love it, I really tried to keep it super not-technical, but hey, I'm even happier to get into the details!
For those who aren't, you can ignore everything except:
the organic bits decay so need boosting as they age, which the compensation cycle tries to do.
TADF was the target for this year but they couldn't make it. Its fascinating stuff but not relevant enough to go into here.
How OLED technology (the WRGB matrix) was made viable for large screen production (and the development and patents of LG.Display) involves using yellow/blue emitters and colour filters. No other manufacturer makes oled tv because none of the methods used for phone sized screen yield anything like a viable production run at television sizes, and the methods used by LG are proprietary.
This link shows how the light is produced as white light (by blue and yellow emitters) before it is filtered to be wrgb.
LG to introduce 3-stack structure for its 2017 OLED lighting and TV panels | OLED-Info
You can see the brightness increase was achieved by an additional yellow emitter within the stack.
There were rumours lg.display had made a breakthrough in large-panel production of a cost-effective OLED rgb matrix, but nothing has yet appeared to show the technology is market ready.
I'd love it because aside from decay of organic emitters the wrgb stack structure is responsible for most of the foibles of the current generation of oled tvs.
OLED also automatically limits brightness to combat decay of the emitters. It's really quite clever, and getting better every year. The underlying issue still remains.
To the best of my knowledge the compensation works by using the age of each sub-pixel to level out the brightness across the screen.
It knows how long each was on for, and the resistance (which changes with age), and probably some other stuff, to be able to evaluate what additional headroom to use.
We know it has specific look-up tables (how could they cause that weird square issue? Write-back under false test conditions I'm not sure) but overall its the TV holding brightness in reserve to use later, as the materials decay the compensation runs them 'brighter' which is now just normal brightness. (or dimmer if a pixel has far less use than the others)