Electronic Paper: What is E-paper and How Does it Work?

Did you know that there are electronic devices that use electronic paper? Though it’s not as popular as LED, LCD, and OLED display technologies, electronic paper has proven to be a flexible and energy-saving option for devices and signage. But what is e-paper exactly, and how does it work? What kind of advantages does it bring to the table?

E-paper, which is also known as electronic paper, electronic ink, or e-ink, is a display technology applied to electronic devices, designed to mimic the appearance of traditional or ordinary ink on paper. E-paper is a special type of display that does not emit light or require electricity to create images like LCD or LED displays. Unlike these traditional displays, e-paper displays reflect light just like ordinary paper does. This makes the e-paper easier on the eyes of the reader, as there are no glares or light reflections. This also makes it more readable in various lighting conditions, whether it be bright sunlight or dim lighting.

Electronic paper has several advantages over traditional display technologies. Here are some of them:

• Low Power Consumption: E-paper displays only consume power when the image or content changes. This makes them ideal for devices that require long battery life, such as e-readers or electronic shelf labels (ESL).
• Sunlight Readability: E-paper displays are highly reflective, making them easy to read even in direct sunlight. This makes them suitable for outdoor use or environments with bright lights.
• Wide Viewing Angle: E-paper displays have a wide viewing angle, similar to traditional paper. This allows users to view content from various angles without distortion.
• Bi-stability: Once an image is displayed on the e-paper, it remains visible even when power is removed. This means that e-paper devices can display static images without consuming any power, further contributing to their overall energy efficiency.

Though it may not be obvious to some consumers, electronic paper technology is now used in various electronic devices. It can make a big difference to the value of products, especially in situations where low power consumption and high readability are important buying considerations.

E-paper technology has a diverse range of applications. Since it mimics the experience of reading on paper, it's used in a lot of panel displays, electronic display boards, computer and laptop monitors, small or mobile electronic devices, electronic tags, and more.

Here are several specific examples of electronic paper devices using this technology:

Amazon Kindle

Perhaps the most well-known example is the Amazon Kindle. This is a series of e-readers known to utilize electronic paper display technology for accessing and reading digital books or e-books. These devices offer a paper-like reading experience, usually in black-and-white images and fonts, with long battery life and excellent readability.

Sony Digital Paper

Sony's Digital Paper is a line of tablet-size e-ink devices, geared towards professionals and students who need to read and annotate documents. They feature large e-paper displays and touchscreen capabilities, and they are known to support PDF files. This makes them suitable for reading and annotating academic papers, legal documents, and more.

PocketBook e-Readers

PocketBook produces a range of e-readers with e-paper displays, making it one of the largest global manufacturers of e-readers based on electronic paper technology. They offer various models catering to different preferences and budgets. These devices support various e-book formats and often include features like adjustable font sizes and built-in lighting.

ReMarkable Tablet

The ReMarkable Tablet is designed for note-taking and sketching, featuring a large e-paper display and a stylus for writing directly on the screen. It offers a paper-like writing and reading experience for users with minimal latency. This makes it popular among artists, designers, and students.

Onyx BOOX E-Readers

Onyx BOOX produces a diverse range of e-book readers with e-paper displays that support both e-books and handwritten notes. These devices often feature large displays, front lighting, and Android operating systems. This allows users to install additional apps for enhanced functionality and entertainment, making it a more flexible option for a variety of users.

Epson E Ink Monochrome Displays

Epson also produces electronic paper displays used in various applications, including smartwatches and digital signage. These displays offer low power consumption and excellent visibility in different lighting conditions.

SOLUM Electronic Shelf Label (ESL)

Apart from entertainment and documentation purposes, electronic paper technology is also used in retail solutions. SOLUM ESL offers a line of electronic shelf labels for various retail environments and businesses. These Newton labels are equipped with e-paper technology for a better reading experience for shoppers and customers. This kind of technology allows shoppers to read product prices and product information clearly and therefore, make informed purchasing decisions.

These are just a few examples of electronic paper devices. It’s best to remember that this technology is continuously evolving and new applications are being developed regularly.

Essentially, electronic paper technology is made through a combination of electronic and material engineering processes. The most common type of e-paper technology is based on electrophoretic displays (EPD). EPD consists of millions of tiny microcapsules filled with charged particles suspended in a transparent fluid.

Here's a simplified overview of how e-paper is made:

1. Microcapsule Preparation: The core component of electrophoretic displays is millions of tiny microcapsules. These microcapsules are typically made of a transparent polymer material and filled with charged particles suspended in a transparent fluid. The charged particles are usually black and white, but other color options exist for more advanced electronic displays.
2. Electrode Formation: Transparent electrodes are prepared, typically made from materials like indium tin oxide (ITO) coated onto a substrate, such as glass or flexible plastic.
3. Microcapsule Dispersion: The prepared microcapsules are dispersed in a fluid and then coated onto one of the transparent electrodes in a thin, uniform layer.
4. Encapsulation: Another transparent electrode is placed over the microcapsule layer, creating a sandwich-like structure. This structure is sealed to prevent the fluid and microcapsules from leaking out.
5. Application of Voltage: When a voltage is applied across the electrodes, the charged particles inside the microcapsules move toward the electrode with the opposite charge. This movement causes the microcapsules to either display a black or white color, depending on the direction of the voltage.
6. Display Control: By selectively applying voltages to different regions of the display, specific patterns or images can be formed. This creates the desired visual output.
7. Backplane Integration: The e-paper display module may be integrated with additional components, such as a backplane for controlling the display, driver circuits, and connection interfaces.

While this is a general overview of how e-paper is made, it’s important to note that the manufacturing process for electronic paper devices may vary depending on the specific type of technology used and the application or product. Various brands and companies will also have their advancements in materials and techniques to improve the performance and value of their electronic paper products.

The way electronic paper works, of course, is based on the principles of electrophoresis. This is known as the movement of charged particles, or molecules, in an electric field. 

Here's how electronic paper works and shows various content on the display screen:

1. Voltage Application: Voltage is applied across the electrodes, and an electric field is generated. The charged particles inside the microcapsules dispersed between two transparent electrodes will then move because of the electric field. The direction of movement depends on the polarity of the applied voltage.
2. Display Output: As the charged particles move within the microcapsules, they migrate toward one of the electrodes, either the top or bottom one. Depending on the direction of movement, the microcapsules appear either black or white when viewed from the outside. This will now create the intended visual output on the display screen.
3. Bi-stability Display: Once the charged particles have moved to their respective positions, they remain in place even after the voltage is removed. This property is known as bi-stability and allows e-paper displays to retain their images even without requiring continuous power consumption.
4. Control and Refresh: To change the displayed image, a new pattern of voltages is applied to the electrodes, causing the charged particles to rearrange and create a new pattern of black and white areas. This process is typically controlled by underlying electronics or systems, which refresh the display as needed.

In conclusion, electronic paper works by selectively manipulating the arrangement of charged particles within microcapsules to create visible patterns and images. This is how users are able to see various texts, images, and any other patterns of formats on the display screen of an e-paper-based device.

While e-paper is usually found in various applications and products, good e-paper technology is needed to achieve a seamless and glare-free reading experience for users and viewers. In general, a good electronic device with electronic paper technology should possess several qualities to provide an optimal user experience, no matter the environment or the application.

These qualities include:

• High Readability: A good e-paper display should offer excellent readability, similar to that of traditional paper. This means providing crisp text and images with high contrast, making it easy for users to read content for extended periods without eye strain.
• Sunlight Visibility: One of the key advantages of e-paper is its ability to remain readable even in bright sunlight. A good e-paper display should maintain its visibility and readability in various lighting conditions. This includes direct sunlight, without glare or reflection hindering the user's ability to view the content.
• Low Power Consumption: Energy efficiency is crucial for e-paper devices, particularly for applications like e-readers and electronic shelf labels where long battery life is desired. A good e-paper display should consume minimal power, especially during static image display, to maximize battery life and reduce the need for frequent recharging.
• Wide Viewing Angle: E-paper displays should offer a wide viewing angle. This is to allow users to view content clearly from various perspectives without distortion or color shift. This ensures that the display remains readable even when viewed from off-center angles.
• Fast Response Time: While e-paper technology typically has slower response times compared to traditional displays like LCD or OLED, a good e-paper display should still offer a reasonably fast refresh rate to provide smooth transitions between images and reduce ghosting effects.
• Durability: E-paper displays should be durable and resistant to damage from scratches, impacts, and other environmental factors. This ensures that the display remains functional and retains its readability over time, even with regular use. This is especially crucial when it comes to busy environments and businesses such as retail stores, transportation hubs, and more.
• Flexibility and Thinness: For applications requiring flexible or thin form factors, such as wearable devices or digital signage, a good e-paper display should be flexible and thin while maintaining its performance and readability characteristics.
• Color variation: Black and white are the usual colors of most electronic paper devices. However, those with more advanced technology can have more than these two colors. Some electronic paper-based devices also have red and yellow colors, offering more design options and possibilities for retailing, documenting, journaling, and more.
• Color Accuracy (if applicable): For color e-paper displays, color accuracy and vibrancy are essential qualities. A good color e-paper display should accurately reproduce colors while maintaining the other desirable characteristics of e-paper technology, such as low power consumption and high readability.

With these qualities, a good electronic paper display can provide users with a comfortable and enjoyable reading experience, whether it's for e-books, digital signage, electronic shelf labels, or other applications.

When it comes to retail technology, specifically, electronic paper-based ESL, SOLUM ESL is known to be a pioneer. SOLUM’s Newton labels are electronic shelf labels equipped with a Full Graphic E-ink Display for an ideal paper-like reading experience. Shoppers at retail stores, convenience stores, groceries, and more can look at product prices and learn more about product offerings.

Newton Color, in particular, offers a more dynamic, color-rich ESL display as it is the latest 4-color variant of the Newton label. It has electronic paper technology that utilizes black, white, red, and yellow, offering a much more vibrant, crisp, and engaging shelf label display. Various retail environments can take advantage of this and create better product pricing content, promotions, and more. This makes Newton Color an impactful factor in the visual merchandising of a store. 

Not only that, but Newton Color also boasts nearly 180˚ of viewing angle. This wide viewing angle will allow shoppers to view and read the display content without any distortion or disruption. This adds to an engaging and informative shopping experience.

With a 5-year battery life and an IP67 rating for dustproof and waterproof capabilities, Newton Color is also a durable ESL solution for most busy retail settings. And since these shelf labels are equipped with the same Newton technology, their breakneck price update speed allows users to update hundreds of ESLs within minutes.

Electronic paper technology is a game changer for a lot of industries. In retail, this kind of technology is what will make electronic shelf labels even more superior and innovative for businesses.

Do you think your retail businesses can take advantage of ESLs with electronic paper technology? Talk to SOLUM experts now to find out more about Newton Color and its colorful possibilities for retail.