Electronic Paper Display or Electronic Ink Display, is a type of display technology which is designed to mimic the appearance of ordinary ink on paper. In this post we will discuss about what is Electronic Paper Display (e-Paper), it’s types, how it works, applications, advantages and disadvantages.
What is Electronic Paper Display (e-Paper)
An e-Paper Display is a display device that has a paper-like ultra contrast appearance, ultra-low power consumption, and a thin light form. It is very different from a traditional display that uses back lighting to brighten pixels.
Fig. 1 – Introduction to Electronic Paper Display
This type of display is based on the scientific phenomena known as “Electrophoresis,” which means the movement of electrically charged molecules in an electric field.
The first e-Paper was developed by Nicholas K Sheridon at Xerox’s Palo Alto Research Center. e-Paper reflects ambient light rather than emitting its own light which makes reading more comfortable even in bright sunlight.
Fig. 2 – Nicholas Sheridon
Types of Electronic Paper Display (e-Paper)
There are two types of Electronic Paper Display.
- Flexible Electronic Paper Display
- Non-Flexible Electronic Paper Display
Flexible e-Paper Display
Flexible displays use plastic substrates and plastic electronics for the display back-plane. These types of screens can be bent unlike other normal screens.
Fig. 3 – Flexible e-Paper Display
Non-Flexible e-Paper Display
Non-Flexible e-Paper are stiff like any other normal screen.
Fig. 4 – Non-Flexible e-Paper Display
Comparison of e-Paper Display and LCD
How does Electronic Paper Display (e-Paper) Work
The primary substance used in the electronic paper display is Electronic Ink. Electronic Ink is the main material that is processed into a film for combining into electronic displays. Electronic ink is a fusion of physics, chemistry and electronics to create this new material.
The basic components of electronic ink are millions of tiny micro-capsules, about the diameter of human hair. Each micro-capsule, in one incarnation contains positively charged white particles and negatively charged black particles put in a clear fluid.
The positive white particles move to the top of the micro-capsule where they become visible to the user when a negative electric field is applied. This makes the surface visible as white spot.
Fig. 5 – Schematic Diagram of e-Paper Display
At the same time, an opposite electric field pulls the negative black particles to the bottom of the micro-capsules where they are hidden and are not visible. If this process is reversed, the negative black particles appear at the top of the capsule, which now makes the surface appear dark at that spot. To form an Electronic Power Display, the ink is printed onto a plastic film sheet that is laminated to a layer of circuitry.
The circuitry forms a pixel pattern that can then be controlled by a display driver. These capsules which are present in a liquid medium allow them to be printed using earlier screen printing processes onto any virtual surface like glass, plastic, fabric and even paper. Finally e-ink will permit surface to become a display, bringing information to us.
Applications of e-Paper Display
The applications include:
- Digital ID Tags
- Digital Price Boards
- Books, News Papers and Magazines
- Mobile phones and gadgets with flexible display units
Advantages of e-Paper Display
The advantages are:
- Paper-like readability
- Sunlight and non-uniform light visibility
- High reflectivity, high contrast & resolution
- Viewing angle ~180 degree.
- Highly flexible
- Ultra Low Power Consumption
- Long-term Bi-stable Image content preserved without power
- Prolonged battery life
- Capable of color & video
- Reduced Eyestrain
Disadvantages of e-Paper Display
The disadvantages include:
- Very low switching speed
- Electrochemical complexity
- Slow response to change
- Too slow for video
- Difficult to read in low lightning condition
- Contrast ratio is poor as compared to LCD, LED and Plasma Displays
As each and every development in the past few years has revolved around mobility & ease of information flow, e-Paper seems to fit right into the mould for the future. Other gadgets can be replaced by e-Paper to decrease battery usage and to read easily even in sunlight.