The magic lantern, also known by its Latin name lanterna magica, was an early type of image projector that used pictures—paintings, prints, or photographs—on transparent plates, one or more lenses, and a light source. Because a single lens inverts an image projected through it, slides were inserted upside down in the magic lantern, rendering the projected image correctly oriented.
19th century magic lantern with printed slide incorrectly inserted (upright, which would be projected by the lantern as an inverted picture)
Magic lantern slide by Carpenter and Westley
A page of Willem 's Gravesande's 1720 book Physices Elementa Mathematica with Jan van Musschenbroek's magic lantern projecting a monster. The depicted lantern is one of the oldest known preserved examples, and is in the collection of Museum Boerhaave, Leiden
Illustration of Kircher's Steganographic mirror in his 1645 book Ars Magna Lucis et Umbrae
A projector or image projector is an optical device that projects an image onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project the image directly, by using lasers. A virtual retinal display, or retinal projector, is a projector that projects an image directly on the retina instead of using an external projection screen.
Acer projector, 2012
DLP type home theatre projector in use
Ancient camera obscura effect caused by balistrarias in the Castelgrande in Bellinzona
Giovanni Fontana's drawing from circa 1420 of a figure with lantern projecting a winged demon