Everything you need to know about... Quantum Dots
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.
It was widely tipped that Apple would use quantum dots in the iPhone 6 and though it didn't in the end, 2015 looks like the year the technology will go mainstream. LG has confirmed it will launch quantum dot 4K TVs in 2015,
and we've already seen Sony use quantum dots in some of its TVs under
the Triluminous brand. Amazon also used quantum dots in the Kindle Fire HDX 7 and HDX 8.9 tablets, while Samsung has diverted attention away from OLED TV development in favour of quantum dot LCDs.
As such, we expect to hear much more at
CES 2015, the annual tech show held every January where TV companies launch their new TV lines.
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.
Higher peak brightnessOne
of the reasons TV manufacturers like quantum dots is that they allow
them to produce TVs with much higher peak brightness. This opens up some
interesting possibilities, such as enabling support for 'high dynamic
range' TVs that support standards such as Dolby Vision.
In simple
terms, Dolby Vision is a new film standard that, when used, will result
in content that retains more colour and contrast information than
existing standards. The result will be pictures that have greater
differences in the brightest and darkest parts of the image and look
more 'dynamic' and real as a result.
Imagine shots where looking
into the sun actually feels like looking in to the sun for real and you
get an idea. To do this you need brighter TVs and quantum dots deliver
exactly that.
Better colour accuracyAnother
big 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.
 |
Colours on the Kindle HDX series are excellent
|
Higher colour saturationOne
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 another colour standard. 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 in mobile gagdetsOne
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 in 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
hasn't 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.
 |
| 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.
Should you be excited about quantum dot technology?
Definitely,
yes. In fact, we'd argue that quantum dots are a more interesting
development than 4K TVs in some respects. With the exception of things
like Dolby Vision, you're more likely the enjoy the benefits without
content specifically enhanced to take advantage. It's also not,
necessarily, a prohibitively expensive technology as we've already seen
it in affordable tablets from Amazon. When done right, quantum dots
could deliver similar colour and contrast to AMOLED screens while
retaining the benefits of LCD.