Patent ID: 11883847
Assignee: ULTRALEAP LIMITED
Field: Audio-visual technology (Electrical engineering)
Classification: CPC B  G  H  F | IPC B  F  H

Claim 7:
8. An acoustic transducer comprising:
1) an acoustic matching structure for a transducer, the structure comprising:
a cavity which, in use, contains a fluid, the cavity having a substantially flat cylindrical shape;
at least one wall bounding the substantially flat cylindrical shape of the cavity;
the structure defining an area Acavity given by the average cross-sectional area in the planar dimension in the cavity within the at least one wall;
wherein the cavity has an effective side wall radius rcavity defined as:

rcavity=(Acavity/π)1/2; and

at least one aperture placed in at the at least one wall;
wherein an area of one of the at least one aperture (Aaperture), and Acavity satisfy the inequality:
Acavity/Aaperture is greater than 2;
wherein the cavity height hcavity is defined as the average separation within the at least one wall;
wherein rcavity and hcavity, satisfy the inequality:
rcavity is greater than hcavity;
wherein, in operation, a transducing element acting on one of the cavity end walls generates acoustic oscillations in the fluid in the cavity;
and whereby, in use, the acoustic oscillations in the fluid in the cavity cause pressure waves to propagate into a surrounding acoustic medium; and
2) an actuator, wherein, in use, the frequency of oscillatory motion of the actuator is within 30% of the lowest resonant frequency of radial acoustic oscillations in the cavity.