The tablet has transformed the electronics marketplace in recent years. Tablets have existed for over a decade, and Microsoft produced Windows tablets running the XP operating system that were unsuccessful. Apple started with its ill-fated Newton PDA device but then launched the iPhone in the mid-2000s. Several years later it launched the 9.7inch version of that phone which it dubbed the iPad - moving the whole electronics marketplace on by a substantial amount. The tablets launched by Apple were powered by iOS and there are now many Android tablets on the marketplace. Windows 8 will be launched with a new metro interface that will add a third competitor to the tablet game in 2012 and 2013.

The big problem with current tablets

Virtually all, if not all, tablets currently use LCD displays which aren’t as good to read text as an e-ink screen, like those found on a devices like the Amazon Kindle or Sony e-readers. In this article we are going to look at how e-ink displays could bring tablets to the next level to make them a truly indispensible productivity and entertainment device.

What is an e-ink display?

An E-ink display is designed to imitate the look of conventional ink on paper, it is also known as electronic paper or electronic ink. They don't use backlights and rely upon reflected light like normal paper. It is often regarded as more comfortable on the eyes due to the lack of it refreshing, wider viewing angle and ability to read in direct sunlight without the image is in contrast. Modern E ink screens have a contrast ratio similar or better than newspapers, and potential uses the ink screens include e-readers, tablets, signs and even on the front of magazines.

History of e-ink technology?

The first electronic paper was developed by Xerox PARC (Palo Alto Research Centre) in the 1970s. The 1st being displays were called Gyricon. This design consisted of a thin layer of transparent plastic in which there were millions of small beads. Each individual leaders contained in an oil filled cavity which allowed them to move within it. Each bead was divided into two sides with different colours e.g. black-and-white, and were charged so they were effectively polarised like a magnet. This allowed voltages to be applied to the sheet which recalls the beads to rotate in the oil filled cavity to display one colour-producing the image. This technology is still in use but most screens now use the newer technology described below.

How does an e-ink screen work?

Most e-ink screens you will find in shops use what is called an electrophoretic display. Basically an e-ink screen works like an etch a sketch, only in a much faster and higher detailed fashion. In an electrophoretic screen, titanium dioxide particles are disbursed in hydrocarbon oil. This oil has a dark coloured dye in it along with chemicals which cause the particles take an electric charge. This mixture is placed between 2 plates separated by around 10 to 100 µm. Like the Gyricon screen, a voltage is then applied to create the image. The images created as the particles will move to the plate bearing the opposite charge like opposite poles of a magnet attracting. When the particles at the front of the display it appears white and when the particles are at the back of the display it appears dark. In electrophoretic displays are used in the Amazon Kindle, Barnes & Noble Nook and Sony Reader lines of e-reader.

The benefits of E-ink

In my opinion the main benefit of being displays are no screen refreshing which makes them much easier on the eyes. An LCD screen refreshes tens if not hundreds of times a second. These refreshes are unperceivable to our conscious eyes, but they are processed by our brains and can contribute to eyestrain, headaches and general discomfort when looking at displays. The effect of LCD displays is amplified when using them to read small text like books, web pages and other documents.

The second benefit is that because it relies on reflected light, it doesn't have a bright backlight. This means that it's very different from a bright LCD monitor that you may have spent 10 hours reading on during the day, and it's more like a real book printed with ink on paper.

E-ink screens take a lot less power than LCD screens which allows them to last for up to a month. Power is only used in an E-ink screen when changing pages and not to keep the image on the page like an LCD.

The problems with E-ink

E-ink screens do have several issues. The main one is the low refresh rates which are currently stopping the implementation of e-ink in applications like laptops, tablets and smart phones. The second is that e-ink screens shadow or ghost. If you look at the new Amazon Kindle it only does a full, strong refresh every 5 page turns. In between that if you look closely you will be able to see a slight ghosting of text from the previous pages. This can be overcome by flashing the entire screen but this takes a lot longer than the partial refreshes the current Amazon Kindle uses.

Pixel Qi displays

Pixel Qi display technology is what could really change the marketplace with tablets. This display technology can offer both reflective e-ink like display for reading and outside, and LCD screens allowing fast refresh rates for video and general computing. This technology has been around for a while but has yet to catch on although you can buy it from the company.

What E-ink tablets are coming out?

The closest thing we have to an e-ink tablet at the moment is the Kindle DX. There have been developments in e-ink technology allowing colour e-ink screens but they have yet to catch up in terms of refresh rates. The new Apple iPad 3 is expected to have an ultra-high-definition LCD display. The higher pixel count should make the tablet easier to read although it will still be backlit and could, like all LCDs, result in eyestrain if used for long periods of time without breaks.


E-ink and other display technologies could combine the e-reader and tablet into a single device. Although many people will read on an LCD screen like an Apple iPad or Android tablet like the Samsung Galaxy Tab, people like me who struggle with eyestrain will always prefer the E-ink like experience.

Would you like E-ink displays in your iPad or Android tablet? Have you heard about e-ink displays? Feel free to leave a comment below.