MONOLITHIC CAPACITIVE TRANSDUCER
First Claim
1. A capacitive transducer, comprising:
- a substrate having a first surface and a second surface, the first surface defining a first plane, the substrate having a cavity with an interior peripheral edge, the cavity extending between the first surface and the second surface;
a body having an exterior peripheral edge, the body being parallel to the first plane and at least partially blocking the cavity, the body being connected to the substrate by resilient hinges such that, upon the application of a force, the body moves perpendicular to the first plane;
a first set of comb fingers mounted to the substrate, the first set of comb fingers being connected to a first electrical connection;
a second set of comb fingers mounted to the body and extending past the exterior peripheral edge of the body, the second set of comb fingers being connected to a second electrical connection that is isolated from the first connection, the first set of comb fingers and the second set of comb finger being interdigitated such that as the body moves, the first set of comb fingers and the second set of comb finger maintain a relative spacing, the first set of comb fingers and the second set of comb fingers defining a capacitance, the capacitance being related to the relative position of the first set of comb drive fingers and the second set of comb drive fingers.
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Accused Products
Abstract
A capacitive transducer includes a substrate having a first surface and a second surface. The first surface of the substrate defines a first plane. The substrate has a cavity with an interior peripheral edge. The cavity extends between the first surface and the second surface. A body is provided that has an exterior peripheral edge. The body is parallel to the first plane and at least partially blocking the cavity. The body is connected to the substrate by resilient hinges such that, upon the application of a force, the body moves perpendicular to the first plane. A first set of comb fingers is mounted to the substrate. The first set of comb fingers is connected to a first electrical connection. A second set of comb fingers is mounted to the body and extends past the exterior peripheral edge of the body. The second set of comb fingers is connected to a second electrical connection that is isolated from the first connection. The first set of comb fingers and the second set of comb finger are interdigitated such that as the body moves, the first set of comb fingers and the second set of comb finger maintain a relative spacing. The first set of comb fingers and the second set of comb fingers define a capacitance. The capacitance is related to the relative position of the first set of comb drive fingers and the second set of comb drive fingers.
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Citations
25 Claims
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1. A capacitive transducer, comprising:
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a substrate having a first surface and a second surface, the first surface defining a first plane, the substrate having a cavity with an interior peripheral edge, the cavity extending between the first surface and the second surface; a body having an exterior peripheral edge, the body being parallel to the first plane and at least partially blocking the cavity, the body being connected to the substrate by resilient hinges such that, upon the application of a force, the body moves perpendicular to the first plane; a first set of comb fingers mounted to the substrate, the first set of comb fingers being connected to a first electrical connection; a second set of comb fingers mounted to the body and extending past the exterior peripheral edge of the body, the second set of comb fingers being connected to a second electrical connection that is isolated from the first connection, the first set of comb fingers and the second set of comb finger being interdigitated such that as the body moves, the first set of comb fingers and the second set of comb finger maintain a relative spacing, the first set of comb fingers and the second set of comb fingers defining a capacitance, the capacitance being related to the relative position of the first set of comb drive fingers and the second set of comb drive fingers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of manufacturing a capacitive transducer comprising the steps of:
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applying a first etching mask on a layer to define the position of one of a movable set of fingers and a fixed set of fingers, the layer being mounted to a substrate; applying a second etching mask to define the movable set of fingers, the fixed set of fingers, a body, and springs, the body being connected to the movable set of fingers and the springs, the movable set of fingers being interdigitated with the fixed set of fingers; etching the layer and the first etching mask using the second etching mask; removing the second etching mask; etching the layer using the etched first etching mask such that one of the movable set of fingers and the fixed set of fingers is shorter than the other of the movable set of fingers and the fixed set of fingers; and releasing the body, the springs, and the movable set of fingers using etching, such that, upon applying a force to the body, the body moves parallel to the substrate. - View Dependent Claims (22, 23, 24, 25)
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Specification