Unidirectional ear microphone and method

An ear piece device for use in a communication system, said device comprising:

• a housing having a speaker end and a microphone end, said speaker end being configured for a snug fit at the ear canal of a user, said speaker end and microphone end being divided by an acoustically insulating wall which encloses the microphone end to form a microphone compartment;
• a microphone casing disposed within the microphone compartment and having first and second opposing walls, said casing defining a microphone enclosure therein;
• a speaker element mounted with sound projection oriented toward the user's ear canal and including isolation means coupled between the speaker element and the housing for absorbing undesirable frequencies that interfere with sensitivity of audio pick up at the microphone end of the housing;
• a microphone element contained within the microphone casing and having first and second opposing ends coupled to the first and second opposing walls of the casing, respectively, such that the microphone element spans the microphone enclosure and is substantially enclosed therein so as to be separated from contact with the skull by the housing, said microphone element being interposed between said first and second opposing walls of the casing;
• first and second mounting rings comprised of acoustical insulation material, said first and second rings being relatively adjustable with respect to and circumscribing the microphone casing, said rings are positioned between an interior surface of the housing and an exterior surface of the microphone casing to receive mechanical vibrations from said housing, said rings defining first and second substantially parallel imaginary planes, respectively, said planes pass through the opposing walls of the casing, said rings further being positioned at approximate equal entry distances from and on opposing sides of the microphone element such that said microphone element resides approximately midway between said parallel planes, said mounting rings thereby enabling cancellation at the microphone element of substantially all mechanical and acoustical vibrations passing through said rings and into the casing to the microphone element wherein (1) said mechanical vibrations enter the microphone compartment from the housing and (2) said acoustical vibrations enter the microphone compartment through air transmission openings from a substantial distance as compared to the relatively nearby location of the user's skull;
• and
• means for coupling signal output from the microphone element to an audio circuit for processing.

A method for isolating an individual's speech for reproduction from an environment of background noise which is not be detected, said method comprising the steps of:

• a) positioning a housing device containing (i) a speaker element and (ii) a casement having first and second opposing walls and containing a microphone element, at an ear canal supported by a user's ear cartilage;
• b) mechanically and acoustically isolating the speaker element from the housing to limit the amount of sound vibration which is carried into the housing;
• c) coupling a first and second end of the microphone element to the opposing walls, respectively, of the casement such that said microphone element is interposed between said opposing walls and substantially enclosed with said casement;
• d) positioning first and second mounting rings between an interior surface of the housing and an exterior surface of the casement for receiving mechanical vibrations from the housing, and circumscribing the casement with the first and second rings which are relatively adjustable with respect to the casement, such that said rings surround the opposing walls of said casement and define first and second substantially parallel imaginary planes which pass through the opposing walls and the casement at approximate equal entry distances from and on opposing sides of the microphone element, such that the microphone element resides approximately midway between said planes to thereby mechanically and acoustically isolating the microphone element from the housing to limit the amount of sound vibration which is carried into the microphone element;
• and
• e) concurrently channelling said sound vibration from the housing through the mounting rings and along sound paths having substantially equivalent lengths into opposite sides of the microphone element within the casement such that the sound vibration reaches the microphone element along the opposing sides of the casement at approximately the same time but in opposing phase relationship to result in wave cancellation at the microphone element.