CES 2018 gave Samsung the occasion to demo its gigantic 146? (3.7 m) display, dubbed The Wall. The Wall’s very large size is not the only thing it has going for it. In fact, this is the first time that Samsung has designed a TV which does not implement traditional LCD technology. No Quantum LEDs, not even AMOLEDs (OLED technology implemented by the brand’s smartphones), but rather an entirely new type of diode called the MicroLED or mLED/µLED for short. In principle, MicroLEDs work the same way as OLEDs, but the former present some serious advantages?
Does this ring the death knell for backlighting systems?
Let?s not forget that the overwhelming majority of Ultra HD TVs on the market use LCD technologies with a LED backlighting system. This ?old’ technology based on a liquid crystal film (LCD) consists of a primary color filter combined with a backlighting system composed of white LEDs. While LCD technology has made great strides, most notably in terms of enhanced control for backlighting systems, it still isn’t able to offer absolute blacks when the video content calls for them. As a result, the contrast and viewing comfort, as well as the realism of the image, are compromised.
OLED technology completely solves this problem as it does not use a backlighting system. Rather, the diodes themselves produce each pixel of the image. Reds, greens and blues; the OLEDs are more or less bright depending on the color they are called to produce. If a bit of black is necessary, the corresponding OLEDs simply shut off. As attractive as this technology may be, it hasn’t managed to convince Samsung, who continues to use it for its smartphones (as Apple does for the iPhone X), yet considers it unsuitable for large displays.
OLEDs are composed of a carbon-based organic compound which changes over time. The quality of the power supply, room temperature, humidity: the diode?s environment can have a long-term effect on its manner of functioning. Certain smartphone displays integrating OLED technology have had a problem with screen burn (images staying on the screen), recalling problems encountered by plasma TVs. Inaccurate colors have also been observed on smartphones fitted with OLED displays, with one color becoming dominant over time (green or blue). While these phenomena don’t affect OLED TVs?which use much bigger diodes?they have nonetheless dissuaded Samsung from integrating its AMOLED technology (smartphones, tablets) into its TVs.
MicroLED: some serious advantages
None of this has kept Samsung from proposing TVs capable of displaying absolute blacks and infinite contrast. What the Korean manufacturer has done for its smartphones and tablets?as well as for those of other brands, including Apple, Huawei, Meizu and Lenovo?it plans to also do for its televisions. To this end, the brand has designed a new type of OLED: the MicroLED.
The principle behind a MicroLED (or mLED, µLED) is the same as for an OLED: green, blue or red MicroLEDs produce their own light. The difference between OLEDs and MicroLEDs is that the latter are not composed of an organic compound (carbon).
In reality, the MicroLED is a NOLED (Non Organic Light Emitting Diode). Instead of carbon, which is unstable over time, it is based on a Gallium nitride on Silicon (GaN) substrate.
Thanks to its exceptionally dense atomic structure, GaN allows MicroLEDs to offer excellent efficiency, which OLEDs are able unable to match. In short, a MicroLED TV uses less electricity (20%), and since it uses a higher-quality current in the heart of the diode, it should also offer a brighter image. In other words, viewers should expect MicroLEDs to significantly improve image quality, with the additional brightness required to display HDR films (Dolby Vision, HLG, HDR10+).
In addition to stability over time (no screen burn), brighter images (HDR) and superior image quality (more natural), MicroLEDs offer another advantage: the diodes employed make it possible to build bigger displays. While the largest OLED displays can measure up to 88?, MicroLED technology allows for displays measuring up to 150? and is only in its beginning phases. There doesn’t seem to be a limit in terms of size. Case in point: Samsung?s The Wall TV is composed of small MicroLED displays put together without any visible joints. As such, MicroLED technology can offer an alternative to video projection, with the possibility of building displays up to 4 meters wide, or even bigger, in various formats: 16:9, 1.85:1 or 2.35:1, for example. We?d compare this to bringing a movie theater into your home, but this would be an understatement, as video projection cannot offer absolute blacks. In short, we can expect unprecedented image quality, in addition to perfect silence.
As of today, no MicroLEDs TVs are available for purchase, but Samsung could launch its first consumer models before 2020. In the meantime, the manufacturer will likely be focused on improving its Quantum LED LCD displays.
This post is also available in: French