Tactile sensing array and preparation method thereof

Abstract

The invention discloses a tactile sensor array, which relates to the technical field of sensors, and comprises a soft and hard coupling packaging layer, an electrode layer attached to the soft and hard coupling packaging layer, and a multi-stage segmented dot matrix supporting layer arranged between the soft and hard coupling packaging layer in a bonding manner, the porous ion medium layer is clamped between the electrode layers or between the electrode layers and the soft and hard coupling packaging layer, and the multi-layer array is arranged cooperatively. The invention further discloses a preparation method of the touch sensor array. The preparation method comprises the steps of preparing the porous ion dielectric layer, preparing the soft and hard coupling packaging layer, preparing the electrode layer, preparing the multi-stage segmented dot matrix supporting layer and assembling the sensor array. The structure is compact, cooperation is tight, excellent strain insensitivity and crosstalk suppression performance can be achieved at the same time, and the touch unit response has high linearity.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a tactile sensor array and a preparation method thereof. Background Art

[0002] The physical contact between the human body and the environment contains a wealth of tactile interaction information, which can help humans perceive the characteristics of objects in the surrounding world (such as shape and material) and achieve fine motion control. In order to imitate the tactile perception ability of organisms, researchers have developed a variety of tactile sensors in recent years to provide robots with perception functions similar to human touch. Tactile sensors are a type of sensor element that can convert physical interaction information (such as pressure, vertical deformation, etc.) into electronic signals that are easy for machines to process. They are often implemented through transduction principles such as resistance and capacitance. This type of sensor has become a key device in the fields of robotics, human-computer interaction, and intelligent systems. Among them, ion capacitive tactile sensors based on the double layer capacitance effect (EDL) have attracted widespread attention due to their performance advantages such as high sensitivity and high signal-to-noise ratio. Its working principle is based on the nanoscale ion-electron double layer interface formed between the electrode and the contact ion dielectric layer, thereby significantly increasing the initial value of the capacitance. Under different pressure states, the contact area or distance between the electrode and the ionic dielectric changes, causing a change in capacitance, achieving a sensitive response to pressure.

[0003] Tactile sensors are often used in flexible structures such as robot skin or artificial hands, which can bend, stretch or deform significantly when in motion or interacting with the external environment. However, existing tactile sensor arrays often lack the ability to adapt to these additional strains, and will produce a wide range of false response signals when bent or stretched. For example, even without actual touch pressure, the sensor array may trigger an error signal due to surface deformation, which greatly limits its reliability and applicability in real application scenarios.

[0004] In addition, when such sensors are made into compact, high-density tactile sensor arrays, since multiple sensing units share the same ionic medium, signal crosstalk may occur between adjacent units. Specifically, when a unit is subjected to pressure, due to the influence of deformation conduction / leakage current, a signal response will also be generated in the adjacent non-contact unit, resulting in erroneous perception results. This crosstalk phenomenon greatly weakens the signal resolution and sensing accuracy of the sensor array, seriously affecting the accurate acquisition of tactile information. Summary of the invention

[0005] In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to provide a strain-insensitive, crosstalk-free tactile sensor array and a preparation method thereof.

[0006] To achieve the above objectives, the present invention solves the above technical problems with a tactile sensor array, comprising a soft-hard coupling packaging layer, an electrode layer attached to the soft-hard coupling packaging layer, a multi-stage segmented lattice support layer arranged between the soft-hard coupling packaging layers by bonding, and a porous ion medium layer clamped between the electrode layers or between the electrode layer and the soft-hard coupling packaging layer. The tactile sensor array is insensitive to strain and suppressed against crosstalk through the coordinated arrangement of the multi-layer array.

[0007] Furthermore, the soft-hard coupling packaging layer includes a high modulus hard area array coated with a low modulus soft material, and a soft connection area formed by filling the gaps between the high modulus hard area array with a low modulus soft material. The material used for the high modulus hard area is a high modulus hard material, the high modulus hard material is PDMS or TPU or PVA, the low modulus soft material is PDMS or Ecoflex series or TPU, and the soft-hard coupling packaging layer has a thickness of 100-300 microns.

[0008] Furthermore, the electrode layer is arranged as an electrode unit array, and the electrode layer adopts a parallel electrode structure or a coplanar electrode structure. The parallel electrodes are row electrodes or column electrodes, and the coplanar electrode structure is interdigitated electrodes or spiral interdigitated electrodes or rectangular electrodes.

[0009] Furthermore, the multi-level segmented lattice support layer is a harder support unit, which is arranged between the layers of the soft connection area. The multi-level segmented lattice support unit adopts a cylindrical, square column or conical lattice structure. The size of a single lattice structure is 100 to 300 microns, and the spacing is 100 to 300 microns. The material used for the multi-level segmented lattice support layer is PDMS or TPU or PVA.

[0010] Furthermore, the porous ion medium layer is an array unit, which is clamped between the electrode unit array layers or between the high modulus hard area array layer and the electrode unit array layer. The material used for the porous ion medium layer is an ion gel formed by mixing PVD (F-HFP) and ionic liquid [EMIM] [TFSI] in a 1:1 ratio attached to a high porosity 3D grid frame. The high porosity 3D grid frame is a melamine open-cell foam or an open-cell sponge or an open-cell foam prepared from PDMS / Ecoflex material.

[0011] Furthermore, the tactile sensor array of the present invention adopts a 5-layer structure, which is arranged from top to bottom as follows: the first layer: a soft-hard coupling packaging layer, the second layer: a row electrode layer, the third layer: a porous ion medium layer array unit and a multi-level segmented lattice support unit located between the porous ion medium layer array units, the fourth layer: a column electrode layer, and the fifth layer: a soft-hard coupling packaging layer. The electrode unit arrays of the row and column electrode layers are arranged on the high modulus hard area arrays of the first and fifth layers, and the array units of the porous ion medium layer are directly contacted and arranged between the electrode array layers of the second and fourth layers.

[0012] Furthermore, the tactile sensor array of the present invention adopts a 4-layer structure, which is arranged from top to bottom as follows: the first layer: a soft-hard coupling packaging layer, the second layer: a porous ion medium layer array unit and a multi-level segmented lattice support unit located between the porous ion medium layer array units, the third layer: a coplanar electrode layer, and the fourth layer: a soft-hard coupling packaging layer. The electrode unit array of the coplanar electrode layer is arranged on the high modulus hard area array of the fourth layer, and the array unit of the porous ion medium layer is directly in contact with the high modulus hard area array layer of the first layer and the electrode array layer of the third layer.

[0013] The present invention also provides a method for preparing the above-mentioned tactile sensor array, comprising the following steps:

[0014] Step 1: preparing a porous ion medium layer;

[0015] Step 2: preparing a soft-hard coupling packaging layer;

[0016] Step 3: preparing an electrode layer;

[0017] Step 4: preparing a multi-level segmented lattice support layer;

[0018] Step 5: Assemble the sensor array.

[0019] further,

[0020] The step one also includes the following steps:

[0021] Step 1.1 dissolving the ion gel in an organic solvent to prepare ion gel solutions of different concentrations;

[0022] Step 1.2: attaching the ion gel solution obtained in the above step to the high-porosity 3D grid framework by coating or embedding;

[0023] Step 1.3: completely drying the 3D grid framework filled with the ion gel solution;

[0024] Step 1.4 Use a die cutter to cut the dried porous ionic medium into array units that match the sensing electrodes.

[0025] The step 2 also includes the following steps:

[0026] Step 2.1 prepare a high modulus hard region of the array by using a high modulus material through molding or dispensing printing;

[0027] Step 2.2 uses an extrusion or doctor blade coating process to press the low modulus material into the gaps between the high modulus hard areas and simultaneously cover the high modulus hard areas.

[0028] The step three also includes the following steps:

[0029] Step 3.1 On the soft-hard coupling encapsulation layer, align the high modulus hard area by printing or dispensing printing to prepare the array electrode;

[0030] Step 3.2 is drying.

[0031] The step 4 is specifically as follows:

[0032] The high modulus material is passed through a multi-level segmented lattice support structure mold, and a multi-level segmented lattice structure support layer is formed by dispensing printing or molding process.

[0033] The step five also includes the following steps:

[0034] Step 5.1: Covering the back of the multi-stage segmented lattice support layer with adhesive;

[0035] Step 5.2 For parallel electrode configuration, use a die cutter to cut out the electrode corresponding area of ​​the multi-level segmented lattice support layer, and then bond it to the soft-hard coupling packaging layer of the printed electrode layer; for coplanar electrode configuration, bond it to the soft-hard coupling packaging layer on the side where the electrode is not printed;

[0036] Step 5.3: After bonding the multi-level segmented lattice support layer to the soft-hard coupling packaging layer, demold and remove the layer, bond the multi-level segmented lattice support layer to another soft-hard coupling packaging layer, and clamp the array-divided porous ion medium between electrode array layers or between high modulus hard area array layers and electrode array layers.

[0037] further,

[0038] The mass ratio of the ion gel to the organic solvent in step 1.1 is 1:16, 1:12, and 1:8, and the organic solvent is acetone;

[0039] The coating / embedding method in step 1.2 is dipping or spraying;

[0040] When the melamine open-cell foam is used as the 3D grid framework in step 1.3, the drying temperature of the ion gel solution is 60°C.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] (1) With less impact on spatial resolution, it can be insensitive to maximum 75% tensile deformation and insensitive to bending with a radius > 10 mm.

[0043] (2) For mechanical crosstalk, the vertical deformation of adjacent units can be reduced by 89.8%, and a crosstalk suppression ratio of about 30 dB can be achieved.

[0044] (3) The prepared ionic tactile sensor can have good response linearity within a large pressure range.

[0045] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention;

[0047] Figure 2 This is a schematic structural diagram of another preferred embodiment of the present invention;

[0048] Figure 3 It is a schematic diagram of the preparation method of the present invention;

[0049] Figure 4 The high modulus hard unit and the soft-hard coupled package-electrode composite layer prepared by the present invention;

[0050] Figure 5 The microscopic morphology of the porous ion medium prepared by the present invention;

[0051] Figure 6 The multi-level segmented lattice support morphology prepared by the present invention and its changes with bending;

[0052] Figure 7 This is a real machine test image of the tensile change of the soft-hard coupled package-electrode composite layer of the present invention;

[0053] Figure 8 The simulated deformation and internal stress of the soft-hard coupled package-electrode composite layer of the present invention;

[0054] Fig. 9 Photographs of tactile arrays prepared for the present invention;

[0055] Fig.10 The response performance of the tactile sensor array of the medium layer with different concentrations of ion gel ratio prepared by the present invention;

[0056] Fig.11 The initial value difference and response difference of the tactile sensor prepared by the present invention under different tensile strains;

[0057] Fig.12 The erroneous response of the tactile sensor prepared by the present invention at different bending radii;

[0058] Fig.13 The figure is a comparison of the crosstalk of the tactile sensor array prepared by the present invention before and after adding the multi-level segmented lattice support structure.

[0059] Among them: 0-tactile sensor array, 1-soft-hard coupling packaging layer, 100-high modulus hard area, 101-soft connection area, 2-row and column electrode layer, 3-multi-level segmented lattice support layer, 4-porous ion medium layer, 6-coplanar electrode layer, 601-spiral interdigitated electrode, 7-soft-hard coupling packaging electrode composite layer. DETAILED DESCRIPTION

[0060] The following describes the preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0061] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings.

[0062] like Figure 1-2 As shown, the tactile sensing array of the present invention adopts a multi-layer structure collaborative design, including a soft-hard coupling packaging layer 1, an electrode layer, a multi-level segmented lattice support layer 3 and a porous ion medium layer 4. Among them, the soft-hard coupling packaging layer 1 includes a high modulus hard area 100 array and a soft connection area 101. The material used for the high modulus hard area 100 is a high modulus hard material such as PDMS, TPU, PVA, etc. The low modulus soft connection area 101 and the packaging material are low modulus soft materials such as PDMS, Ecoflex series, TPU, etc. The low modulus soft material covers the high modulus hard area 100 array and fills the gaps between the high modulus hard area 100 arrays to form the soft connection area 101. The thickness of the soft-hard coupling packaging layer 1 is 100-300 microns. The soft-hard coupling packaging layer 1 can not only concentrate the tensile strain in the soft connection area 101 of the adjacent units, but also ensure that the sensing unit is not affected by lateral strains such as stretching.

[0063] The electrode layer is an electrode unit array. The electrode layer design can adopt a parallel electrode structure (i.e., row and column electrodes) or a coplanar electrode structure. The row and column electrodes are row electrodes or column electrodes. The coplanar electrodes are interdigitated electrodes, spiral interdigitated electrodes, rectangular electrodes, etc. The electrode layer is attached to the high modulus hard region 100 array surface of the soft-hard coupling packaging layer 1. The electrode layer and the soft-hard coupling packaging layer can be integrally composited to form a soft-hard coupling packaging electrode composite layer 7.

[0064] The porous ion medium layer 4 is an ion medium unit / region array, and the material used is an ion gel formed by mixing PVD (F-HFP) and ionic liquid [EMIM] [TFSI] in a 1:1 ratio attached to a high-porosity 3D grid frame, but is not limited to PVD (F-HFP) and ionic liquid [EMIM] [TFSI], and the high-porosity 3D grid frame is melamine open-cell foam, open-cell sponge, and open-cell foam prepared from materials such as PDMS / Ecoflex. The porous ion medium layer 4 is sandwiched between the electrode unit array layers or between the high modulus hard region array layer and the electrode unit array layer. Using high-open-porosity organic foam as the ion gel embedding framework can not only construct the 3D distribution of the ion gel, which can bring about a greater contact area change efficiency, but also due to the extremely high porosity, the Poisson's ratio of the overall material is close to 0, and its compression modulus hardly changes with the compression process, so that the compression amount of the material and the pressure value present an approximately linear relationship, and the effective contact area between the porous ion medium layer 4 and the electrode layer is also nearly proportional to the compression amount, ultimately showing a linear response characteristic of relative capacitance change with pressure.

[0065] The multi-level segmented lattice support layer 3 has high modulus characteristics and is relatively hard. The materials used are PDMS, TPU, PVA, etc. The multi-level segmented lattice support layer 3 adopts cylindrical, square column, conical and other lattice structures distributed in multiple rows and columns between adjacent independent unit ion medium areas. The size of a single lattice structure is 100 to 300 microns, and the spacing is 100 to 300 microns. The multi-level segmented lattice support layer 3 is bonded to the soft connection area 101 of the top soft-hard coupling packaging layer 1 and the soft connection area 101 of the bottom soft-hard coupling packaging layer 1 by an adhesive, playing a vertical support and isolation role. It can resist the vertical strain caused by the bending / Poisson effect of the tactile sensor array without affecting the stretchability, and avoid the false response activation of the sensor unit. The multi-level lattice support layer 3 forms a vertically supported isolation zone between adjacent porous ion medium units to resist vertical deformation, and cooperates with the soft-hard coupling encapsulation layer 1 (the soft-hard coupling encapsulation layer 1 can reduce the stress transfer between units), greatly reducing the mechanical crosstalk caused by deformation / stress conduction between adjacent units. In addition, the multi-level segmented lattice support layer 3 separates the porous ion medium layer 4, realizing the independence of the ion medium layer of each unit, which can reduce the electrical crosstalk between units caused by ion movement.

[0066] Example 1

[0067] like Figure 1 As shown, a preferred embodiment of the tactile sensing array of the present invention includes a soft-hard coupling packaging layer 1, a row-column electrode layer 2 (adopting a parallel electrode structure), a porous ion medium layer 4 independent of each unit, and a multi-level segmented dot matrix support layer 3 located between each unit, wherein the row-column electrode layer 2 is a row electrode layer or a column electrode layer.

[0068] The tactile sensor array adopts a 5-layer structural design, which is the first layer, the second layer, the third layer, the fourth layer and the fifth layer from top to bottom. Among them, the first layer (i.e. the top layer) is the soft-hard coupling packaging layer 1, the second layer is the row electrode layer, the third layer is the porous ion medium layer array unit and the multi-level segmented lattice support unit located between the porous ion medium layer array units, the fourth layer is the column electrode layer, and the fifth layer (i.e. the bottom layer) is the soft-hard coupling packaging layer 1.

[0069] In the tactile sensor array, the sensing electrode unit area of ​​the row electrode layer (the second layer) corresponds to the high modulus hard area 100 of the soft-hard coupling packaging layer 1 (the first layer), and the sensing electrode unit area of ​​the column electrode layer (the fourth layer) corresponds to the high modulus hard area 100 of the soft-hard coupling packaging layer 1 (the fifth layer). This structure makes the sensing electrode area have a high modulus characteristic and is not easy to be stretched, while the soft connection area between adjacent units has a low modulus characteristic and is easy to be stretched. When the tactile sensor array is stretched, the tensile deformation is mainly concentrated in the low modulus soft connection area 101, avoiding the deformation of the sensing electrode area due to the influence of the stretching. Moreover, under the same overall tensile deformation, due to the existence of the low modulus soft connection area 101, the stress generated inside the soft-hard coupling packaging layer 1 is smaller. The independent porous ion medium area of ​​each unit directly contacts the surface of the upper and lower electrode layers (that is, the second layer and the fourth layer), and the multi-stage segmented lattice support layer 3 is distributed between the independent porous ion medium areas of each unit, corresponding to the soft connection area 101 of the soft-hard coupling packaging layer 1.

[0070] Example 2

[0071] like Figure 2 As shown, in another preferred embodiment of the present invention, different from Example 1, the electrode adopts a coplanar electrode structure, and the tactile sensor adopts a 4-layer structure design, which is the first layer, the second layer, the third layer and the fourth layer from top to bottom, wherein the first layer (i.e. the top layer) is the soft-hard coupling packaging layer 1, the second layer is the porous ion medium layer array unit and the multi-level segmented lattice support unit located between the porous ion medium layer array units, the third layer is the coplanar electrode layer 6, and the fourth layer (i.e. the bottom layer) is the soft-hard coupling packaging layer 1.

[0072] In the tactile sensor array, the sensing electrode unit area of ​​the coplanar electrode layer 6 (third layer) corresponds to the high modulus hard area 100 of the soft-hard coupling packaging layer 1 (fourth layer). When the tactile sensor array is stretched, the deformation is mainly concentrated in the low modulus soft connection area 101, while the sensing electrode unit area (that is, the high modulus hard area 100) is almost unaffected. Moreover, under the same overall tensile deformation, due to the existence of the low modulus soft connection area 101, the stress generated inside the soft-hard coupling packaging layer 1 is smaller. The independent ionic medium area of ​​each unit directly contacts the coplanar electrode surface 6 (third layer) and the high modulus hard area 100 of the soft-hard coupling packaging layer 1 (first layer), and the multi-level segmented lattice support layer 3 is distributed between the independent ionic medium areas of each unit, corresponding to the soft connection area 101 of the soft-hard coupling packaging layer 1 (first layer and fourth layer).

[0073] like Figure 3 As shown, the present invention also provides a method for preparing the above-mentioned tactile sensor array, and the specific steps are as follows:

[0074] Step 1: Preparation of porous ion medium layer

[0075] Firstly, the ion gel is dissolved in an organic solvent to prepare ion gel solutions of different concentrations. The mass ratio of the ion gel to the organic solvent is 1:16, 1:12, and 1:8, and the organic solvent is acetone or the like.

[0076] Secondly, the ion gel solution obtained in the above step is attached to the high-porosity 3D grid framework by coating / embedding, wherein the coating / embedding method is dip coating or spray coating.

[0077] Then, the 3D grid frame filled with ion gel solution was completely dried. Finally, a die cutter was used to cut it into array units of the size of sensing electrodes. Melamine open-cell foam was used as the 3D grid frame to attach the ion gel solution, which was completely dried at 60°C.

[0078] Step 2: Prepare soft and hard coupling packaging layer

[0079] First, a high modulus material is used to prepare the high modulus hard area 100 of the array by means of mold turning or dispensing printing using a mold with array openings. Then, a low modulus material is pressed into the gaps between the high modulus hard areas 100 by extrusion or scraping, and the high modulus hard areas 100 are covered to form a low modulus soft connection area 101, and an integrated soft-hard coupling film is formed as a whole.

[0080] Step 3: Prepare the electrode layer

[0081] On the soft-hard coupling packaging layer 1, the high modulus hard area 100 is aligned by printing or dispensing printing to prepare the array electrode, and then the soft-hard coupling packaging electrode composite layer 7 is formed by drying.

[0082] Step 4: Prepare a multi-level segmented lattice support layer

[0083] The high modulus material is passed through a multi-stage segmented lattice support structure mold, and a lattice structure support layer with multiple rows and columns of cylindrical, square column, conical and other shapes is formed through processes such as glue printing or mold turning.

[0084] Step 5: Assemble the sensor array

[0085] First, the back of the multi-level segmented lattice support layer 3 is covered with adhesive. For parallel electrodes, the electrode corresponding area of ​​the multi-level segmented lattice support layer 3 is cut out with a die cutter to expose the electrode, and then it is bonded to the soft-hard coupling packaging layer 1 on which the electrode layer has been printed. For coplanar electrodes, there is no need to cut, and they only need to be bonded to the soft-hard coupling packaging layer 1 on the side where the electrode layer is not printed.

[0086] Then, the multi-level segmented lattice support layer 3 is bonded to the soft-hard coupling packaging layer 1 and then demolded and taken out, the multi-level segmented lattice support layer is bonded to another soft-hard coupling packaging layer 1, and the array-divided porous ion medium layer is clamped between the electrode array layers or between the high modulus hard area 100 array layer and the electrode array layer to form a tactile sensing array.

[0087] like Figure 4 As shown, the left picture is a high modulus hard region 100 prepared by the above preparation method, and the right picture is a soft-hard coupling packaging electrode composite layer 7 prepared by the above method, that is, a composite layer formed by aligning and combining the electrode region of the row and column electrode layer with the high modulus hard region 100 of the soft-hard coupling packaging layer 1.

[0088] like Figure 5 As shown, the microscopic morphology of the porous ion medium prepared by the above preparation method is shown. Figure 4 The 3D-grid embedding forms of different ion gel concentrations can be seen.

[0089] like Figure 6 As shown, the morphology of the multi-level segmented lattice support layer 3 prepared by the above preparation method is shown. Figure 5 The multi-level segmented lattice support structure is distributed in the connection area between different unit electrodes (that is, the soft connection area 101 of the soft-hard coupling packaging layer 1). Figure 5 It can be seen that this multi-level segmented lattice support structure can unfold as the bending radius of the tactile sensor array changes, and continuously form effective support.

[0090] like Figure 7As shown in the figure, it is the tensile change test result of the soft-hard coupling packaging electrode composite layer 7 prepared by the above-mentioned preparation method. It can be seen from the figure that under the overall tensile strain of 50%, the main tensile deformation is mainly caused by the low modulus soft connection area 101 between adjacent electrodes, while the electrode area (that is, corresponding to the high modulus hard area 100) is less affected by the tensile deformation.

[0091] like Figure 8 As shown in the figure, it is the simulation result of the soft-hard coupling package electrode composite layer 7 and the average PDMS substrate, which can reflect the change of its internal state. The upper figure shows the area change rate of the array electrode under the condition of 50% overall stretching. It can be seen that the area change of the soft-hard coupling package electrode composite layer 7 is reduced by 79% compared with the homogeneous PDMS substrate electrode. The lower figure shows the distribution of the internal stress of the two packaging layers, from which it can be seen that the stress inside the soft-hard coupling package electrode composite layer 7 is significantly reduced compared with the homogeneous PDMS substrate, and the average stress is reduced by 90%.

[0092] like Fig. 9 , which is a real photo of the tactile sensor array 0 of Example 1 of the present invention prepared by the above-mentioned preparation method.

[0093] like Fig.10 As shown in the figure, the response performance of the tactile sensor array using different ion gel ratios as the porous ion medium layer 4, it can be seen from the figure that when the ion gel solution concentration is 1:8, it has the highest sensitivity (average 2.733 kPa -1 ) and good linearity (0.986) over a wide detection range (0-1400kPa).

[0094] like Fig.11 As shown, the difference in the initial capacitance value and the difference in the response to pressure of the tactile sensor array prepared by the above preparation method at different overall stretching rates. It can be seen from the figure that at a maximum stretching rate of 75%, the response still maintains a relatively consistent response capability, and the statistical response deviation is within ±10.47%. The initial capacitance value of the tactile unit changes less with the stretching rate, and the relative change at a stretching rate of 75% is <7%, which is less than the response amplitude generated by 1Pa (calculated by the average sensitivity). Therefore, the use of a soft-hard coupling encapsulation layer 1 significantly improves the insensitivity of the tactile sensor array to tensile deformation.

[0095] like Fig.12As shown, the erroneous response of the tactile sensor array prepared by the above preparation method at different bending radii. It can be seen from the figure that when the bending radius is above 10mm, the statistical average erroneous response is about <0.17, which is approximately the response value generated by 0.06kPa pressure (calculated from the average sensitivity). Therefore, the use of the soft-hard coupling packaging layer 1 also significantly improves the insensitivity of the tactile sensor array to bending deformation.

[0096] like Fig.13 As shown in the figure, the crosstalk suppression results of the tactile sensor array are compared when the same soft-hard coupling package electrode composite layer 7 and porous ion medium layer 4 are used, with and without a multi-level segmented lattice support layer 3. It can be seen from the figure that the use of a multi-level segmented lattice support structure significantly reduces the crosstalk effect of the adjacent units (ABCD) on the central loading unit (O), and there is almost no visible crosstalk signal between the diagonally adjacent units. Here, the degree of influence of the adjacent unit signal on the central pressure unit signal is statistically and quantitatively calculated, and the crosstalk suppression ratio is defined as follows:

[0097] I CRR =-20log 10 (ΔC stressed / ΔC adiacent )

[0098] Among them, ΔCstressed is the capacitance signal response generated by the central stressed unit, and ΔCadjacent is the capacitance signal response generated by the vertically adjacent unit. The crosstalk suppression ratio of the tactile sensing array that does not use a multi-level segmented lattice support structure is about 15dB, while the crosstalk suppression ratio of the tactile sensing array that uses a multi-level lattice support structure reaches 30dB. Therefore, the use of a multi-level lattice support structure greatly improves the crosstalk suppression capability of the tactile sensing array.

[0099] The tactile sensor array of the present invention has a compact structure and close coordination. It can achieve excellent strain insensitivity and crosstalk suppression performance while the spatial resolution is less affected. The tactile unit response has high linearity, is insensitive to the maximum 75% tensile deformation (initial value drift <7%, response difference to pressure ±10.47%), and is insensitive to bending with a radius >10mm (the curvature of the finger surface of the human hand is about 10mm. Under a bending radius of 10mm, the relative change in capacitance is <0.17, which corresponds to a response of approximately 0.06kPa). For mechanical crosstalk (vertical deformation conduction), it can reduce the vertical deformation of adjacent units by 89.8%, and can achieve a crosstalk suppression ratio of about 30dB (that is, the adjacent units are affected by the contact unit by about 1 / 30). It maintains effective response capability within a large pressure range (0-1400kPa) and has good response linearity (0.986). It is easy to accurately and robustly capture tactile information on soft and curved human-machine surfaces, and achieve precise response to contact information.

[0100] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A tactile sensor array, characterized in that: The invention comprises a soft-hard coupling packaging layer, an electrode layer attached to the soft-hard coupling packaging layer, a multi-stage segmented lattice support layer arranged between the soft-hard coupling packaging layers by bonding, and a porous ion medium layer clamped between the electrode layers or between the electrode layer and the soft-hard coupling packaging layer. The multi-layer array is cooperatively arranged to achieve the insensitivity of the tactile sensor array to strain and the suppression of crosstalk.

2. The tactile sensor array according to claim 1, characterized in that: The soft-hard coupling packaging layer includes a high modulus hard area array coated with a low modulus soft material, and a soft connection area formed by filling the gaps between the high modulus hard area array with a low modulus soft material. The material used for the high modulus hard area is a high modulus hard material, which is PDMS or TPU or PVA, and the low modulus soft material is PDMS or Ecoflex series or TPU. The soft-hard coupling packaging layer has a thickness of 100-300 microns.

3. The tactile sensor array according to claim 2, characterized in that: The electrode layer is arranged as an electrode unit array, and the electrode layer adopts a parallel electrode structure or a coplanar electrode structure. The parallel electrodes are row electrodes or column electrodes, and the coplanar electrode structure is an interdigitated electrode or a spiral interdigitated electrode or a rectangular electrode.

4. The tactile sensor array according to claim 3, characterized in that: The multi-level segmented lattice support layer is a harder support unit, which is arranged between the layers of the soft connection area. The multi-level segmented lattice support unit adopts a cylindrical, square column or conical lattice structure. The size of a single lattice structure is 100 to 300 microns, and the spacing is 100 to 300 microns. The material used for the multi-level segmented lattice support layer is PDMS, TPU or PVA.

5. The tactile sensor array according to claim 4, characterized in that: The porous ion medium layer is an array unit, which is sandwiched between the electrode unit array layers or between the high modulus hard area array layer and the electrode unit array layer. The material used for the porous ion medium layer is an ion gel formed by mixing PVD (F-HFP) and ionic liquid [EMIM] [TFSI] in a 1:1 ratio attached to a high-porosity 3D grid frame. The high-porosity 3D grid frame is a melamine open-cell foam or an open-cell sponge or an open-cell foam prepared from PDMS / Ecoflex material.

6. The tactile sensor array according to claim 5, characterized in that: A five-layer structure is adopted, which is arranged from top to bottom in the following order: the first layer: a soft-hard coupling packaging layer, the second layer: a row electrode layer, the third layer: a porous ion medium layer array unit and a multi-stage segmented lattice support unit located between the porous ion medium layer array units, the fourth layer: a column electrode layer, and the fifth layer: a soft-hard coupling packaging layer. The electrode unit arrays of the row and column electrode layers are arranged on the high modulus hard area arrays of the first and fifth layers, and the array units of the porous ion medium layer are directly contacted and arranged between the electrode array layers of the second and fourth layers.

7. The tactile sensor array according to claim 5, characterized in that: A four-layer structure is adopted, which is arranged from top to bottom as follows: the first layer: a soft-hard coupling packaging layer, the second layer: a porous ion medium layer array unit and a multi-stage segmented lattice support unit located between the porous ion medium layer array units, the third layer: a coplanar electrode layer, and the fourth layer: a soft-hard coupling packaging layer. The electrode unit array of the coplanar electrode layer is arranged on the high modulus hard area array of the fourth layer, and the array unit of the porous ion medium layer is directly contacted between the high modulus hard area array layer of the first layer and the electrode array layer of the third layer.

8. A method for preparing a tactile sensor array as claimed in any one of claims 1 to 7, characterized in that: The steps include: Step 1: preparing a porous ion medium layer; Step 2: preparing a soft-hard coupling packaging layer; Step 3: preparing an electrode layer; Step 4: preparing a multi-level segmented lattice support layer; Step 5: Assemble the sensor array.

9. The method of the tactile sensing array as claimed in claim 8, characterized in that: The step one also includes the following steps: Step 1.1 dissolving the ion gel in an organic solvent to prepare ion gel solutions of different concentrations; Step 1.2: attaching the ion gel solution obtained in the above step to the high-porosity 3D grid framework by coating or embedding; Step 1.3: completely drying the 3D grid framework filled with the ion gel solution; Step 1.4: Use a die cutter to cut the dried porous ionic medium into array units matching the sensing electrodes; The step 2 also includes the following steps: Step 2.1 prepare a high modulus hard region of the array by using a high modulus material through molding or dispensing printing; Step 2.2: using an extrusion or doctor blade coating process, the low modulus material is pressed into the gap between the high modulus hard areas, while covering the high modulus hard areas; The step three also includes the following steps: Step 3.1 On the soft-hard coupling encapsulation layer, align the high modulus hard area by printing or dispensing printing to prepare the array electrode; Step 3.2 is drying; The step 4 is specifically as follows: The high modulus material is passed through a multi-level segmented lattice support structure mold, and a multi-level segmented lattice structure support layer is formed by dispensing printing or mold turning process; The step five also includes the following steps: Step 5.1: Covering the back of the multi-stage segmented lattice support layer with adhesive; Step 5.2 For parallel electrode configuration, use a die cutter to cut out the electrode corresponding area of ​​the multi-level segmented lattice support layer, and then bond it to the soft-hard coupling packaging layer of the printed electrode layer; for coplanar electrode configuration, bond it to the soft-hard coupling packaging layer on the side where the electrode is not printed; Step 5.3: After bonding the multi-level segmented lattice support layer to the soft-hard coupling packaging layer, demold and remove the layer, bond the multi-level segmented lattice support layer to another soft-hard coupling packaging layer, and clamp the array-divided porous ion medium between electrode array layers or between high modulus hard area array layers and electrode array layers.

10. The method of the tactile sensing array as claimed in claim 9, characterized in that: The mass ratio of the ion gel to the organic solvent in step 1.1 is 1:16, 1:12, and 1:8, and the organic solvent is acetone; The coating / embedding method in step 1.2 is dipping or spraying; When the melamine open-cell foam is used as the 3D grid framework in step 1.3, the drying temperature of the ion gel solution is 60°C.

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