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.

Philips 276E6: The First Color IQ Desktop Monitor Contrast, Brightness, and Gamut
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  • willis936 - Friday, April 29, 2016 - link

    I'm skeptical of your first claim without seeing data.

    As for the second that's why packages lime dispcalgui exist.
    Reply
  • Brandon Chester - Friday, April 29, 2016 - link

    Again, that doesn't help the fact that software needs to support it. I think you're confusing greyscale calibration and color management here. If there was some easy way to fix color management across all Windows programs this would not be such a long standing issue. Reply
  • UrQuan3 - Thursday, May 12, 2016 - link

    "Cheap colorimeters are so inaccurate that they're basically useless."

    I'm going to have to go with willis936 on your first comment. It sounds rather like someone driving a Ferrari saying that a Mustang has so little horsepower it is useless. To the average car owner, they're both godlike. In practice, a little $100-200 colorimeter makes a large improvement on almost any monitor. Expensive calibration for expensive monitors. Of course, use the best gear when doing a review.

    I wonder how you would review calibration tools? That does not sound easy.
    Reply
  • Pork@III - Thursday, April 28, 2016 - link

    Too bad against full cover CCFL Reply
  • Azurael - Friday, April 29, 2016 - link

    It's possible to get a 27" 2K display for $300 equivalent in Europe... I've got a Hannspree HQ271HPG which even with VAT is £200. I wouldn't say it's the best thing in the world (stuck with HDMI 1.4 & DL-DVI and hiding >1cm behind a piece of glass) but it is IPS, it calibrated up nicely (to sRGB) and the backlight consistency is much better than most cheap monitors on my sample (although it does have a bit of bleed visible at the very edges on a totally black screen.) Reply
  • Gunbuster - Friday, April 29, 2016 - link

    I know it's a cheap monitor but dear lord, did they have to make the bezel so chunky that it looks like a 22" in photos? Reply
  • Haravikk - Friday, April 29, 2016 - link

    Why does this include a VGA port?

    I'd also much prefer down-facing ports, and some kind of cable management, monitors that don't include these always confuse me.
    Reply
  • zodiacfml - Saturday, April 30, 2016 - link

    Thanks for always including a tutorial and in-depth look of color management. I quite understand the challenges of the industry.

    You are correct that Philips should be applauded for taking the first step as this will take time to improve as OLED/AMOLED of Samsung has improved throughout the years. For now, the Philips seems useful for increasing saturation/vividness of content for entertainment.

    Questions:

    1) Isn't better for Philips to target a higher color space despite coming short for now (as conversion from a bigger space to smaller seems straightforward)? The Adobe RGB doesn't improve from the sRGB space in the "reds" where the most benefit from quantum dots can be had. I believe this primary color should be given attention as content to show this is widely available in photos such as flowers, sunsets, and red sports cars. I have seen too many red subjects looking flat like plastic.

    2) How does color spaces Rec. 2020 and Pro Photo RGB relate to each other? They seem to have the same coverage but obviously for different applications.
    Reply
  • zodiacfml - Saturday, April 30, 2016 - link

    I did some reading and found the problem already which is color bit depth. What are the currently supported bit depths supported by video cards and monitors? Reply
  • Oxford Guy - Monday, May 2, 2016 - link

    AdobeRGB is obsolete. Reply

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