QLED is a type of display manufactured and marketed by Samsung. It is specifically a type of photo-emissive quantum dot or QD display integrated with LED-based LCD technology. The working principle behind QLED displays center on the use of semiconducting nanocrystals called quantum dots to produce pure monochromatic red, green, and blue lights.
To be more specific, a photo-emissive QD display uses photoluminescent quantum dots that glow to a particular color through exposure to light. Each dot produces a particular color of light depending on their size. For example, large ones emit reds while smaller ones emit blues.
Note that quantum dot technology can also be integrated with other display technologies such as OLED. Nevertheless, the optical and other advantageous properties of quantum dots and the notable characteristics of QD displays, coupled with the advantages of LCD technology provide the core advantages of QLED displays.
The Pros: Advantages of QLED Displays
1. Competent Color Accuracy
One of the key advantages of QLED displays is the production of more vibrant and accurate colors. Note that quantum dots produce light depending on their size. These dots can be tuned precisely to produce light under a specific spectrum that in turn, correspond to precise color reproduction. QLEDs have better color accuracy than conventional LCDs.
It is also worth mentioning that conventional LCDs have smaller color gamut than OLED. However, through quantum dot technology, an LCD can have 40 to 50 percent higher color gamut than conventional LCDs, thus competing head-to-head with OLED displays.
A QLED display also outcompetes an OLED display in terms of color reproduction. Some OLED manufacturers have the tendency to implement oversaturation to make colors and resulting images more vibrant. This means inaccurate color reproduction and image representation. On the other hand, high-end LCDs, including QLEDs, generally have better color accuracy, thus making them suitable for color-critical applications such as photo editing, graphic design, and video editing.
2. Higher Peak Brightness
Remember that a QLED display is technically just an LED-backlit LCD. When pitted against an OLED display, high-range LED-backlit LCDs such as top-tier in-plane switching panels or the Liquid Retina from Apple tend to brighter due to the backlighting from the LED. When viewed under direct light or outdoors under bright sunlight, LCDs have better visibility than OLEDs.
The addition of quantum dots makes LCDs even brighter. Nanocrystalline materials have better optical properties than the larger crystalline found in conventional LCDs. Specifically, using nanocrystals or more specifically, quantum dots render as much as a 30 percent increase in the visible light spectrum, thus making them brighter than conventional LCDs.
A QLED display essentially outcompetes OLED displays and LCDs in terms of brightness level. It can make colors in the visible spectrum brighter without losing saturation. This is the reason why QLED and other quantum dot displays have become an established standard for ultra-high definition viewing.
3. Improved Contrast Ratio
OLEDs remain unparalleled when it comes to having a wider contrast ratio because of their ability to display deep natural blacks. Take note that the blacks in an OLED display are not artificially produced unlike in LCD because they are essentially a product of the absence of light.
However, QLED displays can still demonstrate a better contrast ratio than conventional LCD. Because they are based on photoluminescent quantum dot technology, QLEDs can produce deep blacks because they natively control the light emitted via individual quantum dots. The result is a contrast ratio that closely matches OLED displays.
The use of LED backlighting that results in light bleeds has rendered QLEDs unable to match OLEDs when it comes to deep blacks completely. However, manufacturing modifications such as the use of anti-reflective layers have improved the performance of QLED displays.
4. Thinner and Lighter Panels
The application of quantum dot technology can also result in the production of large, thin, and flexible LCDs, thus competing once again with plastic OLEDs, including flexible OLEDs. Samsung has produced and marketed QLED TVs with 65-inch panels and notable thin profile and slim bezels. Furthermore, the same company has produced and marketed curved QLED TVs with similar physical profiles.
In other words, the application of quantum dot technology in an LCD makes QLEDs thinner and lighter without sacrificing screen size. However, it is important to highlight the fact that OLED technology still has the upper hand when it comes to producing thinner, lighter, and flexible displays. OLED displays are inherently thinner and lighter than QLEDs.
5. Longer Lifespan
When compared to OLED displays, another advantage of QLED display is a longer lifespan. Take note that color-specific organic materials in an OLED panel have varying degradation rate. Blue materials degrade faster than red and green ones. Over time, an OLED panel will develop noticeable burn-in due to the faster degradation of blue materials.
Vulnerability to water damage also shortens the lifespan of an OLED display. Exposure to water will lead to permanent and irreparable damage to exposed organic materials, thus resulting in dead pixels or failure of the entire panel.
On the other hand, because a QLED display is still based on LCD technology, it has the benefit of having a longer lifespan than an OLED display. Take note that specific LCD technologies such as twisted nematic LCD and in-plane switching LCD are naturally more durable than OLEDs.
6. Energy Efficiency
QLEDs can save 20 percent of power than conventional LCDs according to paper. In addition, remember that quantum dots render as much as a 30 percent increase in the visible light spectrum, thus making them brighter than larger crystalline used in conventional LCDs while using 30 to 50 percent less power.
The precise production of colors also makes QLED displays energy efficient. Conventional LCDs can waste energy combining and balancing different colors. However, remember that a quantum dot display produces only the necessary color of a given image for a given time.
However, it is important to note that OLEDs still have the best energy efficiency because of the absence of backlighting. QLED still uses LED backlighting. Furthermore, the lightness and thinness of OLEDs translate to less power consumption.
The Cons: Disadvantages of QLED Displays
The following are the disadvantages and limitations of QLEDs:
• One of the notable drawbacks of QLEDs is that it still cannot achieve a contrast ratio similar or superior to OLED displays. The use of backlighting prevents deep blacks and washes out darker tones of colors.
• Poorer viewing angle, when compared to OLED displays, is another disadvantage of QLED displays. In most IPS LCDs, image quality as determined by color and contrast diminishes when a viewer moves away from the center of the screen.
• QLED displays have a slower response time than OLED displays in general. Take note that in-plane switching LCD technology is known for slower response rates that make them unsuitable for video gaming and other applications that require high frame rates.
• Essentially, QLEDs inherits all of the drawbacks of the general LCD technology, including the cons of IPS LCD such as limited contrast ratio, considerable power inefficiency, and slow pixel response time when compared to OLEDs.
• Blue colors of QLEDs can have a relatively low purity and dynamic range when compared to OLEDs and other LCDs. Furthermore, blue quantum dots require highly precise timing control during the reaction because of their small size.
• QLEDs displays are not true QD LED displays. Note that QLEDs are based on photoluminescent or photo-emissive quantum dots while true QD LED displays are based on electroluminescent or electro-emissive quantum dots.
