Stacked piezoelectric transducer acting as quarter-wave resonator for recording video information

Claim 1

A recording head for applying a pattern to a record medium having an impressionable surface, said head comprising: a transducer comprising a plurality of polarized substantially planar piezoelectric elements each having a first electrode associated with one pole of said element and a second electrode associated with the opposite pole of said element, said elements united in a stack arrangement with adjacently positioned ones of said elements having oppositely directed polarizations and collectively exhibiting a predetermined acoustic impedance; a base member bonded to a first terminus of said stack and having a specific acoustic impedance at least an order of magnitude greater than said stack impedance so as to establish said stack substantially as a quarter-wave resonator; circuit means, including means for establishing a first conductive connection common to said first electrodes and for establishing a second conductive connection common to said second electrodes, for applying an electrical signal across said elements to develop longitudinal mode vibratory displacements of said stacked elements proportional to the excursions of said signal; a coupler bonded to a second terminus of said stack for translating said stack displacements; and a stylus supported by said coupler for presentation to the impressionable record medium surface and responsive to the stack displacements translated by said coupler for generating a pattern on said surface corresponding to said displacements.