Displays in IoT

Introduction

In the 21st century, humans aren't the only ones who communicate with each other, devices have also started to share information among themselves. IoT, which stands for Internet of Things, is a network of physical objects embedded with different technologies that enable them to connect and transfer data with the other devices on the Internet, thus allowing them to communicate. Such devices are known as Smart devices. 

IoT is becoming an essential technology as each and everything we use throughout our days, like thermostats, kitchen appliances, smart lights, cars, and many other things all of them, are becoming a part of IoT and are making our tasks easier and thus transforming the way we conduct our lives. Apart from making our daily household life easier, automated IoT systems are becoming essential to the business day by day. IoT technology provides the user with real-time insights into how their systems works, it helps them monitor the overall business processes, improve productivity, generate more revenue, and save time and money.

Whether a person is a student or a working professional, they spend a large portion of their day in front of a screen. Tho we all are familiar with laptop screens and TV screens, the display technologies driving IoT devices are more diverse. Let us discuss some of the recognized and less common techs and the pros and cons they offer.

IoT Display Technologies

EPD

EPD stands for Electrophoretic display, it is a bistable display allowing only two stable visual states. It is most commonly used in e-book/e-readers such as Amazon Kindle. EPD devices became successful because they only use energy when there is a change from one state to another. These displays are reflective, which means they don't need a backlight for content to be visible in normal light, thus saving energy. Because they require such a low amount of energy, they create the possibility of adding them to the simplest IoT devices in order to present a straightforward human-readable interface. However, EPD devices are not great for multimedia content, as EPD generally presents monochrome displays. 

Pros

• Paper-like appearance of the display
• It uses less power, and the display stays visible for a longer time
• Works well for low-power projects

Cons

• The display is slow when updating
• Not good with multimedia content
• It cannot be used in a dark environment
   

TFT LCD

TFT stands for Thin Film Transistor. These displays are best suited for devices that can be charged regularly or if they have a permanent power supply. They consume more energy than other display technologies such as EPD. Tho, they provide exceptional color reproduction such that it is impossible to notice individual pixels with the naked eye, and they provide a fast response time, making them ideal for multimedia content. TFT LCDs are backlit so that they can be used easily in environments with low ambient light. TFTs are usually found in computer monitors and automotive displays tho they can be integrated into smaller items such as smartwatches. However, these displays are less readable in direct sunlight.

Pros

• High-resolution display
• Sharp visibility
• No burn-in

Cons

• Consumes more energy as compared to EPD
• Uses backlight to provide brightness
• Less readable in sunlight or bright light
   

OLED

OLED stands for Organic Light Emitting Diode. These displays have high contrast ratios as they can control the brightness of individual pixels. They have better power efficiency than TFT LCDs because they use efficient organic light-emitting diodes, whereas the CDs use liquid-crystal materials for each pixel. OLEDs provide better viewing angles and have a decent price/performance ratio. Because of their fast reaction time in smaller devices, they are extensively used in mobile phones. OLEDs are one of the only displays that are showing excellent performance in flexible displays. 

Pros

• Better viewing angles
• Power-efficient as they are self-illuminating 
• Light Weight

Cons

• Short lifespan
• Expensive
• Susceptible to water damage
   

Reflective Segmented LCDs

Reflective segmented liquid crystal displays are most commonly used for everyday items like watches, kitchen appliances, toys, etc. A voltage is applied to the liquid crystal in order to control the light transmission that is either for blocking the light or letting it through. A reflective layer is placed underneath the screen for ambient light so that the light can be reflected back to the user rather than requiring a backlight for illumination. These displays consume very little energy.

Pros

• Cheaper
• Not harmful to the eyes
• Consumes very low energy
• Best suited to be used in direct sunlight

Cons

• Monochrome display
• Reading from certain viewing angles may be difficult
• Not suited for dark environments
   

LED

LED stands for light-emitting diode, they are the most commonly used and most popular of all the IoT displays. They are usually used for devices with simple alphanumeric characters and symbol displays. In LED devices, a process called electroluminescence takes place for emitting the light, in this process, a current is sent through a closely-set group of diodes, and the brightness of the diodes can be easily altered to create an image. These displays can also be used for color-changing feedback.

Pros

• Works well in dark and indoor environments
• Long lifetime
• Easily accessible

Cons

• High power consumption
• Flexible display option is not possible
• Low-cost LED displays have a poor display.

MicroLED

It is one of the upcoming technology which has a promising future. MicroLEDs do not require a backlight which enables them to save a high amount of energy. As they are known for their exceptional brightness, contrast, and definition, they have a promising future in IoT devices that require large screens. Tho they are not just limited to larger screens/devices, rumors are there that Apple is developing its own MicroLED for ultrathin displays.