Patent ID: 8160285

Claim:
Waveguide unit, for use with a transducer unit, and in particular a transducer of the dome type, where the waveguide unit has a shape in a plane view substantially corresponding to the shape of the transducer unit in a plane view so that the waveguide may be arranged around the outside periphery of the transducer unit, where the waveguide unit has a front side on which a front side is provided for reflecting the sound waves from the transducer, and a substantially flat backside, and where substantially, centrally in the waveguide unit an aperture is provided which aperture is suitable for accommodating a transducer unit, and the side of said aperture connects the front and back sides of the waveguide unit, where said waveguide comprises one or more diffraction edges arranged equidistant with the shape of the waveguide unit on said front side of the waveguide unit, and where adjacent on both sides of said one or more diffraction edges, substantially flat inclined surfaces are provided.