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Analysis TVs

Samsung QLED vs. LG OLED TV: What's the difference?

Samsung's QLED TVs aim squarely at LG's OLED models for the picture quality crown. But in spite of the similar-sounding names, they're as different as chalk and cheese.

Sarah Tew/CNET

When it comes to new TV technology, the little line that turns an "O" into a "Q" makes a big difference.

Samsung, the world's No. 1 TV maker, is now branding its best 2017 TVs with an unfamiliar new acronym: "QLED."

Meanwhile its chief rival LG, the world's No. 2 TV maker, will continue selling sets designated "OLED." Philips, Panasonic and Sony are selling OLED TVs too, but all of the panels are produced by LG Display.

In our side-by-side comparison reviews, OLED-based TVs are still the best we've ever tested, and all of them outperform the one QLED TV we've reviewed, Samsung's Q7, by a wide margin.

Which poses the Q: Is Samsung trying to ride the coattails of OLED's overwhelmingly positive reputation by calling its newest TVs something nearly identical?

I asked Samsung. Company representatives didn't answer my question directly, but replied in a statement:

"QLED stands for Quantum Dot LED TV. There are and will be many different types of quantum dot based display technologies today. Some new architectures are likely to arise in the future as well. QLED encompasses all of these variations of architecture just as the term OLED encompasses a variety of different architectures.

"Using your example of OLED, OLEDs can utilize passive or active backplanes and emissive layers that are composed of white emitters with RGB or RGBW filters, or with direct RGB emitting materials and no color filters. Yet these are all classified as 'OLED' displays."


Even so, the fact remains that "QLED" looks and sounds a lot like "OLED," and your average TV buyer doesn't know quantum dots from passive backplanes. And this wouldn't be the first time copycat marketing was used in the TV space. Just last year, in fact, I accused LG of aping Samsung when it called its TVs "Super UHD" -- a telling echo of Samsung's own "SUHD" name (which, incidentally, is being retired in favor of QLED).

What goes around comes around.

A QLED TV is an LCD TV with quantum dots

Marketing aside, the two technologies are very different. Here's a quick summary.

  • OLED stands for "organic light emitting diode."
  • QLED (according to Samsung) stands for "quantum dot LED TV."
  • OLED is a fundamentally different technology from LCD, the major type of TV today.
  • QLED is a variation of LED LCD, adding a quantum dot film to the LCD "sandwich."
  • OLED is "emissive," meaning the pixels emit their own light.
  • QLED, like LCD, is, in its current form, "transmissive" and relies on an LED backlight.

In other words, as much as Samsung wants "the establishment of a category of televisions that are driven by quantum dot technology," the 2017 version of QLED is closer to regular old LCD than it is to OLED, which I (and most other experts) consider a distinctly different class of television, much like plasma was before it.

Quantum dots are microscopic molecules that, when hit by light, emit their own, differently colored light. In Samsung's 2017 QLED TVs, the dots are contained in a film, and the light that hits them is provided by an LED backlight. That light then travels though a few other layers inside the TV, including a liquid crystal (LCD) layer, to create the picture. The light from the LED source is transmitted through the layers to the screen's surface, which is why we say "transmissive."


The LCD "sandwich" is composed of multiple layers. Above is an example of the layers exposed in a typical quantum dot-equipped LCD TV, and below is a diagram Samsung supplied that shows similar structure on its 2017 QLED TVs.

Josh Miller/CNET

Samsung has been using quantum dots in this way for the last two years in its SUHD TVs but says it has improved its quantum dots in 2017 to deliver better color and more brightness. There's a new proprietary structure that "consists of a metal core, a graded ZnSeS layer and a metal jacket."

Here's where I mention that Samsung is actually working on a version of QLED that does use emissive technology, much like OLED and plasma. We covered it in-depth last year. At the time we said QLED stood for "quantum dot light emitting devices," not the broader "quantum dot LED TV" Samsung says it stands for now.

The short version is that emissive QLED TVs have the potential to match the absolute black levels and "infinite" contrast ratio of OLED, with better power efficiency, better color and more. That's pretty exciting, but it'll be a few years before we see emissive QLED TVs available for sale. Hopefully by then they'll think up a new acronym (EQLEDs?).


Emissive QLED elements, like the prototypes shown here, are still a few years away from making it into TVs.


OLED TVs beat a QLED TV in our review

In May 2017 I compared the cheapest QLED TV, Samsung's Q7, directly to an LG OLED TV in a side-by-side review. OLED won handily, with Samsung's QLED scoring a "7" in picture quality compared to "10" for the OLED TVs. Here's the takeaway from that review's picture quality section:

The Samsung Q7 can deliver a very good image, but didn't match the cheaper Vizio P series or the more expensive LG E7 OLED TV I had on-hand to compare. Its black levels and contrast were worse, particularly with HDR material, and the color advantages Samsung claims with its QLED technology were tough to spot.

All OLED TVs I've tested have similar image quality, and they're all better than the Q7. True, the Q7 could get brighter then the OLED TVs in test patterns, and performs very well in bright rooms (but so does OLED). It also showed slightly better color than 2016 OLED TVs in select HDR scenes, perhaps an effect of the "color volume" difference Samsung talks about. Those advantages, however, didn't translate to a superior overall image.

For more details see the Samsung Q7 QLED TV review and our reviews of the LG C7 and E7 OLED TVs.

I haven't tested Samsung's more expensive QLED TVs yet, the Q8 and Q9 series, which could outperform the Q7. All three use similar underlying technology, however, namely edge-lit local dimming, so I don't expect them to beat OLED TVs. Of course, I won't know for sure until I can review them.

In May 2017 the Q7 costs $3,500 for the 65-inch size, which is high-end TV territory for sure. My advice for buyers in that price and size range is to go OLED by either getting a 2016 LG B6 now or waiting until prices fall on the 2017 LG C7. As I review more TVs that advice could change -- check out our best TVs lists for updated information.

Update, May 24: This article was originally published February 8, 2017. It has been updated with information from hands-on reviews.