WO2023210883A1

WO2023210883A1 - Tactile sensor using frictional electric field propagation, and tactile sensing method using same

Info

Publication number: WO2023210883A1
Application number: PCT/KR2022/014787
Authority: WO
Inventors: 최원준; 서병석; 차영선
Original assignee: 고려대학교 산학협력단
Priority date: 2022-04-28
Filing date: 2022-09-30
Publication date: 2023-11-02

Abstract

The present invention relates to a tactile sensor using frictional electric field propagation, comprising: a substrate; (1-1)th to (1-n)th electrodes (where n is a natural number of at least 2) formed on the substrate and spaced from each other; and a dielectric layer formed to cover the (1-1)th to (1-n)th electrodes, and using a ratio (V_ratio) of voltage measured at a pair of adjacent electrodes by means of the propagation of a frictional electric field generated when an object comes into contact with or slides on the dielectric layer, thereby sensing the location at which the object makes contact or a sliding operation thereof.

Description

Tactile sensor using friction electric field propagation and tactile sensing method using the same

The present invention relates to a tactile sensor using friction electric field propagation and a tactile sensing method using the same.

The development of portable electronic devices and electronic skin technology applied to the human body requires the development of a tactile sensor capable of detecting precise contact positions.

Representative tactile sensor technologies include capacitive tactile sensors and resistive tactile sensors.

Capacitive tactile sensors and resistance-type tactile sensors require electrode patterns with micro- to nano-scale microstructures for precise contact position sensing.

In order to manufacture an electrode pattern with such a fine structure, complex and difficult processes are required, and furthermore, inefficient energy consumption is required.

In addition, since capacitive tactile sensors have object specificity, there is a problem in that they only detect contact materials that are compatible with conductive materials (for example, if you are wearing gloves, they may not be able to detect even if you touch them with your finger). Resistive tactile sensors have the problem of severe mechanical aging due to high contact pressure.

In addition to capacitive tactile sensors and resistance-type tactile sensors, triboelectric-based tactile sensors have been proposed as other tactile sensor technologies.

In the case of Korean Patent Publication No. 10-2022-0037970, a “self-powered tactile sensor using impedance matching of a single electrode triboelectric generator” is proposed.

However, the triboelectric-based tactile sensors to date, including "Self-powered tactile sensor using impedance matching of a single-electrode triboelectric generator" in Korean Patent Publication No. 10-2022-0037970, have the problem of not being able to sense precise contact positions.

[Prior patent literature]

Korean Patent Publication No. 10-2022-0037970

Korean Patent Publication No. 10-2019-0072989

Korean Patent Publication No. 10-2008-0054187

Korean Patent Publication No. 10-2011-0124416

One object of the present invention is to provide a tactile sensor using friction electric field propagation and a touch sensing method using the same.

Meanwhile, other unspecified purposes of the present invention will be additionally considered within the scope that can be easily inferred from the following detailed description and its effects.

To achieve the purpose proposed above, we propose the following solutions.

A tactile sensor using triboelectric field propagation according to an embodiment of the present invention includes a substrate; 1-1 to 1-n electrodes formed on the substrate and spaced apart from each other (where n is a natural number of 2 or more); and a dielectric layer formed to cover the 1-1 to 1-n electrodes, wherein the frictional electric field propagation generated when an object touches or slides on the dielectric layer is measured at a pair of adjacent electrodes. It is characterized by detecting the contact position or sliding motion of an object using the voltage ratio (V _ratio ).

In one example, the distance between the 1-1th electrode to the 1-nth electrode may be 27 to 33 mm.

In one example, the 2-1 to 2-m electrodes are formed on the substrate, are formed at different angles from the 1-1 to 1-n electrodes, and are spaced apart from each other. , m may be characterized as further including a natural number of 2 or more).

In one example, the dielectric layer is polyamide (nylon 6,6), poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA), and poly(ethylene terephthalate (Mylar). , polyacrylonitrile (PAN), poly(bisphenol A carbonate) (PC), poly(vinylidene chloride), polystyrene (PS), polyethylene (PE), polypropylene (PP), poly(vinyl chloride) (PVC), polytetrafluoroethylene (PTFE) , polyester, polydimethylsiloxane (PDMS), and polyurethane.

In one example, a voltmeter may be connected to each of the 1-1 to 1-n electrodes.

A tactile sensing method according to another embodiment of the present invention includes a substrate; 1-1 to 1-n electrodes formed on the substrate and spaced apart from each other (where n is a natural number of 2 or more); and a dielectric layer formed to cover the 1-1 to 1-n electrodes, wherein a pair of adjacent electrodes are connected by friction electric field propagation generated when an object touches or slides on the dielectric layer. It is characterized by detecting the position where the object touches or the sliding motion using the ratio of the voltage (V _ratio ) measured at the electrode.

A tactile sensor using triboelectric field propagation and a touch sensing method using the same according to an embodiment of the present invention detect triboelectricity at adjacent electrodes when triboelectricity is generated due to touching or sliding of an object between a plurality of electrodes arranged to face each other. By detecting the touched or slid position using the ratio of one voltage, it is possible to detect a precise touch or slid position without a microstructured electrode pattern.

In addition, the tactile sensor using friction electric field propagation and the touch sensing method using the same according to an embodiment of the present invention, unlike the capacitive tactile sensor, can detect a precise contact position or sliding position regardless of the type of contact material. there is.

Meanwhile, it is to be added that even if the effects are not explicitly mentioned herein, the effects described in the following specification and their potential effects expected from the technical features of the present invention are treated as if described in the specification of the present invention.

Figure 1 is a schematic diagram of a tactile sensor using friction electric field propagation according to an embodiment of the present invention.

Figure 2 is a schematic perspective view of a test device with electrodes installed on one side of the dielectric layer, and schematically shows the propagation of triboelectricity generated by friction charging when an object is brought into contact at one location, and Figure 3 shows the test of Figure 2. This is a schematic cross-sectional view of the device, illustrating the process of dipole energy transfer within the dielectric according to the various contact positions of the object.

Figure 4 shows the open-circuit voltage (OCV) measurement results measured at the electrode when an object is contacted at positions 3 mm, 9 mm, 15 mm, 21 mm, and 27 mm away from the electrode of the test device.

Figure 5 is a graph showing the OCV measurement results according to the position where the object was contacted based on the electrode of the test device.

Figure 6 is a schematic diagram for explaining the operating principle of a tactile sensor using triboelectric field propagation according to an embodiment of the present invention, and Figure 7 shows the ratio of the OCV value measured at each electrode in the tactile sensor of Figure 6 and the voltage of the electrodes. This is the result of measuring .

Figure 8 shows the measurement results of V _ratio according to the spacing between electrodes.

Figure 9 shows the results of evaluating design factors considering detection resolution and panel area to determine optimal design dimensions.

Figure 10 shows the results of evaluating the position detection resolution of a tactile sensor using triboelectric field propagation according to an embodiment of the present invention with an electrode spacing of 30 mm.

Figure 11 shows the V _ratio measurement results according to the contact speed and position of the object.

Figure 12 shows the V _ratio measurement results when an object is contacted at a vertical speed of 50 cm/s and the object types are cellulose, nylon, and silicon.

Figure 13 shows the results of measuring the change over time in the OCV value measured upon contact with an object.

Figure 14 is a schematic diagram of dipole energy transfer in a dielectric layer induced by sliding motion.

Figure 15 shows OCV measurements when sliding at a speed of 11.5 cm/s at initial positions of 0, 6, 15, and 24 mm, and Figure 16 shows V _ratio measurements at various initial positions and sliding distances.

Figure 17 is a touch pad manufactured using a tactile sensor using friction electric field propagation according to an embodiment of the present invention.

Figures 19 and 20 show the results of tracking the mixed motion of contact and sliding.

Figure 21 shows the results when polygonal stimuli such as (a) triangle, (b) square, and (c) star shape are applied.

Figure 22 is a schematic flow chart of a method of manufacturing a tactile sensor using friction electric field propagation according to an embodiment of the present invention.

The attached drawings are intended as reference for understanding the technical idea of the present invention, and are not intended to limit the scope of the present invention.

Hereinafter, with reference to the drawings, we will look at the configuration of the present invention guided by various embodiments of the present invention and the effects resulting from the configuration. In describing the present invention, if it is determined that related known functions may unnecessarily obscure the gist of the present invention as they are obvious to those skilled in the art, the detailed description thereof will be omitted.

In order for a tactile sensor to be commercially viable, it must have high resolution and fast response time, and must be easy to integrate into applications such as displays or electronic skin.

The tactile sensor using triboelectric field propagation according to an embodiment of the present invention has high resolution and fast response time, and its structure is also very simple.

Furthermore, a tactile sensor using friction electric field propagation according to an embodiment of the present invention can detect a precise contact position or sliding position regardless of the type of contact material.

Referring to Figure 1, the tactile sensor 100 using triboelectric field propagation according to an embodiment of the present invention is formed on the substrate 10 and the 1-1 electrode to the 1-1-th electrode formed on the substrate 10 and spaced apart from each other. It includes a first electrode 21 composed of n electrodes (where n is a natural number of 2 or more), and a dielectric layer 30 formed on the first electrode 21 and through which an object touches or slides.

The 1-1th electrode to the 1-nth electrode (where n is a natural number of 2 or more) may be collectively referred to as the first electrode 21.

The tactile sensor 100 using triboelectric field propagation according to an embodiment of the present invention may further include a 2-1 electrode to a 2-m electrode (where m is a natural number of 2 or more) spaced apart from each other.

The 2-1st to 2-m electrodes (where m is a natural number of 2 or more) may be collectively referred to as the second electrode 22.

The first electrode 21 and/or the second electrode 22 may be formed to be long in one direction and may be in the form of a wire or line.

The 1-1 to 1-n electrodes (where n is a natural number of 2 or more) may be formed parallel to each other, and the 2-1 to 2-m electrodes (where m is a natural number of 2 or more) may also be formed. They can be formed parallel to each other.

Parallel here does not mean parallel to the extent that they do not meet each other when extending an infinite straight line, but rather means that they are formed side by side to the extent that they do not meet each other within the device.

Furthermore, even if the 1-1st to 1-nth electrodes (where n is a natural number of 2 or more) are not parallel to each other, the contact position or sliding position can be detected by the adjacent first electrode 21, and the second Even if the -1 to 2-m electrodes (where m is a natural number of 2 or more) are not parallel to each other, the contact position or sliding position can be detected by the adjacent second electrode 22.

The first electrode 21 and the second electrode 22 may be formed in different directions, for example, at right angles.

At this time, the first electrode 21 can be said to be a row electrode, and the second electrode 22 can be said to be a column electrode.

The first electrode 21 and/or the second electrode 22 are made of highly conductive metal such as gold, silver, or copper, carbon material such as carbon nanotube, or conductive polymer. can be formed.

A voltmeter is connected to each of the first electrode 21 and the second electrode 22 to measure the voltage change.

That is, a voltmeter may be connected to the 1-1st electrode to the 1-nth electrode (where n is a natural number of 2 or more) and the 2-1th electrode to the 2-m electrode (where m is a natural number of 2 or more). .

The first electrode 21 and the second electrode 22 may be formed on the substrate 10.

More specifically, the substrate 10 includes a PCB, and its materials include polyamide (nylon 6,6), poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), and poly(methyl methacrylate) (PMMA). , poly(ethylene terephthalate (Mylar), polyacrylonitrile (PAN), poly(bisphenol A carbonate) (PC), poly(vinylidene chloride), polystyrene (PS), polyethylene (PE), polypropylene (PP), poly(vinyl chloride) Any one selected from the group consisting of (PVC), polytetrafluoroethylene (PTFE), polyester, polydimethylsiloxane (PDMS), and polyurethane can be used.

However, the material of the substrate within the scope of the present invention is not limited to the above-mentioned materials, and known materials can be used.

The dielectric layer 30 is formed on the first electrode 21 and the second electrode 22.

The dielectric layer 30 is made of polyamide (nylon 6,6), poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA), poly(ethylene terephthalate (Mylar), polyacrylonitrile ( PAN), poly(bisphenol A carbonate) (PC), poly(vinylidene chloride), polystyrene (PS), polyethylene (PE), polypropylene (PP), poly(vinyl chloride) (PVC), polytetrafluoroethylene (PTFE), polyester, Any one selected from the group consisting of polydimethylsiloxane (PDMS) and polyurethane can be used.

An object such as a human hand or a pencil touches or slides on one surface of the dielectric layer 30.

When an object comes into contact with a dielectric layer, triboelectricity is generated by friction charging, and the triboelectricity propagates in a circle along the surface of the dielectric, forming an electric field around it (see Figure 2).

The electric field of the propagating triboelectricity and the adjacent dipoles interact with each other to change the moment angle of the dipole, and the energy consumed to change the moment angle of the dipole results in the triboelectricity decreasing with the propagation distance (Figure 3 reference).

Therefore, when triboelectricity is sensed using an electrode and the degree of attenuation is measured, the position of the contact point where the object touches the dielectric layer can be inversely derived.

As explained above, it can be seen that the measured OCV value varies depending on the distance from the electrode.

As shown in Figure 5, the OCV value decreases from 9.07 mV to 1.41 mV as the contact position of the object relative to the electrode increases from 3 mm to 15 mm, and when the distance from the electrode is more than 30 mm, there is a significant change in OCV value. is not observed.

From the object contact position-OCV graph of FIG. 5, an empirical spinning calculation as shown in Equation 1 below can be derived.

In Equation 1, V _OCV and x mean the measured OCV value and the contact position of the object based on the electrode, respectively.

The calculation results of FIG. 5 and Equation 1 show that when measuring the voltage change due to triboelectricity in a test device using a single electrode, it is possible to invert the location where the object was in contact, that is, the distance from the electrode. It suggests that there is.

However, in a test device using a single electrode, it is difficult to distinguish locations more than 10 mm from the electrode because the rate of change in the measured voltage is small, and furthermore, the measured voltage value varies depending on factors such as the type of object, type of dielectric layer, temperature, and humidity. There is a problem that is changing.

In other words, methods using a single electrode, such as in a test device, have limitations in deriving the exact location where an object touches.

In order to overcome this limitation, the tactile sensor 100 using triboelectric field propagation according to an embodiment of the present invention includes a plurality of

electrodes

21 and 22, and a dielectric layer 30 formed on the

electrodes

21 and 22. ), when an object touches or slides to generate triboelectricity, the ratio (V _ratio ) of the voltage detected by a pair of adjacent electrodes is used.

When using the ratio of voltages detected by a pair of adjacent electrodes, the contact or sliding position of an object can be detected with high accuracy even if the distance between adjacent electrodes is widened up to 30 mm, and the type of object changes or the operation Even if the environment changes, the contact or sliding position of an object can be detected with high accuracy.

Looking at the specific principles, they are as follows.

As can be seen in Figure 7. As triboelectricity is generated and propagated, adjacent electrodes detect different values of OCV depending on the distance from the object's contact location.

At this time, the location where the object touches is detected using the ratio of OCV (V _ratio ) detected at the 1-1 electrode (Electrode 1) and the 1-2 electrode (Electrode 2).

In other words, even if an object touches an area where no electrode is formed between the 1-1 electrode (Electrode 1) and the 1-2 electrode (Electrode 2), its position can be detected precisely.

When the distance between the 1-1 electrode (Electrode 1) and the 1-2 electrode (Electrode 2) was 30 mm, the OCV values received from both electrodes were almost the same at the central 15 mm position.

As can be seen in Figure 8, the V _ratio has a similar graph shape regardless of the spacing between electrodes, and converges to 1 at the center.

The wider the gap between electrodes, the simpler the manufacturing process, and in particular, the fewer problems such as screen blocking by electrodes.

Meanwhile, the value of the detection resolution varies depending on the target standard. When the target detection resolution is 3mm, the variation ratio of V _ratio according to the contact distance is 99.31%, and when the target detection resolution is 3mm, the variation ratio of V _ratio according to the contact distance is 99.31%. This is only 2.36%.

In Figure 9, the electrode spacing that allows optimal design when the target detection resolution is 100 μm is derived.

Referring to FIG. 9, the spacing between adjacent electrodes may be 27 to 33 mm, and most preferably 30 mm.

Next, performance evaluation of the tactile sensor using friction electric field propagation according to an embodiment of the present invention was performed.

Performance evaluation was performed based on the electrode spacing of 30 mm, which was the best mode.

Objects were contacted every 2 mm within the range of 0 to 30 mm, and as a result, a low level of error was shown, less than 7.14%, regardless of the contact location.

As can be seen in Figure 11, the error is within 6.29% when the object is contacted at vertical speeds of 30, 50, and 70 cm/s, showing a similar level of error regardless of the contact speed.

When objects with different dielectric properties such as cellulose, nylon, and silicon come into contact, the measured OCV value varies depending on the type of material, but the V _ratio can be confirmed to be constant.

In other words, it can be seen that the tactile sensor using triboelectric field propagation according to an embodiment of the present invention has strong sensing characteristics that do not depend on stimulation conditions such as stimulation dynamics and stimulation object material.

Referring to Figure 13, the OCV value increased as the object approached the surface of the dielectric layer through the air gap capacitance, and decreased due to charging after contact.

The refresh time and agility of a tactile sensor using triboelectric field propagation according to an embodiment of the present invention are determined by OCV behavior after contact.

The maximum refresh time of the tactile sensor using friction electric field propagation according to an embodiment of the present invention was 34.72 Hz.

Next, performance evaluation was performed on the sliding motion detection of the tactile sensor using triboelectric field propagation according to an embodiment of the present invention.

When a sliding motion is performed on the dielectric layer of a tactile sensor, dipole polarization is induced within the dielectric in the sliding direction.

This dipole polarization generates OCV signals at both electrodes with opposite signs (i.e., negative or positive signs compared to ground).

For example, when an object slides from the 1-1 electrode (electrode 1) to the 1-2 electrode (electrode 2) in the dielectric layer, voltage pulses of opposite signs are measured at both electrodes.

Therefore, the direction and final position of the sliding motion can be detected based on the V _ratio of the two electrodes and the sign of that value.

Referring to Figures 15 and 16, when using V _ratio , there is an advantage that all initial positions and sliding distances can be detected without hidden areas.

Next, an example of using a tactile sensor using friction electric field propagation according to an embodiment of the present invention will be introduced.

A touch pad with a touch area of 3 cm

The alphabet from A to I was assigned to the virtual area.

Figure 18 shows the results of measuring OCV values generated at each electrode by finger touch stimulation in areas "A", "D", and "E".

As can be seen in Figure 18, it can be confirmed that the position where the finger is in contact with the touch pad manufactured using the tactile sensor using friction electric field propagation according to an embodiment of the present invention can be accurately distinguished.

As shown in Figure 19, when touching area "A" and sequentially sliding to area "G", all electrodes initially detect a positive OCV and detect that the contact position is "A", and then while sliding to area G. Positive OCV was measured only at Line 4 located in the sliding direction, confirming that the sliding direction and position were accurately detected.

As shown in Figure 20, when touching area "A" and sequentially sliding to area "I", all electrodes initially detect positive OCV and detect that the contact position is "A", and then while sliding to area I. Positive OCV was measured only at Lune 2 and Line 4 located in the sliding direction, confirming that the sliding direction and position were accurately detected.

Furthermore, when using V _ratio , the coordinates of the contact location and sliding distance can be estimated.

As shown in Figure 21, it can be seen that the touch pad manufactured using a tactile sensor using triboelectric field propagation according to an embodiment of the present invention smoothly senses even complex forms of contact.

Specifically, a PET substrate (10 cm Х 10 cm, thickness 50 μm) cleaned with ethanol and deionized water is covered with a stainless steel shadow mask with an electrode spacing of 30 mm.

Silver (4N purity) electrodes were formed through DC magnetron sputtering at 100 W for 1.5 hours and deposited on PET substrates for column electrodes in an argon atmosphere with a flow rate of 30 sccm and a pressure of 2.8Х10 ^-3 Torr.

The row electrodes were deposited under identical conditions using aligned cellulose insulators to prevent electrical interference between the column and row electrodes.

After removing impurities by spraying nitrogen, 1 g of PDMS solution (Sigma-Aldrich, SYLGARD 184) mixed with a curing agent at a weight ratio of 10:1 using a vortex mixer was poured and fired at 60°C for 2 hours.

In this way, a tactile sensor using friction electric field propagation according to an embodiment of the present invention was manufactured.

The scope of protection of the present invention is not limited to the description and expression of the embodiments explicitly described above. In addition, it is once again added that the scope of protection of the present invention may not be limited due to changes or substitutions that are obvious in the technical field to which the present invention pertains.

Claims

Board;

1-1 to 1-n electrodes formed on the substrate and spaced apart from each other (where n is a natural number of 2 or more); and

It includes a dielectric layer formed to cover the 1-1 to 1-n electrodes,

Characterized by detecting the contact position or sliding motion of the object using the ratio of voltages (V ratio ) measured at a pair of adjacent electrodes by friction electric field propagation generated when an object touches or slides on the dielectric layer. A tactile sensor using friction electric field propagation.
According to paragraph 1,

A tactile sensor using triboelectric field propagation, characterized in that the distance between the 1-1 electrode to the 1-n electrode is 27 to 33 mm.
According to paragraph 1,

2-1 to 2-m electrodes formed on the substrate, formed at different angles from the 1-1 to 1-n electrodes, and spaced apart from each other (where m is 2 or more) A tactile sensor using friction electric field propagation, characterized in that it further includes natural water).
According to paragraph 1,

The dielectric layer is polyamide (nylon 6,6), poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA), poly(ethylene terephthalate (Mylar), polyacrylonitrile (PAN). , poly(bisphenol A carbonate) (PC), poly(vinylidene chloride), polystyrene (PS), polyethylene (PE), polypropylene (PP), poly(vinyl chloride) (PVC), polytetrafluoroethylene (PTFE), polyester, polydimethylsiloxane ( A tactile sensor using triboelectric field propagation, characterized in that it is selected from the group consisting of PDMS) and polyurethane.
According to paragraph 1,

A tactile sensor using friction electric field propagation, characterized in that a voltmeter is connected to each of the 1-1 to 1-n electrodes.
Board; 1-1 to 1-n electrodes formed on the substrate and spaced apart from each other (where n is a natural number of 2 or more); and a dielectric layer formed to cover the 1-1 to 1-n electrodes. A tactile sensing method using a tactile sensor comprising:

Characterized by detecting the contact position or sliding motion of the object using the ratio of voltages (V ratio ) measured at a pair of adjacent electrodes by friction electric field propagation generated when an object touches or slides on the dielectric layer. A tactile sensing method.