Photo-acoustic conversion based sound emitter device

Abstract

The photo-acoustic conversion based sound emitter device has a sound output surface for transmitting sound wave vibrations to a medium outside the device. An optical waveguide, is used to transmit light through an optical path within the device. First and second photo-acoustic conversion volumes, at different distances from the sound output surface, are used for transmitting sound generated in the first and second volume to the medium via the sound output surface, the optical path extending directly or indirectly successively through the first and second photo-acoustic conversion volume. The device comprises an intermediate volume separating the first and second photo-acoustic conversion volumes along the optical path, the intermediate volume having a lower light absorption coefficient than the first and second photo-acoustic conversion volumes; and/or the first and second photo-acoustic conversion volume have a different cross-section area size and/or shape with virtual planes perpendicular to the optical path; and/or the first and second photo-acoustic conversion volumes have different optical absorption coefficients, or a different optical wavelength dependence of these optical absorption coefficients.

Dependencies are inferred from the claim text.