What is e-ink and how does it work?

If you have been wondering what e-ink is, then you are probably not alone. E ink is one of those revolutionary technologies that’s not many people has ever even heard about. Do you own an Kindle Paperwhite, a Kobo Aura or a Nook Glowlight? If yes, then you already have e ink on your fingertips. But what is e-ink and how does it work? Does it even have real life uses?

E Ink Defined

E-Ink stands for electronic ink. It holds a number of similarities to the ink that used for printing books and newspapers. If you though e-ink was a newfound technology, then you would be very mistaken. The development of electronic paper first took place in 1970. E-ink is a type of electronic paper.

Today’s e ink displays owe their development to the E-Ink Cooperation, which was founded in 1997 at MIT. The first electronic paper display ebook was released 7 years later, in 2004. The launch of the Kindle in 2007 proved, however, to be the moment when e ink displays rose to prominence. Anyway, you probably are not really interested in the historical background, so I will cut it short. For those who would like to know more about the history of E ink, feel free to check out this Wikipedia page.

The idea behind electronic paper

E ink, as already mentioned, is a form of electronic paper. The entire concept of electronic paper is driven by the desire to mimic real paper and ink on an electronic display. The struggle to do so has been ongoing. But why would anyone wish to mimic paper? Well, because, for all the indifference with which we may hold it today, paper has some pretty amazing qualities.

Paper does not consume any power

For one thing, once something has been printed on it, paper does not consume any power. Those books that are in the library will likely remain there for thousands of years. And they do not need to be recharged. The desire to save power rises from the fact that most of the electronic devices that are out there are such power hogs. Take your tablet or your Smartphone as examples.

These are devices that we use on a daily basis. And most of us are crazy in love with them! Yet this love can become a love-hate sort of relationship. But why is that the case? At the back of the modern human’s mind is this fear that they are going to run out of power. Power for their laptop, power for their tablet, power for their Smartphone. It’s an omnipresent fear.

Now, perhaps I exaggerate a little. However, there has always been a quest to find electronic technologies that closely mimic the behavior of real paper. Hence the development of electronic paper.

Paper does not have glare

If you have ever tried reading something on your tablet or on your Smartphone while in direct sunlight, then you will probably be familiar with the resultant headache. For all their wonders, most of the electronic communications devices that we use today a fatally flawed. You get so much glare while in the sun that it’s almost impossible to do any real reading on them. Again, this was another driver behind the creation electronic displays that mimic real paper.

How does e-ink work?

Now that you understand the drive behind the development of electronic paper, it’s time to show you how e-ink works. We have already noted that e ink is revolutionary. But how does e ink work?

Well, in simple terms, e ink displays are composed of capsules that carry white and black pigment. The white capsules are negatively charged, while the black capsules are positively charge. The capsules are about the diameter of a human hair. They are separated by a transparent fluid. When a negative charge is applied to the bottom of the capsules that carry the positive charge, they are repelled and forced to rise to the top where they become visible on the screen. When the charge is reversed, the position of the capsules is switched and a white area is created on the screen. That’s how text and images are rendered on the screen. There are millions of these particles on a e ink display.

One of the notable properties of e ink displays is that they do not need to emit light in order for text and images screen to become visible. Rather, the display reflects light. That’s the major reason why e ink displays consume so little power. They do not need to be backlit, as is the case with LED or LCD displays. Of course, e ink readers do need some form of lighting to be read in the dark. That’s the major reason why most of the e ink readers that are out there now come with LED backlighting. However, the power savings, in spite of this, are still massive when compared to other types of display.

E ink applications

Today, e-ink has a wide range of applications. True, most people probably use it without realizing that they are using electronic ink. However, the fact remains that e ink is not just a conceptual piece of technology. It’s in use in our everyday lives. And that use is growing wider and wider by the day. The following are some of the applications of e ink in today’s world.

E ink readers

This is perhaps the most famous application of e ink technologies in today’s world. E ink readers have become the rage over the past few years. I personally own a Kindle Paperwhite, and it’s a device that has revolutionized the way that I carry around and read books. Before buying the gadget, I used to read books on my tablet. I also tried reading on my laptop, but the experience was a bit traumatizing for my linking.

The major problem with these two devices is one that I have already outlined. When reading books on a tablet or on a computer, one has to deal with glare as well as with short battery lives. The result is an ever present mild headache. Anyway, the Kindle Paperwhite has changed the way that I read books, as already mentioned. I personally believe it is the best e-ink reader that can be found out there. But it is not the only one. The following is a list of some of the e ink readers that can be found in today’s market;

If you are interested in owning an e ink reader, then check out our e ink reader comparison table. It shows you the features for each of the devices that are given above, as well as their prices.

E ink phones

This is another application for e ink technologies. To be frank, this application hasn’t really caught on yet. It’s still something of a novelty. Attend a mobile technologies convention in any part of the world today, and you are likely to see Smartphones that have dual LED and e ink displays. That is not to say e ink technology on mobile phones remains a novelty. Far from it. There are, Smartphones that are already on the market today that come with dual e ink and LED displays. Perhaps the most well known of these is the Yotaphone 3.

Why have e ink displays on mobile phones?

The idea behind the introduction of dual e-ink, LED technogies on mobile phones derives from the motivation behind the introduction of electronic paper that I gave at the top. For one thing, e-ink displays consume very little power.That’s because e ink displays only consume power when the page is being refreshed.

It’s similar to what happens when a person is reading a real book. If you open your favorite novel to a page, displaying the contents of that page does not consume any power. You only get to use up energy when turning over onto the next page. I know, this is a crude analogy, but bear with me.

What happens with e ink is that the words are sort of painted onto the screen. Once they are there, they remain without consuming any power. Here is another crude example; a portrait that’s in your house does not consume energy by simply being on the wall. The same cannot be said of LED and other mobile display technologies. With LED displays, back-lighting is needed to maintain the image on the screen. So, power consumption is constant.

Anyway, e ink in mobile phones is being introduced mainly as a compliment to already existing technologies. The idea is that if you wish, as an example, to read a newspaper or a book on your Smartphone, you can simply turn over to the other side of the phone to use the e ink display. That, in turn, saves a ton of power! On top of that, you take advantage of the fact that e-ink displays are virtually glare-free to do your reading without having to worry about hurting your eyes.

Wrist watches

This is another type of device that uses e ink technologies. Again, the motivation behind the move to e ink displays has to do with their ability to conserve power. There is also the fact e ink displays do not suffer from glare. Check out this e ink wrist watches from Amazon

Smartcards

E ink technology is now in use on credit cards. This type of card gives the banking public a much needed layer of security. Smart cards that have e ink displays on them are able to display codes on demand. If you are worried that your smart card will run out of power, then you would be mistaken. E-ink displays consume little power, as already mentioned, and you will not run out of power on your smartcard for years.

Other applications

The following are the other applications for e ink technologies;

Electronic price tags in supermarkets and stores.
Bus station time tables.
Electronic billboards.

Advantages of e ink displays

I have already alluded to some of the advantages of e ink displays in the preceding discussion. Just to sum up;

E ink displays, also referred to as e paper displays, use very little power. That’s because they come with the amazing ability to paint images and text onto a screen; after which there is no need to consume any more electricity. Power consumption only occurs when switching to next page. As a result, e ink devices have power consumption ratings that are measured in the weeks. The Kindle Paperwhite, as an example, can go for up to 6 weeks without needing to be recharged. Of course, I am always mentioning that e reader manufacturers are a bit dishonest when it comes to measuring power consumption for their devices. The above rating, as an example, is based on 30 minutes of reading every day. Who reads for only 30 minutes every day, honestly? However, power consumption is still really impressive on e ink devices. As an example, I can go for up to 2 weeks without needing to recharge my Kindle Paperwhite. That’s despite the fact that I read books on it for hours on a daily basis. I know, that’s probably a bit too excessive. BUT, I am an e ink reader blogger, so I have to know what I am talking about.
There is no glare on an e ink display. This was the major reason why I got motivated to buy my Kindle Paperwhite. If you have never used an e ink reader, then you have been missing out. I mean, I had already given up on reading before acquiring the device. Now I probably read 3 or so books on a weekly basis. And part of this reading is done out in the open, something that I would never have thought of doing previously. You can stand with your e ink reader in direct sunlight, and you will still not have any glare on the device. As I have already stated, the technology is revolutionary, as far as reading is concerned. To sum up this point, e ink displays have the major advantage that they are very comfortable to the read on. They also have a wide viewing angle and amazing contrasts.
E ink readers can carry thousands of books. This is a peripheral advantage of the development of e ink technologies. My Kindle Paperwhite 2019 edition comes with 8GB storage. Believe it or not, that’s an overkill. See, books do not really take that much space. On mine, I have hundreds of books already. I was checking while writing this article, and I haven’t even used 2GB yet. That’s inclusive of the operation system. So, e ink readers are a marvel in this regard. You can carry around thousands of books without making a dent on you device’s torage capacity.
E ink displays are strong. This is another major advantage of e ink technologies. E ink displays tend to be very strong. One of the things that I have discovered on my Kindle Paperwhite, as an example, is that the screen is virtually un-scratchable. I know, the first thing that most people will do after buying their devices is rush to buy a screen guard. Some will even go further, by buying a tampered glass screen protector for their devices. If you do this, then you don’t deserve to own an e ink display device. Putting a tempered glass screen guard on a Kindle Paperwhite, as I rave in the article in the provided link, only serves to introduce glare onto the device. You are probably better off sticking to reading on your tablet if you are thus inclined. Anyway, another point that I wanted to make here (before I got carried away) was that there are e ink displays out there that are flexible. E ink displays of this nature are particularly strong.

Disadvantages of e ink displays

Okay, e ink displays are wonderful, as already mentioned. So, why haven’t they yet been adopted in major applications. Well, that has to do with the fact the technology is still fraught with a number of disadvantages;

The refresh rate on e ink displays is rather wanting. The refresh rate on my Kindle Paperwhite is rather dismal. I know, things are a bit better of higher end devices, such as the Kindle Oasis. However, in general, this is an area that still needs major work if e ink technologies are to become more widespread in use.
There is also the presence of shadow on the screen when switching from one page to the other. To be frank, these are things that I have learnt to live with. After all, when reading a book, one does not really need an amazing refresh rate.

The future of E Ink

In 2012, the E Ink Cooperation developed of a color e ink display. In 2019, it was announced that a new color technology had been developed. This is probably where the future of e ink displays lies. The development will likely lead to the introduction of color e-ink readers. So, I can look forward to a Kindle Paperwhite that has a color screen.

Whether or not the development will be revolutionary is another matter. I mean, I am pretty happy with my Paperwhite as it is. However those that use their e ink readers for other pastimes, such as reading comics, will likely welcome the development of color e-ink readers. It’s also possible that color e-ink displays will push e-ink displays to become the primary display on mobile devices. Who knows.