Quantum Dot vs OLED, which is the better display?

by: Rob TriggsDecember 2, 2015
1.8K
Are we addicted to smartphones? Or is it not really that bad for most of us?

 

OLED technology may not be new any more, but it has recently seen a big up-tick in momentum. Panel manufacturers are investing large sums of money into new production lines and market researchers are predicting a huge growth in revenue over the next few years.

OLED displays may well replace the traditional LCD as the go to panel in the future, but it is facing competition from new display technologies too. Quantum Dot panels are seen as particularly promising, so let’s take a look at the differences with OLED and if it has what it takes to produce superior quality displays.

Tech differences explained

First up, let’s quickly recap the major differences between the ways that the technologies work. OLED, as the name suggests, is built from an array of tiny light emitting diodes (LEDs) each of which produces a color of light on demand, unlike LCD which requires a backlight. These LED’s are constructed from organic material layers and use phosphorescent color layers to produce different colored lights. Tweaking the make-up of these layers can result in displays with different efficiencies and qualities.

Quantum Dot (QD) displays are quite different as the technology is based on small conducting nanocrystals, usually in the range of 2 to 10 nanometers in diameter. The color of light produced or filtered by a dot is based on its diameter and using a few of these could produce all your necessary colors. Like OLED, light and colors could be supplied on demand and QD-LEDs can be very bright. However, current QD displays are based on a blue LED backlight which is then filtered to a white light before passing through the familiar LCD color producing layer.

Quantum Dot LCD panel layer

Although Quantum Dots can be light emitting, current implementations use them as a filter layer. Image source: DigitalTrends

Wider color gamut and viewing angles

Color gamut is seen as one of OLED’s big advantages over LCD, allowing for more vivid viewing experiences and accurate color reproduction, so long as the media also supports it. LCDs often fall short on color accuracy and gamut because of their reliance on a pseudo-white backlight (this is made from blue LEDs with a yellow phosphor coating). However, the highly accurate nature of Quantum Dots means that developers can use a pure blue back light and accurate red and green filters produce a true white light, which can then be filtered into better looking colors.

As Quantum Dot displays don’t have to worry about inaccuracies in the white light, there is less compensation required in the LCD filtering layer, so manufacturers can drive up the color brightness and gamut of the display. As a result, QD LED TVs are able to match and sometimes even exceed the color accuracy of OLED panels.

LG G4 quantum display

LG boasted a wider color gamut with the Quantum Display found in its G4 flagship

However, as QDs are currently reliant on a backlight, the deep black accuracy and contrast ratio will still suffer from similar drawbacks as existing LCD displays. Therefore, OLED should still win out when it comes to contrast and high dynamic range imagery, as it can switch off pixels for a pure black dot, but QD displays will still see a boost in brightness over traditional LCD.

This leads us onto viewing angles, an area that OLED again boasts superiority over LCD displays and this is unlikely to change much with the introduction of Quantum Dot displays. Because backlight based displays require a filter layer rather than producing light directly on the surface, some light is blocked when you don’t look at the display from head on. While perhaps not likely to be a major problem on your small mobile phone, Quantum Dot displays won’t match OLED’s viewing angles until designs come along that eliminate the need for a backlight.

Production and products

Perhaps the biggest factor in any technology’s success is its cost, which is one of the reasons why LCD is still so popular in mobile devices.

Although costs are falling, high quality OLED displays typically cost around 20 percent more to produce than the same size LCD panels. This is mostly due to the rather tricky production techniques required and lower yields. Fortunately, new manufacturing processes, such as ones based on thermal ink jets, could see prices halve and OLED panel production costs could fall to 20 to 30 percent less than those of LCD by 2017.

It’s also worth considering that OLED based products have a shorter lifespan, due to blue pixel materials, and can also suffer from the dreaded “burn in” issue after a while. Quantum Dot displays don’t have from the same problem, as they are very stable over long periods of time.

Quantum Dot LED vs conventional LED

Quantum Dot LCD displays retain many of the benefits of LCD’s lower production costs. The QD filter layer does not add a huge cost or complexity to the production of a display, as it is simply a mixed assortment of red and green dots rather than an intricately laid out matrix. Typically this adds no more than $100 to the cost of a large-size TV, so we are likely looking at less than $10 for a 5-inch smartphone. However these small costs aren’t always accurately reflected in consumer prices and the falling cost of OLED might make QD technology a tough sell in lower cost products, where LCD is currently commonplace.

Quantum Dot is certainly a viable rival to OLED, but it is more of an evolution of LCD than a likely successor to OLED panels. Both have their pros and cons, much like display types found on the market today, but Quantum Dot panels close some of the most notable gaps between the two. We are likely to see a number of high-quality Quantum Dot and OLED based devices hit the market in the coming years.

Next: AMOLED vs LCD

  • Svnjay

    There are no quantum dots found the G4’s display? The buzz over the G4’s display is that LG claims that it’s calibrated to the Digital Cinema Initiatives colorspace.

    • Alexandru

      Yeah. But there no DCI content. So, nobody wins. Just a marketing spec.

  • Roberto Tomás

    every youtube tech reviewer I’ve seen talk about the two technologies with both present with them says OLED is hands down better. Like night and day .. it is common to brush off QD/LCD as a nice cheap effect but nothing to write home about. Whereas OLED is obviously the wave of the future… both Samsung and LG have invested tens of billions of US dollars _each_ in display fabs for global scale OLED manufacture.

    And the OLED dyes that compose those screens have fallen in prices to lower than inkjet dye costs… it should even be affordable soon. But QD obviously offers something.. even if OLED can be improved in color accuracy, QD probably can be too, and QD could always maintain a subtle edge in color fidelity, even if overall the effect on LCD panels is underwhelming. In a few years I am confident we will see QD/OLED devices (combining both).

  • creep_the_night

    “Quantum Dot displays don’t have from the same problem, as they are very stable over long periods of time.”

    The typo in the sentence…

  • teomor

    OLED whites are still not as white as LCD whites.

    • rock1m1

      LCD Blacks aren’t even Blacks

      • teomor

        Yeah, but we’re now arguing with thin black lines on a vastly bigger white background. As is 90% of the activity people do on screens. Except movies, yeah.

        • rock1m1

          When it comes to OLED, black basically results with the pixels being turned off, saving considerable power. With colors other than white have a lesser strain in the output and also saves battery. A lot of apps offer dark mode these days.

          • Svnjay

            Google removed Android’s dark theme with the switch to Lollipop.

          • BareThingz

            For AOSP users it may be a problem but for touchwizz and such stuff it’s easy to find dark themes !

          • Svnjay

            Sucks for Nexus 6 and 6P owners.

          • rock1m1

            Just download any theme manager and download a dark theme, that’s it.

          • _LLJY L

            Dude, OLED has twice the power consumption of IPS LCDs when displaying whites moreover, QD LCDs are more efficient than IPS’es which make them consume even less power. Not to mention that burn in is an issue

          • Mr james bunt

            May I ask do you look at white or coloured image everyday or u look at black image everyday ? Oled -> wins in black department
            LCD IPS -> wins in whites department.
            *don’t consider individual colour but think of overall image *

          • Κωνσταντίνος Κ.

            I prefer dark themes, dark apps, dark everything …especially when using the phone in the night ..but my OnePlus One doesn’t have OLED or Quantum Dot display :P …even the black lights up the room

    • Karly Johnston

      OLED doesn’t display white, it is either pink or blue.

      • teomor

        Or green, or yellow :)

    • Mircea Marius

      You should try the new OLED from S6 & Note series.

  • Chanon Olley

    The G4 does not have Quantum Dot. This is what people are getting mixed up with. It’s Quantum IPS. Quantum Dot has even brighter pixels.

    You can see in the image attached how Quantum Dot compares with Quantum IPS and other displays. LG uses Quantum IPS for the G4 because Quantum Dot is wasteful and not as naturally coloured as Quantum IPS.

  • Javid Nazim Mammadov

    G4’s screen isn’t QD, it’s “Quantum Display”, which is the trademark of the regular LCD panels made my LG.

  • boris “gamusino petete” sajoni

    all this is great but in my lg g4 im having some image retention problems, specially with blues and reds, if i leave the screen on for a while in lets say snapchat and then go to the homescreen i can see how the previous screen was… big issue for me (BIG PIXEL JUNKY)

  • Sony started the Quantum Dot display thing in mobile first, and didn’t even get a mention, rather LG? From the little research, QD displays, when their full potential is unleashed, no display tech will.come close.

    Sony, I know will do that soon, since the other players are keen on the oled.

    QD, paired with xreality engine on Sony TVs are the best.

  • Avieshek Rajkhowa

    Quantum-Dots is the future

  • G.Crisci

    why not just IPS TV?