What is e-paper? Definition and key use cases

Imagine taking a pen and jotting something down in a notebook. The clear and well-defined lines of your ink will have the exact readability and look as content shown on an electronic paper display.

But how does an e-paper display manage to display such an image? What makes it different from other high-definition displays available on the market?

Here’s how e-paper displays work

To understand what electronic paper is all about, we need to start at the core of this technology. If you take a look, you will see that e-ink is actually a collection of small capsules that are filled with a clear fluid containing small particles. Each display is made of millions of such capsules located on a thin film.

The particles inside these capsules have different colors and electric charges. Both below and above the film, you will find a number of electrodes. When a negative or positive electric field is applied to an individual electrode, the particles with the corresponding charge will be moved to the bottom or top of the capsule. This will make the surface display a certain color.

In the most basic version, electronic paper comes in a black and white variant. In this case, white articles carry a positive charge, while black particles carry a negative charge. If the electric charge applied is negative, then all the negative black ink particles will be raised to the top of the capsule. As a result, they will color this part of the surface black.

This is why electronic paper displays are also sometimes called electrophoretic displays (EPD). EPD paper displays function by using the motion of dispersed particles in the fluid using the influence of an electric field.

Key characteristics of e-paper you need to know

The primary benefit of e-paper is that it’s bistable. What does it mean? Just like a sketch in your notebook, whatever is displayed on the electronic paper display will hold a static image – even when the display isn’t connected to a source of electricity. That’s because e-paper technology is bistable.

The tiny particles that are part of EPD can be either reflective or non-reflective, that is, black or white. In more advanced electronic paper displays, these particles can also be provided in many levels of grayscale. While some energy is required to put color particles in their place, once they’re in place, they stay there forever.

In practice, this means that EPD consumes power only when the content is changing. The rest of the time, the display simply shows the image you set for it to show, with or without a power source, and without having to constantly refresh the content. Just to give you an example from another technology, in an LCD screen, content is refreshed about 30 times per second.

This is why electronic paper is so energy efficient. It’s can work for many weeks on a single battery or even use alternative power sources.

We already mentioned that e-paper displays are reflective, which means that the light from the environment is reflected from the surface of the display towards the eyes of the users. This works just like traditional paper. EPD displays help to avoid light pollution and makes images easier on the eyes of users. Such displays also provide a wider viewing angle than most other types of displays. Moreover, the content displayed on e-paper is perfectly visible even when it’s seen in direct sunlight.

Example use cases of e-paper

Even if the technology has been with us for three decades, the e-paper is now finding more and more uses. Here are some examples:

• E-readers
• Electronic digital signage such as indoor or outdoor displays,
• Passenger information,
• Shelf labels in stores,
• Interactive museum signs,
• Notice boards,
• Traffic signs.

Conclusion

According to experts in the field, the market for e-paper displays will reach more than $8.59 billion by 2022.

Much of this market will be dedicated to applications of electronic paper technology such as digital signage. As the e-paper becomes more advanced and durable, it’s going to find more and more implementations.

At Melrose, we have experience in delivering e-paper solutions to our clients using the most innovative technologies. Our team of experts knows how to customize products and take advantage of this technology to help our clients leverage all the benefits of e-paper for their applications. If you think that your project could benefit from this technology, please reach out to our consultants, who will advise you on the best e-paper choices and help you make the most of e-paper.