When two closely related, similar sounding acronyms are bandied about, confusion is bound to ensue. Hence, QLED and OLED are causing some consternation among shoppers – and among some online reports – about what the differences are and which technology is superior.
Who are the players?
QLED is a marketing acronym created by Samsung for its high-end LCD TVs like the Q7F that use quantum-dot technology. The technology is not unique to Samsung, and it's not new. Sony and Sharp have had quantum-dot sets on the market for some time going back at least four years. TCL and others have different types of quantum-dot TVs on store shelves. Quantum-dot sets are essentially a modification or addendum to conventional LCD TVs, which represent the majority of TVs on the market.
OLED stands for organic light-emitting diode, a very different way of creating a picture. The only company currently making large panel OLEDs for TVs is LG, which offers a variety of OLEDs, including the E7 OLED65E7P. Other companies with OLED TVs, such as Philips, Panasonic and Sony – including the Bravia OLED XBR-65A1E – use LG's panels.
How do they work?
Quantum dot, or QLED, sets use a conventional LCD (liquid crystal display) to which they add another layer of quantum dots of a particular size, which in turn dictates the color those dots emit when hit by light from behind. By adding the extra quantum layer, extra colors (i.e., a wider color gamut) can be displayed.
However, quantum-dot LCDs still require a separate backlight to illuminate the display. That light is created by LEDs behind the panel or along its edge, hence the "LED" part of Samsung's acronym. Incidentally, there is no such thing as an "LED TV," except for those gigantic Mitsubishi screens in football stadiums.
OLED, or organic light-emitting diodes, represent a completely different kind of display. No backlight is required because the organic pixels emit their own light when hit with electricity. So each pixel can be completely turned on or off separately.
Which is sharper?
In technical terms, OLED is theoretically sharper because it can turn on or off each individual pixel. With quantum-dot sets, because there's an afterglow and light leakage behind the LCD layer (caused by the separate backlight), it tends to blur the edges around bright objects.
Active or local dimming on LCD sets helps, but some light leaking still occurs. Consequently, we still commonly see halo effects around bright objects displayed on LCD sets from manufacturers ranging from Samsung to TCL.
Which delivers deeper blacks?
There is no debate: OLEDs are the only sets that can deliver true black.
Quantum-dot LCDs – including Samsung's QLEDs – look grayish next to an OLED set. (The backlighting system necessary to make LCD and quantum-dot LCD sets work means it is virtually impossible to completely eliminate light leakage. Consequently, black areas look gray on QLED TVs.)
Which is brighter?
Quantum-dot LCD sets, including Samsung's QLEDs, are brighter than OLEDs. They simply put out more light, making them more appropriate for sunny rooms where brightness counts.
Compare, for example, our recent brightness test results from an LG E7 of 446.5 nits to our results from Samsung’s Q7 with 1008 nits. On the other hand, if you tend to watch movies in a dimly lit room, OLEDs can seem brighter because of their severe contrast levels.
Which has better color?
Overall, a well-designed quantum-dot LCD or QLED TV can deliver a wider range of colors than an OLED set. They can also be more accurate, with more faithful reds, for example.
In recent tests, the LG E7 OLED earned a Delta-E color accuracy score of 2.3 compared to Samsung's Q7F quantum-dot TV, which had a score of 1.4 (lower is better).
Nevertheless, how wide a color gamut or how many colors a display can reproduce still varies from set to set. Some OLEDs, such as Sony’s A1E, can match or best quantum-dot sets in this regard. Recent Tom’s Guide tests showed the Sony OLED, for example, was able to produce 107.5 percent of the Rec. 709 color spectrum, while Samsung’s QLED reproduced 97.3 percent of the same color gamut.
Current video content may not reveal the differences, but as more HDR 4K programming becomes available, the nuances will be easier to see.
What about contrast?
While quantum-dot LCDs struggle with inky blacks, they tend to do better at eliciting the subtle changes between dark and light areas. Overall, top quantum-dot or QLED sets have a wider contrast range and can reveal some picture details OLEDs miss.
Conversely, it may look to one's eye that OLEDs deliver better contrast because of the striking differences between light and dark areas. However, OLED's contrast range is limited to a narrower frequency range; as it approaches black, an OLED tends to cut off the light completely, eliminating some shadowy picture details in the process.
What about viewing angles?
Most of us don't sit dead center in front of the TV. We're usually at one end of the couch or the other, which means we're looking at the set off-axis. When viewed off-center, LCD TVs such as Samsung’s Q7 QLED sets tend to lose some of their luster; colors look washed out or even strangely skewed. On the other hand, OLEDs such as those from LG and now Sony do not suffer from such shortcomings (at least not nearly to the degree that LCDs do).
Samsung's QLED is definitely an improvement in terms of viewing angles over previous generations of quantum-dot sets and most LCDs. However, LG's OLEDs are still far superior in this regard, holding their images, colors and crispness even if you are sitting a little askew in your bean bag chair.
What about burn-in?
QLED sets come with the same advisories as OLEDs about burn-in and the dangers of letting a static picture sit on the screen for too long (just look in the owner's manual). Personal experience indicates that OLEDs seem slightly more susceptible to the problem, especially in the short term where the ghost of a logo or other icon may appear to linger a minute or two longer on an OLED than on most LCD displays.
Overall Winner: OLED
So which is better, QLED or OLED? Just ask Sony. It started using LG's OLED panels for Sony's top-of-the-line TVs this year, and we praised the Sony Bravia OLED XBR-65A1E for having the best picture quality on the market. If a pristine picture is what you want, OLED is the way to go.