The liquid crystal display
This invention is the reason why we have flat screen tvs, and digital clocks. It is one of the best inventions in terms of power saving, and portability. This invention is pretty great for clocks, and pretty much runs on almost anything with electrity. This invention is pretty cool as it uses liquid crystals combined with polarizers to block light and create a black image directly on the glass plate, showing digits or shapes. The downside of this is mostly having to rely on a source of light, which is either a backlight or ambient light to see the digits. This kind of technology is pretty damn good for low electronic devices like your air conditioning remote, or a digital clock.