A cathode ray tube is an electrovacuum tube used to display visual signals by accelerating a beam of electrons. These electrons are generated at a heated cathode and are then directed across the tube's interior via deflection plates that manipulate their path. The beam strikes a phosphorescent coating lining the interior face of the glass envelope, causing it to emit visible light. By controlling the magnitude and angle of the electron beam using orthogonal electric fields, varying points of light can be precisely illuminated, allowing the device to render images on a display screen.