photophone
/ˈfəʊtəʊfəʊn/Now historical
noun
1 Telecommunications. An instrument for transmitting sound by means of light; specifically that invented by Alexander Graham Bell and Sumner Tainter in 1880.
- The sound to be transmitted is made to cause vibrations in a mirror. Reflected light from this is detected by a photoelectric cell, and the variations in the resulting electric current are used to reproduce the sound..
2 Film. A system for producing synchronized soundtracks on films. Now disused.
Origin
Late 19th century; earliest use found in Alexander Graham Bell (1847–1922), teacher of deaf people and inventor of the telephone. From photo- + -phone.