Low power display technologies have made rapid strides in the electronics sector in recent years. As a result, companies and professionals who need to consider low-power display technologies for their products and solutions have a variety of options to choose from, each with its pros and cons.  

Choosing the right display ultimately depends on the intended use or application; for example, different displays might be used for portable electronic devices, consumer electronics, or industrial solutions. In this article, we will discuss the most prevalent low-power display technologies, and consider the pros and cons of each one.

So, what is a low-power display?

A low-power display is designed to operate with minimal energy consumption while maintaining functionality. Low-power displays are designed to consume low levels of energy, which is often achieved using the concept of bistability, which means energy is only consumed when the image on the display changes, while no energy (or ultra-low energy) is consumed during static usage (same image being displayed during a period of time).  

Most low-power displays are also reflective displays, meaning they rely on ambient light rather than an internal backlight. Instead of emitting light, reflective displays bounce light off their surface, similar to how printed paper reflects light for readability. This characteristic further enhances their energy efficiency. Read more about reflective displays.

The demand for low-power displays is growing, as industries seek to reduce energy consumption and reduce environmental impact. Moreover, certain markets and applications increasingly require wireless products that are not connected to a power grid, and/or that can’t be frequently charged. A low-power display is perfect for situations like these, when trying to maximize a product's battery life, by using the least amount of power during use.

Types of low-power display technologies: LCD vs Electrophoretic Displays vs Electrochromic Displays

Different markets and applications typically use different types of displays. The most popular low-power display technologies available on the market are LCDs and e-paper. For a while, LCDs were the only choice available for low-power displays. That was until two exciting e-paper options arrived into the display market: electrophoretic displays and electrochromic displays.  

This article will discuss these three low-power display technologies in greater detail and compare its different features, such as power consumption, display quality, and more.

Reflective LCDs

Reflective LCDs are common in consumer electronics because they consume little power, are easy to produce and are cost-effective. Low-power seven-segment displays are widely used in calculators, digital clocks, radios, microwave ovens, and washing machines, for example. Reflective LCDs work by reflecting ambient light - such as natural light - from a reflective layer, back to the viewer.

Features:

• Reflective LCD are most suitable for high-frequency switching, i.e. if the display switches images more than 600 times in a day.
• The cost of reflective LCDs is very low, since this is a mature technology, with fully optimized manufacturing and supply chain.
• These displays are not flexible enough to bend.
• Most reflective LCDs have limited viewing angle, i.e. for some displays it is difficult to read the image when it is observed from a 30° angle or higher.
• The typical operating temperature range of reflective LCDs is -40 °C to +85 °C.
• These displays are extremely robust and have a very long lifetime.
• The image is difficult to view in low-light conditions.

Electrophoretic E-paper Displays

Electrophoretic display technology has a paper-like contrast appearance. This means that it replicates the appearance of ordinary ink on paper. This display technology is popular because of its contrast, readability, thickness and low-power consumption. It is widely used in e-readers like Amazon's Kindle, real-time bus arrival information, and electronic shelf labels (ESLs), among other applications. When the display is powered, charged ink particles rise to the top of the display to create images.

Features:

• Electrophoretic displays are bistable, meaning they only need energy when there is a change in the displayed image.
• Electrophoretic displays are up to ten times more expensive than both reflective LCDs and electrochromic displays.
• Much like paper, electrophoretic displays have almost no viewing angle dependency.
• For most electrophoretic displays, the operating temperature ranges from 0 °C to 50 °C.
• The lifetime of electrophoretic displays is between 1 - 10 million display updates.

Electrochromic E-Paper Displays

Electrochromic e-paper displays have several advantages when compared with other low-power display technologies. Like LCDs and electrophoretic displays, electrochromic displays are reflective, which means they work by reflecting ambient light. When a voltage is applied, the display will change color through specific electrochemical reactions. Electrochromic e-paper displays are ultra-low-power, lightweight, thin, flexible, energy-efficient, and cost-effective to produce and operate. In addition, electrochromic e-paper displays are easily customizable to specific product, use and business needs. As a result, these e-paper displays have the potential to be widely used in areas as diverse as:

• Smart labels for supply chain and logistics monitoring
• Wearables
• Medical devices and diagnostics
• Digital signage
• Smart cards

‍

‍

‍

Features:

• Electrochromic displays are semi-bistable, meaning they hold an image without power, but for a shorter period than electrophoretic displays.
• Electrochromic displays are the most energy-efficient display technology for medium-frequency switching, i.e. if the display switches between 4-600 times a day.
• In terms of display cost, electrochromic displays are among the most cost-effective technologies both to operate and produce - as they can be produced cheaply using roll-to-roll screen printing.
• Display design is highly customizable, allowing for a range of design options, including different sizes, shapes, and forms, and it can also easily incorporate graphic overlays.
• Of all three technologies mentioned, only electrochromic displays are bendable and suited for applications that require a flexible display.
• Just like electrophoretic displays, electrochromic displays also have almost no viewing angle dependency.
• Electrochromic e-paper displays can operate between -20 °C to 60 °C, making them suitable for a wide temperature range.

To explore in further detail, we’ve put together a direct comparison of the power consumption of reflective LCDs vs. electrophoretic vs. electrochromic displays.

‍

A side-by-side comparison between reflective LCDs, Electrophoretic Displays and Electrochromic Displays

Try Out Low-Power Electrochromic E-paper Displays For Yourself

At Ynvisible, we offer full end-to-end solutions for prototyping and producing low-power display solutions for a wide range of unique applications. To explore how Ynvisible’s low-power e-paper displays could work for your product ideas, why not get started with our e-paper display kit to see how it works?

Want to discuss more? Contact Ynvisible today to learn more about our ultra-low-power e-paper display solutions.

‍