CN110477928B - Tensile stress sensors and bending sensing devices - Google Patents

Abstract

The invention relates to a tensile stress sensor, which comprises a first conductive fiber and a second conductive fiber, wherein the second conductive fiber is wound on the first conductive fiber to form at least one contact part between the first conductive fiber and the second conductive fiber; the area of the contact part changes along with the change of the state that the second conductive fiber is stretched by external force. The stretching stress sensor has the advantages of small volume, enough response, real-time monitoring, compatibility with the existing textile technology and convenience in wearing. The invention also relates to a bending sensing device which comprises at least one stretching type stress sensor and a flexible substrate, wherein the stretching type stress sensor is arranged on the flexible substrate, and the second conductive fibers are stretched under the bending action of the flexible substrate. The bending sensing device has the advantages of washability, difficulty in falling, motion interference resistance, high resolution, high sensitivity and compatibility with the existing textile technology.

Description

Tensile stress sensors and bending sensing devices

Technical field

The present invention relates to the field of stress sensing, and in particular to a tensile stress sensor and a bending sensing device.

Background technique

Stress sensors have important applications in many aspects, ranging from national defense engineering to civilian medical care. Stress sensing can be seen everywhere. With the development of society, our requirements for the accuracy of stress sensing are getting higher and higher.

Current stress sensing technology is mainly based on capacitive, piezoelectric, resistive or triboelectric effects, etc. No matter what kind of sensor, most of them use pressure-sensitive rubber, organic semiconductor materials, conductive polymers, etc. to respond to pressure. Materials that are sensitive and produce corresponding responses. However, the obvious disadvantages of these materials are that they are large in size and the response is not large enough, which will bring inconvenience to stress measurement.

In recent years, relevant technicians have reported several types of flexible stress sensor technologies: carbon fiber-based plain cotton fabric (CPCF) reported by MingchaoZhang et al., whose experiments showed its superior performance in detecting human movement; reported by Chunya Wang et al. The carbonized silk fabric (CSFS) material can detect large and subtle human movements and is suitable for making super-elastic and highly sensitive strain sensors. Although these reported materials have excellent properties, they still have the following problems: the sensitivity of the sensor is not high enough, and it often requires a very large amount of deformation to produce detectable changes (such as resistance, capacitance, etc.).

For the above reasons, the development of a stress sensor that is small in size and can have a relatively large response with only a small amount of deformation has become an urgent need for the development of smart wearable electronic products.

Contents of the invention

Based on this, the purpose of the present invention is to provide a tensile stress sensor that has the advantages of small size, large enough response, real-time monitoring, and is compatible with existing textile technology and easy to wear.

The technical solutions adopted by the present invention are as follows:

A tensile stress sensor includes a first conductive fiber and a second conductive fiber. The second conductive fiber is wound around the first conductive fiber to form at least one between the first conductive fiber and the second conductive fiber. The area of the contact part changes with the change of the state of the second conductive fiber being stretched by an external force.

The working principle of the tensile stress sensor is: when the second conductive fiber is stretched by an external force, the greater the external force, the larger the area of the contact part between the first conductive fiber and the second conductive fiber, then The smaller the resistance between the first conductive fiber and the second conductive fiber at the contact portion; and the smaller the external force, the smaller the area of the contact portion between the first conductive fiber and the second conductive fiber, the smaller the resistance between the first conductive fiber and the second conductive fiber. The greater the resistance between the two conductive fibers at the contact portion; therefore, measuring the change in resistance can reflect the magnitude of the tensile stress of the second conductive fiber, thereby realizing the sensing and detection of the tensile stress.

The tensile stress sensor of the present invention is made of two conductive fibers and has a simple structure. Since the diameter of the conductive fibers can be very small, flexible and can be woven, the volume of the tensile stress sensor can be very small. , easy to use, and fully compatible with existing textile processes and textile materials, solving the problem that existing wearable devices can only be "worn" but not "weared". At the same time, the tensile stress sensor The resistance response between the two conductive fibers to tensile stress is large enough, and only a small amount of deformation is needed to produce a detectable resistance response. Therefore, the tensile stress sensor has high sensitivity and can be monitored in real time.

The tensile stress sensor can be used to monitor the amplitude of limb movement, and when the limb returns to its original state, its resistance can also return to its original state, with good recovery and high stability.

Further, when the second conductive fiber is not stretched by external force, the area of the contact part is the smallest. At this time, the first conductive fiber and the second conductive fiber are kept tight to prevent the contact part from disappearing, which is conducive to timely detection. to the occurrence of stress.

Further, both ends of the first conductive fiber are fixed, and both ends of the second conductive fiber are fixed, so that the first conductive fiber and the second conductive fiber are always maintained in a tight state to avoid relative displacement between the two. Causes the contact area to disappear.

Further, the first conductive fiber is arranged straight and its two ends are respectively fixed; the second conductive fiber is wound around the first conductive fiber and folded in half at both ends to form a first conductive fiber and a second conductive fiber. At the contact point between the conductive fibers, the two ends of the second conductive fiber are fixed together; the first conductive fiber and the second conductive fiber are perpendicular to each other to form a T-shaped structure. It has been experimentally verified that with this configuration, after the second conductive fiber is stretched or bent multiple times, relative displacement between the first conductive fiber and the second conductive fiber is less likely to occur, and the initial resistance is stable and unchanged, making the measurement error smaller.

Further, the first conductive fiber and the second conductive fiber are respectively provided with fluffy structures at the contact parts; the fluffy structure includes a plurality of conductive fiber filaments, and there are a plurality of gaps between the plurality of conductive fiber filaments. Technical effect

Further, the first conductive fiber is made of carbon, metal or conductive polymer material; the second conductive fiber is made of carbon, metal or conductive polymer material.

Another object of the present invention is to provide a bending sensing device, which includes the tensile stress sensor described in any one of the above and a flexible substrate, where the tensile stress sensor is disposed on the flexible substrate. Both ends of the first conductive fiber and both ends of the second conductive fiber are fixed on the flexible base; the second conductive fiber is stretched by the bending effect of the flexible base.

The working principle of the bending sensing device is: when the flexible substrate is bent and the second conductive fiber is stretched, the greater the degree of bending of the flexible substrate, the greater the stretching effect on the second conductive fiber, and the first conductive fiber is stretched. The larger the area of the contact part between the fiber and the second conductive fiber, the smaller the resistance between the first conductive fiber and the second conductive fiber at the contact part; and the smaller the degree of bending of the flexible substrate, the greater the impact on the second conductive fiber. The smaller the stretching effect of the conductive fiber, the smaller the area of the contact part between the first conductive fiber and the second conductive fiber, and the greater the resistance between the first conductive fiber and the second conductive fiber at the contact part; from Therefore, by measuring the change in resistance, the bending state of the flexible substrate can be reflected, and the bending state can be sensed and detected.

The bending sensing device of the present invention uses the above-mentioned tensile stress sensor as a sensing unit, and uses a flexible substrate to carry the tensile stress sensor and perform bending. It can be used to monitor the bending amplitude of limb movement, for example Measure the bending angle of the joint in the range of 0-180°, and when the limb returns to its original state, its resistance can also return to its original state, with good recovery and high stability.

The bending sensing device of the present invention has the advantages of being cleanable, not easy to fall off, resistant to movement interference, high resolution, high sensitivity, and compatible with existing textile technology.

Further, the bending sensing device includes at least two tensile stress sensors connected in series or parallel.

Preferably, the tensile stress sensors are connected in series with each other; in each tensile stress sensor, the first conductive fiber is arranged straight and its two ends are respectively fixed; the second conductive fiber is wound around the The first conductive fiber is folded in half at both ends to form a contact portion between the first conductive fiber and the second conductive fiber, and the two ends of the second conductive fiber are fixed together; the first conductive fiber and the The second conductive fibers are perpendicular to each other to form a T-shaped structure.

It has been experimentally verified that after the second conductive fiber is stretched or bent multiple times, the tensile stress sensor with this configuration is not prone to relative displacement between the first conductive fiber and the second conductive fiber, and its initial resistance is stable, so that The measurement error of the bending angle is smaller; at the same time, the tensile stress sensors connected in series can obtain a larger resistance change, thereby obtaining a stronger response signal on the circuit and improving the detection sensitivity.

Furthermore, the flexible substrate is a flexible circuit board, which is beneficial to the integration and miniaturization of the device.

For better understanding and implementation, the present invention will be described in detail below with reference to the accompanying drawings.

Description of drawings

Figure 1 is a schematic diagram of the basic structure of the tensile stress sensor of the present invention;

Figure 2 is a schematic diagram of the A-A direction in Figure 1;

Figure 3 is a schematic diagram of a first conductive fiber or a second conductive fiber with a fluffy structure;

Figure 4 is a schematic diagram of the tensile stress sensor with a fluffy structure of the present invention;

Figure 5 is a schematic diagram of the basic structure of the bending sensing device of the present invention;

Figure 6 is a schematic structural diagram of the tensile stress sensor of Embodiment 1;

Figure 7 is a schematic structural diagram of the tensile stress sensor of Embodiment 2;

Figure 8 is a schematic structural diagram of the tensile stress sensor of Embodiment 3;

Figure 9 is a schematic structural diagram of the tensile stress sensor of Embodiment 4;

Figure 10 is a schematic structural diagram of the bending sensing device of Embodiment 5;

Figure 11 is a bending schematic diagram of the bending sensing device of Embodiment 5;

Figure 12 is a resistance-bending angle relationship diagram of the bending sensing device of Embodiment 5;

Figure 13 is a test result diagram of the bending cycle experiment of the bending sensing device of Example 5;

Figure 14 is a schematic structural diagram of an implementation of the bending sensing device of Embodiment 6;

Figure 15 is a schematic structural diagram of another embodiment of the bending sensing device of Embodiment 6;

Figure 16 is a side view of the bending sensing device of Embodiment 6;

Figure 17 is a schematic structural diagram of the bending sensing device of Embodiment 7;

Figure 18 is a schematic diagram of the bending sensing device of Embodiment 7, wherein Figure 18(a) is a schematic diagram of the bending sensing device when the bending angle is 0°, and Figure 18(b) is a schematic diagram of the bending sensing device. A schematic diagram of the device when the bending angle is 60°. Figure 18(c) is a schematic diagram of the bending sensing device when the bending angle is 90°;

Figure 19 is a schematic structural diagram of the bending sensing device of Embodiment 8;

Figure 20 is a schematic structural diagram of the bending sensing device of Embodiment 9, wherein Figure 20(a) is a schematic structural diagram viewed from the front of the flexible substrate, and Figure 20(b) is a schematic structural diagram viewed from the back of the flexible substrate 20e.

Detailed ways

Please refer to Figure 1, which is a schematic diagram of the basic structure of the tensile stress sensor of the present invention.

The tensile stress sensor 10 of the present invention includes a first conductive fiber 11 and a second conductive fiber 12. The second conductive fiber 12 is wound around the first conductive fiber 11 to form at least one first conductive fiber. The contact portion 13 between 11 and the second conductive fiber 12. Figure 1 shows that the second conductive fiber 12 is wound around the first conductive fiber 11 to form a contact portion 13, but the number of the contact portion 13 is not limited to one. Can be two or more. Moreover, the area of the contact portion 13 changes as the second conductive fiber 12 is stretched by an external force. The direction of the arrow in FIG. 1 represents the stretching direction.

As shown in FIG. 2 , from the radial cross-section of the first conductive fiber 11 at each contact location 13 , the second conductive fiber 12 is located between the two central axes on both sides of each contact location 13 . Angle α is less than 90°.

The working principle of the tensile stress sensor 10 is: when the second conductive fiber 12 is stretched by an external force (the direction of the arrow in Figure 1 indicates the stretching direction), the greater the external force, the closer the first conductive fiber 11 and the The larger the area of the contact portion 13 between the second conductive fibers 12, the smaller the resistance between the first conductive fiber 11 and the second conductive fiber 12 at the contact portion 13; and the smaller the external force, the smaller the resistance between the first conductive fiber 11 and the second conductive fiber 12. The smaller the area of the contact portion 13 between the second conductive fibers 12, the greater the resistance between the first conductive fiber 11 and the second conductive fiber 12 at the contact portion 13; therefore, it can be reflected by measuring the change in resistance. The magnitude of the tensile stress of the second conductive fiber 12 enables sensing and detection of the tensile stress.

In order to promptly detect the occurrence of tensile stress, in one embodiment, when the second conductive fiber 12 is not stretched by external force, the first conductive fiber 11 and the second conductive fiber 12 are also kept as tight as possible to prevent the The contact part 13 disappears, and the area of the contact part 13 reaches the minimum.

In order to keep the first conductive fiber 11 and the second conductive fiber 12 in a tight state and avoid the relative displacement between the two causing the contact part 13 to disappear, in one embodiment, the two sides of the first conductive fiber 11 are The two ends of the second conductive fiber 12 are also fixed.

In order to further improve the sensitivity of induction, as a preferred embodiment, as shown in Figures 3-4, the first conductive fiber 11 and the second conductive fiber 12 are respectively provided with fluffy structures 14 at the contact portion 13; so The fluffy structure 14 includes a plurality of conductive fiber filaments 140, and there are a plurality of gaps between the plurality of conductive fiber filaments 140. The number of the conductive fiber filaments 140 is preferably no less than ten; wherein, the first conductive fiber filament 140 is The conductive fiber filaments 140 in the fluffy structure 14 of the fiber 11 and the conductive fiber filaments 140 in the fluffy structure 14 of the second conductive fiber 12 contact each other to form a plurality of conductive channels, and the total contact area between them is the The area of the contact part 13;

Therefore, even though the state of the second conductive fiber 12 being stretched by an external force only changes slightly (the direction of the arrow in FIG. 4 indicates the stretching direction), the number of gaps between the conductive fiber filaments 140 in the fluffy structure 14 can also change with the change. This change causes the number of formed conductive channels to also change, that is, the area of the contact portion 13 changes accordingly, which is beneficial to the resistance generated between the first conductive fiber 11 and the second conductive fiber 12 between the contact portion 13. detect changes;

Therefore, by using the first conductive fiber 11 and the second conductive fiber 12 respectively with fluffy structures 14 to form the tensile stress sensor, the area of the contact part 13 can change with the change of the tensile state of the second conductive fiber 12 It is more significant, which helps to improve the sensitivity of induction and achieve effective sensing and detection of tiny tensile stress.

Specifically, as shown in Figure 3, the conductive fiber filaments 140 of the first conductive fiber 11 are arranged along the axial direction of the first conductive fiber 11, and both ends thereof are connected to the first conductive fiber 11; the second conductive fiber The conductive fiber 140 in 12 is arranged along the axial direction of the second conductive fiber 12, and its two ends are connected to the second conductive fiber 12; however, the direction of the conductive fiber 140 is not limited by this, for example, it can also be Different directions such as perpendicular to the side surface of the first conductive fiber 11 or the second conductive fiber 12 where it is located.

Specifically, the first conductive fiber 11 is made of carbon, metal or conductive polymer material, the second conductive fiber 12 is made of carbon, metal or conductive polymer material, and the conductive fiber filaments 140 in the fluffy structure 14 are made of carbon. , metal or conductive polymer materials. In addition, the length and diameter of the first conductive fiber 11 and the second conductive fiber 12 are not limited and depend on actual needs.

In the tensile stress sensor of the present invention, the second conductive fiber can be wound around the first conductive fiber in a variety of ways, and the first conductive fiber and the second conductive fiber can be arranged in a variety of ways, including the following However, the tensile stress sensor of the present invention is not limited to the configuration of Example 1-4.

Please refer to Figure 5, which is a schematic diagram of the basic structure of the bending sensing device of the present invention.

The bending sensing device B of the present invention includes at least one of the tensile stress sensor 10 and a flexible substrate 20. The tensile stress sensor 10 is arranged on the flexible substrate 20. The first conductive fiber 11 Both ends of the second conductive fiber 12 and both ends of the second conductive fiber 12 are fixed on the flexible base 20; the second conductive fiber 12 is stretched by the bending effect of the flexible base 20, and the arrow in Figure 5 indicates the bending state. .

The working principle of the bending sensing device B is: when the flexible substrate 20 bends and the second conductive fiber 12 is stretched (the arrow in FIG. 5 indicates the bending state), the greater the degree of bending of the flexible substrate 20, the greater the bending degree of the flexible substrate 20. The greater the tensile effect of the second conductive fiber 12, the larger the area of the contact part 13 between the first conductive fiber 11 and the second conductive fiber 12. Then the first conductive fiber 11 and the second conductive fiber 12 are at the contact part. The smaller the resistance between the first conductive fiber 11 and the second conductive fiber 12; and the smaller the bending degree of the flexible substrate 20, the smaller the stretching effect on the second conductive fiber 12. The smaller the area, the greater the resistance between the first conductive fiber 11 and the second conductive fiber 12 at the contact portion 13; therefore, by measuring the change in resistance, the bending state of the flexible substrate 20 can be reflected, and the bending state can be measured. sensing and detection.

In order to detect the bending state of each part of the flexible substrate 20, in one embodiment, the bending sensing device B includes at least two tensile stress sensors 10 connected in series or in parallel. The above series connection refers to The resistance between the first conductive fiber 11 and the second conductive fiber 12 in each tensile stress sensor 10 is connected in series using a connecting circuit. The above-mentioned parallel connection refers to using a connecting circuit to connect the first conductive fiber 11 in each tensile stress sensor 10 They are connected in parallel with the resistance between the second conductive fibers 12; as a preferred embodiment, the tensile stress sensors 10 are connected in series with each other, which is beneficial to obtaining a larger resistance change.

The flexible substrate 20 is insulating, and its thickness and material depend on actual needs. In order to facilitate the integration and miniaturization of the device, in one embodiment, the flexible substrate 20 uses a flexible circuit board.

In order to achieve better packaging and protection effects, in one embodiment, the bending sensing device B further includes an insulating flexible protective film covering the flexible base 20 and the tensile type On the stress sensor 10, the thickness and material of the flexible protective film depend on actual needs.

Specifically, two or more tensile stress sensors 10 can be jointly disposed on the same surface of the flexible substrate 20 to measure the state of the flexible substrate 20 bending toward its other surface, such as As shown in Figure 5; they can also be respectively provided on both surfaces of the flexible substrate 20 to measure the state of the flexible substrate 20 when it is bent in any direction of its surface.

In the bending sensing device of the present invention, the tensile stress sensors are arranged in a variety of ways on the flexible substrate, and there are also multiple ways of connecting two or more tensile stress sensors, including the following implementations Although the configuration is described in Example 5-9, the bend sensing device of the present invention is not limited to the configuration of Example 5-9.

Example 1: Tensile stress sensor

As shown in Figure 6, the tensile stress sensor 10a of this embodiment includes a first conductive fiber 11a and a second conductive fiber 12a. The first conductive fiber 11a is arranged straight and its two ends are respectively fixed; The conductive fiber 12a is wound around the first conductive fiber 11a and folded at both ends to form a contact portion 13 between the first conductive fiber 11a and the second conductive fiber 12a. The two ends of the second conductive fiber 12a fixed together; the first conductive fiber 11a and the second conductive fiber 12a are perpendicular to each other to form a T-shaped structure; the area of the contact portion 13 changes with the state of the second conductive fiber 12a being stretched by an external force. Variety.

Example 2: Tensile stress sensor

As shown in Figure 7, the tensile stress sensor 10b of this embodiment includes a first conductive fiber 11b and a second conductive fiber 12b. The first conductive fiber 11b is arranged straight and its two ends are respectively fixed; The conductive fiber 12b is wound around the first conductive fiber 11b to form a contact portion 13 between the first conductive fiber 11b and the second conductive fiber 12b, and the two ends of the second conductive fiber 12b are respectively fixed; The area of the contact portion 13 changes as the second conductive fiber 12b is stretched by an external force.

Example 3: Tensile stress sensor

As shown in Figure 8, the tensile stress sensor 10c of this embodiment includes a first conductive fiber 11c and a second conductive fiber 12c. The two ends of the first conductive fiber 11c are folded in half and fixed together; the second conductive fiber 11c is folded in half and fixed together; The fiber 12c is wound around the first conductive fiber 11c and folded at both ends to form a contact portion 13 between the first conductive fiber 11c and the second conductive fiber 12c. The two ends of the second conductive fiber 12c are fixed. together.

The stretching direction of the first conductive fiber 11c when subjected to external force is opposite to the stretching direction of the second conductive fiber 12c when subjected to external force. When the first conductive fiber 11c is stretched, the second conductive fiber 12c is also stretched. When the second conductive fiber is stretched 12c, the first conductive fiber 11c is also stretched. Therefore, the area of the contact part 13 is pulled by the external force as the first conductive fiber 11c and the second conductive fiber 12c. Changes due to changes in stretching state.

Example 4: Tensile stress sensor

As shown in Figure 9, the tensile stress sensor 10d of this embodiment includes a first conductive fiber 11d and a second conductive fiber 12d. The first conductive fiber 11d is arranged straight and its two ends are respectively fixed; The conductive fiber 12d is spirally wound around the first conductive fiber 11d, forming more than one contact portion 13 between the first conductive fiber 11d and the second conductive fiber 12d; both sides of the second conductive fiber 12d The ends are respectively fixed; the total area of the contact portion 13 changes as the state of the second conductive fiber 12d is stretched by external force.

Example 5: Bending Sensing Device

As shown in Figure 10, the bending sensing device B1 of this embodiment includes a tensile stress sensor 10a of Embodiment 1 and a flexible substrate 20a.

The flexible substrate 20a is a flexible circuit board, and its two surfaces are the front and the back respectively. Figure 10 shows the front of the flexible substrate 20a; three through holes 201, 202 and 203 are provided on the flexible substrate 20a, and their The front side is provided with conductors 31 and 32, and the conductors 31 and 32 can be copper wires.

The tensile stress sensor 10a is provided on the front surface of the flexible substrate 20a, wherein both ends of the first conductive fiber 11a are respectively fixed on the front surface of the flexible substrate 20a through silver glue, and the first conductive fiber 11a is fixed on the front surface of the flexible substrate 20a. The two ends of the fiber 11a pass through the through holes 201 and 202 to the back of the flexible substrate 20a respectively; the two ends of the second conductive fiber 12a are fixed together on the front of the flexible substrate 20a through silver glue. And the two ends of the second conductive fiber 12a pass out from the through hole 203 to the back of the flexible substrate 20a.

One end of the wire 31 is electrically connected to both ends of the first conductive fiber 11a, and the other end is a free end led out of the flexible substrate 20a; one end of the wire 32 is connected to the second conductive fiber 11a. The two ends of 12a are electrically connected, and the other end is a free end that is led out of the flexible base 20a. Specifically, the wire 31 can be fixedly connected to the silver glue at both ends of the first conductive fiber 11a without direct contact with the first conductive fiber 11a; the wire 32 can be connected to the second conductive fiber 12a The silver glue at both ends is fixedly connected without direct contact with the second conductive fiber 12a. The resistance between the free end of the conductor 31 and the free end of the conductor 32 is the resistance of the bending sensing device B1.

Through holes 201, 202 and 203 are provided on the flexible substrate 20a for the ends of the first conductive fiber 11a and the second conductive fiber 12a to pass through, so that when the tensile stress sensor 10a is installed on the front side of the flexible substrate 20a, it can be easily removed from the flexible substrate 20a. The back side of the base 20a pulls the ends of the first conductive fiber 11a and the second conductive fiber 12a to tighten the first conductive fiber 11a and the second conductive fiber 12a as much as possible.

The purpose of using silver glue is that, on the one hand, the silver glue has an adhesive effect and can fix the two ends of the first conductive fiber 11a and the second conductive fiber 12a so that the first conductive fiber 11a and the second conductive fiber 12a remain in a tight state. , to avoid relative displacement between the two and causing the contact part 13 to disappear; on the other hand, the silver glue has a conductive effect, and the conductors 31 and 32 are connected to the silver glue to realize the connection between the conductor 31 and the first conductive fiber 11a, and between the conductor 32 and the first conductive fiber 11a. The non-contact electrical connection between the second conductive fibers 12a prevents the movement of the wires 31 and 32 from stretching the first conductive fiber 11a or the second conductive fiber 12a and causing measurement errors.

As shown in Figure 11, the relationship between the resistance of the bending sensing device B1 of this embodiment and the bending angle β is measured. Specifically, the side of the flexible substrate 20a divided by the center line L1 is bent toward the back direction. The angle formed when The resistance change of is obtained by measuring the resistance value between the free end of wire 31 and the free end of wire 32;

The measurement results are shown in Figure 12. From this figure, it can be seen that the resistance and the bending angle β (in the range of 0-90°) are basically linear, indicating that the bending sensing device B1 has good sensing performance and can make good use of electricity. signal to represent the bending angle.

In order to verify the bending recovery performance of the bending sensing device B1, it is installed on the index finger joint of the robot hand, and the back side of the flexible base 20a is in contact with the index finger joint, as shown in Figure 11, so that the index finger joint is Bend multiple times at a bending angle β, and return to the original straightened state after each bending for a period of time. At the same time, the resistance of the bending sensing device B1 is detected in real time to conduct a bending cycle experiment;

The test results are shown in Figure 13, which shows the change of the bending sensing device B1 when the bending angle β is 0°→10°→0°→15°→0°→5°→90°→45°→0° From the resistance curve during the process, it can be seen that the bending sensing device B1 can still return to its original resistance after multiple bends, which illustrates its feasibility for detecting joint bending angles during movement, and it also has good stability and sensitivity.

Example 6: Bending Sensing Device

As shown in Figures 14-16, the bending sensing device B2 of this embodiment includes three tensile stress sensors 10a, 10a' and 10a" of Embodiment 1, a flexible substrate 20b and a flexible protective film 50.

The flexible substrate 20b is a flexible circuit board, and its two surfaces are the front and the back respectively. Figures 14 and 15 show the front of the flexible substrate 20b.

The three tensile stress sensors 10a, 10a' and 10a" are all disposed on the front side of the flexible base 20b. Specifically, the installation method of each tensile stress sensor on the flexible base 20b is the same as in Embodiment 5 The installation method of the tensile stress sensor 10a in the flexible substrate 20a is the same, that is, the two ends of its first conductive fiber and the second conductive fiber are fixed on the front surface of the flexible substrate 20b through silver glue, and the first conductive fiber and the two ends of the second conductive fiber respectively pass through the through holes on the flexible substrate 20b to the back thereof.

The three tensile stress sensors 10a, 10a' and 10a" are connected in series with each other.

Specifically, as shown in Figure 14, the three tensile stress sensors 10a, 10a' and 10a" are arranged in a row and aligned up and down, and the three tensile stress sensors 10a, 10a' and 10a" are The direction of the formed T-shaped structure is consistent; wherein, both ends of the second conductive fiber 12a of the tensile stress sensor 10a are connected to one end of the first conductive fiber 11a' of the tensile stress sensor 10a' through wires 33 Electrically connected, both ends of the second conductive fiber 12a' of the tensile stress sensor 10a' are electrically connected to one end of the first conductive fiber 11a" of the tensile stress sensor 10a" through a wire 34. The two ends of the second conductive fiber 12a" of the tensile stress sensor 10a" are connected to one end 35 of the wire, and one end of the first conductive fiber 11a of the tensile stress sensor 10a is connected to one end of the wire 36. The wire 35 The resistance between the other end of the wire 36 and the other end of the wire 36 is the resistance of the bending sensing device B2. A resistance measuring instrument can be connected between the other end of the wire 35 and the other end of the wire 36 to measure the resistance. ;The conductors 33, 34, 35 and 36 are all made of copper wires;

Or, as shown in Figure 15, the three tensile stress sensors 10a, 10a' and 10a" are arranged in a line and aligned left and right, and the T-shaped structure formed by two adjacent tensile stress sensors has opposite directions; Wherein, one end of the first conductive fiber 11a of the tensile stress sensor 10a is electrically connected to one end of the first conductive fiber 11a' of the tensile stress sensor 10a' through a printed circuit 41. Both ends of the second conductive fiber 12a' of the sensor 10a' are electrically connected to one end of the first conductive fiber 11a" of the tensile stress sensor 10a" through the printed circuit 42, and the third conductive fiber 11a" of the tensile stress sensor 10a" Two ends of the second conductive fiber 12a" are connected to one end of the printed circuit 43, two ends of the second conductive fiber 12a of the tensile stress sensor 10a are connected to one end of the printed circuit 44, and the other end of the printed circuit 43 is connected to The resistance between the other ends of the printed circuit 44 is the resistance of the bend sensing device B2; the printed circuits 41, 42, 43 and 44 are all silver layers.

As shown in Figure 16, the bending sensing device B2 can be regarded as having a three-layer structure, which is a flexible protective film 50, a sensing layer 60 and a flexible substrate 20b from top to bottom; wherein, the three stretchable The stress sensors 10a, 10a' and 10a" can be regarded as constituting the sensing layer 60, and the flexible protective film 50 covers the front side of the flexible substrate 20b and the sensing layer 60 to provide packaging protection. effect.

Example 7: Bending Sensing Device

As shown in Figure 17, the bending sensing device B3 of this embodiment includes two tensile stress sensors 10e, 10f and a flexible substrate 20c.

Each tensile stress sensor has basically the same structure as the tensile stress sensor 10a in Embodiment 1, except that the second conductive fibers of the two tensile stress sensors 10e and 10f share a conductive fiber. Fiber 12ef, the conductive fiber 12ef is perpendicular to the first conductive fibers 11e and 11f of the two tensile stress sensors 10e and 10f respectively, and is respectively connected to the first conductive fibers 11e and 11f of the two tensile stress sensors 10e and 10f. The conductive fibers 11e and 11f form a T-shaped structure, and both ends of the conductive fiber 12ef are fixed respectively.

The flexible substrate 20c is a flexible circuit board, and its two surfaces are the front and the back respectively. Figure 17 shows the front of the flexible substrate 20c; the flexible substrate 20c is provided with six through holes 204, 205, 206, 207 , 208 and 209, and the front side is provided with conductors 37 and 38, and the conductors 37 and 38 can be copper wires.

The two tensile stress sensors 10e and 10f are both disposed on the front side of the flexible substrate 20c and are aligned up and down, and the direction of the T-shaped structure formed by the two tensile stress sensors 10e and 10f is on the contrary.

Specifically, both ends of the first conductive fiber 11e of the tensile stress sensor 10e are respectively fixed on the front surface of the flexible substrate 20c through silver glue, and the ends of the two ends of the first conductive fiber 11e are respectively removed from the Through holes 204 and 205 penetrate to the back of the flexible substrate 20c; both ends of the first conductive fiber 11f of the tensile stress sensor 10f are respectively fixed on the front of the flexible substrate 20c through silver glue, and the third The two ends of a conductive fiber 11f respectively pass through the through holes 206 and 207 to the back of the flexible substrate 20c; the two ends of the conductive fiber 12ef pass through the through holes 208 and 209 respectively to the back surface of the flexible substrate 20c. The back side of the flexible substrate 20c.

One end of the wire 37 is electrically connected to both ends of the first conductive fiber 11e of the tensile stress sensor 10e, and the other end is a free end led out of the flexible substrate 20c; one end of the wire 38 is connected to The two ends of the first conductive fiber 11f of the tensile stress sensor 10f are electrically connected, and the other end is a free end that is led out of the flexible base 20c. Specifically, the wire 37 can be fixedly connected to the silver glue at both ends of the first conductive fiber 11e without directly contacting the first conductive fiber 11e; the wire 38 can be connected to the first conductive fiber 11f. The silver glue at both ends is fixedly connected without direct contact with the first conductive fiber 11f. Therefore, the two tensile stress sensors 10e and 10f are connected in series through the common conductive fiber 12ef, and the resistance between the free end of the wire 37 and the free end of the wire 38 is the bending sensing device. Resistor of B3.

In the bending sensing device B3 of this embodiment, when the side of the flexible substrate 20c divided by its center line L2 is bent toward the back direction, the conductive fiber 12ef is stretched, and the two stretching The resistances of the stress sensors 10e and 10f both change, thereby producing a response to changes in the bending state, and the center line L2 is perpendicular to the middle of the conductive fiber 12ef. Please refer to Figure 18, where Figure 18(a), Figure 18(b) and Figure 18(c) respectively show the bending sensing device B3 when the bending angle is 0° (no bending), 60° and 90°. time diagram.

Example 8: Bending Sensing Device

As shown in Figure 19, the bending sensing device B4 of this embodiment includes two tensile stress sensors 10a, 10a' of Embodiment 1 and a flexible substrate 20d.

The flexible substrate 20d is a flexible circuit board, and its two surfaces are the front and the back respectively. Figure 19 shows the front of the flexible substrate 23d.

The two tensile stress sensors 10a and 10a' are both disposed on the front side of the flexible substrate 20d. Specifically, the installation method of each tensile stress sensor on the flexible substrate 20d is the same as that in Embodiment 5. The installation method of the extension type stress sensor 10a on the flexible substrate 20a is the same, that is, the two ends of its first conductive fiber and the second conductive fiber are fixed on the front surface of the flexible substrate 20d through silver glue, and the first conductive fiber and the second conductive fiber are fixed on the front surface of the flexible substrate 20d through silver glue. The ends of both ends of the conductive fiber pass through the through holes on the flexible substrate 20d to the back side thereof.

The two tensile stress sensors 10a, 10a' are connected in parallel. Specifically, the two tensile stress sensors 10a and 10a' are aligned left and right, and the directions of the T-shaped structures formed by the two tensile stress sensors 10a and 10a' are consistent; wherein, the tensile stress sensors 10a and 10a' are aligned in the same direction. One end of the first conductive fiber 11a of the tensile stress sensor 10a and one end of the first conductive fiber 11a' of the tensile stress sensor 10a' are connected together through a printed circuit 45, and the second end of the tensile stress sensor 10a Both ends of the conductive fiber 12a and the two ends of the second conductive fiber 12a' of the tensile stress sensor 10a' are connected together through a printed circuit 46, and the resistance between the printed circuit 45 and the printed circuit 46 is The resistance of the bend sensing device B4; the printed circuits 45 and 46 are both silver layers.

Example 9: Bending Sensing Device

As shown in FIG. 20 , the bending sensing device B5 of this embodiment includes two tensile stress sensors 10a and 10g of Embodiment 1 and a flexible substrate 20e.

The flexible substrate 20e is a flexible circuit board, and its two surfaces are the front and the back respectively. Figure 20(a) shows the front of the flexible substrate 20e, and Figure 20(b) shows the back of the flexible substrate 20e; The flexible substrate 20e is provided with six through holes 201', 202', 203', 204', 205' and 206', and the front side is provided with wires 31' and 32', and the back side is provided with wires 33' and 34' , these wires can be copper wires.

The two tensile stress sensors 10a and 10g are respectively provided on the front and back of the flexible substrate 20e.

Specifically, as shown in Figure 20(a), the installation method of the tensile stress sensor 10a on the flexible substrate 20e is the same as the installation method of the tensile stress sensor 10a on the flexible substrate 20a in Embodiment 5, that is, , the two ends of the first conductive fiber 11a and the second conductive fiber 12a are fixed on the front surface of the flexible substrate 20e through silver glue, and the ends of the first conductive fiber 11a are respectively separated from the through holes 201 on the flexible substrate 20e ' and 202' penetrate to the back thereof, and the ends of the two ends of the second conductive fiber 12a penetrate from the through holes 203' on the flexible substrate 20e to the back thereof; at the same time, one end of the conductor 31' is connected to the respective The two ends of the first conductive fiber 11a are electrically connected, and the other end is a free end that is led out of the flexible substrate 20e; one end of the wire 32' is electrically connected to both ends of the second conductive fiber 12a, and The other end is a free end led out of the flexible base 20e.

Specifically, as shown in Figure 20(b), in the tensile stress sensor 10g, both ends of the first conductive fiber 11g and the second conductive fiber 12g are fixed on the back of the flexible substrate 20e through silver glue, and the The two ends of the first conductive fiber 11g respectively pass through the through holes 204' and 205' on the flexible base 20e to the front thereof, and the two ends of the second conductive fiber 12g pass through the through holes on the flexible base 20e. 206' penetrates to the front thereof; at the same time, one end of the wire 33' is electrically connected to both ends of the first conductive fiber 11g, and the other end is a free end led out to the outside of the flexible substrate 20e; the One end of the wire 34' is electrically connected to both ends of the second conductive fiber 12g, and the other end is a free end that is led out of the flexible substrate 20e.

The two tensile stress sensors 10a and 10g are insulated from each other. Therefore, the two tensile stress sensors 10a and 10g measure independently, wherein the tensile stress sensor 10a measures the direction of the flexible substrate 20e towards it. The tensile stress sensor 10g measures the bending state of the flexible substrate 20e toward its front direction, so the bending sensing device B5 can be used to measure a bending angle greater than 180°.

The above-mentioned embodiments only express several implementation modes of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims (6)

1. A bending sensing device, characterized by: the flexible substrate comprises at least one stretching type stress sensor and a flexible substrate, wherein the stretching type stress sensor comprises first conductive fibers and second conductive fibers, and the second conductive fibers are wound on the first conductive fibers to form at least one contact part between the first conductive fibers and the second conductive fibers;

the stretching stress sensor is arranged on the flexible substrate, and both ends of the first conductive fiber and both ends of the second conductive fiber are fixed on the flexible substrate, so that the first conductive fiber and the second conductive fiber are kept taut; the second conductive fiber is stretched under the bending action of the flexible substrate, and the area of the contact part is changed along with the change of the state that the second conductive fiber is stretched under the external force;

in each stretching stress sensor, the first conductive fibers are arranged straight, and two ends of each first conductive fiber are fixed respectively; the second conductive fiber is wound on the first conductive fiber, two ends of the second conductive fiber are folded in half to form a contact part between the first conductive fiber and the second conductive fiber, and two ends of the second conductive fiber are fixed together; the first conductive fibers and the second conductive fibers are perpendicular to each other to form a T-shaped structure.

2. The bending sensing device of claim 1, wherein: comprising at least two tension-type stress sensors connected in series or in parallel.

3. The bending sensing device of claim 2, wherein: the tensile stress sensors are mutually connected in series.

4. The bending sensing device of claim 2, wherein: the flexible substrate is a flexible circuit board.

5. The bending sensing device according to any one of claims 1-4, wherein: the first conductive fiber and the second conductive fiber are respectively provided with a fluffy structure at the contact part; the fluffy structure comprises a plurality of conductive fiber filaments, and a plurality of gaps exist among the conductive fiber filaments.

6. The bending sensing device according to any one of claims 1-4, wherein: the first conductive fibers are made of carbon, metal or conductive polymer materials; the second conductive fiber is made of carbon, metal or conductive polymer material.