Working of Electronic Ink (E-ink) Technology

We have seen the working of electronic displays like Liquid Crystal Displays, SED TV’s, and Touch screen technology and so on. Even though we rely mostly on monitors nowadays we must not forget the fact that the basic display mechanism is paper the early 105 AD when the Chinese invented it. Before the invention of paper, the only way to print your writing was on silk scrolls, which only wealthy people could afford. This would have made literacy rate lesser.

People communicate through paper by writing on it with ink. They display their ideas with the help of words and images, which may differ in many languages as well. The paper technology has not yet been beaten by other display technologies in the matter of portability and price. But this technology also has some disadvantages like you cannot rewrite on top of the printed words and it is difficult to carry a large number of books.

Now, these disadvantages are also being minimised with the help of a new technology called electronic ink [e-ink]. In this post we will discuss about how e-ink is made, how large bundles of books can be carried easily and its efficiency in replacing other computer displays.

Making E-ink

E-ink may look similar to the regular ink, though they are different. In fact it can also be applied on the same material in which regular ink is applied. Although different companies manufacture E-ink in different ways, there are three basic components that give them the ability to rearrange upon command. They are

1. Millions of tiny microcapsules
2. The ink substance present in an oily form which fills the microcapsules
3. Negative charged pigmented chips or balls which float inside the microcapsules

When using the e-ink in a digital book, the pages will be made of an ultra-thin plastic material. The ink is allowed to spread through the entire page, and they will be separated by cells that somewhat resemble the cells on graph paper. They also resemble to the way in which pixels are arranged on a computer screen, with each cell connected to microelectronics which are embedded in this plastic sheet.  When this type of a design is setup the text or image that is to be displayed is done by applying a positive or negative charge to the microcapsules.

A company called Xerox from Palo Alto, CA is one of the major manufacturers of E-ink. To know the working of this technology in a better sense, the company has given a better example. You have to compare the microcapsules inside ink to clear beach balls. These beach balls should be filled with hundreds of tiny, white ping-pong balls. And instead of air, the beach ball is filled with a blue dye. If you notice this design from the top position, you can see that the beach ball is white in colour and that the smaller ping-pong balls are floating in the liquid. If you looked at the top of this beach ball, you would see the ping-pong balls floating in the liquid, and the beach ball would appear white. But if you looked at the bottom of the ball, it would appear blue.

If these beach balls were laid on a field and the ping-pong balls were made to move between the top and bottom of the beach balls, you could make the field change colour. This is the basic working of E-ink.

Now in reality, the microcapsules are very small that almost 100,000 microcapsules can be put in a square inch of paper. Their width does not exceed 100 microns and each microcapsule contains hundreds of smaller chips.

Given below is a diagram on how the pigment chips inside the E-ink reacts to the +ve and –ve charges.

From the figure you must have noticed that when a charge is applied to the microcapsules, the chips are forced to move to the top or pulled down to the bottom. When they move to the top, the chips make the capsules look white and when they are pulled down to the bottom, the capsules look dark. This is because the person seeing it only sees the dark ink. When these small black and white spots are arranged in patterns, words, sentences and images can easily be formed.

Uses of E-ink

The biggest advantage of E-ink is that it can be easily printed on surfaces like walls, billboards, clothes and so on. This idea has already caught the eye of many advertising agencies and you may have noticed advertisements on walls using this technology. The ink is so flexible that it is possible to develop roll-up displays for electronic devices. They also need very little power for its usage. When compared to LCD displays, they consume almost 100 times lesser power than LCD’s do.

Another advantage includes its readability. As the text is printed in format, it does not cause strain to the eyes. There are studies going on in increasing the resolution in products so that they can be viable in book or other small-print publications

One of the main use of this technology is its application in digital books which can typeset itself and that readers could go through it like it were made of regular paper. You could even borrow stories from the library by wireless transaction and after reading it you can send it back to the library. Nowadays you may have noticed the presence of E-books that are available in sites in downloadable format.

The above mentioned ways are applicable in the way you receive your newspaper as well. All you have to do is press a button on your computer that would update how many ever ‘e-newspapers’ you need. Thus you will have no worries on what to do with the lump of papers at your home. As papers are made from trees you are able to reduce the environmental pollution by lessening the cutting of trees.