Inorganic leds that are not pushed too far outside their comfort zone do not meaningfully degrade over time. The problem with them is that you cannot make the three different colors needed in a single material, so unlike oled you need to physically produce three separate kinds of components, and then transfer 25 million individual components onto a substrate to manufacture a 4k display.
Every time you print a document on a laser printer, >25 million particles of coloured plastic are arranged to within ~10um of where you want them to be on a sheet of paper, all for a total cost of a cent or two.
Moving millions of items to precise locations isn't expensive, as long as you do it the right way...
Those 25 million separate devices are electronic components with terminals that need to align with solder balls, and they need to stay in place until the entire assembly goes into the reflow oven.
We are not exactly talking about plastic particles here.
> The problem with them is that you cannot make the three different colors needed in a single material,
If that's the problem, why not just make 3x white leds per pixel and have a layer of color filters, like LCDs have.
Or at least make the leds in vertical stripes, so you're not assembling 25 million components onto a substrate, but instead 4k*3 components (each assembled from 2k components, I suppose).
I think I might’ve heard of someone trying to do that, where all the LEDs are the same and they use quantum dots on top two emit the color that they want.
Maybe that’s how it’ll work. Honestly an LCD with one LED backlight per pixel would still be really nice.
This will never be cheap.