Is QLED Better than OLED?
Organic light emitting diode (OLED) technologies have cornered an increasingly large share of the premium display market in recent years, offering an excellent viewing experience bolstered primarily by unprecedented black levels. With relatively low power consumption, excellent viewing angles, and intrinsically low reflectance, OLED displays are now widely accepted as the best solution for smartphones and wearable devices. However, OLED TVs have faced growing competition from liquid crystal display (LCD) TVs which have been revitalized by the use of quantum dots (QDs).
QD-enhanced displays are marketed using a range of acronyms and slogans, including QD-LED, QD-LCD, and more. Yet the preeminent term pioneered by Samsung Electronics, and subsequently adopted by TCL, is QLED, meaning quantum light emitting diode. We discussed this branding versus technology issue in our previous article exploring the difference between OLED and QLED. For the purposes of this comparison, we will use the term QLED as a catchall term for QD-enhanced LCDs.
QLED TVs currently represent the main competition to the large OLED panels which have come to dominate the premium display market. They are known for their higher brightness levels, courtesy of a dedicated LED backlight, and extraordinary image quality thanks to the integration of a quantum dot enhancement film (QDEF) into the panel’s lamellar stack.
With that overview in-mind, is QLED TV technology better than that of OLED TV systems? The competition largely hinges on brightness, contrast ratios, and wide colour gamut (WCG) capabilities, but they compete on a range of other performance metrics such as energy efficiency.
The benchmark for brightness when displaying High Dynamic Range (HDR) content is 1,000 nits, and the maximum luminance of a TV expressed in nits is known as its peak brightness. With an integrated LED backlight, modern QLED displays can produce up to 2,000 nits, while self-emissive OLEDs are limited to an output of around 450 nits.
The significantly reduced peak brightness of OLEDs does not preclude them from meeting HDR standards, as their unique self-emissive nature required a secondary standard of certification. Using an active matrix addressing scheme, and benefitting from the lack of a backlight, OLEDs can switch off individual pixels to achieve technically infinite contrast ratios at the pixel-to-pixel range. QLEDs are disadvantaged by their powerful backlights in this area.
Coverage of next-generation color spaces is where QLED TVs retain a clear advantage over OLED TVs. Using fine-tuned red and green QDs in a QD emission film (QDEF) overlaid on a white, or blue, backlight, allows for greater accuracy, saturation, and color volume than ever before. Most premium OLEDs today reach approximately 98% coverage of the DCI-P3 color space, while QLEDs can exceed 99%. The sharpness of QLED RGB emission peaks is, however, so impressive that they are better expressed on the newer expanded color space known as Rec.2020.
One of the long-standing pain points of traditional LED technologies is their inherently poor energy efficiency. Emitting white or blue light through a series of color filters theoretically leads to immediate energy losses of up to 66%, meaning the vibrant brightness that comes courtesy of having a built-in backlight is impinged by a significant ecological footprint. OLED TVs do not have this problem. Their self-emissivity means that virtually all light generated is projected out at the front-end of the thin film stack, resulting in comparably better energy efficiency ratings.
QLED Vs OLED: What’s the Verdict?
There is no clear frontrunner as each technology excels on its own distinct merits. However, OLED perhaps benefits from the greater technological maturity, even though QLEDs are effectively based on decades old LCD systems. There have been multiple iterations of QD chemistries and integration formats which resulted in a period of uncertainty regarding QD implementation. Early formulations contained cadmium and were integrated on the basis of a speculative RoHS exemption, for instance. This issue is becoming less pertinent with the rise of safer, and better QD formulations based on the likes of cadmium-free metal halide perovskites.
If you would like to learn more about cadmium-free quantum dots for display applications, refer to our article on the benefits of cadmium-free quantum dots. Or contact a member of the Avantama team today if you would like to discuss novel QD formulations for display applications.