There is a broad variety of display technologies. Noctiluca specialises in display high-performance materials dedicated for OLED displays. The description below is to introduce you to the world of displays.
LCDs, or liquid crystal displays, are the oldest of all display types. They are made up of two primary components: a backlight and a liquid crystal layer. Particularly, liquid crystals are tiny rod-shaped molecules that change their orientation in the presence of an electric current. In a display, this property can be manipulated to allow or block light from passing through. This process is also aided by colour filters to produce different subpixels. These are essentially shading of red, green, and blue primary colors that combine to form the desired colour. Since liquid crystals don’t produce any light by themselves, LCDs rely on a white (or sometimes blue) backlight. The liquid crystal layer then simply has to let this light pass through, depending on the image that needs to be displayed. Also, LCD with a backlight unit, not only increases the panel thickness but also limits its flexibility and form factor.
The current top-of-the-line display technology is OLED, which stands for organic light-emitting diode. The OLED is built from an electroluminescent layer that consists of organic compounds which emit light when electrified. Due to their light emitting characteristics, OLED-based panels do not need backlighting. OLED have a much better contrast ratio when it comes to displaying the blackest blacks and whitest whites. The tones show superior quality when compared to other types of displays. From the outset, OLED has been a premium technology, offering superior picture quality, but at a substantially higher price than cheaper display options, such as LCD. Since OLED are organic, their lifespan comes into question. While red and green OLED films have longer lifetimes (46,000 to 230,000 hours), blue organics currently have much shorter lifetimes (up to around 14,000 hours). Blue light emitter remains a challenge when it comes to longevity. That could lead to colour accuracy problems when the device gets older.
The “Q” in QLED stands for “quantum dot,” a tiny semiconductor nanocrystal smaller than 10 nanometers. How small is that? There are a million nanometers in a millimeter, and a human hair measures around 80,000-100,000 nanometers. Each of these microscopic quantum dots is capable of emitting either red, green, or blue, from which billions of colours can be created. QLED TVs – sometimes expressed as “QD-LED” – include a panel of quantum dots that sits between the LCD panel and the LED backlight. Quantum dots heighten an LCD TV display’s overall colour accuracy and colour brightness, create deeper blacks, and enhance HDR (High Dynamic Range) contrast. In this type of display, the LCD matrix plays the role of shutters to prevent the light from bleeding into the colors. Plus, it filters the light to reconstruct the color on display. It is a modern and complicated method that companies like Samsung have made for providing a high-quality display to the users. This technology can produce bit brightness in some devices but doesn’t reproduce the dark and light tones like the OLED. We should consider QLED based on following 3 points: Size, brightness and color. OLED are much harder to build for larger screen sizes and when it comes to brightness, QLED can produce lighter than what individual OLED pixels can emit. More brightness is the advantage of backlit panels like QLED. Another QLED advantage is a precise colour quality that has been certified 100% by the colour volume measured to the DCI-P3 standards.
Micro-LED and Mini-LED:
Recently, micro-LEDs (μLEDs) and mini-LEDs (mLEDs) have emerged as the next-generation displays; the former is particularly attractive for transparent displays and high luminance displays, while the latter can serve either as a locally dimmable backlight for high dynamic range (HDR) LCDs or as emissive displays. Both mLEDs and μLEDs offer ultrahigh luminance and long lifetimes. These features are highly desirable for sunlight readable displays, such as smartphones, public information displays, and vehicle displays. Like OLED, each microLED in a microLED display is a pixel, and each microLED is self-illuminating and supplies its own colour. Unlike OLED, microLED sets could be 30 times brighter with no burn-in or lifespan issues.
Particularly, the Mini-LED is another type of backlighting used for LCD TV. They are tinier than Quantum Dots, and almost at the pixel level. They are a form of miniature backlights that are configured in a Full Array Local Dimming (FALD) zones. They are used with QLED to provide much better control of the backlighting. This leads to better imaging quality that some say is comparable to OLED. The features Mini-LED provide improves contrast and brightness that is similar to OLED. Like OLED, Mini-LED uses techniques that allow control at the pixel level. This allows it to achieve the level of deeper blacks that OLED displays can provide. OLED do not have backlighting since they are capable of emitting visible light on their own. Mini-LED emits lights, but still requires a layer of LCD to illuminate in order to reproduce the colour.
On the other hand, MicroLED displays are similar to OLED because they emit their own light, therefore requiring no backlighting. MicroLED is actually being touted as more superior in quality to OLED displays. They can provide more brightness along with higher contrast and richer colours, combining the best features of OLED and backlit LED. MicroLED are much smaller than Mini-LED. The size of the diodes is in the order of microns, so they are a millionth of a meter in size. Each MicroLED is placed in a pixel, thus they illuminate at the pixel level. Since they are tinier, they are also harder and costlier to produce, but more demand will bring economies of scale. MicroLED provide better luminance and higher resolution than OLED, so they are ideal for premium displays. MicroLED displays are exciting to many, as the technology seems to be the front runner for the next-generation display of choice in many market segments – from AR/VR glasses through wearables to TVs and IT displays. The MicroLED industry though, even after billions of dollars spent on R&D, is still at a very early stage. Production costs are high, processes are not reliable enough, and there are several technical challenges to overcome before production can begin (except for some niche areas such as ultra large-size premium TVs). However, some critical issues, such as burn-in and lifetime, still need to be improved. The main advantages of microLED displays will be the high-power efficiency and high brightness, and long lifetime of the LEDs and the ability to create very small pixels. In addition, the technology enables unique business models, and sometimes unique designs which may enable it to succeed in certain applications.
- OLED TVs consistently top every side-by-side TV picture quality comparison competition. But OLED TVs also suffer four major drawbacks when compared to any type of LED TV: screen brightness, price, burn-in, and lifespan.
- While an OLED TV’s image is spectacular in a dim or dark room, its image loses its impact in a bright, sun-lit room.
- Producing OLED panels is understandably an expensive process, which is why OLED TVs are priced twice to three times as high as other LED TVs.
- Although manufacturers use OLED in monitors, smartphones, and televisions, there are other alternatives.
- MicroLED is pretty similar to the OLED when it comes to pixels. But they have excellent resolution images with higher luminance. This technology is however in early R&D stages and will take a lot of time to mature.
- Lastly, LEDs are simply the base of all these three TVs with lesser features and specs.
|LED- backlit LCD||Mini – LED||OLED||Micro Led|
|Contrast||Low to medium||Medium||High||High|
|Response time||Low (ms)||Low (ms)||High (um)||Very High (ns)|
|Power Efficiency||Medium||Medium – High||Medium||High|
|Only lit pixels draw power||No||No||Yes||Yes|
|Operating Temperature||-20 to 80 C||-20 to 80 C||-30 to 70 C||-100 to 12 C|
|Need for encapsulation||No||No||Yes||Yes|
|Touch maturity||High||Medium – High||Medium – High||Low|