Novel stannous sulfide force sensitive resistor

Abstract

The utility model discloses a novel stannous sulfide force sensitive resistor which can output a larger electric signal under smaller stress and has excellent sensitivity. The method can be applied to the fields of pressure gauges, wearable devices and the like. The resistor is composed of a force sensitive element and a packaging material. The force sensitive element comprises a stannous sulfide film and a copper wire. The packaging material comprises polyimide and polydimethylsiloxane. The stannous sulfide thin film is packaged by polyimide at the bottom and polydimethylsiloxane on the upper surface. And four copper wires are equidistantly arranged side by side at the joint of the upper surface of the stannous sulfide thin film and the polydimethylsiloxane. The copper wire is connected with the stannous sulfide film through silver paste or soldering tin, and the other end of the copper wire extends outwards to output electric signals. The prepared stannous sulfide force-sensitive resistor is low in cost and convenient and fast to prepare, has a huge piezoresistive effect when being used under a simply supported beam structure, and is higher in sensitivity compared with a traditional silicon-based force-sensitive resistor.

Description

TECHNICAL FIELD

[0001] The utility model relates to force sensitive resistance technical field, and specifically is a novel stannous sulfide force sensitive resistance. BACKGROUND

[0002] In order to measure the stress condition of object, mechanical signal is converted into electric signal, and force sensitive resistance connected by bridge is widely used in various mechanical measuring instruments. Force sensitive resistance is made of semiconductor material, and when the surface of semiconductor material is applied with stress, its resistivity will change obviously, and this phenomenon is called piezoresistive effect. Many materials with piezoresistive effect are developed and designed into complex electronic components, and force sensitive resistance is one of them.

[0003] Traditional force sensitive materials mainly include semiconductor materials such as silicon. In recent years, force sensitive materials represented by carbon black rubber and graphene polymer have appeared one after another, greatly enriching the types of force sensitive materials and widening the application range of force sensitive components. However, these materials generally have many problems to be solved, such as high cost, complex preparation process, small storage window, large quality, non-flexible, expensive and easy to damage. The resistivity of most materials will quickly return to the initial state after removing the stress applied by itself, and its application is often accompanied by complex Wheatstone circuit.

[0004] In addition, the excellent characteristics of stannous sulfide, such as giant piezoresistive effect, have been verified and studied in experiments, and its preliminary application in pressure sensors is provided, that is, a metal-semiconductor-metal double-end device is constructed by using a single stannous sulfide nanobelt

Zhou Haitao. Piezoresistive and temperature properties of SnS two-dimensional micro / nanomaterials [D]. Nanchang University, 2022. DOI: 10.27232 / d.cnki.gnchu.2022.003191.

[0005] Therefore, the utility model wants to solve the technical problem of making a novel stannous sulfide force sensitive resistance. The resistance made has giant piezoresistive effect when connected to circuit in simply supported beam structure, and its resistivity changes greatly under small stress, which is significantly better than traditional silicon-based materials. In addition, due to its high sensitivity, the novel stannous sulfide force sensitive resistance provided by the utility model can be connected to circuit without Wheatstone bridge.

[0006] To solve the above technical problems, the utility model provides a novel stannous sulfide force sensitive resistance technical scheme, which comprises:

[0007] A force sensing element includes a stannous sulfide film and copper wires. The stannous sulfide film is rectangular, and the copper wires are distributed equidistantly and side by side on the upper surface of the stannous sulfide film, and

[0008] A packaging material includes polyimide and polydimethylsiloxane to coat the force sensing element.

[0009] According to an embodiment of the present application, the stannous sulfide force sensing resistor is arranged in a simply supported beam structure and connected in a circuit.

[0010] According to an embodiment of the present application, the polyimide and the polydimethylsiloxane in the packaging material of the stannous sulfide force sensing resistor are respectively located at the bottom and the top of the force sensing element. The packaging materials are connected to each other.

[0011] According to an embodiment of the present application, the copper wires in the force sensing element of the stannous sulfide force sensing resistor are connected to the upper surface of the stannous sulfide film by silver paste or solder, and after cooling and solidification, the copper wires and the stannous sulfide film form ohmic contact, and the silver paste or solder at the connection forms an electrode.

[0012] According to an embodiment of the present application, the number of copper wires of the stannous sulfide force sensing resistor is four, of which the copper wires on the two sides are used to output current signals, and the two copper wires in the middle are used to output voltage signals.

[0013] According to an embodiment of the present application, the thickness of the stannous sulfide film of the stannous sulfide force sensing resistor is between 30 and 50 microns. According to actual conditions, the thickness of the stannous sulfide film can be adjusted, and different thicknesses of the stannous sulfide force sensing resistor have different real-time sensing capabilities for stress. The diameter of the copper wire is 100 microns to 150 microns.

[0014] According to an embodiment of the present application, the stannous sulfide film of the stannous sulfide force sensing resistor is a layered orthorhombic structure semiconductor with a two-dimensional structure.

[0015] According to an embodiment of the present application, the principle of the stannous sulfide force sensing resistor in the circuit is further described as follows:

[0016] The stannous sulfide force sensing resistor is connected in series in the circuit in a simply supported beam structure, and is connected with a sensitive galvanometer. At a certain moment, the power supply in the circuit is turned on, at this time, the sensitive galvanometer is connected in series to the two copper wires in the middle for outputting current signals and the current at this time is read out.

[0017] The stannous sulfide force-sensitive resistor is connected in series in a circuit in a simple beam structure and is connected with a modified sensitive ammeter.

[0018] Unequal stress is applied to the upper surface of the stannous sulfide force-sensitive resistor, and the above steps are repeatedly performed.

[0019] The resistivity of the force-sensitive resistor at this time can be obtained according to ρ=2πSV / I, wherein ρ is the resistivity of the force-sensitive resistor, S is the stress area, V and I are output voltage and output current respectively. In fact, the change of the resistivity of the stannous sulfide force-sensitive resistor is obtained by real-time processing of the electrical signal output by the stannous sulfide force-sensitive resistor using the four-probe method. The change of the resistivity is proportional to the stress, so the conversion from mechanical signal to electrical signal is completed.

[0020] According to one embodiment of the present application, the technical scheme has the following advantages.

[0021] One advantage of the present application is that the prepared stannous sulfide thin film material has large yield, low cost and convenient and fast preparation process.

[0022] Another advantage of the present application is that the prepared stannous sulfide force-sensitive resistor has more excellent piezoresistive characteristics than traditional silicon-based force-sensitive resistors in a simple beam structure, and is more sensitive to real-time sensing of stress. The resistivity of the traditional silicon-based resistor hardly changes when it is subjected to a small stress, and it cannot apply stress to the middle of the resistor like the stannous sulfide force-sensitive resistor, so it has broad application prospects.

[0023] Another advantage of the present application is that the total number of electrons in the trap changes due to mechanical excitation after the prepared stannous sulfide force-sensitive resistor is removed from the applied stress, and can be well maintained for a period of time, showing non-volatile memory performance. By loading a larger bias, the resistivity of the stannous sulfide force-sensitive resistor can be restored, showing an erasable stress storage effect, and having broad application prospects in stress sensors. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The X-ray diffraction pattern of the two-dimensional stannous sulfide material prepared by the chemical vapor deposition method in one embodiment of the present application.

[0025] Figure 2The tin sulfide force sensitive resistor structure prepared in one embodiment of the application is shown in the schematic diagram, wherein A is a polyimide substrate of a bottom layer, B is a tin sulfide film of a middle cutting and packaging, C is an electrode made on the surface of the tin sulfide film, D is four copper wires corresponding to electrode leads, and arranged in sequence and named as probe 1, probe 2, probe 3 and probe 4. E is a polydimethylsiloxane sheet of a top layer. B, C and D jointly constitute a force sensitive element, and A and E are packaging materials.

[0026] Figure 3 The tin sulfide force sensitive resistor in one embodiment of the application is shown in the schematic diagram, wherein A is a polyimide substrate of a bottom layer, B is a tin sulfide film of a middle cutting and packaging, C is an electrode made on the surface of the tin sulfide film, D is four copper wires corresponding to electrode leads, and arranged in sequence and named as probe 1, probe 2, probe 3 and probe 4. E is a polydimethylsiloxane sheet of a top layer. B, C and D jointly constitute a force sensitive element, and A and E are packaging materials.

[0027] Figure 4 The tin sulfide force sensitive resistor in one embodiment of the application is shown in the schematic diagram, wherein A is a polyimide substrate of a bottom layer, B is a tin sulfide film of a middle cutting and packaging, C is an electrode made on the surface of the tin sulfide film, D is four copper wires corresponding to electrode leads, and arranged in sequence and named as probe 1, probe 2, probe 3 and probe 4. E is a polydimethylsiloxane sheet of a top layer. B, C and D jointly constitute a force sensitive element, and A and E are packaging materials. DETAILED DESCRIPTION

[0028] The specific embodiment of the utility model is described in detail below in combination with the drawings and embodiments. In order to show the superior performance of the novel tin sulfide force sensitive resistor relative to the traditional silicon-based force sensitive resistor, a silicon-based force sensitive resistor arranged as a simply supported beam structure is also prepared. Except that the part of the force sensitive element involving the tin sulfide film is replaced by a silicon wafer film, the other structures remain the same. The novel tin sulfide force sensitive resistor has the following embodiments:

[0029] Embodiment 1

[0030] According to the drawings, Figure 2 , the utility model discloses polyimide film A, tin sulfide film B, silver paste / solder electrode C, copper wire D and polydimethylsiloxane E.

[0031] Specifically, as shown in the tin sulfide force sensitive resistor structure plan view shown in the drawings, Figure 2 the polyimide film A is closely attached to the tin sulfide film B. The polyimide A is used to carry the tin sulfide film B and plays a fixed supporting role.

[0032] Specifically, the copper wire D on the tin sulfide film B is respectively adhered to the tin sulfide film B at 1, 2, 3 and 4. The copper wire D is respectively led out from the two sides of the tin sulfide force sensitive resistor perpendicular to the circuit end and respectively named as probe 1, probe 2, probe 3 and probe 4. The four probe leads have good conductivity and certain ductility and are used to output electrical signals.

[0033] Further, the probe 1 and the probe 3 of the copper wire D are led in one direction, and the probe 2 and the probe 4 are led in the opposite direction of the probe 1 and the probe 3. The probe 1, the probe 2, the probe 3 and the probe 4 are parallel to each other and have equal spacing. The distance between the silver paste / solder electrodes C is also equal. The silver paste / solder electrodes C ensure the ohmic contact between the copper wire D and the stannous sulfide film B.

[0034] Further, the silver paste / solder electrodes C at the adhesion position of the stannous sulfide film B and the led copper wire D are located between the stannous sulfide film B and the polydimethylsiloxane film E. The silver paste / solder electrodes fix the stannous sulfide film B and the polydimethylsiloxane film E at the same time.

[0035] Further, the polyimide film A and the polydimethylsiloxane film E are connected to each other, and constitute an encapsulating material, which encapsulates the force sensing element composed of the stannous sulfide film B, the silver paste / solder electrodes C and the copper wire D.

[0036] The stannous sulfide force sensing resistor and the silicon-based force sensing resistor are connected in a simple beam structure in a circuit. The sensitive ammeter is connected in series at the probe 1 and the probe 4, then the power supply is turned on and the data is read. The power supply is turned off, the sensitive ammeter is changed and connected in parallel at the probe 2 and the probe 3, then the power supply is turned on and the data is read. The voltage passing through the probe 2 and the probe 3 is calculated. The resistivity of the force sensing resistor at this time can be obtained by substituting p=2piSV / I.

[0037] The stress is applied by adding weights with different masses at the geometric center of the upper surface of the stannous sulfide force sensing resistor and the silicon-based force sensing resistor. The weights with 1g, 2g and 5g are selected according to the conditions, and the change of the resistivity of the stannous sulfide force sensing resistor and the silicon-based force sensing resistor with the stress is obtained according to the electrical signals output by the stannous sulfide force sensing resistor and the silicon-based force sensing resistor, and the results are shown in the accompanying Figure 3 , and the accompanying Figure 4 With the increase of the stress, the resistivity of the stannous sulfide force sensing resistor is increased by 2.15 times, and the resistivity of the traditional silicon-based force sensing resistor does not change obviously, so it is proved that the performance of the stannous sulfide force sensing resistor is superior to that of the traditional silicon-based force sensing resistor, and the real-time sensing of the stress is more sensitive.

[0038] Embodiment 2

[0039] According to the accompanying Figure 2 , the utility model discloses a polyimide film A, stannous sulfide film B, silver paste / solder electrode C, copper wire D and polydimethylsiloxane E.

[0040] Specifically, as shown in the accompanying Figure 2The tin sulfide force sensitive resistor structure plan view is shown, wherein the polyimide film A is close to the tin sulfide film B. The polyimide A is used to bear the tin sulfide film B and plays a fixed support role.

[0041] Specifically, the copper wire D on the tin sulfide film B is adhered to the tin sulfide film B at 1, 2, 3, and 4, respectively. The copper wire D is led out from the two sides of the tin sulfide force sensitive resistor perpendicular to the circuit end, and is respectively named as probe 1, probe 2, probe 3, and probe 4. The four probes have good conductivity and certain ductility, and are used to output electrical signals.

[0042] Further, the probe 1 and the probe 3 of the copper wire D are led out in one direction, and the probe 2 and the probe 4 are led out in the opposite direction of the probe 1 and the probe 3. The probe 1, the probe 2, the probe 3, and the probe 4 are parallel to each other and have equal spacing. The distance between the silver paste / solder electrodes C is also equal. The silver paste / solder electrodes C ensure the ohmic contact between the copper wire D and the tin sulfide film B.

[0043] Further, the silver paste / solder electrodes C at the adhesion position of the tin sulfide film B and the led-out copper wire D are located between the tin sulfide film B and the polydimethylsiloxane film E. The silver paste / solder electrodes simultaneously adhere and fix the copper wire D and the tin sulfide film B, and also connect and fix the polydimethylsiloxane film E and the tin sulfide film B.

[0044] Further, the polyimide film A and the polydimethylsiloxane film E are also connected to each other to form a packaging material, which collectively packages the force sensitive element composed of the tin sulfide film B, the silver paste / solder electrodes C, and the copper wire D.

[0045] The tin sulfide force sensitive resistor and the silicon-based force sensitive resistor are connected in the circuit in a simply supported beam structure. The sensitive ammeter is connected in series at the probe 1 and the probe 4, then the power is turned on and the data is read. The power is turned off, the sensitive ammeter is replaced and connected in parallel at the probe 2 and the probe 3, then the power is turned on and the data is read. The voltage through the probe 2 and the probe 3 is calculated. The resistivity of the force sensitive resistor at this time can be obtained by substituting ρ=2πSV / I.

[0046] By adding weights of different masses on the geometric center of the upper surface of the tin sulfide force sensitive resistor and the silicon-based force sensitive resistor to apply stress, 10g, 20g, and 50g weights are selected according to the conditions, and the change of the resistivity of the tin sulfide force sensitive resistor and the silicon-based force sensitive resistor with the stress is obtained according to the electrical signals output by the tin sulfide force sensitive resistor and the silicon-based force sensitive resistor. The results show that the performance of the tin sulfide force sensitive resistor is superior to that of the traditional silicon-based force sensitive resistor, and the real-time sensing of stress is more sensitive.

[0047] Example 3

[0048] According to the attached Figure 2 , the utility model discloses polyimide film A, stannous sulfide film B, silver paste / solder electrode C, copper wire D and polydimethylsiloxane E.

[0049] Specifically, as the stannous sulfide force-sensitive resistance structure plan view shown in the attached Figure 2 , wherein polyimide film A is close to stannous sulfide film B. The polyimide A is used to bear the stannous sulfide film B, and plays a fixed support role.

[0050] Specifically, the copper wire D on the stannous sulfide film B is adhered to 1, 2, 3, 4 respectively with the stannous sulfide film B, and the copper wire D is respectively led out by the stannous sulfide force-sensitive resistance perpendicular to the two sides of the circuit terminal, and is respectively named as probe 1, probe 2, probe 3 and probe 4. Four probes have good conductivity and certain ductility, and are used to output electric signal.

[0051] Further, the probe 1 and the probe 3 in the copper wire D are led out in one direction, and the probe 2 and the probe 4 are led out in the opposite direction of the probe 1 and the probe 3. The probe 1, the probe 2, the probe 3 and the probe 4 are parallel to each other and have equal spacing. The distance between the silver paste / solder electrodes C is also equal. The silver paste / solder electrodes C ensure the ohmic contact between the copper wire D and the stannous sulfide film B.

[0052] Further, the silver paste / solder electrodes C at the adhering place of the stannous sulfide film B and the led-out copper wire D are located between the stannous sulfide film B and the polydimethylsiloxane film E. The silver paste / solder electrodes are used to adhere and fix the copper wire D and the stannous sulfide film B, and also connect and fix the polydimethylsiloxane film E and the stannous sulfide film B.

[0053] Further, the polyimide film A and the polydimethylsiloxane film E are also connected with each other, constitute packaging material, and jointly package the force-sensitive element composed of the stannous sulfide film B, the silver paste / solder electrodes C and the copper wire D.

[0054] The stannous sulfide force-sensitive resistance and the silicon-based force-sensitive resistance are connected in the circuit in the simple supported beam structure. The sensitive ammeter is connected in series at the probe 1 and the probe 4, then the power is turned on and the data is read. The power is turned off, the sensitive ammeter is replaced and connected in parallel at the probe 2 and the probe 3, then the power is turned on and the data is read. The voltage through the probe 2 and the probe 3 is calculated. The resistivity of the force-sensitive resistance at this time can be obtained by substituting ρ=2πSV / I.

[0055] The stress is applied by adding weights with different mass on the geometric center of the upper surface of stannous sulfide force-sensitive resistor and silicon-based force-sensitive resistor, 100g and 200g weights are selected according to conditions, and the change of resistivity of stannous sulfide force-sensitive resistor and silicon-based force-sensitive resistor with the stress is obtained according to the electrical signal output by the stannous sulfide force-sensitive resistor and silicon-based force-sensitive resistor, and the result shows that the performance of stannous sulfide force-sensitive resistor is more superior than that of traditional silicon-based force-sensitive resistor, and the real-time sensing of stress is more sensitive.

[0056] The technical features of the above embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered that the combinations are within the scope of the present disclosure.

[0057] The above discloses only three specific embodiments of the present application, but the embodiments of the present application are not limited to this, any changes that can be thought of by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A novel tin sulfide force-sensitive resistor, characterized in that, include: A force-sensitive element comprising a tin sulfide thin film and copper wires, wherein the tin sulfide thin film is rectangular, and the copper wires are arranged side-by-side at equal intervals laterally on the upper surface of the tin sulfide thin film. The encapsulation material, comprising polyimide and polydimethylsiloxane, is used to encapsulate the force-sensitive element.

2. The tin sulfide force-sensitive resistor according to claim 1, characterized in that... It is configured as a simply supported beam structure and connected to the circuit.

3. The tin sulfide force-sensitive resistor according to claim 1, characterized in that... In the encapsulation material, polyimide and polydimethylsiloxane are located at the bottom and top of the force-sensitive element, respectively, and the encapsulation materials are interconnected.

4. The tin sulfide force-sensitive resistor according to claim 1, characterized in that... In the force-sensitive element, the copper wire is connected to the upper surface of the tin sulfide film with silver paste or solder. After cooling and solidification, the copper wire and the tin sulfide film are in ohmic contact, and the silver paste or solder at the connection point forms an electrode.

5. The tin sulfide force-sensitive resistor according to claim 4, characterized in that... The number of copper wires is four, of which the two horizontal copper wires on both sides are used to output current signals, and the two copper wires in the middle are used to output voltage signals.

6. The tin sulfide force-sensitive resistor according to claim 5, characterized in that... The thickness of the tin sulfide film is between 30 and 50 micrometers, and the diameter of the copper wire is between 100 and 150 micrometers.

7. The tin sulfide force-sensitive resistor according to claim 6, characterized in that... The tin sulfide thin film is a layered orthogonal semiconductor with a two-dimensional structure.

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