A Look At QD Vision's Color IQ And The Philips 276E6 Monitor: Quantum Dots for Wider Color Gamuts
by Brandon Chester on April 28, 2016 8:00 AM EST- Posted in
- Monitors
- Philips
- Quantum Dot
- QD Vision
Color IQ
As I mentioned earlier, the technology at the heart of the Philips 276E6 monitor is QD Vision's Color IQ quantum dot technology. To gain a better understanding of how this differs from other quantum dot implementations currently used in the market, I spoke with QD Vision's Chief Marketing Officer John Volkmann.
Quantum dots are a type of semiconducting nanocrystal. They're typically made of cadmium selenide or indium phosphide, and when used in displays they have a diameter less than ten nanometers. What makes them interesting is that they exhibit a property known as photoluminescence, which means that they emit light after absorbing photons.
In LCD displays this property is highly desirable, as it means that you're able to place an array of quantum dots between the backlight and the color filters to reduce the frequency of the light emitted by the blue backlighting. By altering the diameter of the quantum dots you can control the frequency and wavelength of the light that is emitted, which allows for the emission of specific red, blue, and green wavelengths at the required intensity to cover your target color gamut. Smaller quantum dots on the scale of one or two nanometers emit wavelengths of light in the blue part of the visible spectrum, while larger quantum dots with a diameter of six or seven nanometers emit red light.
A question you may have is why this is actually necessary. I mentioned above that quantum dots are typically used to convert blue light into red and green light, and the use of blue LEDs for backlighting is not unique to quantum dot displays. Almost all modern LCD displays use LED backlighting, and the majority of them use what is commonly referred to as WLED backlighting. In truth, these "white" LEDs are really blue LEDs paired with a yellow phosphor, and through this process wavelengths of blue, green, and red light are produced. Unfortunately, there is still a very significant blue bias in the final output, and the intensity of the desired red and green wavelengths is relatively low. Because of this, these displays are limited in the range of green and red colors they can reproduce, and to date most monitors of this type have been limited to roughly 99% of the sRGB color gamut.
To produce a wider color gamut with LED backlights alone, vendors have employed the use of different technologies. The most prominent is GB-r backlighting, which pairs green and blue LEDs with a red phosphor to allow for green and red light of a greater intensity. Unfortunately, such designs have shown to be quite expensive, and this has kept wide gamut displays priced well outside what is affordable for the average consumer. An even smaller group of displays has employed full RGB backlighting, but due to cost this did not see much adoption by any display vendor.
The cost-related issues of RGB and GB-r backlighting is the problem that QD Vision hopes to solve with their Color IQ technology. Color IQ's appeal is that it works with standard edge-lit displays, and it takes advantage of the blue LED backlighting that those displays employ. Most quantum dot technologies require the use of expensive full-array backlighting because they use a thin film layer with quantum dots embedded throughout it which sits between the backlighting array and the color filter layer. In contrast, Color IQ uses small glass cylinders that sit in front of the blue LEDs at the edge of the display. According to QD Vision, the cost of a film-based solution for a display around the size of a 50" television can cost around $100, while their quantum dot solution for edge-lit displays will only cost around $20.
With QD Vision's current technology the cylinders with quantum dots sit between the blue LEDs and the light guide plate that distributes the light across the panel. With such an implementation one can expect displays that closely cover the Adobe RGB and DCI-P3 color gamuts depending on exactly how the quantum dots are tuned. According to QD Vision, quantum dot technologies perform best when the quantum dot array is as close to the backlight as possible. Within the next few years they hope to be able to deliver a "chiplet" solution, which consists of a quantum dot matrix mounted in a bead of glass right atop the LEDs. Moving beyond that will be integrating the quantum dot matrix right into the LEDs themselves. Right now such solutions are infeasible due to heat degradation, but they will be necessary as we move toward full coverage of the Rec. 2020 color gamut.
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Brandon Chester - Thursday, April 28, 2016 - link
Ryan was up very late doing some editing and must have made it when he expanded on my admittedly sparce placeholder title (Monitor Review). My apologies.Infy2 - Thursday, April 28, 2016 - link
The message of this article is for average Windows user to stay away from wide gamut monitors.Murloc - Thursday, April 28, 2016 - link
average user thinks oversaturation looks coolwatersb - Thursday, April 28, 2016 - link
Excellent. Thanks for this in-depth discussion. I know very little about color and color management.Yesterday, I was in an Apple Store and I compared wide-gamut images side by side on the new, 9.7-inch iPad Pro, the 12-inch one, and the 5K iMac. I used iconFactory's blog post for reference images. Wow. http://blog.iconfactory.com/2016/04/looking-at-the...
This is becoming a real thing for popular consumer devices. Interesting times!
theduckofdeath - Thursday, April 28, 2016 - link
The only thing I'm getting from this review is, I have a strong feeling that markets with stronger marketing regulations will soon nerf the Quantum Dot term the same way "LED" displays were a few years ago. The marketing implies that QD is as advanced as OLED while the displays clearly still use edge lighting with all of its issues.saratoga4 - Thursday, April 28, 2016 - link
The marketing on hype on QD is particularly ridiculous given that they're essentially a cost-reduction measure designed to save a few dollars on multi-color LEDs or OLED while (hopefully) being good enough.Murloc - Thursday, April 28, 2016 - link
80$ is not a few.A new thing or a cost reduction are the same thing in this case: consumers will have something they didn't have before.
saratoga4 - Thursday, April 28, 2016 - link
Going from 1 type of LED to 2 types of LED in an array doesn't anywhere near $80. The savings is much larger compared to OLED, but OLED has other advantages beyond gamut that QDs can't match anyway.name99 - Thursday, April 28, 2016 - link
I think you're missing the larger picture.Of course any technology can be cost-cut to the point where it is a joke, and Phillips seem to have done that here. OK, Phillips being stupid, nothing new there. But that's not interesting.
The more interesting aspect is that we are moving towards richer monitor technology. It started with retina (sorry HiDPI !) displays, now we're going to wider gamut. At some point wider gamut is going to move to something like 16 bits per pixel rather than 8 (or occasionally 10 or 12), along with maybe even 4 phosphors. And at some point the standard device frame rate is going to up to 120fps.
OK, so with this hardware background, it's now interesting to contemplate the SW background.
In one corner we have MS. Apparently still incapable of handling color correction after all these years, and incapable of handling the UI. Ad that to their HiDPI support. They seem unlikely to adapt well to this new world...
In the second corner we have Android. Not clear to me how much better off they are. They have handled DPI a lot better, which is a good start. As far as I know there is still no color correction built into Android; but the larger issue is one of how easily their architecture would allow for inserting color correction. Can they do it in such a way that all (or at least most) apps just do the right thing? And would it rely on the phone OEMs to create drivers and lookup tables that most of them would screw up?
In the third corner we have Apple which seems perfectly positioned for all this (meaning that they will likely drive it). They've been happy to push hiDPI (including on OSX as fast as Intel's built-in GPU's allows it ---which wasn't very fast, suggesting that maybe they'd be better off with another vendor for OSX SoCs, but that's a different issue), and they're now pushing color accuracy both on the camera side (TrueTone flash, high dynamic range sensors) and the screen side (new iPad Pro screen, presumably to spread throughout the product line as manufacturing volumes and power budgets allow).
I fully expect them to stay on this path for a while, never actually stating technical phrases like "full Adobe RGB Gamut" but constantly subtly pointing out in their keynotes and advertising "Our colors look good, and look correct, across ALL our devices --- photos on your iPhone look exactly the same on your iMac. Good luck getting that consistency with photo from your Android phone on your Windows screen."
From this point of view, then, the relevance and interest of QD technology is whether it allows larger gamut to move to iPhone this year or at least soon.
jlabelle - Friday, April 29, 2016 - link
- Apparently still incapable of handling color correction after all these years, and incapable of handling the UI. Ad that to their HiDPI support. They seem unlikely to adapt well to this new world... -such statement is not correct and the article describes it pretty clearly. Beyond the way to set it up (which, yes, is somehow confusing), the real issue is simply that many programs are not color managed.
This is not only limited to Windows and OS X is suffering of the same issue so it has nothing to do with Windows per see but the programs you are using.
The issue behind is that some default program on Windows are not color managed. It seems it is the issue with Store app (like it is for iOS apps that make iPad useless for photo editing for instance). So some important apps like Photo and Edge do not take care of that. That is a big issue.
But many programs does.
That is why there are 3 different cases :
1/ Use a screen very accurate within sRGB gamut out of the box - only use sRGB images --> no issue anymore but obviously you will never display any image beyond sRGB
2/ Use a screen with sRGB gamut (or a wide gamut screen that you switch to sRGB mode) with calibrated with an ICC profile set as default (as described) - use only sRGB images --> here, you will have perfect color accuracy for all applications color managed. In case of applications not color managed (Edge, Photo, Chrome...), you will have the color inaccuracy of the screen default (because ICC profile not applied) BUT you will not have images under or over saturated. Therefore, the impact will still be minimal for the user.
3/ use a wide gamut screen : then, you have no other choice that carefully use color managed application --> for every application color managed, display will be fine and you will take advantage of the wider gamut. For all others, the images will appear oversaturated.
It is such an issue that I used to have a wide color gamut DELL U2711 screen.
1/ first, you only have a good accuracy in color managed applications but in others, everything is oversatured.
2/ Second, while shooting FF DSLR in aRGB, I may have seen less than 10 pictures out of 70 000 where you could see in an direct A-B comparison a tiny difference between the sRGB version and aRGB. In real world, it is VERY unlikely to go beyond sRGB.
3/ Third, even if you keep for you aRGB versions of your pictures (to take advantage of your screen), you have to have a sRGB copy because when you share it outside, other people will face the issue on non color managed application that your pictures will be completely washed out. And even many online print shop only take sRGB.
At the end of the day, it is so much a hassle for virtually almost 0 visual benefit (speaking of photo of real color in the nature) that I now have a Dell U2313UH which is a sRGB gamut screen.
Bottom line : wide gamut screen currently is a chore and NOT recommended. And not only Windows, nowhere because even if your browser is displaying correctly the image (Safari, Firefox with a certain flag activated), what is the point then to have a wide color gamut screen to see sRGB pictures ?