Today’s Display Technologies, LCD, LED, OLED, QLED and MicroLED

Display technology has come a long way since the days of CRT displays, anyone of you from the 90s would remember the days when your TV or monitor was still a big hunky box; that was heavy and a testament of how deep your parents’ pockets were, depending how big it was.

Then came the age of plasma displays that were revolutionary, and readily available for purchase. Plasma displays were the next big thing after CRT, it offered TV displays that were flat and wide; it was mind blowing. LCD displays came around the same time, but there was more buzz around plasma displays before LCD took the crown, partially due to pricing and features offered by LCD.

Plasma displays

Plasma displays were great, it offered great brightness and contrast in comparison with LCD displays during those periods. It was relatively cheaper than LCD displays as well. Plasma displays are called “plasma” because it uses small cells containing electrically charged ionized gases, which are plasmas. Hence, this was where you usually hear people saying that plasma displays had “gas” in them. In its simplest explanatory form, the gas is electrically excited to create each pixel’s colour and brightness. There are no backlight panels required like LCDs do. Basically, if you electrically charge each pixel pocket of a plasma display, it glows and shows colour. The colour can be accurately controlled by limiting electrical power and frequency for each pixel.

Plasma displays lost all its market as of today, as better and more economically feasible display technologies took over. A note should also be taken for plasma display lovers, it was very expensive and unfeasible to produce plasma displays that were any smaller than 30inches. This also partially contributed to its demise.

What is LCD

As LCD display technology improved, and display companies poured more money into its development, plasma slowly lost its traction due to its technology limitations. LCD requires backlight for anyone to see what colours are being emitted, as the liquid crystal layer produces no illumination at all. Common calculators utilized today are also LCD displays, but in its simpler form. LCD was able to triumph both CRT and plasma displays due to its ability to scale from very small to very large display types. And its ability to be very thin assisted in its ability to replace those display types quickly.

What is LED

LED displays are nothing too different from LCD displays. Basically, LED displays are still LCDs, just the backlight are powered by an array of energy efficient white LEDs rather than fluorescent as compared to conventional LCD displays. As the market demand for better colour reproduction and contrast ratio increased, display manufacturers started introducing localized white LEDs backlight and RGB LEDs backlights. The former option basically allowed certain regions of the display to have brighter backlit than conventionally brightening the entire panel. This allowed deeper blacks to be reproduced but under total darkness, you could still see the backlight being illuminated. The latter option was introduced into very expensive designer panels, which saw array of RGB-coloured LEDs being used to boost colour contrast, instead of just emitting pure white lights.

What about LCD panel types?

To make things even more complicated, LCD can be further broken down into different panel types. The underlying technology principals are still the same, but the panel enabling it is different. Hence, here are some more common LCD panels you should take note of when purchasing your next TV or monitor.

TN panels

Twisted nematic displays are the most common LCD panel types in the market, due to its cheap production cost. It works by twisting the liquid crystals at varying degrees to allow light to pass through, producing different colour levels. TN panels are usually considered the low-quality LCD displays, but there are some very high-quality TN panels as well that manufacturers have produced. TN panels are less preferred as it offers very lousy viewing angles.

VA panels

Vertical Alignment panels are considered as the middle ground between TN and IPS panels. Unlike TN panels, VA panels provides great viewing angles, better colour reproduction and higher brightness as well. But it suffers from high response time, which creates motion blur (ghosting) for fast moving visuals.

IPS & PLS panels

In-Plane Switching panels, are usually considered as the premium panels when it comes to LCD screens. With great viewing angles and colour reproduction, it is always the go-to panel type for artists, gamers and moviegoers. IPS works by arranging and switching the orientation of molecules of the liquid crystal layer between glass substrates. This works way better than what TN panels do, which limits their emittance at different angles.

Various improvements and variations were made to the IPS technology, with different manufacturers concocting their methods of improving colour production further and offering lower response time to appease hardcore gamers.

Plan to Line Switching is in almost every way similar to IPS, but perhaps some minor differences. The technology was developed by Samsung, with advertised advantages that are marginally better than IPS. In real-world scenario, both panels perform as good as each other, albeit some people may beg to differ.

OLED, the Premium Display

Then comes the next-gen stuff, introducing Organic Light-Emitting Diode. The “organic” part of the name comes from the organic compound that is found in this panel type. What makes OLED so much more awesome than other panel type is that each pixel in the panel itself emits light on its own; without the need for any backlight. This allowed true black to be produced when viewing very dark scenes, allowing almost true to life colours to be reproduced. OLED also allows the display panel to be very thin, so thin that it seems almost impossible; and we’re talking about thinner than what LCD could achieve.

OLED should also not be confused with standard LEDs, which in terms of basic concept they may work principally the same, the underlying technology is very different.

Contrast ratio and brightness on modern OLED screens are also way off the charts, allowing High-Dynamic Range (HDR) contents to be easily presented effortlessly. HDR contents would make you see colours you never thought possible through a screen display.

QLED, the Samsung Contender

While Samsung is considered one of the pioneers of making OLED mainstream in consumer devices, there has been more and more competition from other display manufacturers such as LG, Sony and Japan Display. Seeing that OLED is expensive to manufacture when it scales up, Samsung decided that it was more feasible for them to bank on traditional LCD and invest in complementary technologies to enhance its appeal.

Enter Quantum dot LED. Essentially LED backlit LCD screens, but Samsung took it one step ahead by using Quantum dots instead of just standard LEDs. Quantum dot works by placing a layer or film of quantum dots in front of a regular LED backlight panel. The layer is made up of tiny particles each of which transmits its own individual colour depending on its size (anywhere between 2 and 10 nanometers). Quantum dots still require an LED backlight, as by itself is incapable of producing light. Basically, the size of the particle dictates the wavelength of light that it emits, hence the different colours. Samsung boasts that quantum dots enable over a billion colours.

If you look at it this way, each Quantum dot acts like a colour filter for the LED backlight. And since the latest generation of Quantum dots can limit the amount of backlight that is transmitted as well, but not entirely dimming out to achieve true black like OLED can.

MicroLED, the future of Premium Display

Just when you thought we already have enough screen technologies in the market already, here comes the next generation display. Introducing, MicroLED, where essentially it still uses a LCD layer but supported by super small LEDs. Imagine the standard Light Emitting Diodes that is found in various type of electronics including our standard LED screens, scaled down further to nanoscale.

With these LEDs operating at the same scale as per LCD pixel, we can achieve true black like OLED can as each pixel can be individually disabled. While it can be argued that OLED still triumphs as it has less layers to make up the display, in theory, MicroLED is better as it has less chance of suffering burn-in.

Burn-in happens when you display a static content on the screen for long durations and the image then seems “burned” onto the display.

When MicroLED can be manufactured into scale, it should cost less than OLED as well, as the organic compound used in OLEDs are the most expensive component of the entire screen.

As of now, Samsung is only offering very large MicroLED displays aimed mainly at commercial displays. They are attempting to perfect their manufacturing techniques and hopefully, we’ll see MicroLED TVs and monitors in our homes soon.

Which is your favourite display technology and why? Let us know.

Info Trek is the premier IT training and certification provider in Malaysia and is now offering Scaled Agile framework certification. The Scaled Agile Framework (SAFe®) helps businesses address the significant challenges of developing and delivering enterprise-class software and systems in the shortest sustainable lead time. It is a freely revealed, online knowledge base of proven success patterns, for people building the world’s most important software and systems

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