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Quantum Dots Explained: What are quantum dots and why are they so awesome?

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Quantum Dots Explained

Quantum Dots and the iPhone 6 Screen

Quantum dots. Sound cool, don't they? But for once this is a technology that's actually as good as it sounds. Quantum dots, among other things, have the potential to revitalise the LCD screens in our phones, tablets, TVs and laptops.

Apple is widely tipped to use them in the iPhone 6 when it comes out later this year, but it isn't the first and won't be the last. Sony already uses quantum dots in some of its TVs under the Triluminous brand, though it's not believed any of its phones currently use the tech despite the Triluminous brand being applied to some of them. Amazon used quantum dots to good effect in the Kindle Fire HDX 7 and HDX 8.9 tablets as well.

But, as things go on the internet, when Apple is rumoured to do something it's a seriously big deal, even if it isn't first to do so. Such excitement isn't misplaced, however, as you'll find out if you read on.

What are quantum dots?

Simplifying things greatly (as this guide aims to do, mostly), quantum dots are incredibly small particles. They range between 2 to 10 nanometers in diameter, which is equivalent to 50 atoms. Yes, atoms. You can't measure these things using your old school shatter proof ruler. It's this small size that gives quantum dots the unique properties to improve our tech.

The colour light that a quantum dot emits is directly related to its size; smaller dots appear blue, larger ones more red. In LCD screens they're applied as a way of eliminating the need for White LED backlights and colour filters. As Dr. Raymond M. Soneira, President of DisplayMate, explains: "Instead of using existing White LEDs (which have yellow phosphors) that produce a broad light spectrum that makes it hard to efficiently produce saturated colors, Quantum Dots directly convert the light from Blue LEDs into highly saturated narrow band primary colors for LCDs."

What are the benefits of quantum dots?

For LCD screens, the benefits are numerous. They're the kind of benefits that are simply no-brainers.

Better colour accuracy
The key benefit of quantum dots is improved colour accuracy. The light produced by quantum dots is so closely tied to their size that they can be tuned very precisely to emit the exact kind of light needed. This means purer, cleaner whites and more precise colours.

Amazon Kindle HDX
Colours on the Kindle HDX series are excellent

Higher colour saturation

One advantage, though some might call it a disadvantage in some contexts, of OLED screens over LCDs is colour saturation. Colours on OLED screens simply 'pop' more due to the huge colour gamut OLED screens can achieve. Quantum dots can, according to Dr. Soneira, increase the colour gamut on LCD screens by in the region of 40 to 50 per cent. This is great, but it's the combination of high colour gamut and great accuracy that's really exciting. OLED screens look fantastic to the untrained eye, but many of those found in phones thus far aren't very accurate or 'faithful' to the actual colours they're presenting. This can create imbalances, such as radioactive colours and iffy skin tones in videos and photos.

Taking a long term view, the impact of more devices with larger colour gamuts could mean a serious increase in the quality of video and other content. Specifically, in the level of detail you can see due to greater number of colours available. The only caveat here is that for most purposes sRGB is the colour standard for computing – it's the standard colour space for everything you see on the internet, for instance. That means you might not enjoy the full benefits of a higher colour gamut screen straightaway due to content being created to cater for sRGB, and not Adobe RGB or the broadcasting standard Rec.709 for example. Still, with many screens unable to produce 100 per cent of the sRGB colour space, there's still a benefit to be had in the short term.


Improved battery life
One of the contradictions of modern tech is that people say they want better battery life, but when it comes to it they'll choose a slimmer, sleeker and 'sexier' phone over a chunky one with better battery life. Some of you reading this will be jumping up and down saying that's not you, but it is most people. Phones haven't been getting slimmer and lighter by accident. Companies make them that way because that's what sells.

Another truism is that the most effective way, by far, to improve your phone, tablet or laptop's battery life is to simply turn the brightness down. You can fiddle with the settings as much as you like, but it's the screen that sucks down the most power. Which is why the potential power savings of quantum dots, believed to be up to 20 per cent, are so attractive.

What quantum dots promise, on paper, is superior image quality and a reduction power use. That's a powerful combination, especially for a company like Apple that's loathed to compromise on design for the sake of practical things like larger batteries.

(This is also yet another reminder that the slow pace of battery tech development is holding back our tech. Since it has improved markedly, companies are forced to find power savings elsewhere.)


What are the downsides of quantum dots?

While there are doubtless plenty of complexities in integrating quantum dots into screens, from an end user perspective the only downside we've seen thus far is (an actually quite serious) light bleed issue. This was seen on the new Kindle HDX tablets, the first quantum dot tablets. While not visible under many conditions, any white background (i.e. when reading a book) exposed very irritating bleed from the edges. Rather than white light, the bleed on the Amazon Fires was blue. Why? Because the backlight LEDs are blue.

Kindle Backlight
Here you can see the backlight issue on the Kindle Fire HDX is severe

This isn't a trivial problem. When we reviewed both the new Amazon tablets we were impressed by the colours, contrast and brightness, but the light bleed was profoundly annoying – enough so that it devalued the good parts. Solving this issue is vital to whether we see quantum dot phones and tablets, but we'd put our money on it getting sorted fairly soon. Apple reportedly has patents describing how it plans to solve this particular problem.

Quantum Dots and the iPhone 6 Screen: Will it happen?

Assuming the bleed issue seen on the Kindles can be sorted, quantum dots have the potential to radically improve our tech. We've already seen them at work in Sony's 4K TVs, which were outstanding. Moreover, the fact they're already in use shows this isn't some outlandish new tech that's years away. For that reason there's a very decent chance, we'd say, of Apple using the tech in the iPhone 6. It clearly won't be alone, however, so the idea that this is some silver bullet that will wipe the competition away is misleading.

Next, read our in-depth analysis of the new HTC One M8's camera

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