Force sensor array having magnetostrictive magnetoresistive sensors and method for determining a force
First Claim
1. A force sensor having a layer sequence for determining a force acting on the layer sequence along a predefined force axis, the layer sequence comprising:
- a first magnetic layer with a first magnetization direction;
a separating layer; and
a second magnetic layer with a second magnetization direction, the first magnetic layer, separating layer, and second magnetic layer arranged successively in a vertical direction;
wherein the first magnetization direction is fixed with respect to the layer sequence;
wherein the second magnetic layer has a magnetostriction constant that is different from zero;
wherein the second magnetic layer has a uniaxial magnetic anisotropy with an anisotropy axis;
wherein the uniaxial magnetic anisotropy is generated using shape anisotropy;
wherein the second magnetization direction encloses an angle of more than 0° and
less than 90°
with the force axis in the quiescent state; and
wherein the anisotropy axis encloses an angle of more than 0° and
less than 90°
with the force axis.
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Abstract
The invention relates to a force sensor having a layer sequence for determining a force acting on the layer sequence along a predefined force axis. The layer sequence includes, arranged successively in a vertical direction, a first magnetic layer with a first magnetization direction, a separating layer and a second magnetic layer with a second magnetization direction. Here, the first magnetization direction is secured with respect to the layer sequence. The second magnetic layer has a magnetostriction constant that is different from zero and a uniaxial magnetic anisotropy with an anisotropy axis. The uniaxial magnetic anisotropy is generated using shape anisotropy. The second magnetization direction encloses an angle of more than 0° and less than 90° with the force axis in the quiescent state, and the anisotropy axis encloses an angle of more than 0° and less than 90° with the force axis.
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Citations
24 Claims
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1. A force sensor having a layer sequence for determining a force acting on the layer sequence along a predefined force axis, the layer sequence comprising:
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a first magnetic layer with a first magnetization direction;
a separating layer; and
a second magnetic layer with a second magnetization direction, the first magnetic layer, separating layer, and second magnetic layer arranged successively in a vertical direction;
wherein the first magnetization direction is fixed with respect to the layer sequence;
wherein the second magnetic layer has a magnetostriction constant that is different from zero;
wherein the second magnetic layer has a uniaxial magnetic anisotropy with an anisotropy axis;
wherein the uniaxial magnetic anisotropy is generated using shape anisotropy;
wherein the second magnetization direction encloses an angle of more than 0° and
less than 90°
with the force axis in the quiescent state; and
wherein the anisotropy axis encloses an angle of more than 0° and
less than 90°
with the force axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A force sensor array comprising:
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a first layer sequence of a first force sensor comprising a first magnetic layer with a first magnetization direction, a separating layer, and a second magnetic layer with a second magnetization direction, wherein the first magnetization direction is fixed with respect to the layer sequence, the second magnetic layer has a magnetostriction constant that is different from zero, the second magnetic layer has a uniaxial magnetic anisotropy with an anisotropy axis, the uniaxial magnetic anisotropy is generated using shape anisotropy, the second magnetization direction encloses an angle of more than 0° and
less than 90°
with the force axis in the quiescent state, and wherein the anisotropy axis enclosing an angle of more than 0° and
less than 90°
with the force axis;
a second layer sequence of a second force sensor;
wherein the first and second force sensors are arranged on a common carrier in such a way that when the carrier is deformed mechanically the first layer sequence has a higher electrical resistance than in the quiescent state, and the second layer sequence has a lower electrical resistance than in the quiescent state. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method for determining a mechanical force acting on a carrier of a force sensor array comprising:
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providing a force sensor array, the force sensor array comprising;
a first layer sequence of a first force sensor comprising a first magnetic layer with a first magnetization direction, a separating layer, and a second magnetic layer with a second magnetization direction, wherein the first magnetization direction is fixed with respect to the layer sequence, the second magnetic layer has a magnetostriction constant that is different from zero, the second magnetic layer has a uniaxial magnetic anisotropy with an anisotropy axis, the uniaxial magnetic anisotropy is generated using shape anisotropy, the second magnetization direction encloses an angle of more than 0° and
less than 90°
with the force axis in the quiescent state, and wherein the anisotropy axis enclosing an angle of more than 0° and
less than 90°
with the force axis;
a second layer sequence of a second force sensor; and
wherein the first and second force sensors are arranged on a common carrier in such a way that when the carrier is deformed mechanically the first layer sequence has a higher electrical resistance than in the quiescent state, and the second layer sequence has a lower electrical resistance than in the quiescent state;
deforming the common carrier by means of a mechanical force acting on it;
providing a supply voltage connected between a first connecting point and a fourth connecting point;
determining an output voltage present between the second connecting point and a third connecting point;
providing a characteristic curve which represents the relationship between the output voltage and the force acting on the common carrier; and
determining the force acting on the common carrier by using the output voltage which has been determined from the characteristic curve.
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Specification