Lots of Activity in 8K (and above!) Displays at Display Week 2023
The SID Display Week took place from 21st to 26th May in the Los Angeles Convention Center and there was lots to see for those of us that like high resolution displays.
One of the most eye-catching demonstrations was of a prototype LCD panel developed by BOE of China that was not only 110” in diagonal, but was actually showing 16K content – that is to say 15,360 x 8,640 or 132 megapixels – that’s four times the number of pixels that you have in 8K sets. The dot pitch was small enough that, even close up, you couldn’t see the pixels. The performance was not dramatic (400 cd/m2 of luminance, 99% of P3 color and 1,200:1 contrast) but that really wasn’t the point of the demo.
It’s hard to drive LCDs that are as big as 110” which is one of the reasons that LCD displays are limited to that kind of size. Very high resolution displays are also very hard to drive as the you have to address each of the lines in the vertical resolution. For a constant frame rate, you only have a quarter of the time available to drive each pixel of a 16K display than you do for a 4K display. Increasing the frequency causes challenges because of the capacitance of the electrodes and pixel structure. A bigger display also has more capacitance because of the line length, so, all in all, it’s really hard to make a 16K panel in such a large size.
On that basis, a very large display with very high resolution is doubly difficult to make. Kudos to BOE for the effort. The lessons it learned in developing the set should improve 8K panels, especially those with higher refresh rates.
BOE also had an impressive 65” LCD with a miniLED backlight and 3,000:1 contrast, but sadly they were only showing a 4K version of that technology. It used UB Cell technology which allows good contrast with great viewing angles. The UB Cell technology is not related to the resolution, so could also be used on 8K panels in the future. It demonstrated that despite the praise for OLEDs in the press, LCD is still capable of very high image quality.
TCL/CSOT had a very good looking 85” 8K panel with support for 120Hz frame rates. Like the 16K panel from BOE, the TCL panel has to drive the lines of the display in a very short time, so it represents a similar technical challenge. However, this panel is much closer to market than the 16K which was very much just a test of the technology. The demonstration of the 120Hz 8K images showed that the 120Hz technology really makes difficult content look very good with smooth panning, even on difficult content that might show some judder at low frame rates on other panels.
The firm uses a 1G1D Oxide TFT architecture for controlling the pixel and has a novel way of using the capacitance of the ITO address line as part of the TFT circuit. That reduces the space used by the active TFTs and allows an aperture ratio of 5.4% (compared to just 2% on the 16K panel)
A Foldable 8K OLED TV Concept
TCL/CSOT also caught the eye with a 65” foldable OLED 8K TV that was made using inkjet printing. TCL has been developing the inkjet technology for around three years and is based on developments that it licensed from JOLED in Japan. JOLED has recently got into financial difficulty but we were lucky enough to interview TCL/CSOT’s CEO who told us that it was confident that it did not have any problems because of this as so much of the technology had been adopted already. He also confirmed that the technology would be able to use the new phosphorescent blue material that is due from UDC and that will significantly boost OLED brightness.
The foldable IJP OLED won a ‘People’s Choice’ award after a vote by exhibition visitors.
The firm told us that although it was continuing to develop the inkjet printing (IJP) technology, mass production of TV-sized panels is still some time away. It does plan to make IJP panels from next year but these will initially be large monitor sizes around the 32” level of a 4K monitor panel that it showed that will roll up to 20mm radius and has support for 99% DCI-P3 color. There will also be just a limited supply at that time.
New Patterning for OLEDs
IJP is one of the techniques for patterning OLEDs – making sure that the RGB material is in the right place. Up to now, smaller OLEDs have been patterned using a fine metal mask (FMM – which is like a sophisticated stencilling system) but there are significant barriers to making big panels with the technology. Larger OLEDs for TVs have been made so far using unpatterned OLED as the emissive layer and then either filtering (LG Display) or converting the colours using Quantum Dots (QDs) (Samsung).
At Display Week, Visionox, an OLED specialist in China was showing its patterning tecchnology using photolithography. Although that firm is a maker of small displays, if the technology is made to work in production, there is no technical reason why it could not be extended to larger displays and that would reduce one of the technical barriers that make 8K OLED TVs difficult to make. The technique promises to boost lifetimes of OLEDs by up to 6 times or brightness by 4 times, because the size of the RGB sub-pixels can be made bigger, with less black area between them.
LG Display showed the latest variation of its 77″ 8K WOLED panel which uses the firm’s ‘Meta’ microlens array (MLA) which means higher brightness as more of the light from the OLED material is directed towards the viewer. LG won a ‘People’s Choice’ Award for the unit.
Other 8K Developments
Taiwanese panel maker Innolux is the biggest supplier of displays to the automotive market and was showing a very good looking wide 8K display designed for those in the back of a car to use for entertainment. It was 31.3” wide and had 7680 x 2160 resolution (32:9 aspect ratio). Luminance is 700 cd/m2 and contrast is 1,400:1.
And on the topic of wide 8K displays, TCL/CSOT was showing a 45” curved LCD with 8K horizontal resolution, but just 2160 vertically and intended for desktop gaming. We think that the panel is used in a gaming monitor from Samsung, the Odyssey Neo G9 that was announced at CES, but has not yet hit the market.
8K Association member, Hyphy, which has clever ‘sampled analogue’ driving technology to reduce the cost and complexity of driving 8K display panels was showing its technology at the show. The great news is that the firm is moving to ‘tape out’ on the first chips to use its technology in the next few months. This is a key step in developing the technology and in the firm’s progress. Hyphy expects its technology to be in a commercial LCD by the end of the year.
TCL/CSOT was also showing a number of autostereo 3D displays based on 8K panels. Developers of this kind of system are really happy to have access the high pixel count of 8K sets.
