Screen Technology: LED vs OLED vs QLED, What are the Differences and Which is Better?
By Adama Brown,
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To anyone in the market for a new TV, the variety of different screen types might be overwhelming: LED, OLED, QLED, LCD, all with competing claims about producing the best picture, and sometimes with wild differences in price for reasons that might not be apparent at first glance. We break down what each technology means to you in real-world usage, and what your best options are.
Several of these types of screen technology are very closely related, those being LED, QLED, and LCD. In fact, you’ll sometimes see screens referred to as LED LCD. The reason for this is tied up in the evolution of flat-panel displays and how they’re built.
LCDs: the parent of modern displays
LCD or “liquid crystal display” screens have been around in one form or another for decades, and traditional LCDs have always been built with a design that involves two layers. One is made up of the liquid crystals that make up the actual picture; the other layer illuminates them by projecting light through the crystals towards the user. That’s why you’ll see LCDs referred to as having a “backlight.”
Older LCDs used a small fluorescent tube to provide this light, however newer ones have a background of light-emitting diodes, or LEDs. LED-based backlights provide more even lighting, better viewing angles, and longer life than the old fluorescent tube systems. Thus, many manufacturers will label their products as “LED” screens to emphasize the improvement over older models.
The downside of this kind of design is that because light has to be projected through the displayed picture in order to be seen, it affects the contrast and color fidelity. A part of the screen which is supposed to be black is never quite entirely black, because some light will get out in between the pixels, making it appear slightly gray. Higher resolution screens suffer less of this because more pixels block more light, but it’s still there.
This where the term “contrast ratio” applies for TV screens: the ratio of how much brighter white is than black. A newer model TV might run anywhere from 1000:1 all the way up to 8000:1, with higher numbers being better; more contrast meaning a richer black and more faithful picture.
One LED-based LCD TV that provides an example of the best the basic class has to offer is the Sony X95K, which incorporates a robust LED backlight to illuminate its 4K HDR screen, and comes with Google TV functionality.
QLEDs: Nanoparticles enter the mix
QLED, also known as QD-LED or “quantum dot LED,” is another evolution of the same basic LCD technology. It too has an LED backlight layer and an LCD layer. However, in between these, QLED screens sandwich a layer of “quantum dots,” tiny crystals which effectively filter and clean up the light coming from the LEDs.
The net result of this is backlighting which has improved color and contrast compared to unfiltered backlights. Images are more vivid, and brighter, than they would be with LEDs alone.
But like the switch from fluorescent backlights to LED ones, the addition of quantum dots is more of an evolutionary improvement for LED LCDs than a revolutionary one.
A top of the line example of QLED technology can be found in the TCL 6 Series/R655. It rounds out its improved contrast and color with 4K resolution, HDR, and Roku smart TV apps.
OLEDs: A different way of doing things
OLED screens, however, work on an entirely different principle. Instead of having two layers, they have just one: a grid of tiny multicolored LEDs which emit their own light, providing both illumination and picture all in one package.
This means that contrast is far better on OLED screens: since they only emit light as needed, black is really black instead of having some light still filtering through it. Thus, an OLED screen has a contrast ratio that is effectively infinite, making them particularly well suited to displaying dark images with high fidelity. And colors are more vibrant than traditional LED LCDs, as white light isn’t seeping through them washing them out.
OLED also provides better performance when viewed at an angle than LCD screens; since you’re looking at the actual image, rather than light being projected through it, the colors and contrast don’t change depending on where you look at it from.
One excellent example of the best that OLED TVs have to offer is the Samsung S95B. Available in 55 and 65 inch sizes, it shows off the best picture quality that OLED has to offer, alongside 4K resolution, HDR, and Samsung’s Smart TV Hub.
LED vs OLED: A matter of maturity
But while OLEDs have obvious advantages over LED and even QLED displays, they also have some notable drawbacks, as newer technologies which are still maturing often do. For one thing, OLEDs are expensive. An OLED TV will currently cost several times as much as a comparably sized LED TV, and more even than many QLED TVs. LED screens benefit from being a long-established technology whose mass production has been made cheap.
OLEDs also have one major technical weakness. Like some older display technologies, OLED screens can suffer from “burn in,” where a static image that’s left on the display long enough can leave a permanent visual mark. This means that OLEDs can suffer in situations where they might show the same things over and over: news tickers, network logos, user interfaces, etc. LED LCDs have no such problems, which is why they remain particularly dominant in computer usage.
Different technologies for different usage cases
In the end, LED or QLED displays and OLED displays have different strengths. If you’re looking for the absolute best picture quality you can get, and don’t mind paying extra for it, as well as being careful with how you use your TV, OLED screens offer the best contrast and picture quality on the market. They’re particularly well suited to home theater use, where contrast is vital to picture quality.
For applications where constant use or displaying static images is a priority, such as for news watchers, informational displays, and use as computer monitors, LED-based screens are the clear choice and will remain unscarred no matter what they have to display or for how long.
QLED screens offer a balance of the two options, providing improved performance over regular LEDs without the drawback of burn-in issues, and at a price point that sits somewhere in the middle of the two.