Dual resistive strain and pressure sensor for force touch
First Claim
Patent Images
1. An electronic device comprising:
- an input layer defining an input surface;
a force-sensing stack coupled to the input layer and operable to detect a force applied to the input surface, the force-sensing stack comprising;
a strain sensor; and
a pressure sensor;
an additional component positioned below the force-sensing stack;
a compressible gap positioned between the input layer and the additional component and separate from the strain sensor and the pressure sensor; and
processing circuitry;
wherein the processing circuitry;
is coupled to the force-sensing stack to receive a first signal from the strain sensor and to receive a second signal from the pressure sensor;
determines, using at least one of the first signal and the second signal, whether compression of the compressible gap exceeds a threshold;
operates in an at least partial strain-sensing mode when compression of the compressible gap exceeds the threshold, the at least partial strain-sensing mode applying first different weights to values of the first signal and values of the second signal to estimate the force applied to the input surface; and
operates in an at least partial pressure-sensing mode when compression of the compressible gap does not exceed the threshold, the at least partial pressure-sensing mode applying second different weights to values of the first signal and values of the second signal to estimate the force applied to the input surface.
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Abstract
Structures and methods are disclosed for an electronic device having an input surface that uses dual sensors to measure forces applied to the input surface. The forces can be estimated over a greater range of values than would be possible with either sensor alone. A second sensor can be used after a first sensor has reached a limit. A first sensor can be a strain sensor and a second sensor a pressure sensor. Both sensors may be resistance based, with signals from both sensors can be combined and measured by processing circuitry. Each sensor type may be part of planar arrays disposed beneath the input surface.
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Citations
19 Claims
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1. An electronic device comprising:
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an input layer defining an input surface; a force-sensing stack coupled to the input layer and operable to detect a force applied to the input surface, the force-sensing stack comprising; a strain sensor; and a pressure sensor; an additional component positioned below the force-sensing stack; a compressible gap positioned between the input layer and the additional component and separate from the strain sensor and the pressure sensor; and processing circuitry; wherein the processing circuitry; is coupled to the force-sensing stack to receive a first signal from the strain sensor and to receive a second signal from the pressure sensor; determines, using at least one of the first signal and the second signal, whether compression of the compressible gap exceeds a threshold; operates in an at least partial strain-sensing mode when compression of the compressible gap exceeds the threshold, the at least partial strain-sensing mode applying first different weights to values of the first signal and values of the second signal to estimate the force applied to the input surface; and operates in an at least partial pressure-sensing mode when compression of the compressible gap does not exceed the threshold, the at least partial pressure-sensing mode applying second different weights to values of the first signal and values of the second signal to estimate the force applied to the input surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An electronic device comprising:
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a cover sheet defining an input surface; a strain sensor coupled to the input surface; a pressure sensor coupled to the input surface; an additional component separate from the strain sensor and the pressure sensor and positioned below the input surface; a compressible gap positioned between the additional component and the strain and pressure sensors; and processing circuitry operably connected to the strain sensor and the pressure sensor; wherein the processing circuitry is operable to; receive a first signal from the strain sensor and a second signal from the pressure sensor; determine, using at least one of the first signal and the second signal, whether compression of the compressible gap exceeds a threshold; operate in an at least partial strain-sensing mode when compression of the compressible gap exceeds the threshold, the at least partial strain-sensing mode applying first different weights to values of the first signal and values of the second signal to estimate a force applied to the input surface; and operate in an at least partial pressure-sensing mode when compression of the compressible gap does not exceed the threshold, the at least partial pressure-sensing mode applying second different weights to values of the first signal and values of the second signal to estimate the force applied to the input surface. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of estimating a force applied to an input surface of an electronic device, the method comprising:
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receiving at a processing circuitry a first signal from a strain sensor linked with the input surface; receiving at the processing circuitry a second signal from a pressure sensor; using the second signal to determine whether a deflection of the input surface has exceeded a threshold; when it is determined that the deflection has not exceeded the threshold, operating in an at least partial strain-sensing mode, the at least partial strain-sensing mode applying first different weights to values of the first signal and values of the second signal to estimate the force applied to the input surface; when it is determined that the deflection has exceeded the threshold, operating in an at least partial pressure-sensing mode, the at least partial pressure-sensing mode applying second different weights to values of the first signal and values of the second signal to estimate the force applied to the input surface. - View Dependent Claims (18, 19)
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Specification