Just to expand slightly, an AMOLED display means that each pixel only produces light while it's activated. There is no full-screen backlight like you'd see on a typical LCD screen, so if a pixel is not given a signal to illuminate a specific color, it just remains off, so you get the best blacks you can find. So the contrast ratio is basically 1:infinite. This is, in my opinion, the best screen technology for a cell phone. The reason it's not more prevalent on TVs and monitors is because of (a) the cost, but more importantly (b) burn in. Static images will cause permanent (or semi-permanent) shadow images. You can easily see this if you find a retail store with a display model OLED TV. Cell phones displays are, for most people, more often off than on, and the image is frequently changing while they are on, so it's not really a concern there. Hope this helps!
