Microphone assembly
A microphone assembly comprising a housing in which a transducer element is positioned. In the housing, an upper and a lower chamber are defined, the lower chamber extending at least at one edge of the transducer element and potentially to an upper side thereof. An element, such as a horse-shoe shaped element or a circular element, is provided for separating the upper side of the transducer element into the upper and lower chambers. The transducer element is fixed using flexible fixing means, and space is provided at one or more sides of the transducer element to take up thermal expansion and retraction of the housing and the transducer element.
1. A microphone assembly comprising:
a microphone casing comprising a sound inlet, an internal surface, and a miniature transducer element disposed in the microphone casing, the miniature transducer element being bounded by first and second oppositely arranged outer surfaces and by a peripheral edge surface, the miniature transducer element comprising a diaphragm acoustically connected to the sound inlet at the first outer surface of the transducer element; and
a first internal chamber at least delimited by the second outer surface of the miniature transducer element, a portion of the first outer surface, a portion of the peripheral edge surface, and a portion of the internal surface of the microphone casing that opposes the second outer surface,
wherein the first internal chamber extends around the portion of the peripheral edge surface and above a portion of the first outer surface of the miniature transducer element.
2. A microphone assembly according to claim 1 , further comprising an attachment means adapted to attach the first outer surface of the miniature transducer element to the internal surface of the microphone casing, the attachment means comprising a layer of a flexible gluing agent.
3. A microphone assembly according to claim 2 , wherein the first outer surface of the miniature transducer element abuts the internal surface of the microphone casing with the flexible gluing agent interposed between the first outer surface of the transducer element and the internal surface of the microphone casing.
4. A microphone assembly according to claim 1 , wherein a distance of at least 50-1000 μm exists between the portion of the peripheral edge surface of the miniature transducer element and the internal surface of the microphone casing.
5. A microphone assembly according to claim 1 , wherein a minimum distance of at least 50-1000 μm exists between each of at least two portions of the peripheral edge surface of the miniature transducer element and the internal surface of the microphone casing.
6. A microphone assembly according to claim 1 , comprising one or more attachment means having a horse-shoe shape for abutting the transducer element.
7. A microphone assembly according to claim 6 , wherein the one or more attachment means comprises an acoustical seal between the first internal chamber and a second internal microphone chamber, the second internal microphone chamber extending above the diaphragm of the miniature transducer element and being acoustically coupled to a sound inlet of the microphone casing.
8. A microphone assembly according to claim 7 , wherein the miniature transducer element is positioned so that the sound inlet and the diaphragm overlap, in the plane of the diaphragm, and wherein the one or more attachment means encircle, in the plane of the diaphragm, the sound inlet and the diaphragm.
9. A microphone assembly according to claim 1 , further comprising a substantially circular vent or opening connecting a first side of the diaphragm with another side thereof, the vent or opening having diameter between about 3 and about 100 μm.
10. A microphone assembly according to claim 1 , wherein a second internal chamber is delimited by the internal surface of the microphone casing and at least part of the first outer surface, including the diaphragm of the miniature transducer element, the microphone assembly further comprising one or more electric or electronic components electrically connected to the miniature transducer element and being positioned in the second internal chamber.