Laptop screen foil. Coloured scanning electron micrograph (SEM) of the surface of a brightness- enhancing foil used to make laptop personal computer screens look brighter. The principle is the same as that by which the tiny individual scales (one seen in orange) on a butterfly's wings make the wing as a whole look bright and shiny. Light is reflected from the tiny grooves between the blue and green ridges. Laptop computers are designed to be compact and portable, and do not have much room for screen projection hardware. The lightweight foil is a simple way to improve the image without adding any new electronics. Magnification: x200 at 6x7cm size.