• (n.) An apparatus for the production of sound by the action of the actinic, or ultraviolet, rays.
Ac·tin'o·phone noun [ Greek ..., ..., ray + ... voice.] (Physics) An apparatus for the production of sound by the action of the actinic, or ultraviolet, rays. 
actinophone The production of sound with actinic rays (that property or force in the sun's rays by which chemical changes are produced, as in photography).