Sensor array comprising soft force sensors

Abstract

A sensor array for measuring a force is provided. The sensor array includes a plurality of soft sensor elements, each comprising: a sensor; a deformable element, the deformable element being deformable due to a force; and at least one element for interacting with the sensor for measuring a force by deformation of the deformable element, the deformable element extending at least partially between the sensor and the at least one element. Further, a method for measuring a force using the sensor array is provided.

Description

Technical Field

[0001] The invention of the present application relates to a sensor array comprising an arrangement of soft force sensors, and a corresponding method for measuring force or position using the sensor array. Background Art

[0002] The force sensor returns an electronic signal proportional to the mechanical force applied to the sensor. In other words, the force sensor converts the magnitude of the applied force into a related electronic signal. The measured force can be a mechanical quantity such as tension, pressure, weight, torque, strain, and internal stress. Force sensors have become an indispensable core component of power equipment, engineering machinery, various working machines, and industrial automation systems.

[0003] Today, force sensors have a wide range of applications, from the automotive industry to the medical field.

[0004] For example, using existing force sensors, the force applied to a workpiece during an automated manufacturing process can be measured in real time to control the force applied to the workpiece. In this way, the force load on the workpiece can be controlled and potentially limited during the manufacturing process. This is particularly important when the workpiece is sensitive.

[0005] However, measuring force may also be important when the stiffness of an object should be determined, since stiffness is defined as how much an object resists deformation in response to an applied force.

[0006] Typically, force sensors are used with multi-axis robotic devices to move, position, hold or sense objects. For example, a multi-axis robotic device may include a robotic finger or a gripper. A robotic finger is similar to a humanoid finger, but may be movable in more directions. A force sensor may be applied at the tip of the finger, which allows sensing of the object. A gripper is a mechatronic device that applies a force and a corresponding reaction force to an object. Thus, the force and reaction force press the object against a corresponding portion of the gripper, causing the object and the corresponding gripper portion to come into contact.

[0007] However, sensors used in the prior art suffer from the disadvantage that the force applied to the object is not measured with sufficient accuracy. This may cause damage to the object due to either too much force or too little force. Both need to be prevented, so accurate force measurement is necessary.

[0008] In all fields of application, the shape of the workpiece, object or tissue on which the force is applied may be irregular. The force that may be applied to the object then needs to adapt to the shape. It is therefore necessary to measure the force applied to the object over a larger surface area and not just punctually. For some applications, it may even be necessary to use a sensor that can adapt to the irregular shape itself. Summary of the invention

[0009] The sensor array for measuring force according to the present invention solves the above needs. The sensor array comprises a plurality of soft sensor elements. A plurality as used throughout the present disclosure comprises any number of two or more elements.

[0010] The soft sensor element according to the present invention comprises a sensor, a deformable element, and at least one element for acting with the sensor. The sensor can be an integrated circuit, a semiconductor die, a bare die, an unpackaged chip, or an unpackaged integrated circuit. The sensor can be enclosed by a deformable element, which can provide passivation and sealing of the sensor, which avoids the use of any lead frame or overmolding of the sensor. This allows the sensor array to be flexible and allows the sensor array to be formed in different shapes. The element for acting with the sensor can be composed of a single element or multiple elements. Multiple elements can include elements of similar shape and / or similar size, or elements of different shapes and different sizes.

[0011] The deformable element may be deformable and may extend at least partially between the sensor and the element. Thus, the deformable element may also include a pocket forming a certain free space into which the material of the deformable element does not extend. The free space may be filled with air, an ambient medium or an inert gas. The pocket still forms part of the deformable element so that even if the free space is between the element and the sensor, the deformable element still extends between the element and the sensor. In such an arrangement, it can also be said that the element and / or the sensor may extend partially or completely into the free space of the deformable element. It can also be said that the element is partially embedded in or attached to the wall of the formed pocket.

[0012] An element is deformable when it undergoes a change in shape and / or volume when an external force acts on it. Preferably, deformable means that the deformable element undergoes elastic deformation, that is, once the external force is no longer acting on the element, the element returns to its original shape and / or volume. The deformable element can be an elastic element and can include an elastomer. In some cases, the elastomer can be a biocompatible elastomer, which allows the soft sensor array to be used in medical applications. In some cases, the deformable element can form a bag into which the deformable element can extend when the deformable element is deformed due to an external force. For example, when an external force causes a substantial deformation of the deformable element, a portion of the deformable element may be displaced by the force and may extend into a bag in the bag. Thus, the bag is a hollow space into which the material of the deformable element can extend when deformed. The formation of the bag not only has the advantage of allowing the deformable element to extend therein, but can also be used to provide some stability to the deformable element.

[0013] Furthermore, the deformable element not only provides the element with the ability to move to a certain extent and change its position when a force is applied, but also can seal and possibly electrically isolate the sensor, and accordingly the sensor chip, so that packaging of the sensor chip is unnecessary, which makes it possible to have very thin sensor arrays, which are also flexible themselves. A further advantage is that the sensor chips of different soft sensor elements can be arranged closer to each other, since there is no packaging around each chip, which inherently increases the spatial resolution of the sensor array.

[0014] During operation, the object applies a force to the soft sensor element. Technically, it also covers the case where the soft sensor element is pressed against the object so that the soft sensor element applies a force to the object, but in the present disclosure, no distinction will be made between these two cases, because in both cases, the forces are the same in amount, but only in two opposite directions. Thus, either the element for acting with the sensor or the deformable element can be in contact with the object. The contact can be direct or indirect. The element for acting with the sensor or the deformable element can thus be in contact with the object directly or indirectly. In the case of direct contact, at least one surface of the element for acting with the sensor or the deformable element touches at least one surface of the object. In the case of indirect contact, at least some other parts are between the contact surfaces. For the element for acting with the sensor, this can be the deformable element itself, so that the element for acting with the sensor is in indirect contact with the object, but the deformable element is in direct contact. In this case, it can also be said that the element for acting with the sensor is embedded in the deformable element. Thus, the element for acting with the sensor can be partially or completely embedded in the deformable element. In the latter case, all surfaces of the element for interacting with the sensor are in contact with the deformable element. It can also be said that the material of the deformable element surrounds the element for interacting with the sensor. Conversely, if the deformable element is in indirect contact with the object, the element for interacting with the sensor can be in direct contact with the object. However, it is also covered that other parts are in direct contact with the object, while the element for interacting with the sensor and the deformable element are only in indirect contact with the object. For example, the element for interacting with the sensor can be embedded in a plastic part that is in contact with the deformable element. In another example, the plastic part still contacts the deformable element and the object, but the element for interacting with the sensor is embedded in the deformable element, or the element contacts the deformable element and the plastic part. In all three cases, the object will directly contact the plastic part, but neither the element for interacting with the sensor nor the deformable element.

[0015] Since the deformable element at least partially extends between the sensor and the element or even surrounds the element, it holds the element in a specific position relative to the sensor. This position can be defined as a first position of the element relative to the sensor. It can also be said that the deformable element holds the element at a specific distance from the sensor. If the deformable element is deformed, the element itself performs a coaligned movement in the deformation direction of the deformable element. If the deformation is compression, the distance from the element to the sensor is reduced; and if the deformation is tension, the distance is increased.

[0016] The deformation of the deformable element means that at least one spatial extension of the deformable element in at least one corresponding spatial dimension is changed. Thus, the deformable element of the sensor arrangement can be soft in the sense that it is deformable. The deformability (and in particular how much the deformable element can be deformed) depends on the material used for the deformable element. For example, the deformable element can be made of a flexible material. A flexible material is a material that returns to its initial shape once an external force is released. Therefore, if any external force is released, the deformable element can return to its initial shape. Therefore, the deformable element can also be referred to as a flexible element or an elastic element. In another example, the deformable element can be an elastomer. Elastomers are typically made of monomers linked by weak intermolecular forces. Due to the weak intermolecular forces of the chemical elements of the elastomer, changes in the conformation of the compound are possible without destroying the covalent bonds or only partially destroying the covalent bonds. This causes the elastomer to be viscous and elastic at the same time. Therefore, the elastomer can be deformed by an external force.

[0017] The deformation of the deformable element causes the element for interacting with the sensor to move to a second position different from the first position. If the deformable element is compressed, the second position of the element is closer to the sensor than the first position of the element. If tension is applied, the second position of the element is further away from the sensor than the first position. The change in position can be detected by the sensor of the sensor arrangement interacting with the element. When interacting with the sensor, the element affects the measurement of the sensor. It can also be said that the element is coupled to the sensor by a physical effect, which is a characteristic of the sensor and the element. This coupling of the element to the sensor depends on the position of the element relative to the sensor. It can also be said that by position-dependent coupling, the measurement of the sensor is a unique function of the position of the element relative to the sensor. In this sense, it can be said that the sensor used in the soft sensor element is a distance measuring sensor. Such sensors return an electronic signal that is proportional to the position of the element relative to the sensor.

[0018] If no external force is applied to the soft sensor element, the deformable element is not deformed, and the element is located at a first position relative to the sensor. Therefore, a first signal can be measured by the sensor, which corresponds to a zero force measurement. If a limited external force is applied to the element, the deformable element is deformed, and the element moves to a second position different from the first position. The second position of the element relative to the sensor generates a second signal of the sensor, which corresponds to the applied external force. Therefore, the spatial difference between the first position and the second position can be uniquely mapped to the corresponding applied external force. The spatial difference covers any axial and / or rotational differences between the two positions. The spatial difference can also be referred to as the displacement of the element. The mapping can be done using a nonlinear model because the force may not be proportional to the displacement of the element, but follows a nonlinear function. Since the change in the interaction between the element and the sensor can be measured with high accuracy, the applied force can be measured, derived, calculated or estimated with high accuracy. In other words, the change in the effect of the element on the sensor allows the external stimulus that causes the change, i.e., the applied external force, to be inferred. For example, as described above, the sensor can be sensitive to the displacement of the element relative to the sensor.

[0019] The soft sensor element can use a magnetic field to measure a change in the position of the element for interacting with the sensor. The magnetic field can be a magnetic field caused by a permanent magnet (e.g., the element for interacting with the sensor can be a permanent magnet), or it can be a magnetic field induced by a change in an electric field (e.g., the sensor can generate a magnetic field that couples with the element for interacting with the sensor (e.g., through the generation of eddy currents in the element)).

[0020] According to the present invention, multiple soft sensor elements are arranged in a sensor array. Such an arrangement not only allows the force acting on a single sensor to be accurately measured, but also how the force acts on multiple sensors can be measured. For example, since the sensor array is spatially sensitive, the spatial distribution of the applied force can be measured with high precision. This allows locating the location where the applied force exceeds a threshold, or when the sensor array performs continuous measurements or multiple measurements in discrete time instances, thereby allowing the sensor array to identify how the applied force changes over time or propagates over time. Since the deformable element can provide passivation and / or sealing of the sensor, adjacent soft sensor elements can be placed close to each other, which provides high resolution for force determination and can even determine the location of the applied force.

[0021] One of the benefits of the present invention is that the sensor array allows to be folded or rolled due to the deformable element, so that the sensor array can be adjusted to match any surface.

[0022] Due to its deformability, the sensor array according to the invention is particularly suitable for measuring forces applied to objects of arbitrary shape. This can be the case not only in the automotive industry, but also in medical applications. For example, in palpation in minimally invasive surgery, because it allows the absolute or relative hardness of an object or a part of an object to be determined. Thereby, hardness is the degree to which an object resists deformation in response to an applied force. Based on the measurement, abnormal tissue formations can be identified, which requires high resolution in order to identify even small anomalies. By being foldable or rollable, the sensor array can be adjusted to arbitrary surfaces, such as the outer surfaces of diagnostic devices and instruments, or even to the surface of a glove used by a surgeon.

[0023] In order to further improve the spatial sensitivity of the sensor array, multiple soft sensor elements can be distributed in space in a predetermined manner. In a preferred embodiment of the present invention, the soft sensor elements in the multiple soft sensor elements are arranged in a line. For example, the sensor array can have a spatial extension along a spatial direction, and then the soft sensor elements can be arranged in a line parallel to the spatial direction. This allows measuring how an applied force acts along a line defined by multiple soft sensor elements, or how an applied force propagates along the line.

[0024] In another preferred embodiment of the present invention, the soft sensor elements in a plurality of soft sensor elements are arranged in a grid. The grid may be a two-dimensional grid. The grid may be a so-called regular grid with a structured topology. Such regular grids may be formed by parallel and orthogonal lines, such as a Cartesian grid in which the cross lines form a 90-degree angle. In other regular grids, it is also possible that the cross lines form other angles, such as in a hexagonal grid or a diamond grid. Alternatively, the grid may be an irregular grid.

[0025] In a grid, the soft sensor elements may be arranged in a plane. Alternatively, the grid may be curved (e.g., convex or concave). It is also possible that the soft sensor elements of the sensor array are arranged in a planar grid and may be foldable into a curved shape. In this case, it can also be said that the grid spans or covers the surface on which the sensor array is applied.

[0026] Compared to the aforementioned embodiment examples in which a plurality of soft sensor elements are arranged along a line, the grid-like arrangement allows the distribution of applied forces or the propagation of applied forces along two spatial directions (i.e., the two spatial directions spanned by the grid) to be measured. In addition, more complex arrangements corresponding to three-dimensional configurations can be used. For example, the sensor array can be configured on a curved surface. The curved surface can be convex or concave. One example is a spherical arrangement. For example, the sensor array can be arranged on the fingertips of a robotic gripper and can be smoothly adjusted to the shape of the fingertips so that the deformable elements form an outer layer that allows the gripping force of the gripper to be registered. The sensor arrangement can also be adapted to at least partially cover the surface of the glove. It can also be possible that a spherical or otherwise shaped sensor array can wrap an element so that the element is located inside the wrapped surface so that the movement of the enclosed element can exert a force on the deformable element.

[0027] In some preferred embodiments of the present invention, a plurality of soft sensor elements may be arranged on a substrate. For example, the substrate may be a carrier substrate such as a printed circuit board (PCB). Sensors of a plurality of soft sensor elements may be mounted on a substrate. Thus, a flip chip design may be used, which means that the sensor is a die with an active side, and the active side is placed on a substrate. In this regard, the active side refers to the side of the sensor including the circuit system and the connection to the external circuit system. The active side may also be configured to record the displacement of an element for acting with the sensor. However, it is also contemplated that the sensor is mounted on the substrate with its non-active side and is connected to the circuit system of the substrate via wire bonding. In addition, it may also be possible that the active side may not be configured to also record the displacement of an element for acting with the sensor, and in fact, the sensor may include a side for connecting to the substrate and an opposite side for recording the displacement. In this case as well, the active side may be directly connected to the substrate with a flip chip design, or the side may be facing away from the substrate and may be connected to the substrate via wires.

[0028] Sometimes, it may be desirable that the sensor array can be folded or rolled, for example, in order to allow the sensor array to smoothly adjust its surface to the surface of an arbitrarily shaped object, or to allow the sensor array to be clamped around an object, or mounted on a device (e.g. a medical device) or a (non-planar) fixture. In this case, a thin sensor array may be desired. Thus, the thickness of the substrate may be approximately 60 μm to 600 μm, while the thickness of the deformable element may be approximately 4 mm. Preferably, the ratio between the thickness of the substrate and the thickness of the deformable element is 0.1% to 15%, more preferably 1% to 5%.

[0029] In some preferred embodiments of the present invention, the spacing between two adjacent elements of the plurality of soft sensor elements may be equidistant. For example, the spacing from the center point of a soft sensor element to the center point of an adjacent soft sensor element may be measured. Alternatively, the spacing from the edge of a soft sensor element to the corresponding edge of an adjacent soft sensor element may be measured. Figure 4 ) describes this aspect in more detail. The equidistant spacing allows for measurements of the spatial characteristics of the applied force to be provided at a particular resolution associated with the equidistant spacing.

[0030] Further, each soft sensor element may have a specific size, for example represented by the length or diameter of the edge of the sensor. Preferably, each sensor of the soft sensor element has the same size. Using soft sensor elements of the same or similar type improves the spatial resolution of the measurement performed by the sensor array. The size of the sensor may be represented as L. The spacing p between two adjacent soft sensor elements in a plurality of soft sensor elements may be given as p≤3L, or preferably, p≤2L or p≤1.5L. Therefore, in some examples, the spacing may be 1.1, 1.5, 2 or 3 times the size of the soft sensor element. In other words, the spacing of the arrangement of the soft sensor elements has the same ratio as the size of the soft sensor elements, which allows the generation of a sensor array with high resolution - the resolution is inversely proportional to the spacing. Since the deformable element can provide passivation and sealing of the sensor, adjacent soft sensor elements can be placed in very close positions, which allows high resolution to be achieved.

[0031] In another further embodiment of the present invention, the sensor of each of the plurality of soft sensor elements may be a multi-pixel sensor. A multi-pixel sensor may have more than one sensitive element capable of recording a change in the position of an element for interacting with the sensor. For example, a multi-pixel sensor may have two sensitive elements (hereinafter also referred to as pixels). Preferably, the multi-pixel sensor may have four sensitive elements arranged in a 2×2 grid, while also covering other numbers of sensitive elements, such as but not limited to 1×2, 2×3 or 3×3 grids. In a multi-pixel sensor, two or more sensitive elements may be located on the same die. The use of a multi-pixel sensor may improve the spatial resolution of the sensor array and may even reduce the effects caused by external influences other than the applied force. For example, when a soft sensor element uses a magnetic field to measure a change in the position of an element for interacting with the sensor, the effects caused by the external magnetic field may be reduced by measuring the differential field.

[0032] Thus, each sensitive element of the multi-pixel sensor can be configured to determine a force acting on the deformable element and / or the location of the force. The location of the force can be determined based on a gradient or difference in data obtained from two or more sensitive elements of the one or more multi-pixel sensors. Advantageously, the influence of external stray fields can be reduced or even eliminated.

[0033] Adjacent pixels of the multi-pixel sensor may have a first spacing s1. A second spacing s2 between the last pixel of the multi-pixel sensor of the first sensor element and the first pixel of the multi-pixel sensor of the adjacent second sensor element may be less than or equal to the first spacing s1. In this way, a homogeneous arrangement of sensitive elements is achieved. For example, in the case of using multiple 1×2 multi-pixel sensors, the first spacing s1 refers to the spacing between two adjacent sensitive elements of one 1×2 multi-pixel sensor. The second spacing s2 refers to the spacing between the second sensitive element of the first 1×2 multi-pixel sensor and the first sensitive element of the second 1×2 multi-pixel sensor. The same applies to 2×2 multi-pixel sensors and other grid-like multi-pixel sensors, where the first spacing and the second spacing can be applied in both directions of the grid spanned by the 2×2 sensitive elements. Ensuring that the first spacing s1 is identical to the second spacing s2 allows ensuring a homogeneous resolution of the sensor array.

[0034] In some preferred embodiments, the pitch p between adjacent sensors may be related to the spacing s1 between sensitive elements of the multi-pixel sensor. For example, the pitch p may be p≤3s1.

[0035] In another preferred embodiment of the present invention, a plurality of soft sensor elements may be embedded in a common deformable element. In other words, a plurality of soft sensor elements may share a common deformable element.

[0036] However, in some cases, the use of a common deformable element may suffer from so-called crosstalk between adjacent soft sensor elements when a force applied at a first position causes the deformable element to continue to deform at a second position a short distance from the first position. Since this type of crosstalk is caused by the mechanical coupling of adjacent soft sensor elements via the common deformable element, in some preferred embodiments, the sensor array may have mechanically decoupled parts. For example, a subset of a plurality of soft sensor elements is arranged in at least two parts of the sensor array, and the at least two parts may be mechanically decoupled. For example, mechanical decoupling of the sensor array may be performed by separating parts of the sensor array by recesses in the common deformable element. In this way, deformation of the deformable element in the first part does not cause deformation of the deformable element in the adjacent second part. This ensures that a part of the deformable element will only deform when an external force is applied to the part. Since the recess hinders further propagation, the deformation will not propagate through the common deformable element. Because the recess separates the deformable element into parts, it can also be said that the common deformable element includes pillars, wherein each pillar corresponds to a part separated from other parts by one or more recesses. The pillars may form a line where two or more recesses are arranged substantially parallel to each other, or in another example, the pillars may form a grid when two or more recesses are arranged in a grid.

[0037] In a preferred embodiment, the soft sensor array may comprise a plurality of sections, and each section comprises only one soft sensor element. In this case, a high spatial resolution with minimal crosstalk may be obtained.

[0038] In another preferred embodiment of the present invention, the sensor of the soft sensor element can be a passive magnetic sensor, and the element for acting with the sensor can be a magnetic field emitting element, such as a permanent magnet. A magnetic sensor is a sensor that measures at least one attribute of a magnetic field emitted by an element. By passive magnetic sensor, it is meant that the sensor detects at least one attribute of a magnetic field caused by an element, but does not create a magnetic field to be measured by itself. In general, a magnetic field is a vector field. This means that at each point in space, the magnetic field is characterized by a three-dimensional vector of magnetic field strength. A passive magnetic sensor can measure one or more magnetic fluxes obtained by projecting a magnetic field vector onto one or more surfaces associated with the passive magnetic sensor. Therefore, it can be said that at least one attribute measured is the magnetic flux through the corresponding surface. The measured magnetic flux is proportional to the density of magnetic field lines that pass through the corresponding surface and cut the corresponding surface at an orthogonal angle. Each of the magnetic fluxes passing through the corresponding surface causes the passive magnetic sensor to output a corresponding signal, such as a current or a corresponding voltage signal. Specifically, the output signal can be proportional to the distance from the element to the sensor. If the element changes its position, the magnetic field lines change their position. In this way, the positional change of the element directly leads to a change in the magnetic flux measured at the passive magnetic sensor. The output signal then either gives a direct indication of how the element has changed its position, or can be further processed or combined for determining the position of the element relative to the sensor. Thus, the algorithm for determining the position of the element from the measured flux signal can rely on the difference between the signals and / or calculate the gradient based on the signal measured for the element that is displaced in the case of a deformed deformable element, and the signal measured for the element in its initial position in the case of an undeformed deformable element. Then, another algorithm can be used to infer the externally applied force from the position determined by the algorithm. However, the externally applied force can also be inferred directly from the measured flux signal without calculating the position of the element as an intermediate value. In general, it can be said that a change in the interaction of the element with the passive magnetic sensor causes a change in at least one attribute of the magnetic field measured by the passive magnetic sensor. The algorithm can then be used to infer the external force responsible for the change in the interaction from at least one attribute measured of the magnetic field.

[0039] In addition, or as an alternative, the flux gradient can be measured directly using a transducer that is sensitive to the magnetic field gradient. The use of the difference or the use of the gradient enables a stray field immune position determination because the effects of static stray magnetic fields are eliminated when the measured signal is subtracted. In addition to the magnetic flux, or as an alternative to the magnetic flux, the passive magnetic sensor can also measure the orientation of the vector of the magnetic field strength. The orientation of the vector measuring the magnetic field strength produces one or more angles, thereby describing the orientation of the magnetic field in space. Based on this orientation, the force applied to the deformable element can be derived. It is also possible to derive the angle at which the object deforms the deformable element by using the change in the orientation of the element relative to the sensor. In other words, whether the applied force is uniform or non-uniform.

[0040] A passive magnetic sensor may comprise at least one sensor element which measures at least one physical property of a magnetic field. The at least one sensor element may be a magnetoresistive sensor or a Hall sensor, or any other device suitable for measuring at least one property of a magnetic field emitted by the element.

[0041] In another preferred embodiment of the present invention, the sensor of the soft sensor element may be an active magnetic sensor, and the element may be a target. The active magnetic sensor measures at least one physical property of a magnetic field. Thus, compared to the passive magnetic sensor described above, the active magnetic sensor itself creates at least one magnetic field. In other words, the active magnetic sensor does emit a magnetic field itself. The magnetic interaction of the emitted magnetic field with the target is observed by the active magnetic sensor. The active magnetic sensor may include a sensor element configured to both generate a magnetic field and measure changes in the magnetic field caused by the target. For example, a sensor element may be suitable for acting as a generator of a magnetic field in a first time interval and as a detector of changes in the magnetic field caused by the target in a second time interval. Alternatively, the active magnetic sensor may also include at least two sensor elements-at least two sensor elements may be either different sensor elements or sensitive elements of a multi-pixel sensor as described above. Thus, at least one of the at least two sensor elements may be configured to generate a magnetic field, and at least another of the at least two sensor elements may be configured to measure changes in the magnetic field caused by the target. The sensor element configured to measure at least one physical property may be similar to the sensor element of the passive magnetic sensor described above. Thus, the sensor element may be configured to measure properties of a magnetic field, a magnetic field gradient, and / or a differential magnetic field.

[0042] The generated magnetic field is affected by the target, and at least one physical property of the affected magnetic field is measured by a sensor element configured to measure at least one physical property. The shape of the target may not be rotationally invariant. Specifically, the target may be planar or nearly planar. Thus, the target may have a shape that affects the magnetic field in a preferred direction, which shape may be substantially the same for the entire target. For example, the target may be configured so that the induced current preferably flows in a specific linear direction, so that the effect of the target on the generated magnetic field is also directional. To this end, the target may include at least one slit extending from one end of the target to the other end of the target. However, different target designs are equally possible.

[0043] It can also be said that the target affects the magnetic flux coupling between the generator of the magnetic field and the detector that measures at least one physical property of the magnetic field. The target can include a soft magnetic material or a non-magnetic conductive material. Thus, a soft magnetic material means that the magnetic material of which the target is made can be easily magnetized and demagnetized. It can also be said that a soft magnetic material is characterized by: if the external magnetic field is removed, its magnetization decays rapidly over time. Soft magnetic materials can have higher relative permeability and / or lower coercivity. Coercivity (also known as magnetic coercivity, coercive field or coercivity) is a measurement of the ability of a ferromagnetic material to withstand an external magnetic field without becoming demagnetized. Ferromagnetic materials with high coercivity are called hard magnetic materials and are used, for example, to make permanent magnets. Materials with low coercivity are considered to be soft magnetic. It can also be said that a soft magnetic material can have a lower residual magnetization. Typically, but not limited to, if the coercivity of a magnetic material is less than 1000 A / m, it is called a soft magnetic material. However, the latter should only be used as an example and should not be understood as limiting.

[0044] If the target is made of a soft magnetic material, the target may affect the magnetic flux coupling by concentrating the magnetic field lines of the generated magnetic field. The soft magnetic material may consist of an isotropic material that is not characterized by any preferred direction. If the target is made of a non-magnetic conductive material, the energy may be dissipated by induced currents in the conductive material of the target. The induced currents may be eddy currents. In this case, the target affects the magnetic flux coupling by introducing magnetic field losses generated due to dissipation. Optionally, the form of the target may be such that the magnetic field lines of the generated magnetic field are aligned in a preferred direction. Additionally or alternatively, it can also be said that the target may act as a magnetic field line rectifier, which aligns the magnetic field lines in a preferred direction. If the target is positioned and / or oriented so that the preferred direction of the magnetic field lines is in the direction of the sensor element measuring at least one physical property, the at least one physical property measured will have a maximum value.

[0045] In another preferred embodiment of the present invention, the sensor array may include a plurality of additional elements that act on the sensor. The additional element may be, for example, an additional magnet or an additional target. The additional element may be located between elements that act on the sensors of two adjacent soft sensor elements. For example, when a plurality of soft sensor elements are arranged in the sensor array, the additional element may be located at a position between adjacent soft sensor elements. If additional elements are used, they are preferably placed between each pair of adjacent soft sensor elements. However, it is also contemplated that only some adjacent pairs of soft sensor elements have additional elements between them. In this case, there may be regularity between pairs with additional elements in the middle and pairs without such additional elements in the middle.

[0046] In case the additional elements are magnetic elements, they may have a magnetization different from the magnetization of the elements of the soft sensor element. Alternatively, they may be made of another magnetic material different from the elements used to interact with the sensor of the soft sensor element. The other magnetic material may have different magnetic properties (e.g. magnetic permeability) that are different from the magnetic properties of the elements used to interact with the sensor.

[0047] In case the additional elements are targets, they may have different electrical or magnetic properties than the targets used in the soft sensor elements.

[0048] In another preferred embodiment of the present invention, the sensor array may include one or more evaluation circuits. One or more evaluation circuits may be configured to receive at least one signal from one or more sensors and to evaluate the signal to derive, calculate or estimate the applied force. Thus, each soft sensor element may include a separate evaluation circuit that outputs the force applied to the sensor element. In some embodiments, the signals provided by these multiple evaluation circuits may then be forwarded to a common evaluation circuit of the sensor array for further processing, or may be directly forwarded to an external circuit system.

[0049] Alternatively or additionally, the sensor array may also include a common evaluation circuit, which is connected to a plurality of soft sensor elements and may be configured to communicate with a plurality of soft sensing elements. In this sense, communication means that the evaluation circuit is configured to receive signals from a plurality of soft sensor elements or to read data from a plurality of soft sensor elements. Thus, the data may already be the force applied to each soft sensor element, in case they cover their own evaluation circuits or raw data, thereby threatening the data provided by the sensor. The common evaluation circuit may be further adapted to either only forward data collected from a plurality of soft sensor elements, or to evaluate the data itself to derive the force applied to the sensor array. Thus, the common evaluation circuit may perform the calculations required to determine the distance, position, etc. of the element acting on the sensor, thereby realizing force measurement. Further, the evaluation circuit may perform differential measurements between adjacent soft sensor elements or sensitive elements of a multi-pixel sensor, and may also be used to drive the sensor, such as when an active magnetic sensor is used.

[0050] Where a multi-pixel sensor is used, the evaluation circuit may be configured to calculate the force based on multiple signals from the multi-pixel sensor (e.g., based on a difference, a sum, or a combination). As mentioned above, one or more evaluation circuits may be configured to determine the location of the applied force based on a gradient or difference in data provided by two or more sensitive elements of two or more multi-pixel sensors.

[0051] In any case, the sensors may be connected to the digital bus to communicate data. Each sensor may have a unique ID and may be arranged to transmit the unique ID.

[0052] In another preferred embodiment of the present invention, the other deformable element is in contact with the deformable element and / or with the element. The other deformable element may extend at least partially between the deformable element and the object. It can also be said that in this case, the deformable element is a first deformable element and the other deformable element is a second deformable element. The second deformable element may be in contact with the object when the object is moved towards the second deformable element. When the object applies a force to the second deformable element during such contact, the second deformable element applies a force to the first deformable element and / or the element, and the first deformable element deforms, as described above. Thereby, the second deformable element may also be deformed. However, the deformability of the second deformable element may be less than the deformability of the first deformable element, or the second deformable element may not be deformed at all. In the absence of any applied force, the thickness of the second deformable element perpendicular to the sensor surface may be less than the thickness of the first deformable element. The second deformable element may have a different bulk modulus and / or shear modulus compared to the first deformable element. In particular, the bulk modulus of the second deformable element may be higher than the bulk modulus of the first deformable element. It can also be said that the stiffness of the second deformable element can be greater than the stiffness of the first deformable element and / or the flexibility of the second deformable element can be less flexible than the first deformable element. Therefore, due to being more rigid, the second deformable element is less likely to be damaged by contact with the object than the first deformable element. It can also be said that the second deformable element provides a protective layer to the first deformable element, which prevents damage to the first deformable element by avoiding direct contact between the first deformable element and the object. Therefore, by virtue of the second deformable element, the deformation properties of the first deformable element are protected. In addition, the second deformable element can act as a transducer of the force applied by the object to the second deformable element. It can also be said that the second deformable element distributes the force applied by the object to the first deformable element in a homogenous and uniform manner. For example, if the contact of the second deformable element with the object is above a first contact surface, and the contact of the element and / or the first deformable element with the second deformable element is above a second contact surface, the second deformable element distributes the force received above the first contact surface to the second contact surface. Depending on the shape of the object, the first contact surface can be smaller than the second contact surface. In this case, the second deformable element reduces the force or pressure applied to the first deformable element and / or the element compared to the case where the object would directly contact the first deformable element and / or the element itself. Thereby, the risk of damaging the first deformable element is reduced. In other words, the second deformable element avoids point stresses of the object onto the first deformable element and / or the element. In addition, or alternatively, the second deformable element may have a specific friction coefficient adapted to the object. In this way, the surface roughness of the second deformable element may be adjusted to the surface roughness of the object contacting the second deformable element.For example, if the surface of the object has a low coefficient of friction, the coefficient of friction of the second deformable element can be increased so that a stable contact of the object and the second deformable element is maintained. If the surface of the object has a high coefficient of friction, the coefficient of friction of the second deformable element can be reduced while still maintaining the same stable contact. In this way, the clamping between the object and the second deformable element can be stabilized even if the type of object changes. Thus, the second deformable element can be adjusted to the type of object without changing the first deformable element. This makes the soft sensor element universal for a wide range of different objects while still using the same deformable element. It is also contemplated that the second deformable element can be reversibly attached to the first deformable element. In other words, the second deformable element can be replaceable. Thereby, different second deformable elements can be selected for different applications or for different objects.

[0053] In a further preferred embodiment of the invention, the deformable element can be characterized by its shape and / or its bulk modulus and / or its shear modulus. The shape of the deformable element in the undeformed state can be at least one of the following: a cylinder, a cube, a pyramid, or a dome. The shape and other selected properties are thus adapted to the realization conditions.

[0054] In a further preferred embodiment of the invention, the deformable element may be attached to the sensor. For example, the deformable element may be bonded to the sensor. Thereby, for example, an adhesive layer (such as tape) may be used. It is also possible that the deformable element only touches the sensor without being unstably attached to the sensor. As a further example, it is also possible that the deformable element does not touch the sensor at all. In this case, there may be free space between the deformable element and the sensor and a holding device to hold the deformable element spaced apart from the sensor. The aforementioned examples should not be understood as limiting.

[0055] In a further preferred embodiment of the present invention, the soft sensor element may further include a mechanical stopper, wherein the mechanical stopper limits the deformation of the deformable element. The mechanical stopper acts as a physical barrier such as to limit the amount of possible deformation (i.e., the amount of force acting on the deformable element). The mechanical stopper thereby applies a reaction force to the force applied to the deformable element. As a result, the force and the reaction force at least partially offset each other. It can also be said that the mechanical stopper acts as a force absorber, which absorbs at least a portion of the force applied to the deformable element. The mechanical stopper may be a rigid element whose range relative to the sensor is shorter than the range of the undeformed deformable element relative to the sensor. This allows the deformable element to be at least partially deformed by such an amount: the amount is equal to the difference in degree between the mechanical stopper and the deformable element in the undeformed state. The mechanical stopper may also be an element composed of a material that is less elastic than the deformable element itself, rather than a rigid element. In this case, the mechanical stop does not act as a hard stop but rather acts as a damper, which dampens the deformation of the deformable element because a larger force must be applied to compress both the deformable element and the mechanical stop.

[0056] The above preferred embodiments are not exclusive. On the contrary, the combination of two or more aspects of the above preferred embodiments is within the scope of the present invention. Thus, all the above mentioned aspects or embodiments are combinable.

[0057] Further, the above needs are also solved by a method for measuring force using a soft sensor element. According to the method, a sensor array is provided, wherein the sensor array includes a plurality of soft sensor elements. Each of the soft sensor elements includes a sensor, a deformable element, and at least one element for interacting with the sensor. The deformable element extends at least partially between the sensor and the at least one element for interacting with the sensor.

[0058] Further, a plurality of signals are received from the sensor. The signal is received when the deformable element is deformed due to an external force. In other words, the signal may be a feedback signal providing feedback indicative of an applied external force.

[0059] Based on a predefined correlation between the value of the applied force and the value of the signal, the intensity of the force is derived.

[0060] The sensor array used in the method according to the invention may have any of the properties that have been described above with respect to the sensor array according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The following description and accompanying drawings set forth in detail certain illustrative aspects of the soft sensor arrangement, the fixture, and the corresponding two methods described above. However, these aspects are merely indicative of several of the various ways in which the principles of the various embodiments may be employed, and the described embodiments are intended to include all such aspects and their equivalents.

[0062] In the drawings, like reference numerals generally refer to like parts throughout the different drawings. The drawings are not necessarily drawn to scale. Instead, general focus is placed on explaining the general principles of the invention.

[0063] In the following description, various embodiments of the present invention are described with reference to the following drawings:

[0064] Figure 1 A cross-sectional view showing an example of an embodiment of a soft sensor element that can be used in a sensor array according to the present invention; in the state depicted in the figure, no external force is applied to the soft sensor element;

[0065] Figure 2 shows the case where a linear external force is applied. Figure 1 A cross-sectional view of a soft sensor element;

[0066] Figure 3 shows that when nonlinear external forces are applied, Figure 1 A cross-sectional view of a soft sensor element;

[0067] Figure 4 A cross-sectional view showing an example of an embodiment of a sensor array according to the present invention;

[0068] Figure 5 shows a cross-sectional view of another embodiment example of a sensor array according to the invention, wherein recesses are formed in the deformable element in order to mechanically decouple parts of the sensor array from each other;

[0069] Figure 6 A cross-sectional view showing another embodiment example of a sensor array according to the present invention, wherein recesses are formed in the deformable element in order to mechanically decouple parts of the sensor array from each other; and Figure 4 In contrast, the soft sensor element does not include parts of a common deformable element;

[0070] Figure 7 A cross-sectional view showing another example of embodiment of a sensor array according to the present invention, wherein sensors of a plurality of soft sensor elements are embedded in a passivation layer, and elements for interacting with the sensors of the plurality of soft sensor elements are embedded in a common deformable element;

[0071] Figure 8shows a cross-sectional view of another embodiment example of a sensor array according to the invention, wherein an additional element is placed in the space between elements for interacting with sensors of a plurality of soft sensor elements;

[0072] Fig. 9 A top view of a sensor according to another embodiment example of a sensor array according to the present invention is shown, wherein the sensor of a plurality of soft sensor elements is configured as a multi-pixel sensor;

[0073] Fig.10 A cross-sectional view of another embodiment example of a sensor array according to the present invention is shown, wherein the element for interacting with sensors of a plurality of soft sensor elements is configured as a powder material. DETAILED DESCRIPTION

[0074] The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced.

[0075] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0076] Figure 1A cross-sectional view of a soft sensor element 100 according to an example of an embodiment of the present invention is depicted. The soft sensor element 100 includes a sensor 110, a deformable element 120, and an element 130 for acting with the sensor 110. For example, the deformable element 120 may include at least one of the following: an elastomer, a polymer, a rubber, and a vulcanized rubber. The deformable element 120 may also include a flexible element, an elastic element, or a flexible structure. The flexible element or the flexible structure may be made of a metal. For example, the flexible element or the flexible structure may be made of a metal flexible beam. In the example of the embodiment shown here, the element 130 is completely embedded in the deformable element 120. Completely embedded means that the deformable element 120 completely surrounds the element 130, which means that all surfaces of the element 130 are in contact with the deformable element 120. It can also be said that the element 130 is encapsulated by the material of the deformable element 120. The deformable element 120 can be deformed by applying an external force. The applied external force can cause the deformable element 120 to be compressed so that the distance between the element 130 and the sensor 110 changes. This change in distance can be detected by sensor 110. For example, if element 130 is a magnet and sensor 110 is a magnetic sensor, the reduction in the distance between element 130 and sensor 110 causes the sensor to detect a different magnetic field, such as a different magnetic field strength and / or orientation than before the deformation. Thus, based on the change in the measured physical units, it can be inferred how much deformable element 120 has deformed. However, those skilled in the art will note that other types of sensor 110 / element 130 combinations can also be used to measure the amount of distance that deformable element 120 has been compressed.

[0077] Each individual deformation of the deformable element 120 corresponds to a different applied external force, which in turn is associated with a corresponding physical measurement obtained by the sensor 110. Therefore, there is a correlation between the applied external force value and the corresponding measurement value of the sensor 110. This correlation can be determined during an initial calibration step of the sensor 110, or can be predetermined by knowing the bulk modulus and / or shear modulus of the deformable element 120. For example, the correlation itself can be established as a lookup table, including the external force value and its associated sensor reading. A model trained by machine learning can be used to establish the correlation between the applied external force value and the corresponding measurement value of the sensor 110. Those skilled in the art are also aware of other ways to establish the corresponding correlation, all of which are covered herein. Once the actual measurement of the sensor 110 is obtained, the lookup table can be used to infer an estimate for the external force. However, by knowing the bulk modulus and / or shear modulus of the deformable element 120, an algorithm can also be used that outputs the actual force applied relative to the deformation through easy calculation. The algorithm can be a nonlinear model that defines the actual force as a nonlinear function of the measurement value of the sensor 110. The algorithm or correlation may be implemented inside an integrated circuit (IC) containing the sensor 110, or outside the integrated circuit containing the sensor 100, or partially inside the integrated circuit containing the sensor 110 (e.g., for calculating the position of the element 130 based on the sensor signal) and partially outside the integrated circuit containing the sensor 110 (e.g., for inferring the force based on the displacement of the element 130). The sensor 110 may be configured to provide dual sensing, which allows detection of linear forces as well as shear forces, such as a linear force in the direction of the external force and a shear force in one direction or two orthogonal directions in a plane perpendicular to the direction of the external force. The correlation or algorithm may provide a direct link between the applied external force value and the measured value of the sensor 110. Alternatively, the correlation or algorithm may calculate the displacement of the element 130 as an intermediate step. In this case, a first correlation or a first algorithm determines the position of the element 130 based on the measured value of the sensor 110, and a second correlation or a second algorithm determines the applied external force value based on the position of the element 130. Thus, in this case, determining the position of the element 130 acts as an intermediate step.

[0078] In the embodiment example shown here, the element 130 embedded in the deformable element 120 has a distance d1 from the sensor 110 that is smaller than a distance d2 from the second end of the deformable element 120 to the sensor 110 .

[0079] In a non-limiting sense, the distance d1 between the element 130 and the sensor 110 may be 3 mm, and the distance d2 between the second end of the deformable element 120 and the sensor may be 4 mm. Those skilled in the art understand that these dimensions are named for illustrative purposes only and should not be construed as limiting if not explicitly mentioned.

[0080] Figure 2 Shows Figure 1 20 is a cross-sectional view of the soft sensor element 200 under application of an external force ("pressure"). The applied external force may be uniform, i.e. constant over the surface to which the force is applied. However, the applied external force may also be non-uniform, i.e. varying over the surface to which the force is applied. This variation of the force over the surface to which the force is applied may be linear or non-linear. In other words, each point on the surface to which the force is applied may be assigned a different force value which is related to adjacent force values ​​according to a linear or non-linear relationship. In the example shown, the external force is uniform over the surface of the deformable element 120 and is applied perpendicularly to the surface of the sensor 110. The applied external force compresses the deformable element 120. This reduces the distance d2 of the second end of the deformable element relative to the sensor 110 to a shorter distance d 2’ Due to the fact that the element 130 is embedded in the deformable element 120, the distance d1 from the element 130 to the sensor 110 is also reduced to a shorter distance d 1’ .

[0081] The sensor 110 is configured to detect the distance d1 to d by interacting with the element 130. 1’ If sensor 110 is a magnetic sensor and element 130 is a magnet, a lower distance between sensor 110 and element 130 causes sensor 110 to detect a higher magnetic field strength, since magnetic field strength is proportional to distance. This change in magnetic field strength allows the force applied to deformable element 120 to be derived. In some cases, if sensor 110 is a magnetic sensor, sensor 110 may detect a change in the orientation of the magnetic field strength vector (i.e., one or more angles assigned to the magnetic field vector) in addition to or instead of the magnetic field strength. In this case, the magnetic sensor may be located at an offset relative to the axis of the magnet. Although only one-dimensional distance measurement, and the force applied perpendicularly thereby, is described herein, those skilled in the art will note that element 130 may also be configured as a magnetic sensor. Figure 2 The ground is tilted at an angle as shown in b.

[0082] exist Figure 3In the embodiment of FIG. 1 , the external force (“pressure”) is applied uniformly but not perpendicularly to the surface of the sensor 110. Thus, the applied external force causes the deformable element 120 to deform in a direction that is not perpendicular to the surface of the sensor 110. This causes the distance d1 of the element 130 from the sensor 110 to be changed in a non-homogeneous manner. For example, the upper end of the element 130 moves to a larger distance d 1’ , but the lower end of element 130 moves to a lower distance d 1” . Since the distance d 1’ and d 1” In the case of application of a non-linear force, the element 130 is different, so that the element 130 is tilted by a non-zero angle α relative to the sensor 110. Thus, in the case of a non-vertical external force, the element 130 is not only translated, but also rotated. The sensor 110 is adapted to detect the change of the angle α by acting with the element 130. If the sensor 110 is a magnetic sensor and the element 130 is a magnet, the different angles α between the sensor 110 and the element 130 cause the sensor 110 to detect different magnetic fields, because the orientation of the magnetic field lines of the magnet 130 relative to the sensor 110 has been changed. It can also be said that the rotation of the element 130 by the angle α causes the sensor 110 to sense the three-dimensional magnetic field from the rotation of the element 130. Under rotation, the absolute magnetic field strength does not change, but the orientation of the magnetic field vector in space is changed. Therefore, compared with the non-rotation of the element 130, the sensor 110 senses a different magnetic flux, because the projection of the magnetic field vector to the surface on which the sensor 110 measures the magnetic flux is different. The change in the measured magnetic flux allows the change in the position of the element 130 to be inferred. The positional change of element 130 is uniquely linked to the force applied to deformable element 120. Thus, if a non-perpendicular force is applied to deformable element 120, the rotation of element 130 can be used to determine the force applied to deformable element 120.

[0083] Figure 4 4 shows a cross-sectional view of an example of an embodiment of a sensor array according to the present invention. The sensor array 400 includes a plurality of soft sensor elements. Each of the soft sensor elements can be connected to a Figure 1 , Figure 2 and Figure 3 The soft sensor elements illustrated in the embodiment examples are configured in a similar or identical manner.

[0084] A plurality of soft sensor elements are arranged on a substrate 410. The substrate 410 may provide mechanical and / or electrical support. Further, it may provide connections to circuitry and allow the sensor array to be connected to other electrical devices.

[0085] Each of the plurality of soft sensor elements includes a sensor 440, a deformable element 420, and an element 430 for interacting with the sensor 440. Figure 4 In the embodiment example depicted in , the deformable element 420 of the soft sensor element is shown as a common deformable element in which a plurality of sensors 440 and a plurality of elements 430 for interacting with the sensors 440 of the plurality of soft sensor elements are embedded.

[0086] In the example of the embodiment shown here, the sensor 440 of each soft sensor element in the plurality of soft sensor elements can be configured as a semiconductor die, a bare die, an unpackaged chip, or an unpackaged integrated circuit, for example. The die is mounted on the substrate 410 as a flip chip. The die includes a sensitive element 450 and an electrical connection 445 connecting the die to the circuit system of the substrate 410. In some embodiments, the electrical connection to the substrate may not exceed the periphery of the sensor and / or be in direct contact with the active surface of the sensor.

[0087] The substrate 410 has a thickness h s And the deformable element 420 has a thickness h de The thickness of the sensor array is h = h s +h de Preferably, if Figure 4 As shown in FIG. 1 , the thickness h of the substrate 410 s is smaller than the thickness h of the deformable element 420 de . Generally, it is preferred to keep the thickness of the sensor array as small as possible. Since the element 430 for interacting with the sensor 440 of each of the plurality of soft sensor elements moves relative to the sensor 440 when a force is applied, a certain thickness is necessary to ensure proper operation. In contrast, the substrate 410 can be substantially thinner. Thus, the thickness h of the deformable element 420 is de Preferably, it is greater than the thickness h of the substrate 410 s Preferably, the thickness h of the substrate 410 is s can be about 60 μm to 600 μm, and the thickness h of the deformable element 420 de Preferably, the thickness h of the substrate 410 is about 4 mm. s The thickness h of the deformable element 420 de The ratio between them is 0.1% to 15%, more preferably 1% to 5%.

[0088] Sensor 440 has a width in one dimension, which may also be referred to as a size, and a Figure 34. Preferably, the soft sensor elements in the plurality of soft sensor elements are homogeneous so that all sensors 440 have the same size. The element 430 for interacting with the sensor 440 is illustrated as having a smaller size, i.e., length l. This is preferred, but not necessary. The elements 430 for interacting with the sensor 440 may also have an equal size or a larger size. In some embodiments, since the sensor is not a sealed or packaged die, but a seal is provided by a deformable element, the length L corresponds to the length of the die of the sensor and is not the length of the packaged chip.

[0089] Preferably, the spacing p between two adjacent soft sensor elements in the plurality of soft sensor elements is uniform, which means that the arrangement of the plurality of soft sensor elements is equidistant, such as Figure 4 The pitch p may be measured from the center of one soft sensor element to an adjacent soft sensor element, or from an edge of one soft sensor element (eg, the edge of sensor 440) to the same edge of an adjacent soft sensor element.

[0090] Figure 4 The sensor array 400 depicted in FIG. 4 is shown in a cross-sectional view. In the cross-sectional view, a plurality of soft sensor elements are arranged in a line along the illustrated cross-section. The sensor 400 may include such a single line of a plurality of soft sensor elements, or a plurality of soft sensor elements may be arranged in a two-dimensional grid, wherein the remaining soft sensor elements arranged in the second spatial dimension of the grid are located in a direction perpendicular to the image plane and are therefore not shown.

[0091] Will describe Figures 5 to 10 Further example embodiments are described in Figure 4 When not explicitly explained differently, Figures 5 to 10 Further example embodiments may include Figure 4 The sensor array has the same features as depicted in FIG.

[0092] Figure 5 A cross-sectional view of another embodiment example of a sensor array according to the invention is shown, wherein recesses are formed in the deformable element in order to mechanically decouple parts of the sensor array from each other.

[0093] and Figure 4 Similar to the embodiment example depicted in , the sensor array 500 includes a substrate 510 and a plurality of soft sensor elements, the plurality of soft sensor elements having a deformable element 520 , a sensor 540 , and an element 530 for interacting with the sensor 540 .

[0094] and Figure 4Compared to the embodiment example depicted in , the sensor array still includes a common deformable element 520, but the common deformable element 520 includes a recess 560. The recess 560 divides the common deformable element 520 into parts 550. Such separation is a mechanical separation and reduces crosstalk between adjacent soft sensor elements because a force applied only to a part does not affect an adjacent part.

[0095] and Figure 4 similar, Figure 5 A cross-sectional view is depicted in which a plurality of soft sensor elements are arranged in a line. As mentioned above, a plurality of soft sensor elements may be arranged in a two-dimensional grid. In this case, there may be a plurality of soft sensor elements arranged perpendicular to the line. Figure 5 5. These additional recesses may further separate subsets of the plurality of soft sensor elements into portions.

[0096] Figure 6 A cross-sectional view showing another embodiment example of a sensor array according to the present invention, wherein recesses are formed in the deformable element in order to mechanically decouple parts of the sensor array from each other; and Figure 5 In contrast, the soft sensor element does not comprise part of a common deformable element.

[0097] and Figure 4 Similar to the embodiment example depicted in , the sensor array 600 includes a substrate 610 and a plurality of soft sensor elements, the plurality of soft sensor elements having a deformable element 620, a sensor 640, and an element 630 for interacting with the sensor 640. Figure 5 Similar to the embodiment example depicted in , the plurality of soft sensor elements are divided into parts. Figure 6 In the case illustrated in , the recess 660 is deeper and separates the deformable elements 620 in a manner that the deformable elements 620 of adjacent soft sensor elements can be considered to be completely separated, thereby even further reducing crosstalk. In this case, it can be said that the multiple soft sensor elements do not include a common deformable element.

[0098] Figure 7 A cross-sectional view of another embodiment example of a sensor array according to the present invention is shown, wherein sensors of a plurality of soft sensor elements are embedded in a passivation layer and elements for interacting with the sensors of the plurality of soft sensor elements are embedded in a common deformable element.

[0099] and Figure 4 Similar to the embodiment example depicted in , the sensor array 700 includes a substrate 710 and a plurality of soft sensor elements, the plurality of soft sensor elements having a deformable element 720 , a sensor 740 , and an element 730 for interacting with the sensor 740 .

[0100] In contrast to the example embodiments described above, only the elements 730 for interacting with the sensors 740 are embedded in the common deformable element 720. However, the sensors 740 are embedded in another layer, the so-called passivation layer 750. The passivation layer 750 may also be referred to as a sealing layer, and may include a thermoplastic material, an epoxy resin, a mold material, or a photoresist such as SU-8. Such a sealing layer is used to provide a seal for a sensor of multiple soft sensor elements. As mentioned above, in some embodiments, the deformable element can provide a seal, thereby protecting the sensors from humidity, contamination or damage, and can even electrically isolate the sensors 740 from each other. In Figure 7 In embodiments where a sealing layer is provided for sealing, this sealing layer may be preferred if a particular application requires a highly flexible deformable element but a more robust protective layer for the sensor.

[0101] Figure 8 A cross-sectional view of another embodiment example of a sensor array according to the invention is shown, wherein additional elements are placed in the spaces between elements for interacting with sensors of a plurality of soft sensor elements.

[0102] and Figure 4 Similar to the embodiment example depicted in , the sensor array 800 includes a substrate 810 and a plurality of soft sensor elements, the plurality of soft sensor elements having a deformable element 820 , a sensor 840 , and an element 830 for interacting with the sensor 840 .

[0103] Additionally, the sensor array 800 includes additional elements 850. These additional elements 850 are placed in the space between the elements 830 for interacting with the sensors 840 of the plurality of soft sensor elements. The additional elements 850 can be, for example, magnets or targets that have other properties that are the same as the elements 830. For example, the additional elements can provide a magnetic field with a different direction than the elements of the soft sensor elements. In one example, the magnetic field of the additional elements 850 can be rotated 90° compared to the magnetic field of the element 830 for interacting with the sensor 840. The additional elements 850 can be placed at equidistant positions between the elements 830.

[0104] Fig. 9 A top view of a sensor according to another embodiment example of a sensor array according to the present invention is shown, wherein the sensor of a plurality of soft sensor elements is configured as a multi-pixel sensor.

[0105] The sensor array 900 includes sensors having a so-called multi-pixel configuration. This means that each sensor 940 includes a plurality of sensitive elements 950. Fig. 9, each multi-pixel sensor includes four sensitive elements 950. The four sensitive elements 950 are symmetrically arranged in the four corners of the sensor 940 or placed on a diagonal line. The spacing s1 between adjacent sensitive elements 950 is preferably uniform in all sensors 940. Further, the spacing s2 between adjacent sensitive elements 950 of adjacent sensors 940 is preferably uniform over the entire sensor array 900 to provide uniform resolution. Further preferably, the spacing s1 between the sensitive elements 950 of the same sensor 940 is equal to the spacing s2 between the adjacent sensitive elements 950 of the adjacent sensors 940.

[0106] for Fig. 9 In the multi-pixel sensor shown in FIG. 1 , each pixel can be a magnetic field sensor. Thus, each pixel can measure at least one component of the magnetic field.

[0107] Fig.10 A cross-sectional view of another embodiment example of a sensor array according to the present invention is shown, wherein the element for interacting with sensors of a plurality of soft sensor elements is configured as a powder material.

[0108] and Figure 4 Similar to the embodiment example depicted in , the sensor array 1000 includes a substrate 1010 and a plurality of soft sensor elements, the plurality of soft sensor elements having a deformable element 1020 , a sensor 1040 , and an element 1030 for interacting with the sensor 1040 .

[0109] In contrast to the embodiment examples described above, the element 1030 for interacting with the sensor 1040 is formed of a powder material. For example, the powder material may be a magnetic material or a magnetizable material. The use of such a powder material may improve the bending behavior of the sensor array and thus may improve the folding or rolling of the sensor array.

[0110] Each of the above-described embodiment examples can be used to determine the intensity of an applied external force. In addition, each embodiment example can be used to locate the point at which the external force is applied. If measured continuously or at discrete intervals, each of the above-described embodiments can determine the propagation of the external force, which means that movement can be recorded. For example, if used in a clamp, insufficient clamping may be detected at an early stage.

[0111] What has been described above includes examples of one or more embodiments. Of course, for the purposes of describing the foregoing embodiments, it is not possible to describe every conceivable combination of components or methods, but one of ordinary skill in the art will recognize that many further combinations and permutations of the various embodiments are possible. Therefore, the described embodiments are intended to encompass all such changes, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. A sensor array for measuring force, comprising a plurality of soft sensor elements, each of the soft sensor elements (100) comprising: sensor(110,440); a deformable element (120, 420), wherein the deformable element (120, 420) is deformable due to the force; and At least one element (130, 430) for interacting with the sensor (110, 440) for measuring the force by deformation of the deformable element (120, 420), wherein the deformable element (120, 420) extends at least partially between the sensor (110, 440) and the at least one element (130, 430).

2. The sensor array according to claim 1, wherein: The at least one element (130, 430) is embedded in the deformable element (120, 420).

3. The sensor array according to any one of claims 1 and 2, wherein: The soft sensor elements of the plurality of soft sensor elements are arranged in a line or in a grid.

4. A sensor array according to any one of the preceding claims, wherein The spacing (p) between two adjacent elements of the plurality of soft sensor elements is equidistant.

5. A sensor array according to any one of the preceding claims, wherein The sensor (110, 440) of each soft sensor element has a size (L), and wherein a spacing (p) between two adjacent elements of the plurality of soft sensor elements is p≤3L.

6. A sensor array according to any one of the preceding claims, wherein The sensor of each soft sensor element of the plurality of soft sensor elements is a multi-pixel sensor (940).

7. The sensor array according to claim 6, wherein: Two adjacent pixels of the multi-pixel sensor have a first interval (s1), and wherein a second interval (s2) between a last pixel in the multi-pixel sensor of a first sensor element and a first pixel in the multi-pixel sensor of an adjacent second sensor element is less than or equal to the first interval (s1).

8. A sensor array according to any one of the preceding claims, wherein The plurality of soft sensor elements are embedded in a common deformable element (120, 420).

9. The sensor array according to claim 8, wherein: A subset of the plurality of soft sensor elements is arranged in at least two portions of the sensor array, and wherein the at least two portions are mechanically decoupled.

10. The sensor array according to claim 9, wherein: Portions of the sensor array are separated by recesses (560, 660) in the common deformable element (120, 420).

11. A sensor array according to any one of the preceding claims, wherein The sensor (110, 440) is a passive magnetic sensor and the at least one element (130, 430) is a magnetic field emitting element.

12. The sensor array according to any one of claims 1 to 10, wherein: The sensor (110, 440) is an active magnetic sensor and the at least one element (130, 430) is a target.

13. The sensor array according to any of the preceding claims, further comprising a plurality of additional elements (850), wherein: At least one additional element of the plurality of additional elements (850) is located between a corresponding at least one element (130, 430, 830) of two adjacent soft sensor elements.

14. The sensor array according to any one of the preceding claims, further comprising: One or more evaluation circuits are configured for receiving at least one signal from the one or more sensors and for evaluating the at least one signal to derive the applied force.

15. A method for measuring force using a sensor array, the method comprising: A sensor array is provided, the sensor array comprising a plurality of soft sensor elements, each of the plurality of soft sensor elements comprising a sensor (110, 440), a deformable element (120, 420), and at least one element (130, 430) for interacting with the sensor, wherein the deformable element (120, 420) at least partially extends between the sensor (110, 440) and the at least one element (130, 430); receiving one or more signals from one or more sensors, wherein the signals are received when the deformable element (120, 420) is deformed due to a force; and An applied force is derived from the one or more received signals.

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