Electronic ink, due to its ability to be read in direct sunlight and to be energy efficient, is widely used in digital readers. This technology, which is still quite limited, could be developed in new fields of application in the coming years.
The Consumer Electronic Show (CES) 2022 barely finished in Los Angeles, an image will undoubtedly remain in the minds: that of a car, the BMW iX Flow Concept, whose body goes from black to white in a few moments. The concept car is actually based on a technology, electronic ink, in partnership with the pioneer and master of the sector, the company E Ink, founded at MIT in 1997 and acquired in 2009 by Prime View International, a manufacturing company of Taiwanese LCD screens. A technology that still has a long way to go, but that has many advantages.
A basic principle
Many people have already taken advantage of the basic principle of electronic ink. There is no question here of mentioning the kindle, Kobo, or other digital readers, but the magic slate… that surface on which you or your child have already drawn, then erased, then rewritten, using neither ink nor brush. The magic slate, from 1974, is composed of magnetic particles in suspension between two plates, attracted by a stylus which is also magnetic.
The principle of electronic ink is the same. A particle, positively or negatively charged, is necessarily attracted to its opposite: the positive or the negative. Antoine Charbonnier is an engineer, he wrote a thesis on electronic inks. He explains : ” It is an ink like a pen. Inside this ink there are small particles of different colors : if it is a black and white display it will be black and white particles. Black positively charged, white negatively charged. These particles, when they are going to be put between two electrodes, with a positive pole and a negative pole, they will move to join the opposite charge. Multiply this process by 10, 100, or 1000, and you get 10, 100, or 1000 pixels in white, black, or a mixture of the two, gray.
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Where the thing becomes more complex for electronic ink is to multiply the colors. How to do, when we only have two different charges, positive or negative, to display more colors? “ You have to either make color filters, that is to say that the original pixels will be divided, like on projectors, with plastics of the desired color and we will attract the white particle in the division that we want to light up, but this will cause the displays to lose a lot of contrast “says Antoine Charbonnier. Techniques are also developed to make displays with particles that migrate differently on variations of positivity and negativity, but the thing is more complex, and therefore more expensive.
Benefits, but limited applications
The main advantage of electronic ink is that it consumes almost no energy. A dormant Kindle can wake up months and months later because the standby image, once displayed, is frozen, its particles no longer moving and don’t need an electric current to stay in place. Electronic ink has other advantages, it reflects less sunlight, is readable from any angle of view, and above all, does not produce blue light.
Despite all its advantages, do not expect e-ink screens to become the alpha and omega of conventional screens. Indeed, there is no question in the state of using electronic screens to make video, recalls Antoine Charbonnier: ” The particles must take the time to move: but if it’s fast, for video it would be relatively jerky, and we lose the main advantage of knowing that it doesn’t consume energy: if we make the images move the time we consume electricity continuously so you might as well take a more classic display. »
For now, the applications are still quite limited. We mainly find electronic ink to replace digital price displays in supermarkets, in e-readers, in certain connected note-taking pads, but whose latency time makes fast writing difficult. The fault of a still underdeveloped sector, and so-called “classic” screens better known to the public.
A potential revolution?
But e-ink has potential. E Ink, the main company on the market, multiplies the examples of future use, some already experienced, on its website. In hospitals, pencil-filled papers used to track the client could be replaced by e-ink screens. They do not emit any light that could disturb customers, and they are connected, which would allow them to be updated automatically. In the cockpits of military aircraft, electronic ink could be used to give out lists of instructions without fear that they would be made less readable by the sun. Museums could seize the technology to change their panels according to the current exhibition. Connected ink could be integrated into interior designs, logistics, delivery…
Despite BMW’s spectacular concept car, “repainting” its car with electronic ink is not yet for now. The risks of distraction for other road users would be too high without legislation prohibiting changing color while driving, and the additional cost too high. On the other hand, electronic ink on bodywork has real interests in terms of security and energy saving. A black car, at night, could turn white in the event of damage to be better spotted on the side of the road, it could also reflect the sun in summer in white, and absorb the light in black in winter, to reduce the use of air conditioning.
At a time of energy transition, electronic ink consumes less raw resources and electricity. Interactive maps on conventional screens, both in metros and shopping centers could be replaced by electronic ink maps, advertising displays too, just like menu displays in fast food restaurants. All these examples would reduce the electrical consumption of the public and private display sector, while avoiding overexposure of urban dwellers to artificial light, without however removing the advantage of rapid updating.
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