Transducer for sensing body sounds

An electronic stethoscope including an acoustic-to-electrical transducer for detecting body sounds, the transducer comprising:

• a stethoscope diaphragm having an electrically conductive surface, the diaphragm being mounted in a stethoscope chestpiece such that the diaphragm can contact the body for body sound detection and vibrate in response to body sounds;
• a fixed conductive plate substantially parallel to the diaphragm, mounted within the chestpiece, the conductive plate being positioned at a distance about or exceeding 0.1 mm from the diaphragm, the diaphragm conductive surface and fixed conductive plate forming two plates of a capacitor and connected in the form of an electrical capacitance to electrical circuitry;
• a capacitance-to-electrical signal conversion means to convert diaphragm-plate capacitance changes due to body sound vibrations to electrical signals;
• the stethoscope further comprising signal amplification means and at least one electrical-to-acoustic transducer connected to signal amplification means, to reproduce body sounds as detected by said transducer.

An acoustic-to-electrical transducer for detecting body sounds, the transducer comprising:

• a diaphragm having an electrically conductive surface, the diaphragm being mounted in a housing such that the diaphragm can make contact with the body and vibrate in response to body sounds;
• a fixed conductive plate substantially parallel to the diaphragm, mounted within the housing, the conductive plate being positioned behind the diaphragm the conductive plate being positioned at a distance about or exceeding 0.1 mm from the diaphragm, the diaphragm conductive surface and fixed conductive plate forming two plates of a capacitor and connected in the form of an electrical capacitance to electrical circuitry;
• a capacitance-to-electrical conversion means to convert diaphragm-plate capacitance changes due to body sound vibration to electrical signals;
• the capacitance-to-electrical conversion means having gain and frequency response characteristics that are adjustable by variation of the static displacement of the diaphragm due to pressure of the body against the diaphragm.

An acoustic-to-electrical transducer for detecting body sounds, the transducer comprising:

• a diaphragm mounted in a housing such that the diaphragm can make contact with the body and vibrate in response to body sounds;
• the diaphragm including means to modulate an electromagnetic signal via mechanical movement, said electromagnetic signal being an electric or magnetic field in the space behind the diaphragm or a light beam in the space behind the diaphragm;
• the diaphragm being mounted such that the diaphragm can be displaced at least about or exceeding 0.1 mm due to a combination of body vibration and static pressure of the body on the diaphragm;
• conversion means to convert said electromagnetic signal to an electrical signal measurement of diaphragm movement.

An acoustic-to-electrical transducer for detecting body sounds, the transducer comprising:

• a diaphragm having an electrically conductive surface, the diaphragm being mounted such that the diaphragm can make contact with the body and vibrate in response to body sounds;
• a fixed conductive plate substantially parallel to the diaphragm, positioned behind the diaphragm, the conductive plate being positioned at a distance about or exceeding 0.1 mm from the diaphragm, the diaphragm conductive surface and fixed conductive plate forming two plates of a capacitor and connected in the form of an electrical capacitance to electrical circuitry;
• a capacitance-to-electrical conversion means to convert diaphragm-plate capacitance changes due to body sound vibration to electrical signals;
• the conductive plate and capacitance-to-electrical conversion means being combined on a semiconductor substrate to form an integrated circuit acoustic-to-electrical transducer.