A projector is an optical device that projects images or moving visuals onto a surface, typically a projection screen. It works by shining light through a lens, which magnifies and focuses the image onto the desired surface, creating a larger representation of the content being displayed. Most projectors use a small transparent lens to create the image, but newer types can project directly using lasers. Video projectors, commonly used today, are digital replacements for older types like slide projectors and overhead projectors.