What Exactly is a “Quantum Dot” TV?

TV manufacturers are in a constant race to add new “features” so they can convince you to buy a new TV. Next up after 3D, 4K, and curved displays: Quantum dots!

Quantum dot displays aren’t a new technology, but they’re making their way to TVs and you’ll see them advertised more soon. LG showed off a quantum dot TV at CES 2015. Sony, Samsung, and TCL will also be selling quantum dot TVs.

Why LED TVs Can’t Match Plasma or OLED TVs

First, never mind how they work: We’ll tell you why they’re useful. Quantum dots address a big problem with common LED TVs. Many people prefer plasmas (which are no longer being manufactured) and organic LED (OLED) displays. These types of displays are noted for their deep blacks and richer colors than garden-variety LED TVs.

Modern LED TVs are really just LCD TVs, but with LED backlighting. Years ago, LCD TVs used fluorescent tube (CCFL) lighting, which produced a white light. That white light then passed through the pixels on the screen to become whatever color of light was necessary. LED TVs use LED backlighting instead, which uses less power, produces less heat, and requires less space. That’s why modern TVs can be so much thinner and more power efficient.

But something was lost in the transition to LED backlighting. LED TVs use LEDs that produce blue light for their backlight. The light then passes through the filters on the screen and becomes the necessary color of light. But, instead of starting with white light, the LED TV starts with blue light. This results in blacks that appear brighter than they should, and colors that appear less vibrant than they should. To help alleviate this problem, manufacturers attempt to dim the LED backlight in dark areas of the screen — that’s why you see TVs advertised with features like “local dimming” to achieve blacker blacks.

How Quantum Dots Solve the Problem

“Quantum dots” are light-emitting nanocrystals that absorb light of one wavelength and convert it to another. They were actually invented at Bell Labs in 1982.

Basically, they’re tiny crystals that can be added above the backlight layer on an LED TV or another such display. When the typical blue LED light is shone through a layer of quantum dots, the crystals break down the light and produce a richer white light that contains all the colors of the spectrum. This light then results in a better picture quality with darker blacks and more vibrant non-blue colors. An LED TV with quantum dot technology is closer to a plasma or OLED TV in picture quality.

If the TV is edge-lit, the quantum dot technology will be incorporated into tubes on the edge of the display where the light shines through. But, with most TVs, the quantum dots will be another layer of film just above the backlight.

Why Not Just Use Plasma or OLED?

Plasma TVs get a lot of love from home theater enthusiasts, but manufacturers aren’t making them anymore. They’re big, heavy, and consume a lot of power. Some manufacturers were really betting on OLED displays — organic light-emitting diodes, that is — which don’t need a traditional backlight. Instead, each pixel essentially produced its own backlight, if necessary. So, if a pixel needs to be black, that pixel is completely black and no light is shining through it at all. This is why using a black wallpaper can save battery power on your smartphone if it has an OLED display.

That’s all well-and-good, but there have been issues getting OLED manufacturing to scale. OLED TVs are still more expensive and difficult to manufacture than expected. The industry has bet on LED TVs (which are really LCD TVs with an LED backlight). “Quantum dot” technology works with the existing LED displays, as it just requires another layer of film on those TVs. It can be incorporated into existing LED TV manufacturing processes.

Quantum Dots Are Great, But You Might Want to Wait

Quantum dot TVs sound good. In practice, quantum dots are currently a pricier technology that manufacturers are using to differentiate their more expensive, high-end TVs from their budget or mid-range TVs. With 4K coming down in price, why would you need to buy a more expensive TV? Well, for quantum dots, of course! To be fair, it does cost more to produce quantum dot TVs at the moment.

This at least sounds like a worthwhile upgrade, unlike curved displays and the 3D TVs we don’t hear about anymore. But, although this all sounds good, most people probably won’t want to spend thousands more for a quantum dot display.

In the long run, though, this technology will hopefully come down in price and filter down to even the cheaper TVs, making LED TVs better and closing that unfortunate gap with plasma and OLED technology.

So yes, the phrase “quantum dot” actually means something. It even sounds like a nice upgrade. But that doesn’t mean it’s worth paying four times as much for a TV with this feature. You’re probably better off waiting for it to come down in price.

Image Credit: Antipoff at Wikimedia CommonsKarlis Dambrans on Flickr

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.