Picture projection system

摘要

A video projection system ( 50 ) comprises a rotary disc ( 31 ) having light guiding devices ( 35 ) extending radially thereof and in a helical configuration circumferentially at the disc ( 31 ) and corresponding in number to the number of lines to be scanned on a screen ( 48 ) the arrangement being such that, as the disc ( 31 ) rotates, a light bundle is directed through successive devices ( 35 ) which cause the bundle to be scanned on the screen ( 48 ).