthrough in developing an Advanced Colour ePaper (ACeP) display – which is both high quality and boasts 32,000 colours.

For the first time ever, an electrophoretic display (EPD) can produce full color at every pixel without the use of a color filter array (CFA). ACeP sets a new standard for bright, reflective color achievable with EPDs. The initial target application for ACeP will be for digital signage.

ACeP achieves a full colour gamut, including all eight primary colours, using only coloured pigments. The display utilises a single layer of electrophoretic fluid, which is controlled using voltages compatible with commercial TFT backplanes. The fluid can be incorporated into either microcapsule or Microcup structures.

The richness of the colours is achieved by having all the coloured pigments in every picture element (pixel) rather than the side-by-side pixel colours achieved with a CFA. This eliminates the light attenuation, which can be quite significant. Like regular E Ink ePaper, ACeP maintains the ultra-low-power and paper-like readability under all lighting conditions.

Digital signage manufacturers are constantly boasting ultra-affordable technologies and excellent power consumption, but that’s a claim E-Ink Holdings is taking to a new level. E-Ink displays use very little power and can run for months on a single charge – if the installation happened to use a battery. The company’s chairman, Frank Ko, is also keen to stress that the technology could be perfect as bus stop signage, given it could quite easily be powered using solar panels.

“At its heart, E Ink is a materials and technology company,” notes Frank, chairman of E-Ink Holdings. “It’s this core that provides the energy and the foundation for the stream of products being developed at E Ink. We expect ACeP to become the basis upon which another generation of EPD display products can be developed.”

Digital signage is a growing market, with Samsung and other vendors recently throwing their weight behind LED technology – although this could change things.

In developing ACeP, E-Ink researchers solved the very complex problem of how to get reflective colour at every pixel in a commercially viable structure. Other approaches have utilised stacked backplane structures that are complex, difficult to manufacture and costly. The E Ink approach utilises only a single backplane. Many materials and waveform inventions were required to independently control the position of the multiple color pigments.

“The technical team was convinced this was achievable,” says Michael McCreary, CTO for E-Ink Corporation. “E Ink’s global R&D team has a deep understanding and experience with electrophoretic displays. During the years of hard work applying this experience to full colour, the breakthroughs required to achieve this milestone were numerous and frequent. We are very proud of the team’s accomplishment and dedication to this task.”

Multiple 20” displays with a resolution of 1600 x 2500 at 150 ppi have been constructed. That’s a notable number, as it means it’s half as sharp as some of the E-Ink displays currently on the market – some of which boast 300 ppi. The displays are also slower than traditional digital signage, taking a full two seconds for the display to refresh.

E-Ink Holdings plans to show off ACeP during SID’s Display Week at the Moscone Conference Center from May 24 through May 26.

The company will likely not face any competition in this space either, with Qualcomm’s competing Mirasol technology having gone dormant over the past couple of years. The technology was acquired by Apple however which, given the two-year timeframe E-Ink Holdings has given itself for a commercially viable product, could come up with a competing product.

 

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