A Complete Guide To LED Displays

What are LED displays?

Many readers here will already know that the acronym LED stands for ‘light-emitting diode’, meaning a small cell or conductor that glows and becomes illuminated when a voltage is applied to it.

In entertainment tech sales, the phrase ‘LED display’ is often used very broadly to describe screens on all manner of devices (most commonly for products such as TVs, mobile phones and computer monitors). These high-resolution LED displays tend to use hugely dense diode arrays - often numbering in the thousands - to control illumination and colour cycling across millions of individual pixels, allowing for the rendering of highly detailed images at pixel densities of up to 4k and even beyond.

However, in engineering component terms, the definition of an ‘LED display’ is more commonly taken to be a discrete light-up readout board - often relatively small and simple - that’s designed to be attached to an instrument panel or mounted on a printed circuit board (PCB).  The purpose of these types of LED displays is typically just to provide clear and concise information readout for the user.

Types of LED displays

There are numerous LED display panel types available on today’s market - as noted in the opening section of this guide, some of the more common configurations include segmented displays, dot matrix, alphanumeric and light bar versions.

In this section we’ll look a little more closely at what the differences between these types of LED screens are, and when a particular model or style might prove more useful/economical than another.

Dot matrix LED displays

LED dot matrix displays can be thought of as the next logical step up from 16-segment alphanumeric arrangements. In a typical dot matrix LED display, the clustering of individual diodes is denser still, while the ‘dots’ (LEDs) themselves are most often arranged in a rectangular grid that’s wider than it is tall.

LED vs OLED displays

When talking about different types of LED displays - particularly in terms of specs for smartphone, TV and monitor screens - you’ll doubtless have heard the term ‘OLED’ used alongside the more familiar LED display. So what is the difference between OLED and LED?

Well, there are numerous more complicated and (as it were) illuminating answers to that question, but the simplest version is this: standard LED displays tend to rely on backlighting to illuminate pixels, whereas OLED does not.

To add slightly more detail, an LED screen lights pixels (to a greater or lesser extent, according to the image being shown) either from behind or from the side. An OLED display is a newer and much more costly technology that delivers the ability to illuminate or completely switch off each individual pixel. As a result, OLED displays offer deeper blacks and thinner screens by removing the need for backlit arrays.

LED vs LCD displays

There’s often a degree of confusion around questions such as “which is better, LED or LCD?” when it comes to display or screen types. In attempting to clarify exactly what the ‘difference’ is between LCD and LED displays, the key fact to underline is that LED displays are LCD displays - they’re just a specific subset of the broader LCD technology.

As many will already be aware, LCD stands for liquid crystal display. The acronym can be used to describe any panel or display that uses liquid crystal to control where (and how much) light is displayed in each on-screen pixel at any given moment.

Many types of LED displays, particularly in TV screens and computer monitors, use precisely this technology - and so they’re LCD screens by definition. The fact that they also use LEDs to backlight these pixels is what defines LED displays as a subset.

To make matters even more straightforward, be aware that pretty much all LCD displays currently in production are LED variants. The previous common method of lighting LCD screens was using cold cathode fluorescent lamps (CCFLs), and while a few budget panel-makers do still include CCFL options at lower tiers, for most brands that standard has all but been rendered obsolete by the rise of LED technology today.

In short, if you’re looking at purchasing any sort of LCD display made in the last few years, it’s extremely likely to be an LED version (and will almost certainly be referred to as an LED screen specifically, rather than the more generic LCD).

LED display advantages

The advantages of LED displays over other panel and screen types are numerous, depending on what sort of application you’re looking to use them in. Some commonly cited LED display advantages include:

• • • They’re highly scalable, and can be used for all screen/panel sizes from large LED displays to very small LED displays.
    • LEDs themselves are bright, crisp and eye-catching, for excellent colour reproduction and high contrast visibility in a wide range of scenarios and environments
    • LED displays can be configured into very slim and flat panels for sleek aesthetics and great space-saving potential - they can be mounted almost anywhere and look good
    • The diodes tend to produce a quality flicker-free image/signal, which is helpful for both general readability and for reduced eye strain
    • LED displays draw very little power and are extremely long-lasting, even in continuous use - as such they’re both highly economical and far better for the environment than many alternatives
    • They can be manufactured to be completely addressable (100% individually programmable) when fed with the right software, making displays infinitely flexible and customisable
    • LED displays are very safe for installers and users alike, as they don’t produce heat and run off far lower voltages than many other display types

Potential LED display problems

As with all technologies that deliver so many characteristic advantages, there will inevitably be some occasional disadvantages, compromises and possible display issues with LED screens.

Thankfully, these are relatively low-impact for the most part, and LED displays are generally known for fairly solid dependability. As they ought to be, in fairness - they’re considerably more expensive than many other lighting types, which is one of the main downsides of LED displays at present.

Even so, further examples of LED display problems you might potentially find yourself troubleshooting at some point could include:

• • • Gradual colour-shift and potential burn-in over time
    • Typically weaker performance in producing pure white light (LEDs tend to display white by mixing other colours at high intensities, which usually results in a tint of some kind)
    • Somewhat inconsistent colour and contrast ratios between different brands/configurations of diodes and displays
    • Comparatively difficult user maintenance; most basic users would feel less comfortable tinkering with LED arrays than with some other lighting types

How to clean LED displays and screens

By far the best approach for cleaning and maintenance of LED displays, panels and screens is to keep it simple and regular: a gentle wiping with a good quality microfibre cloth is all you’ll need for the most part. For more stubborn dust, grease or spills, you can dampen the cloth with a little water, but always try to avoid spraying fluids of any kind directly at an LED screen or display. There’s always a risk of ingress and liquid damage unless the display in question is specifically IP rated against it.

Don’t use cleaning chemicals or waxes with LED displays unless the manufacturer’s notes explicitly state it’s ok to do so, and always be sure to power off and fully unplug displays before cleaning. Although LEDs themselves don’t tend to get hot, you may need to let displays cool in other areas before starting to work on them - and of course, they should be given plenty of time to dry off fully before being plugged back in.

Summary

LED displays of all types are incredibly versatile tools for providing clear, crisp, energy-saving and environmentally conscious readouts of visual information across a wide range of applications, industries and projects.

They’re increasingly widely used both at home and in the workplace, and their ever-growing popularity means that the catalogue of available LED display products is continually growing. The sheer range of LED display panel prices, suppliers and models on the market today can seem intimidating at first, but it’s easily navigated with a basic knowledge of their various configurations and functions.

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