MEMS device for an implant assembly
Disclosed is an implant and method of making an implant. The implant having a housing that defines a cavity. The housing includes a sensor comprising a base attached to a diaphragm wherein said base may be positioned within said cavity. The sensor may be a capacitive pressure sensor. The diaphragm may be connected to the housing to hermetically seal said housing. The sensor may include electrical contacts positioned on the diaphragm. The attachment between the base and the diaphragm may define a capacitive gap and at least one discontinuity configured to enhance at least one performance parameter of said implant.
1 . An implant comprising:
a housing;
a sensor positioned in the housing, the sensor comprising:
a diaphragm configured to flex in response to external changes in pressure; and
a floating base attached to the diaphragm defining a capacitive gap between the diaphragm and the floating base at an attachment portion, the attachment portion being positioned along a perimeter of the capacitive gap, wherein the capacitive gap comprises at least one patterned electrode positioned on the floating base and wherein the attachment portion along the perimeter contains at least one open portion, wherein the floating base is positioned entirely within the housing and said floating base is attached only to said diaphragm.
2 . The implant of claim 1 , wherein said sensor is a capacitive pressure sensor.
3 . The implant of claim 2 , wherein the diaphragm is connected to the housing to form a hermetic seal.
4 . The implant of claim 1 , wherein the sensor comprises electrical contacts positioned on the diaphragm.
5 . The implant of claim 1 , wherein the at least one open portion vents the capacitive gap within the housing such that liquid or gas passes between the capacitive gap and the housing.
6 . The implant of claim 1 , wherein the at least one open portion allows at least one electrical trace to connect at least one electrical contact outside of the capacitive gap to at least one electrode positioned at least partially within the capacitive gap.
7 . The implant of claim 1 , wherein the capacitive gap comprises at least one electrode positioned on the diaphragm.
8 . The implant of claim 1 , wherein location and size of the at least one open portion enhance at least one performance parameter of the sensor.
9 . The implant of claim 8 , wherein the at least one performance parameter is selected from a group comprising: sensitivity to pressure, sensitivity to temperature, mechanical strength, reduction of mechanical stress in said diaphragm, and long-term accuracy.
10 . The implant of claim 9 , wherein the sensitivity to temperature is achieved by positioning the at least one open portion such that a coefficient of thermal expansion mismatch effect counteracts a gas expansion effect to reduce capacitive gap change due to temperature.
11 . An implant comprising:
a housing;
a sensor positioned in the housing, the sensor comprising:
a diaphragm configured to flex in response to external changes in pressure; and
a floating base attached to the diaphragm defining a capacitive gap between the diaphragm and the floating base at an attachment portion, the attachment portion being positioned along a perimeter of the capacitive gap, wherein the capacitive gap comprises at least one patterned electrode positioned on the floating base and wherein the attachment portion along the perimeter contains at least one open portion, wherein the floating base is positioned entirely within the housing and said floating base is attached only to said diaphragm; and
a coil in electrical communication with the sensor, the coil positioned within the housing and wherein location and size of the at least one open portion enhance at least one performance parameter of the sensor.
12 . The implant of claim 11 , wherein the floating base comprises at least one through hole providing access to electrically connect the at least one patterned electrode to a component outside the capacitive gap.
13 . The implant of claim 11 , further comprising a circuit having a resonant frequency that changes in response to a sensed parameter.
14 . The implant of claim 11 , wherein the housing is filled with a liquid or gel.
15 . The implant of claim 11 , wherein the floating base comprises at least one through substrate via (TSV) to electrically connect at least one of the at least one patterned electrode and a diaphragm electrode to a component outside the capacitive gap.
16 . The implant of claim 11 , wherein the diaphragm comprises a first region and a second region wherein the first region is thicker than the second region, and the second region is aligned with the capacitive gap.
17 . The implant of claim 11 , wherein the at least one performance parameter is selected from a group comprising: sensitivity to pressure, sensitivity to temperature, mechanical strength, and long term accuracy.
18 . The implant of claim 17 , wherein the sensitivity to temperature is achieved by positioning the at least one open portion such that a coefficient of thermal expansion mismatch effect counteracts a gas expansion effect to reduce capacitive gap change due to temperature.
19 . The implant of claim 11 , wherein the housing is filled with vacuum, inert gas, other gas species, or gas at a predetermined pressure.
20 . An implant comprising:
a housing;
a capacitive pressure sensor positioned in the housing, the capacitive pressure sensor comprising:
a diaphragm configured to flex in response to external changes in pressure and is connected to the housing to form a hermetic seal; and
a floating base positioned entirely within the housing and attached only to the diaphragm defining a capacitive gap between the diaphragm and the floating base at an attachment portion, the attachment portion being positioned along a perimeter of the capacitive gap, wherein the capacitive gap comprises at least one patterned electrode positioned on the floating base and wherein the attachment portion along the perimeter contains at least one open portion and wherein the capacitive gap comprises at least one electrode positioned on the diaphragm; and
electrical contacts positioned on the diaphragm and wherein location and size of the at least one open portion enhance at least one performance parameter of the sensor;
wherein the at least one open portion allows at least one electrical trace to connect at least one electrical contact outside of the capacitive gap to at least one electrode positioned at least partially within the capacitive gap and wherein the at least one performance parameter is selected from a group comprising: sensitivity to pressure, sensitivity to temperature, mechanical strength, reduction of mechanical stress in said diaphragm, and long-term accuracy.
21 . The implant of claim 20 , wherein the at least one open portion vents the capacitive gap within the housing such that liquid or gas passes between the capacitive gap and the housing.
22 . The implant of claim 21 , wherein the diaphragm is made of a glass material and the floating base is made of silicon.
23 . The implant of claim 22 , wherein the sensitivity to temperature is achieved by positioning the at least one open portion such that a coefficient of thermal expansion mismatch effect counteracts a gas expansion effect to reduce capacitive gap change due to temperature.