CN106706176A - Capacitive touch sensor having patterned microstructure array - Google Patents

Abstract

The invention discloses a capacitive touch sensor with a patterned microstructure array. It is composed of fingerprint-like surface micro-protrusions, upper capacitive electrode substrate, upper capacitive electrode, two-dimensional sinusoidal micro-protrusion dielectric layer, lower capacitive electrode and lower capacitive electrode substrate from top to bottom. The fingerprint-like surface micro-convex It is used to receive external force stimulation, the base of the upper and lower capacitive electrodes is used as a structural support, and the series direction of the electrode sheets on the upper and lower capacitive electrodes is arranged in an orthogonal manner, and together with the two-dimensional sinusoidal micro-protruding dielectric layer, the three-dimensional sensor is formed The capacitive main body, after the upper surface of the micro-protrusion on the fingerprint-like surface is stimulated by an external force, senses the capacitance change through the capacitive main body and converts it to obtain the magnitude and direction of the force. The invention solves the problem of high-sensitivity real-time detection of multi-dimensional force by the sensor, and can be applied in fields such as artificial limbs and surgical manipulators that require high sensitivity.

Description

Capacitive tactile sensor with array of patterned microstructures

technical field

The invention relates to a flexible touch sensor, in particular to a capacitive touch sensor with a patterned microstructure array.

technical background

In order to make the working and behavioral capabilities of robots as close as possible to humans, and to be able to work with humans, in addition to more precise motion and operation control, a recognition and perception system close to humans is also required. Usually, the control of the robot is mainly accomplished through the continuous feedback of the spatial position information of mechanical parts or certain image recognition information. The appearance of the tactile sensor makes it increase the contact information between the mechanical parts and the external environment on the original basis, making the mutual feedback between the mechanical parts and the control program more perfect. At the same time, tactile sensors are also building a new human-machine interface between humans and robots. It can be seen that the research of tactile sensors is indispensable. Smart prosthetics are a big area of application for tactile sensors. The lack of tactile perception ability of traditional prosthetics greatly reduces its rehabilitation effect and disability repair ability. Therefore, the tactile sensor is of great significance for the establishment of the tactile perception system of prosthetics. The introduction of tactile sensors can make the artificial prosthesis a part of the patient's body, build an effective information exchange channel between the prosthesis and the patient, and between the prosthesis and the environment, establish tactile perception capabilities for the patient, and realize the bionic and intelligent artificial prosthesis. At the same time, tactile sensors can provide high-sensitivity tactile perception for surgical manipulators, and can play a huge role in minimally invasive surgery.

At present, tactile sensors can be divided into the following types according to their sensing mechanisms: resistive, capacitive, piezoelectric, optical and other forms of sensors, among which capacitive tactile sensors are due to their good sensitivity and spatial resolution, and are affected by The characteristic of small temperature influence has been widely concerned.

Although there are many types of existing tactile sensors, their sensitivity has not yet met the requirements for precise detection of small forces. Therefore, it is very important to design a sensor with high sensitivity.

Contents of the invention

In order to make up for the deficiencies in the prior art, the object of the present invention is to provide a capacitive tactile sensor with a patterned microstructure array, which has the characteristics of high sensitivity.

The technical scheme adopted in the present invention is:

The capacitive touch sensor of the present invention is mainly composed of fingerprint-like surface micro-protrusions, upper capacitive electrode base, upper capacitive electrode, two-dimensional sinusoidal micro-protrusion dielectric layer, lower capacitive electrode and lower capacitive electrode base from top to bottom It is tightly stacked and has the ability to measure multi-dimensional force. Among them, the micro-protrusions on the fingerprint-like surface are used to receive external force stimulation, the base of the upper capacitive electrode and the base of the lower capacitive electrode are used as structural supports, and the direction of series connection between the upper capacitive electrode and the electrode plate on the lower capacitive electrode is arranged orthogonally, and is aligned with the two-dimensional The three sinusoidal micro-protrusion dielectric layers together constitute the capacitive body of the sensor. After the upper surface of the micro-protrusion on the fingerprint-like surface is stimulated by an external force, the capacitance change is sensed by the capacitive body, and the force is obtained through the conversion of the capacitance change. size and direction.

The upper fingerprint-like surface micro-protrusions, the capacitive electrode base, the two-dimensional sinusoidal micro-protrusion dielectric layer, and the lower capacitive electrode substrate are all made of materials with good flexibility, specifically, they can be made of organic polymers.

The micro-protrusion dielectric layer is a flexible film with a two-dimensional orthogonal sine wave top surface, the height of a single protrusion is 6-10 μm, the width is 65-75 μm, and the average thickness of the dielectric layer is 55-60 μm, so that it can strengthen Sensitivity of the sensor for multi-dimensional force detection. The two-dimensional orthogonal sinusoidal upper surface means that the cross-sections of the upper surface along two orthogonal directions are sinusoidal.

The upper surface of the micro-protrusions on the fingerprint-like surface has a texture morphology similar to that of the human fingertip skin, the height of a single protrusion is 3-5 μm, the width is 65-75 μm, and the average thickness of the micro-protrusion layer is 45-50 μm, so that it can receive The external force stimulates and improves the stress situation.

Both the upper capacitor electrode and the lower capacitor electrode are arranged in a spaced array of multiple electrode sheets, and the array arrangement of the upper capacitor electrode electrode sheet is the same as the array arrangement of the lower capacitor electrode electrode sheet, so that the upper layer Each electrode piece of the capacitor electrode corresponds to one electrode piece of the lower capacitor electrode directly below to form a flat plate capacitance; all electrode pieces are connected in series in the same column direction or in series in the same row direction. A plurality of electrode plates, the electrode pole piece series connection direction of the upper capacitor electrode and the electrode pole piece series connection direction of the lower capacitor electrode are orthogonal (perpendicular).

In the specific implementation, the end of each electrode plate is connected to the external signal acquisition device, and the disconnection process is performed in the middle of each electrode plate between the upper capacitor electrode and the lower capacitor electrode, so that each electrode plate It is divided into two electrode plates, and all the electrode plates of the upper capacitor electrode and the lower capacitor electrode are divided into four parts by the four areas at the four corners, so that all the plate capacitors formed between the upper capacitor electrode and the lower capacitor electrode It is divided into four parts, and each part is connected to an external signal acquisition device to traverse the acquisition capacitance value, so as to improve the efficiency of acquisition.

The number of plate capacitors in the row direction and the column direction of the upper layer capacitor electrode and the lower layer capacitor electrode is the same, and both include N rows×N column plate capacitors, and form a multidimensional force with every 2 rows×2 column plate capacitors. Detection unit, after the multi-dimensional force detection unit is stimulated by external force, the capacitance value of the four plate capacitors changes, and is converted into the magnitude and direction of the force according to the change of capacitance value, so as to convert the capacitance change caused by external force stimulation For force information, realize tactile sensing detection.

The beneficial effects that the present invention has are:

(1) Combining the good sensitivity characteristics of the capacitive tactile sensor itself with the highly flexible two-dimensional sinusoidal micro-protrusion dielectric layer, the tactile sensor has high sensitivity, which solves the problem of high-sensitivity real-time detection of multi-dimensional forces by the sensor, and can be used in Applications in artificial prosthetics, surgical manipulators and other fields that require high sensitivity.

(2) Micro-protrusions on the surface of the sensor with a texture similar to that of the human fingertip skin are used to improve the stress situation when the sensor is stimulated by external forces.

(3) Using 2 rows × 2 columns of capacitors as a multi-dimensional force detection unit, the changes of the 4 capacitors are converted into the magnitude and direction of the external force.

(4) The capacitive tactile sensor is made of highly flexible organic polymer, which makes the sensor have good flexibility and good adaptability to curved surface loading.

Description of drawings

Fig. 1 is an exploded perspective view of the layered structure of the present invention.

Fig. 2 is a perspective view of micro-protrusions on the fingerprint-like surface of the present invention.

Fig. 3 is a perspective view of a two-dimensional sinusoidal micro-protrusion dielectric layer of the present invention.

Fig. 4 is a plan view of the upper capacitive electrode and a partition diagram of the multi-dimensional force detection unit of the present invention.

Fig. 5 is a plan view of the lower capacitive electrode and a divisional diagram of the multi-dimensional force detection unit of the present invention.

Fig. 6 is a perspective view of the layout of the upper and lower capacitive electrodes of the present invention.

Fig. 7 is a perspective view of a single multi-dimensional force detection unit and detection principle of the present invention.

FIG. 8 is a cross-sectional view of the final capacitive touch sensor of the present invention.

FIG. 9 is a perspective view of the final capacitive touch sensor of the present invention.

In the figure: 1. Micro-protrusions on the fingerprint-like surface, 2. The base of the upper capacitor electrode, 3. The upper capacitor electrode, 4. The two-dimensional sinusoidal micro-protrusion dielectric layer, 5. The lower capacitor electrode, 6. The base of the lower capacitor electrode, 7. Multi-dimensional force detection unit.

detailed description

The present invention will be further described below in conjunction with drawings and embodiments.

As shown in Figure 1, Figure 8, and Figure 9, the capacitive touch sensor of the present invention is mainly composed of fingerprint-like surface micro-protrusions 1, upper-layer capacitive electrode base 2, upper-layer capacitive electrode 3, two-dimensional sinusoidal The micro-protrusion dielectric layer 4, the lower capacitive electrode 5 and the lower capacitive electrode base 6 are closely stacked, and have multi-dimensional force measurement capability.

Among them, as shown in Figure 1, the fingerprint-like surface micro-protrusion 1 is used to receive external force stimulation, the upper layer capacitor electrode base 2 and the lower layer capacitor electrode base 6 are used as structural supports, and the electrode pads on the upper layer capacitor electrode 3 and the lower layer capacitor electrode 5 The series direction is arranged orthogonally, and together with the two-dimensional sinusoidal micro-protrusion dielectric layer 4, the capacitive body of the sensor is formed. After the upper surface of the micro-protrusion 1 on the fingerprint-like surface is stimulated by an external force, it is sensed as The capacitance changes, and then the magnitude and direction of the force are obtained through the conversion of the capacitance change.

As shown in FIG. 3 , the micro-protrusion dielectric layer 4 is a flexible film with a two-dimensional orthogonal sinusoidal top surface. As shown in FIG. 2 , the upper surface of the fingerprint-like surface micro-protrusion 1 has a texture morphology similar to that of the human fingertip skin. The upper surface of the micro-protrusion on the fingerprint-like surface in Fig. 2 is only for illustration, and the upper surface of the micro-protrusion 1 on the actual fingerprint-like surface should be irregular.

As shown in Fig. 4 and Fig. 5, the upper capacitor electrode 3 and the lower capacitor electrode 5 are all arranged in a spaced array of multiple electrode pole pieces, and the array arrangement of the upper capacitor electrode 3 electrode pole pieces is the same as that of the lower capacitor electrode 5 electrodes. The array arrangement of the pole pieces is the same, so that each electrode pole piece of the upper capacitor electrode 3 corresponds to one electrode pole piece of the lower capacitor electrode 5 directly below to form a flat capacitor; all electrode pole pieces are connected in series in the same column direction Or be connected in series in the same row direction and be divided into a plurality of electrode plates, the electrode plate series direction of the upper capacitor electrode 3 is orthogonal (perpendicular) to the electrode plate series direction of the lower layer capacitor electrode 5 . For example, the electrode pads of the upper capacitor electrode 3 are arranged and connected in series in the same column, and the electrode pads of the lower capacitor electrode 5 are arranged and connected in series in the same row. And vice versa.

As shown in Figure 4-6, the number of plate capacitors in the row direction and the column direction of the upper capacitive electrode 3 and the lower capacitive electrode 5 are the same. ×2 columns of plate capacitors form a multidimensional force detection unit 7. After the multidimensional force detection unit 7 is stimulated by an external force, the capacitance values of the four plate capacitors change, and are converted into the magnitude and Direction, so that the capacitance change caused by external force stimulation is converted into force information to realize tactile sensing detection.

As shown in Figure 6, in specific implementation, the end of each electrode plate is connected to an external signal acquisition device, and the disconnection process is performed in the middle of each electrode plate of the upper capacitor electrode 3 and the lower layer capacitor electrode 5 , so that each electrode plate is divided into two electrode plates, and all the electrode plates of the upper capacitor electrode 3 and the lower capacitor electrode 5 are divided into four parts by the four regions of the four corners, so that the upper capacitor electrode 3 All plate capacitors formed between the capacitive electrode 5 and the lower layer are divided into four parts, and each part is connected to an external signal acquisition device to traverse the acquisition capacitance value, thereby improving acquisition efficiency.

The working principle of the present invention is described as follows:

By controlling the circuit to gate the corresponding upper capacitor electrode 3 and the lower capacitor electrode 5, one capacitor in the touch sensor is gated and connected to the capacitance detection circuit, and the remaining capacitors are shielded. As shown in Fig. 8 and Fig. 9, when the tactile sensor is subjected to external force, the sensor is pressed so that the distance between the upper capacitive electrode 3 and the lower capacitive electrode 5 becomes smaller, and the capacitance value increases. As shown in FIG. 7 , by measuring the changes of the four capacitances in a multi-dimensional force detection unit 7 , the magnitude and direction of the external force on the unit can be obtained. When the multidimensional force detection unit 7 is subjected to an external force F, it can decompose F into three orthogonal directions of force: normal force F _z , tangential force F _x , and tangential force F _y . The normal force F _z causes the four capacitors in the multidimensional force detection unit 7 to be compressed, and the electrode spacing decreases by the same amount; the tangential force F _x makes the two capacitors located on one side in the direction of the tangential force among the four capacitors The capacitance is pressed, and the distance between the electrodes decreases by the same amount, and the other two capacitors are pulled, and the distance between the electrodes increases by the same amount; the tangential force F _y is the same. By scanning the capacitors in the sensor one by one at high speed through the control circuit, and then measuring the value of each capacitor through the detection circuit, the force of each multi-dimensional force detection unit 7 in the entire sensor can be detected.

Embodiments of the present invention are as follows:

The fabrication steps to complete the capacitive tactile sensor with patterned microstructure array are as follows:

(1) The upper and lower capacitive electrodes and the substrate are manufactured by MEMS micro-nano manufacturing process. Among them, the substrate is made of PET film with a thickness of 25 μm, and the upper and lower capacitor plates are made of copper through magnetron sputtering process.

(2) Using PEGDA material, using 3D printing technology to manufacture a two-dimensional sinusoidal micro-protrusion dielectric layer and fingerprint-like surface micro-protrusions.

(3) As shown in FIG. 9 , paste and assemble each manufactured layer into a touch sensor. After testing, the sensitivity of the sensor is 0.03%/mN.

The parameters of the tactile sensor in the embodiment of the present invention are: a square with a total thickness of about 200 μm and a side length of 10 mm, a single capacitor is a square with a side length of 500 μm, and the spatial resolution of the multidimensional force detection unit is 800 μm. In the micro-protrusion dielectric layer 4 , the height of a single protrusion is 6-10 μm, the width is 65-75 μm, and the average thickness of the dielectric layer is 45-50 μm. In micro-protrusion 1 on the fingerprint-like surface, the height of a single protrusion is 3-5 μm, the width is 65-75 μm, and the average thickness of the micro-protrusion layer is 55-60 μm.

Embodiment According to the above steps, the sensitivity of the manufactured tactile sensor reaches 0.03%/mN, which has the characteristics of high sensitivity and high flexibility, and is of great significance for the establishment of tactile perception of human intelligent prosthesis.

The tactile sensor of the present invention can be used as the "flexible tactile sensitive skin" of the robot, which enhances its ability to complete fine and complex operations in various environments, and greatly improves the intelligence of the robot. In terms of biomedicine, tactile sensors can be applied to the fields of high-precision surgical robots and minimally invasive surgical smart devices.

Claims (7)

1. A capacitive touch sensor with a patterned microstructure array, characterized in that: said capacitive touch sensor is mainly composed of fingerprint-like surface micro-protrusions (1) from top to bottom, upper capacitive electrode base ( 2), the upper capacitive electrode (3), the two-dimensional sinusoidal micro-protrusion dielectric layer (4), the lower capacitive electrode (5) and the lower capacitive electrode substrate (6) are closely laminated, and the fingerprint-like surface micro-protrusion (1 ) is used to receive external force stimulation, the upper capacitive electrode base (2) and the lower capacitive electrode base (6) are used as structural supports, and the upper capacitive electrode (3) is orthogonal to the electrode pole pieces on the lower capacitive electrode (5) in series Arranged, and together with the two-dimensional sinusoidal micro-protrusion dielectric layer (4) constitute the capacitive body of the sensor, after the upper surface of the fingerprint-like surface micro-protrusion (1) is stimulated by an external force, it is sensed as a capacitance through the capacitive body Change, and then transform to obtain the magnitude and direction of the force. 2. A capacitive touch sensor with a patterned microstructure array according to claim 1, characterized in that: said upper fingerprint-like surface micro-protrusions (1), capacitive electrode base (2), two-dimensional sinusoidal The micro-protrusion dielectric layer (4) and the capacitor electrode base (6) of the lower layer are all made of materials with good flexibility. 3. A capacitive touch sensor with a patterned microstructure array according to claim 1, characterized in that: the micro-protrusion dielectric layer (4) has a two-dimensional orthogonal sine wave top surface The flexible film has a single protrusion height of 6-10 μm, a width of 65-75 μm, and an average thickness of the dielectric layer of 55-60 μm, so that the sensitivity of the sensor for multi-dimensional force detection can be enhanced. 4. A capacitive touch sensor with a patterned microstructure array according to claim 1, characterized in that: the upper surface of the fingerprint-like surface micro-protrusion (1) has a texture similar to that of the human fingertip skin Morphology, the height of a single protrusion is 3-5 μm, the width is 65-75 μm, and the average thickness of the micro-protrusion layer is 45-50 μm, so that it can receive external force stimulation and improve the stress situation. 5. A capacitive touch sensor with a patterned microstructure array according to claim 1, characterized in that: the upper capacitive electrode (3) and the lower capacitive electrode (5) are all separated by a plurality of electrode pole pieces Arranged in an array, the array arrangement of the upper capacitive electrodes (3) electrode sheets is the same as the array arrangement of the lower capacitive electrodes (5) electrode sheets, so that each electrode sheet of the upper capacitive electrodes (3) and its The lower capacitor electrode (5) directly below one electrode plate corresponds to form a flat plate capacitor; all electrode plates are divided into multiple electrode plates in the same column direction or connected in series in the same row direction, and the upper layer capacitor The electrode pole piece series connection direction of the electrode (3) is orthogonal to the electrode pole piece series connection direction of the lower capacitor electrode (5). 6. A kind of capacitive touch sensor with patterned microstructure array according to claim 1, is characterized in that: the end of each electrode plate is all connected in the signal acquisition device of outside, in upper strata capacitive electrode ( 3) Disconnect the middle of each electrode plate of the lower capacitor electrode (5), so that each electrode plate is divided into two electrode plates, and the upper layer capacitor electrode (3) is divided into four areas at the four corners. All electrode plates with the lower capacitor electrode (5) are equally divided into four parts, and each part is connected to an external signal acquisition device to traverse and collect capacitance values. 7. A kind of capacitive touch sensor with patterned microstructure array according to claim 1, is characterized in that: described upper capacitive electrode (3) and lower capacitive electrode (5) on row direction and column direction The number of plate capacitors is the same, and a multi-dimensional force detection unit (7) is formed with 2 rows×2 column plate capacitors. After the multi-dimensional force detection unit (7) is stimulated by external force, the capacitance values of the four plate capacitors are According to the change of the capacitance value, it is converted into the magnitude and direction of the force to realize the tactile sensing detection.