I see everyone talk about OLED like it’s the best thing ever and it’s been a thing for years yet it’s not a standard in the industry. Like for example an original PS Vita had a OLED screen then they removed it for the 2nd version of the PS Vita.
Even the Nintendo Switch which came out years after the PS Vita didn’t have an OLED and just a few years ago now it does.
Why isn’t it the standard if it’s so good?
In: Engineering
LED has little lights behind a screen. There’s some number of lights from something like 12 up to several thousand depending on the type/model of TV.
With LED screens, the screen which creates the image is a layer in front of the lights. It has millions of tiny crystals which twist when voltage is applied to them, which changes how much light they let through. This is how the image is made – each pixel is made of a red, a green and a blue “sub-pixel”, and those sub-pixels have the crystals twisted by different amounts which each allows a different amount of light through, which determines the colour and brightness you see.
With LED screens, it’s important to note that the crystals can’t *completely* block light, so if you have a “black” screen, some light is still getting through. Some models of screen have “local dimming” or “array dimming” or they might call it something else, where they can actually dim or turn off the LED light behind as well…. but depending on how many lights there are behind the screen, you can sometimes see this as a darker or brighter “block” rather than only affecting the pixels that really need it. It might be particularly noticeable where you have e.g. a mostly black screen with a few bright objects on it. The more LEDs and “dimming zones” a screen has, the better and less blocky the “local dimming” effect will be. Manufacturers are coming out with “mini-LED” and “micro-LED” TVs which have hundreds, up to millions of tiny LEDs to try to achieve similar or better performance than OLEDs.
OLEDs are a different technology. Each sub-pixel is actually it’s own little light. There’s no screen selectively blocking the light, between the bulb and your eyes, each sub pixel just varies its brightness directly. OLEDs can be completely off, so you get a “true” black, on the pixel level. This means you can get really great contrast on images, so things really “pop”. Supposedly they might not be able to get quite as bright at peak brightness as LED, and there are also some issues with image burn-in – where if the same images are displayed for a long time, an after-image “ghost” stays on the screen, perhaps permanently.
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