Flexible apparatus and method to enhance capacitive force sensing
First Claim
1. A force measuring device comprising:
- a sensor capacitor having a fixed surface and a movable surface substantially parallel to the fixed surface;
at least one spring assembly positioned between the fixed surface and the movable surface;
the at least one spring assembly to alter in height in response to a force applied perpendicular to the movable surface and to cause a change in a gap between the fixed surface and the movable surface;
a circuit to generate a measurement of the force based on an algorithm that considers a change in a capacitance of the sensor capacitor; and
a shielding spacer between the reference capacitor and a bottom layer to minimize an effect of a stray capacitance affecting the measurement.
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Accused Products
Abstract
A flexible apparatus and method to enhance capacitive force sensing is disclosed. In one embodiment, a force measuring device includes a sensor capacitor having a fixed surface and a movable surface substantially parallel to the fixed surface, at least one spring assembly (e.g., may deflect longitudinally and/or perpendicularly to a direction of the force) positioned between the fixed surface and the movable surface (e.g., the spring assembly may alter in height in response to a force applied perpendicular to the movable surface and to cause a change in the gap between the fixed surface and the movable surface), and a circuit to generate a measurement of the force based on an algorithm that considers a change in a capacitance of the sensor capacitor. A reference capacitor may adjust the measurement of the applied force based on one or more environmental conditions.
91 Citations
19 Claims
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1. A force measuring device comprising:
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a sensor capacitor having a fixed surface and a movable surface substantially parallel to the fixed surface; at least one spring assembly positioned between the fixed surface and the movable surface; the at least one spring assembly to alter in height in response to a force applied perpendicular to the movable surface and to cause a change in a gap between the fixed surface and the movable surface; a circuit to generate a measurement of the force based on an algorithm that considers a change in a capacitance of the sensor capacitor; and a shielding spacer between the reference capacitor and a bottom layer to minimize an effect of a stray capacitance affecting the measurement. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A force measuring device, comprising:
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a sensor capacitor having a fixed surface and a movable surface substantially parallel to the fixed surface; a fixed layer perpendicular to the fixed surface; at least one spring assembly positioned between the movable surface and the fixed layer to alter in height in response to a force applied adjacent to the movable surface, and to cause a change in an overlap area between the fixed surface and the movable surface; a circuit to determine a measurement based on an algorithm that considers a change in capacitance when the overlap area changes; and a shielding spacer between a reference capacitor adjacent to the sensor capacitor and a bottom layer of the force measuring device to minimize an effect of a stray capacitance affecting the measurement. - View Dependent Claims (8, 9, 10, 11)
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12. A method to measure force, comprising:
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positioning at least one spring assembly between a fixed surface and a movable surface; applying a force perpendicular to the movable surface to cause a change in the height of the at least one spring assembly and to cause a change in a gap between the fixed surface and the movable surface; automatically generating a measurement of a force based on an algorithm that considers a change in a capacitance between the fixed surface and the movable surface; and minimizing an effect of a stray capacitance affecting the measurement through a shielding spacer between a reference capacitor adjacent to the fixed surface and the movable surface and a bottom layer of a device encompassing the fixed surface, the movable surface, and the reference capacitor. - View Dependent Claims (13, 14, 15)
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16. A system to measure force, which comprises:
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means for positioning an elastic device between a movable surface and a fixed surface perpendicular to the movable surface; means for causing the elastic device to change form based on a force applied adjacent to the movable surface; means for automatically generating a measurement of the force based on a change in an overlap area between a fixed surface and the movable surface; and means for minimizing an effect of a stray capacitance affecting the measurement through a shielding spacer between a reference capacitor adjacent to the fixed surface and the movable surface and a bottom layer of a device encompassing the fixed surface, the movable surface, and the reference capacitor. - View Dependent Claims (17, 18, 19)
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Specification