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Quantum dots explained: How this nanotechnology could give OLED TVs a run for the money

Jon L. Jacobi | Sept. 14, 2015
Quantum dot technology is helping LED LCD TVs deliver richer, broader color spectrums. Almost as rich as OLED TVs.

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Credit: Samsung

The word quantum grabs most people’s attention. Largely because of its association with quantum mechanics, the awesome and extremely difficult-to-understand study of all things very small and the way they behave.Quantum dots are crystal semiconductors measuring just a few nanometers in width. Hit these nanocrystals with white light, and they’ll emit colored light in strict correlation to their size.

Since this discussion is related to using quantum dots in TVs, you might think the nanotech is replacing the LCDs and OLEDs used to generate color on today’s flat panels. Nope. Someday maybe, but for the moment they are being employed solely as LED backlight filters.

What’s wrong with LEDs?

Look carefully and critically at an LED-backlit LCD TV (often referred to as an LED TV), and you’ll notice that the picture looks a bit cool, perhaps even washed out. It’s difficult to do in the absence of something better to compare, so you’ll have to trust me on this one. The reason for this phenomena (the coolness, not the trust-me factor) is that the light today’s TV LEDs produce is heavily skewed towards the blue end of the spectrum. Blue, as in icy and cold.

LED backlighting remains popular partially because it’s more energy efficient overall than the preceding CCFL (cold cathode fluorescent lamp) backlight technology. On higher-end TVs, LEDs can be spread across the entire panel and controlled individually (a feature known as local dimming), enabling the TV to produce darker blacks. LED backlights are also much smaller than CCFLs, enabling the ultra-thin profiles that are in vogue today. Thin is in—and it’s likely to stay so.

If color gamut is a concern, you can always buy an OLED TV with its super rich colors and deep blacks. But the prices for OLED start at $2000 for 1080p resolution and only get absurd from there. With UHD (3820 by 2160 resolution, opportunistically marketed as 4K, even though it’s only twice the resolution of 1080p) LCD TVs starting at $600 in smaller sizes, getting consumers to pay several times that for an OLED TV is tough—superior image or not. And to be perfectly honest, even without quantum dots, an LED/LCD TV offers a pretty nice picture.

Inexpensive, but not available in cheap TVs

So here comes the easily producible quantum dot, which seems to be just about the ideal solution for improving the color gamut of the everyday LED/LCD TV and low-balling OLED out of existence. Just filter that harsh white LED light with richly-radiating quantum dots and voila!

Alas, it hasn’t worked out that way so far. Quantum dots seem to be showing up only in pricier TVs. Vendors want to steal some thunder from OLED at the top-end rather than improve the color spackes of their entire range. At least that was the case as this article published—just about a month before the vast majority of 2016 models are announced.

 

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