Patent US 4,122,495

A method and a device for the one-dimensional analysis of an optical image and its conversion into an electrical signal, of which the amplitude characterizes the luminous intensity at each point. The device comprises, disposed opposite one another, a piezoelectric substrate and a semiconductive substrate onto which the image is projected. Reading is effected in two steps; the first step supplies a stationary distribution (q) of charges in the semiconductor by scanning the image by a non-linear interaction between two elastic waves; the second step, carried out after an integration time .DELTA.t of the image gives a reading signal arising out of the non-linear interaction between a third elastic pulse and the charge distribution (q) as modified by the incident illumination during the time .DELTA.t.