OLED technology for monitors and televisions


With its UltraFine OLED Pro 32EP950 and 27EP950 PC monitors, LG is presenting large RGB OLED displays with a diagonal of 80 centimeters and almost 70 centimeters, respectively. So far, only Asus and Eizo have OLED monitors with a diagonal of almost 55 centimeters (22 inches) in their product range; their panel comes from Japan Display.

In contrast to TVs, the organic luminescent layer in the monitor is not applied over a large area and a color filter is placed in front of it, but structured in red, green and blue stripes for the RGB subpixels.

LG uses 8 million pixels in its OLED monitors, the 32-inch display thus achieves a pixel density of 140 dpi, the 27-inch model even 163 dpi. According to LG, both 4K displays cover 99 percent of Adobe RGB and the DCI-P3 color space, process 10 bits per color channel and achieve a peak luminance of 540 cd / m2. Together with the black level of just 0.0005 cd / m22 this results in a theoretical contrast of 1 million to one – in a bright environment, reflections in the image ensure that the black value is higher and thus the contrast is lower.

The monitor equipment includes a USB hub with three downstreams and a USB-C connection that receives DisplayPort signals and charges connected devices with up to 90 watts. The displays can be hardware-calibrated and can be adjusted and rotated in height.

With its UltraFine OLED Pro series, LG offers large OLED monitors; the first model shows 4K resolution and measures 32 inches diagonally.

(Image: LG)

LG recommends the UltraFine OLED Pro devices for professional applications such as video editing, and their price is correspondingly professional: the 32-inch device is traded from 3250 euros; LG has not yet given the price for the 27-inch model, which will be available from autumn.

According to rumors, Samsung could soon also introduce PC monitors with OLED panels. These should have a diagonal of between 32 and 35 inches, which is significantly larger than the OLED panels for notebooks previously produced by Samsung. Samsung also wants to sell the organic panels to other monitor manufacturers. This would bring renewed movement to the monitor market, which has just been kissed awake by new formats and mini LEDs in the backlight.

The situation on the market for TV screens is clear to date: LG supplies organic displays, while Samsung is setting the tone for TVs with liquid crystal technology. That should change soon, because Samsung apparently wants to produce large OLED TVs again. The display division of the Korean group has been developing panels with OLED technology for some time, which like LG use a luminous organic layer, but generate the colors with inorganic quantum dots instead of organic color filters. The color-converting quantum dots virtually replace the color filters above the organic layer, which shines in blue here.

After internal criticism, Samsung has further refined its OLED technology for TVs. In the meantime, four instead of three blue glowing layers in the OLED stack ensure higher luminance levels.

(Image: DSCC)

Samsung is likely to rely on cadmium-free quantum dots for this new TV panel technology, because the currently applicable exemption from the EU authorities for the toxic material could soon expire. Currently, nanoparticles for green sometimes still contain small amounts of cadmium, which is temporarily permitted under the RoHS directive (Restriction of Hazardous Substances) and due to the lack of efficient alternatives.

The heads of Samsung’s TV division had initially spoken out against the new OLEDs because they feared some disadvantages compared to LCDs: lower peak luminance, risk of burn-in, higher production costs. In addition, the first models probably did not show the expected image quality. After the developers have made improvements, the new OLED technology should now find its way into Samsung televisions. The first devices are to appear with a diagonal of 55 and 65 inches, the company has not yet given any prices.

Samsung’s mini LED TVs with locally dimmable backlights use particularly flat diodes. Samsung itself is positioning the upcoming QD OLED TVs below the LCD TVs.

(Image: Samsung)

Samsung continues to put its LC displays at the top, which should convince with color-enhancing quantum dots and mini LEDs in the backlight. At the very top, Samsung also sees televisions with micro-LEDs as image pixels. However, these are only offered with large diagonals (soon from 77 inches) and a relatively low pixel density (then up to 57 dpi) and are horrendously expensive – at least 100,000 euros should be due.

With the start of new LCD TVs with mini LEDs in up to 2500 individually dimmable zones, LG would like to counter the higher-priced TVs with liquid crystal technology. The manufacturer had left this segment to its Korean competitor Samsung almost without a fight, because they had the OLEDs.

The QNED televisions with LC displays announced in January use quantum dots and LG’s NanoCell technology, in which a yellow filter improves the distinction between red and green color spectrum – whether this is even necessary when using color-converting nanoparticles remains to be seen. Perhaps the manufacturer uses it to be able to claim the combination of yellow filter and quantum dots as LG’s own technology.

LG televisions with mini LEDs in the backlight are divided into up to 2500 zones. LG positions the LCD TVs below its OLED televisions.

(Image: LG)

The QNED mini LED TVs are available from diagonals of 65 inches with 4K and 8K resolution. You can currently find the 4K models QNED919 with 75 inches and 86 inches for 4600 euros and 7000 euros, respectively; whether there will be a smaller model in this country is still open. The higher-resolution 8K variant QNED999 is listed with 65 inches for 5000 euros, with 75 inches for 7000 euros and with 86 inches for 10,000 euros in price comparators. This means that the QNED models are significantly more expensive than the manufacturer’s OLED TVs, which is remarkable in that LG continues to classify the OLEDs as its premium class, which means that they are of higher quality than LC displays with mini LEDs.

In c’t 18/2021 we take a close look at the technology of current e-bikes, test bikes and show legal tuning tricks. In one focus we describe the pitfalls of VPN and explain how you can navigate the Internet safely. How to shed light on why CureVac’s vaccine failed (so far) and how to rescue data from muddy hard drives. You will find issue 18/2021 from August 13th in Heise shop and at the well-stocked newspaper kiosk.

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