Hearing aid with large diaphragm microphone element including a printed circuit board
View Patent ↗A disposable-type hearing aid uses a relatively large single diaphragm or a large single diaphragm subdivided into a plurality of smaller active diaphragm areas obtained using a grate-like back support plate with ridges which contact and divide the diaphragm into the several smaller active diaphragm areas. The diaphragm and a backplate are enclosed in a metal housing and are disposed proximal and parallel to a shell-like hearing aid enclosure having sound inlets. The metal housing is closed at an end opposite the sound inlets by a printed circuit board (PCB) forming an acoustical seal for a back volume of the microphone. The PCB also carries substantially all the electronic components for the hearing aid thereon. The PCB has a ground plane in contact with the housing whereby the PCB also acts as an EMI shield. An electrical connection is formed in various ways between the back support plate and the PCB during assembly of the metal housing and components with the PCB. Mass production of disposable hearing aids with large diaphragms and relatively low noise levels is thus possible using this invention.
1. A hearing aid comprising:
a hearing aid enclosure having a faceplate located at a proximal end of said enclosure, said faceplate having sound openings formed through said faceplate;
a housing of lateral width “W” and longitudinal length “L” disposed at the proximal end of said enclosure, the housing containing a transducer formed of a diaphragm comprising an electrically conductive membrane disposed opposite a conductive backplate, said membrane and conductive backplate extending in a plane parallel to and proximate to and opposite the faceplate of said enclosure having sound openings formed through said faceplate; and
a printed circuit board (PCB) within the hearing aid enclosure, the housing and the printed circuit board (PCB) being configured to provide an electromagnetic interference (EMI) shield around the transducer.
2. The hearing aid of claim 1 wherein the housing is electrically conductive and is formed of a front surface open to a said faceplate and a sidewall extending longitudinally inward from said faceplate; the PCB having 4 conductive ground plane extending across said sidewall in electrical communication with the housing to form an acoustic seal for the transducer, electrical components to process signals generated by said transducer provided on said PCB; and wherein said housing and PCB form an EMI shield around said components and transducer.
3. The hearing aid of claim 1 wherein the ratio of the area of the housing opposite the faceplate to the area of the faceplate is at least 0.5.
4. The hearing aid of claim 1 wherein the housing has a greater lateral dimension than longitudinal dimension.