Will Narrow Bezels Enable Low Cost 8K OLED TVs?
The consumer press has got quite excited about a demonstration at the Mobile World Congress in Barcelona, when Samsung Display (the part of Samsung that makes display panels, rather than complete products) showed a demo of an OLED made up of tiles with narrow (0.6mm) bezels. These were put together to create a larger single display. Many have speculated that this will lead to cheaper large 8K OLED TVs. Well, there’s good news and there is bad news on this subject.
The Good News
As we have reported on the 8K news channel a lot, OLEDs are much more tricky to make than LCDs and that makes them more likely to have areas of defects when being made on the huge sheets of glass that are needed to make them cost competitive. If you are making small displays, you simply throw away the ones with defects and you can sell the rest. However, if you are making very large displays, a defect can cause the whole large panel to have to be thrown away.
This ‘yield’ problem has always been a challenge for all flat panel displays and is one of the reasons that LCDs succeeded first in smaller sizes (e.g. for notebooks) before developing to monitors and then to TVs. The more complicated circuitry in OLEDs makes the problem worse.
Making a display from tiles gets around this challenge as you can just throw away the tiles that are defective and keep the good ones. That makes the idea of tiled displays attractive. One of the titles that has an explanation of these cost savings is here.
Consumers are buying larger and larger TVs but that can mean real logistical issues in shipment. The author had conversations with Panasonic about the challenges that the firm had when it made a few 150″ PDP panels some years ago. Moving them around cost an absolute fortune. If you can’t get a TV into the boot of a car, or if it’s too big to go into an elevator, the market becomes limited. Tiling gets around these logistical issues.
In non-TV applications, similar to those where large LED walls are used, tiling is a big advantage. However, those applications often need high brightness, long lifetimes and sometimes static content. These are all challenges for OLEDs, so it’s not easy to imagine the technology competing effectively with
The Less Good News
Sorry, there is also bad news. First, although the bezels that Samsung showed are slimmer at 0.6mm, they are on each tile, so there are 1.2mm borders between Samsung’s panels. That makes the borders very visible. By our calculation, an 8K display with a pitch between pixels of 1.2mm would be around 420″ (10.67 M) in diagonal. That’s a bit big for anyone outside a theater!
The second issue is that they human eye is extremely sensitive to patterns and the seams between panels would be extremely hard to really hide. It has taken a good number of years for Samsung, Sony and other makers of fine pitch LED tiled displays to get the joins to be invisible, although for trade shows and demos they can now do a fine job. Of course, what they learned in this period could also be helpful in aligning OLED modules.
The third issue is that the complexity of the transistor backplanes for OLEDs is likely to continue to make OLEDs more expensive than LCDs on a cost/area basis. Of course, if novel display technologies such as emissive quantum dots could use simpler substrates, the learnings in making the narrow bezel OLEDs could still be useful. Still, there is still work to be done to bring that technology to mass production.
In Conclusion
It would be wonderful for viewers to be able to get the undoubted benefits of OLED displays on very large 8K screens at prices that were competitive with LCDs, but as the saying has it, “Don’t hold your breath”! The tiling concept could make large OLED TVs lower cost, but not, we think, low cost.
