Maybe you have seen a sticker with the letters OLED on it when looking for a new TV or smartphone. Maybe you haven’t given it much thought other than “Oh it’s probably a good thing since they put it on a sticker.”
If that’s the case then read on for a brief and (hopefully) easily understandable explanation.
Most displays today are either what is called LCD (Liquid Crystal Display) or LED (Light-Emitting Diode) displays. Both work by shining a constant white light through a grid of pixels. For every pixel there are three subpixels; one red, one green and one blue. These pixels can either let light through or block it, so if only the green subpixel lets light through that pixel will be green. Same goes for the red and blue ones. If all three subpixels (red, green and blue) let light through, the pixel will be white and if they block it, the pixel will be black. But even if the entire display shows only black, the backlight is still on; the pixels are just blocking it.
If that made any sense, you should be thinking to yourself: “Doesn’t that waste a lot of energy?” and you’d be correct in answering: “Yes, yes it does.”
OLED (Organic Light-Emitting Diode) displays have no constant backlight like LCD and LED displays do. Instead each subpixel can light up on their own. So if a pixel needs to be black, say in the black stribes on a zebra, that subpixel is simply turned off. This is much more energy efficient because the display only emits the amount of light it needs instead of constantly emitting light that might just be blocked by the pixels. Because each pixel can turn off, the display can also create much darker blacks than traditional displays that leak a little light when showing black.
So next time you go looking for a TV or smartphone – consider going for the one with an OLED display. It might be more expensive, but it consumes less energy and the image quality is a lot better.