Raster scan displays are the most common type of display device. They work by scanning a beam of light across the screen, one line at a time. The intensity of the light beam is varied to create the image. Raster scan displays are capable of producing high-quality images, but they can be slow to refresh the screen, especially when displaying complex images.
Vector scan displays work by drawing lines on the screen, one at a time. The lines are drawn by moving a beam of light across the screen, and the intensity of the light beam is varied to create the image. Vector scan displays are capable of producing very fast refresh rates, but they can only display simple images.