How QLED TV could help Samsung finally beat LG’s OLEDs

How QLED TV could help Samsung finally beat LG’s OLEDs

Samsung is developing TVs based on quantum dot LEDs, pinpricks of light that promise even better picture quality than OLED TVs

Most TVs today — including all of those made by Samsung, Sony, Vizio and just about every other TV brand — are based on decades-old LCD, or liquid crystal display, technology. In the last few years something better has come along, called OLED, or organic light-emitting diode. OLED TVs have the best picture quality we’ve ever tested, keeping LCD-only companies from achieving the coveted top positions on certain lists.

Now there’s a new TV display technology on the horizon called QLED, and it might be even better than OLED. Short for “quantum dot light emitting devices,” QLED has the potential to match the “infinite” contrast ratio of OLED, with better power efficiency, better color and more.

QLED could be the next big thing in TV tech. Samsung, the world’s number one TV maker, has confirmed that it’s working on developing QLED TVs for the commercial market, while continuing to deny it has plans to mass-produce OLED. That leaves Samsung’s arch-rival LG as the sole manufacturer of OLED, and Samsung itself with plenty of motivation to work on an alternative like QLED.

Even for a company with the manufacturing clout of Samsung, QLED TVs are likely still a few years off, but you’ll probably be hearing more about them soon. Here’s what we know so far.

Quantum dots

For several years, many high-end TVs, in particular Samsung’s SUHD models, have used what are called quantum dots. They’re a way for LCD manufacturers to improve color reproduction and energy efficiency, and in our tests they do. The quantum dot-powered Samsung KS8000, for example, achieved higher peak brightness, and wider color, than any TV we’ve reviewed.

At this point you’re probably asking…what the frak is a quantum dot?

Quantum dots are fascinating. They’re microscopic molecules that, when hit by light, emit their own, differently colored light. Imagine shining a flashlight on a baseball and it glowing bright red. That’s the general idea of a quantum dot, except way smaller. It’s pretty mind-boggling.

The specific wavelength — and therefore color — of the created light depends on the size of the quantum dot. Larger quantum dots emit light in the red end of the spectrum, the smaller ones towards the blue end. So in the oversized example from before, imagine a marble next to the baseball. Your flashlight makes the baseball glow red and at the same time the marble glows blue. A golf ball in between might glow green.

What’s the real size of these dots? Around 4 nanometers. As in, really, really small. Just a fraction of the width of a human hair.

QD now, QLED later

All TVs with quantum dots so far have used photoluminescent quantum dots. When a photoluminecent QD is hit by light, they emit their own color of light. In current generation TVs, these QDs work in concert with the blue LEDs that power the TVs’ backlight.

The blue LEDs create blue light, and supply the photonic energy for two different sizes of quantum dots to create red and green and light. One method is to use a tube along the edge of the TV with blue LEDs wrapped with red and green quantum dots. Another, used by Samsung with its SUHD TVs, is to add an entire QD layer in the “sandwich” that makes up the LED LCD TV.

Quantum dots let LCD TVs offer wide color gamut (WCG) without losing a significant amount of light output. There’s a problem, however: they’re still LCDs.

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