Haven’t you ever felt clueless when the salesperson goes on with the never-ending list of the newest technology in the market?
It is most likely that you must have come across two very similar sounding words- OLED and QLED in case you have deliberated on purchasing a 4K television. Since the two terms sound similar it is important to know what they actually mean.
Is it the case of Hen and the chicken or is it something else altogether?
The terms LED and LCD have been around for long and so people often mistake OLED to be the latest generation of the LED.
Contrary to that belief, Organic Light Emitting Diode a.k.a OLED was a revolutionary invention for which an Industrial Innovation Award by the American Chemical Society was presented to Ching W. Tang and Steven Van Slyke in the year 2001 for coming up with OLED diode technology for the very first time in the year 1987.
It was launched for the use of the general public in the late 2000s, and ever since then, there has been no looking back.
On the other hand, one can trace links of QLED with LCD. It can be said that the QLED is the extension of LED. Although LCD has been around for quite some time, QLED technology has been recently developed.
Hence, it can be said that the case of OLED Vs QLED is not the same as the case of the hen and the chicken!
Before we understand how OLED functions lets first understand how LED works:
What happens in LED is that a “Junction diode” is created. Here the flow of current is in one direction. Two semiconductors are placed together, one positively charged and the other negatively charged.
The surplus electrons in the positively charged semiconductor move in the direction of the negatively charged semiconductor. In this transition, excess energy is released and this lights up. In case they are connected the other way, you will notice that the current does not flow and the light does not turn up.
What does OLED technology do differently from the regular LED?
OLED is an acronym for Organic Light Emitting Display. In this technology, there are two conductors of electricity that is used to light up the background while in between them; a carbon (organic) based thin sheet is inserted.
Looking closely, the entire structure contains 6 distinct layers– the two ends being the top and the bottom are protective layers made out of either plastic or glass called the seal and substrate respectively.
The next closest layers are the negative and positive terminals, between the two terminals lie two more sheets they are the emissive layer and conductive layer.
But when does the light get produced in the entire process?
When the voltage is attached between the anode and cathode, the electricity starts to flow.
The electrons flow from the anode to the cathode. Now the added electrons make the emissive layer negatively charged, on the other hand the conductive layer becomes positively charged, losing their original character.
These positive charges are much more agile and hence move around and meet a hole.
They both annul out each other and this gives out energy by way of the release of a photon which is the illuminating factor.
In order for the LED to glow continuously, this procedure takes place uninterrupted.
In simple terms, the whole technological idea of LED/LED worked upon having a sheet of fluorescent light (CCFL) at the back that would emit light in the foreground to give the shades to the colours.
But OLED technology is a complete 360-degree revolution as it does not use any dependable source for the purpose of lighting but each pixel has light emitters of its own.
Thereby letting the users manually control each pixel to get the exact colour, shade, definition and a higher contrast ratio.
Types of OLED
The traditional OLED contains organic carbon sheets between two terminal sheets made out of glass.
Unlike Polymer OLED, the two-terminal sheets are made out of large plastic molecules that are not just cost-effective but also makes the structure more flexible, making it curve.
Passive Matrix OLED
PMOLEDs have 3 segments being: strips of cathode, organic layers of carbon and strips of the anode. The anode strips are arranged in a way that the layers cross each other perpendicular to the other, making little squares. The squares formed make up the pixels.
The light is emitted from these little boxes. The current flows to these strips as per the need of the external, which turns on the required pixel to give it colour or darkness.
The shades and brightness of the pixels depend on the amount of current that passes to the particular pixel.
Active Matrix OLED
AMOLEDs have the generic OLED model with cathode, anode and organic molecules. The difference lies in the anode layer which lays on top of a thin film transistor array known as TFT.
The TFT array in itself is the circuitry and does not require a separate external circuitry. This array regulates which pixels get turned on or off to form a particular image.
AMOLEDs, compared to traditional or polymer OLEDs consume less power. This is because the TFT array needs less power to function than external circuitry, making them much more proficient for large displays.
AMOLEDs have faster refresh rates suitable for video as it minimises the lag.
The key feature of Transparent OLEDs is that the light can pass in both the directions when the OLED is turned on.
The components that go into this technology are all transparent like the substrate, cathode and anode. A transparent OLED display can either be active-matrix or passive-matrix.
Active Matrix: where the display system allows individual pixel control.
Passive Matrix: The pixels here are controlled by intersections in the grid. The fluctuations in the charge that flows in the grid alter the colours and brightness.
The substrate can either be opaque or reflective OLEDs. They are best suited for active-matrix design and are widely used in cards that use a micro processing chip.
The substrate is made out of any malleable material which gives them longer life as it does not break and also gave way to bendable screens.
These emit crisp and very bright white light. The lights in the background are fluorescent and hence energy efficeient.
Advantages of OLED
- The plastic or organic external layers of an OLED are sleek, light and flexible than the glass layers in an LED or LCD.
- The light-emitting layers of an OLED are light hence making the substrate of the OLED flexible and not rigid. Although it should be noted that OLED substrates can be made out of both plastic and glass.
- OLED displays are bright. Since the organic layers are used which are thinner than any of the inorganic crystalline layers, the conductive and emissive layers of an OLED can be stacked one upon the other making them multi-layered. Also, LEDs and LCDs require glass for support, and glass absorbs some light. OLEDs do not require glass.
- Since OLEDs do not particularly require glass as the support giver, it is brighter as glass absorbs some of the light.
- OLEDs do not need backlighting as they generate their light themselves. As OLEDs do not use any backlighting, the power consumption is lesser. For example- the use of OLED screen in the smartphone will render longer battery life.
- Size ability of OLED is wide as OLEDs can be made in small to thinner yet large sizes.
OLEDs have wider viewing angle as they produce their own light; right about 170 degrees.
Disadvantages of OLED
- The manufacturing costs are high.
- Water or any form of liquid can damage the system.
As discussed before, QLED in plain vanilla terms is just an augmentation of LED. It is not a new fund invention at all. QLED stands for Quantum dot Light Emitting Diode.
Unlike its ancestors, it does not merely depend on the production of white lights and a combination of the same for it to produce the final display. QLEDs have a whole different way to function, although prima facie it may sound the same as an LED technology.
That being said, QLED does share quite a bit of its functioning ability with OLED.
What makes QLED stand out from its competitors is that, in this technology, each and every pixel can create and emit its own light and is independent of the other pixels.
Therefore, each pixel of a few nanometres in size. The colour of each pixel depends on its size. Like, the pixels larger in size emit red light and the smaller ones emit blue light.
Technically speaking, how exactly does this technology work?
The idea of Quantum Dot technology was first coined in 1990s. QDs can be of two types: –
Photo-emissive: meaning the electrons or positively charged ions that come from metals when energy is passed in the form of light; or
electro-emissive: it is an occurrence that happens when a substance emits light whenever electrical energy passes through it.
A traditional LED panel is taken and a sheet of quantum dots is arranged in front of it. This sheet of quantum dots is able enough to produce their own light.
The size of the pixel varies anywhere from 2 nanometres to 10 nanometres.
The structural makeup and the size of the quantum dot largely determine the energy levels and the diameter of each pixel decides the wavelength of the rays which gives effect to the light it emits. Controlling the size of the pixel can give rise to innumerable colours.
In the recent QLED technology that has been used, the composition of the components that are placed inside has changed. The mainstay and the outer layer are now made up of metallic alloy.
This is said to enhance the colour effects and retain the colours even at high brightness levels, as we often see that the brightness fades out the colours.
Advantages of QLED
- Bright vibrant Colours
- No lag or burn-in
- Renders sharp colours even in extreme brightness
Disadvantages of QLED
- The problem is that the quantum dots in current QLED TVs do not emit their own light. Instead they simply have the light from a backlight passed through them, in just the same way that an LCD layer does on non-QLED/LED backlit sets.
Brands that support OLED & QLED
The battle between OLED and QLED is often concluded to be the story about branding. You can say that almost every OLED panel found inside OLED TV is made by LG Displays, and the QLED panel is made by Samsung.
Most of the big names in the TV industry are lining-up behind to lay their hands on OLED, as they believe that it will carry the baton tomorrow it as OLED gives amazing picture quality.
Although the increased takers of OLED means that there would be greater supply, the prices of these TVs are still on the higher end.
The production costs need to be cut before OLED makes it to every household. Till then it shall remain to be a premium class of TV display.
Samsung at the moment is the only producer of QLED. It had started way back in 2014.
Due to monetary impracticability that arose due to marginal production profit it had stopped producing QLED TVs. It bounced back in 2017 and has ever since trying to pocket other brands to make QLED a reality in real sense.
QLED Vs OLED
From the basic understanding of how QLED works, we understand that it uses the backlight and to top it all, the quantum dots further add to the brightness while not fading out the colours.
OLEDs can not produce this amount of light as QLED does. If the TV is placed in a relatively dark room, OLED might work just as fine, but in a well-lit space, QLED produced unmatched brightness with saturated colours.
It checks how quickly a pixel switches its output as per the complete display. The faster it is, the lesser lag it will have.
On an average, the response time of a QLED screen is of 2 to 8 milliseconds which is way too long in comparison with OLED which takes about 0.1 millisecond, making OLED the undisputed winner here.
Theoretically, QLEDs produce better colours and also have a wider spectrum of colours to offer. But the performance is yet to be tested in real life.
One of the major drawbacks of QLED screens is that the quality of colour and contrasts both keeping falling once the viewer moves from the centre.
On the other hand, OLED screens offer extremely wide viewing angles that go up to 84 degrees.
Although some of the QLED screens come with anti-glare coating, intrinsically OLED wins this segment.
On the basis of how OLED technology operates and the claims made by LG (which produces OLED) which says the screens will lose only 50% brightness if they are used every single day for at least 5 hours for 54 years!
QLED screens are tried and tested. They certainly do not last for a lifetime but they do have a decent life span.
Considering this we can say that QLED wins here.
The dark blacks and the bright white make up the contrast. The contrast can be achieved by having extremely dark shades of black; as in comparison the white automatically starts to look brighter. This alone can give great levels of contrast.
QLED has to deliberately dim the light produced in the background and block the residual light. This always leaves room for flaws called “Light bleed”, it’s a phenomenon when the light that has been tried to be blocked still penetrates through.
OLED, on the other hand, does not have to face this issue as it has the ability to turn off the light and go completely dark. Therefore being able to produce the darkest of blacks, helps OLED ace the contrast ratio segment between OLED Vs QLED.
OLED has been around in the market for quite some time and has come a long way from having a maximum size of 55 inches to 88 inches in today’s date.
But the star here remains QLED with a whopping 100 inches which may further grow.
Consumption of Electricity
As mentioned earlier, OLEDs are highly energy efficient. Even though QLED technology is recent and hence often it is thought to be more energy-efficient, OLED is a sure shot winner here.
We can only make apple to apple comparison hence we should take the fact into account that both the technologies make a premium segment of screens.
The most economical screen that uses QLED is just a couple of numbers less than OLED.
One can say that they are priced the same.
What is a Quantum Dot?
Quantum dots are little particles sized between two and 10 nanometres in diameter. Each dot gives off a different colour according to its size is the reason why the display is luminous and accurate
What’s the difference between OLED and QLED?
OLED is an acronym of Organic Light-Emitting Diode, which is an organic, organic carbon-based coat that’s inserted between two conductors. When electricity passes through, it emits light.
Active-Matrix type of OLED technology is often used in televisions is Here the electronics switch each pixel on or off individually. This inturn gives deeper blacks hence more vibrant display.
QLED is short for Quantum Dot Light Emitting Diode. Instead of the photoluminescent particles that are used in OLED, QLED particles are electroluminescent nanoparticles.
This technology supports the light to be supplied directly to a display, instead of transferring to an LED backlight and then the display. This transfer of light via another medium distorts the pureness of colours; QLED technology keeps a check on the same.
What is Burn-in?
Burn-in is a phenomenon where a static image is displayed for a prolonged period of time. It was caused due to the use of phosphorus coating which was used at the back of the screen.
With the QLED, burn-in isn’t something that one will experience inn QLED technology as this the technology guards the screen from burn-in. Whereas, in very rare cases, burn-in can be seen in OLED screens.
What does colour volume mean?
It refers to the effect of colours washing out. A good colour volume means that regardless of lighting in the surrounding area, the technology can deliver accurate colours, unmatched brightness and the darkest blacks can be achieved on an active display.
With OLED being around in the market and having a good market grasp, QLED does have to push it to make it through.
Given the great feature that QLED has to offer, like: Unimaginable brightness with sharp details, life-size screen size and the unbeatable life span.
While OLED has proved its worth in the market by delivering features like Wide viewing angles, better contrasts, less power consumption, lighter in weight.
These both shall remain the king in their own spheres till the next generation come up with the best of both worlds perhaps!
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Srinivasa is Vsbytes’s Editor-In-Chief. He Is A Microsoft Certified Solutions Expert And Has Been Interested In Computer Hardware, Software, And Gaming Right Since The Time He Was A Child.