There is huge potential for development in the IoT market, with the market estimated to grow from $381 billion in 2021 to $1,854 billion in 2028. The future of IoT devices is likely to see a move towards a more sophisticated user interface as businesses and consumers come to expect advanced smart technology they can visually interact with. So, display solutions will take centre stage. This article will delve into the different IoT display technology solutions available for IoT devices, evaluating optical performance and energy efficiency.

So, What Is The Internet of Things?

The Internet of Things (commonly known as IoT) is a network of physical "things" embedded with other technologies to connect and transfer data with devices on the internet. These devices can be everyday household objects or complex industrial tools. Since we can connect everyday things like thermostats, kitchen appliances and baby monitors to the internet, IoT has become an essential technology, transforming the way we live and work. 

Besides enabling smart homes, automated IoT systems have become essential to business. IoT technology offers businesses real-time insight into how their systems work, right from the performance of machines to the supply chain and logistics processes. As a result, it helps monitor the overall business processes, improve productivity, generate more revenue, improve customer experience, and save time and money.

Exploring IoT Display Display Technologies in Detail

It’s likely that as the IoT market grows, there will be greater demand for displays catering to both commercial needs and consumers. Selecting the best display for your IoT device involves understanding the application requirements and then finding the IoT display technology that serves those needs the best. We’ve compared six display technologies suitable for integration with IoT devices.

1. EPD (aka. Electrophoretic Display)

An electrophoretic display is bistable, allowing for two stable visual states. It is used in e-readers like the Amazon Kindle. The main reason for its success is that the display only uses energy when it changes from one state to the other, thus saving energy. Secondly, these displays are reflective; therefore, they do not need a backlight for content to be visible in normal light, which further reduces energy consumption.

These low-energy displays create possibilities to add displays to even the simplest IoT devices to present a straightforward, human-readable interface. The main drawback of an EPD is that it is less effective when an IoT device needs to display fast-changing data or work in a dark place. In these cases, there are better display alternatives.

Pros

• Consumes less power
• Display stays visible for a long time even without power
• Works well for low-power projects
• HD and paper-like appearance display

Cons

• Display is slow to update
• Cannot display moving images like videos
• Cannot be used in the dark

2. TFT LCD

TCT LCDs have seen improvements over the last decade. Some LCDs offer such high resolution that it is practically impossible to notice individual pixels with the naked eye. Moreover, movie enthusiasts and gamers have pushed display refresh rates to the stage of displaying even the fastest action clearly.  LCDs can be used in applications needing a rich multimedia experience or in dimly lit places. However, LCDs are less readable in direct sunlight.

LCDs consume more energy than display technology such as EPD. Therefore, these are best suited for devices that can be charged regularly, like mobile phones or IoT devices that are continuously powered, such as thermostats and automotive displays. In addition, since LCDs require a backlight, the LCD module is thicker than the EPD module.

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Pros

• Very high resolutions
• Full color
• Sharp visibility
• No burn-in

Cons

• Less readable in bright light
• Costly and more energy-consuming compared to EPD
• Depends on backlighting to provide brightness

3. OLED

OLED technology has seen a rapid increase in mobiles, high-end TVs and smartwatches. It can display high contrast ratios as it can control the brightness of individual pixels. In theory, the power efficiency of OLED technology is better than TFT LCDs. This is because they use efficient organic light-emitting diodes, whereas LCDs use liquid-crystal materials to either block or show the backlight from each pixel. Moreover, the viewing angles are also much better than most LCDs.

Like many technologies, there are some disadvantages of OLEDs. For example, there are ageing issues with some electroluminescent materials, sensitivity to water, same daylight readability problems as with LCDs. Moreover, they are costly when compared to LCDs.

Pros

• Self-illuminating
• More power-efficient than LCD
• Better viewing angles
• Light-weight and small in size

Cons

• Susceptible to water damage
• Overall luminance degradation
• Expensive compared to LCD
• Shorter lifetime

4. Reflective Segmented LCDs

Reflective segmented liquid crystal displays are a common display option, most commonly used for everyday items such as toys, medical devices, watches and ovens. A voltage is applied to the liquid crystal to control light transmission - either blocking light or letting it through. A reflective layer sits underneath the screen which means ambient light - a light source such as lamplight or sunlight - can be reflected back to the user rather than requiring a backlight for illumination. This keeps energy consumption very low.

Pros

• Very low energy consumption
• Excellent visibility in direct sunlight
• Cheap to operate
• No risk of eye damage
• Ideal for high-use devices that require many image updates‍

Cons

• Not visible in the dark and low visibility in dim light
• Usually monochrome rather than color display
• Can be difficult to read from certain viewing angles

5. LED

Probably the most common and well-established of all IoT display options is the LED (light-emitting diode) display, often used for devices with simple alphanumeric characters and symbol displays, such as smart kettles or signage. LED displays emit light when a current is sent through a closely-set group of diodes; a process also known as electroluminescence. The brightness of the diodes can be altered to create an image. LED display can also be used for color-changing feedback, for example, red equals bad and green equals good.

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Pros

• Display works well in dark and indoor environments
• Good appearance for good quality LED displays
• Easily accessible - many vendors sell this technology
• Robust, long lifetime
  

Cons

• Low-cost LED displays have poor display appearance
• High-power consumption when compared with other options
• Expensive to run (50% to 100% more expensive than reflective LCD or electrochromic display)
• Flexible display options not possible
• Questionable visibility from certain viewing angles

6. Electrochromic E-Paper Display - the best option for IoT devices

This fast-emerging innovative display technology is considered one of the best options for IoT displays. There are many reasons to use printed  e-paper displays. It is a semi-bistable display using electrochromic technology, whereby the color or opacity of a material can be controlled by applying a voltage. It is an ultra-low-power display solution that can be scaled up quickly due to its low cost. Electrochromic printed e-paper display technology is being rolled out across industries such as food technology, cold chain and green technology, and is perfect for use in consumer electronics, medical devices, smart cards and point-of-service applications. Learn more about printed e-paper display applications here.

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Pros

• Ultra-low-power consumption
• Suits an endless range of applications due to easy integration with drivers
• Very easily scalable
• Very flexible design options
• Extremely thin and bendable
• Extremely cost-efficient
• More optically appealing than LCD
• Multiple color options

Cons

• Not high resolution
• Not full RGB color
• Low refresh rate

Key Takeaway

The evolution of IoT display technology is developing at a rapid pace. At present, some of the biggest manufacturers are testing newly emerging display technologies, such as electrochromic displays. As a result, the next generation of displays may look the same as today but function entirely differently as we push to more energy-efficient, flexible display designs.

We Produce Ultra-Low-Power, Low-Cost Printed E-Paper IOT Displays

At Ynvisible, we have developed a display solution for IoT devices with very low energy consumption. This is why we’re considered one of the most energy-efficient, low-cost display technologies available - perfect for IoT displays requiring a low-power solution. To explore the design capabilities of our displays, why not get started with our segment display kit to see how it all works.