Application of PI semiconductor material in pressure sensor and pressure sensor

Abstract

The invention relates to the technical field of pressure sensors, in particular to application of a PI semiconductor material in a pressure sensor and the pressure sensor. The PI semiconductor material has a piezoresistive effect, is high in glass transition temperature and can resist high temperature, high humidity and high acid environments; the pressure sensor prepared by using the PI semiconductor material as a pressure sensitive element has good long-term stability and is suitable for a high-temperature, high-humidity and high-acid environment. The PI semiconductor material is good in flexibility and thin in thickness, can be conveniently attached to the surface of a base material or a component to serve as a pressure sensitive element, and has a good application prospect. In addition, the pressure sensor comprises a PI semiconductor diaphragm made of a PI semiconductor material, a pressure sensing circuit arranged on the surface of the PI semiconductor diaphragm, and a CPU chip electrically connected with the pressure sensing circuit. The pressure sensor has the advantages of being good in long-term stability, suitable for high-temperature, high-humidity and high-acid environments, low in production cost, high in precision and fast in reaction.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure sensors, and in particular to an application of a PI semiconductor material in a pressure sensor and a pressure sensor. Background Art

[0002] A pressure sensor is a device or apparatus that can sense pressure signals and convert them into usable output electrical signals according to certain rules. Pressure sensors are usually composed of pressure sensitive elements and signal processing units. At present, pressure sensors are widely used in industrial automation, mechanical engineering, aerospace, environmental testing, transportation, food and beverage industry, household appliances, etc.

[0003] Traditional pressure sensors include the following: (1) Piezoresistive pressure sensor: The main component is a metal resistance strain gauge, which uses the metal resistance strain gauge adsorbed on the base material to detect the pressure signal by changing the resistance of the strain resistor with mechanical deformation. (2) Ceramic pressure sensor: The pressure acts directly on the front surface of the ceramic diaphragm, causing the diaphragm to deform slightly. The back of the ceramic diaphragm is also printed with thick film resistors and connected to form a Wheatstone bridge. (3) Diffused silicon pressure sensor: The pressure of the measured medium acts directly on the diaphragm of the sensor (stainless steel or ceramic), causing the diaphragm to produce a micro-displacement proportional to the medium pressure, causing the resistance of the sensor to change to detect the pressure signal. (4) Sapphire pressure sensor: Silicon-sapphire is used as a semiconductor sensitive element. (5) Piezoelectric pressure sensor: Based on the piezoelectric effect, it cannot be used for static measurement and can only measure dynamic stress.

[0004] It can be seen that the pressure sensitive elements of traditional pressure sensors mostly use metal resistance strain gauges, ceramic diaphragms, stainless steel diaphragms, and silicon-sapphire semiconductor sensitive elements. However, the structure of traditional pressure sensors is relatively complex. Due to the installation of various strain gauges or diaphragms, the long-term stability is poor. After long-term use, the measurement accuracy of the pressure sensor may decrease, resulting in deviations in the measurement results. In addition, traditional pressure sensors are easily affected by temperature, humidity, and acidic environmental factors, especially high temperature, high humidity, and high acid environments. For example, metal resistance strain gauges are easily corroded and damaged in high temperature, high humidity, and high acid environments, which leads to inaccurate measurement results. In addition, traditional pressure sensors also have the defect of high production costs. For example, the cost of the silicon-sapphire semiconductor sensitive element used in sapphire pressure sensors is relatively high.

[0005] In addition, due to the complex structure and large size of traditional pressure sensors, they are not suitable for use in some special scenarios. For example, they are used to detect whether the battery is bulging or as pressure sensors at the end of manipulators. They are inconvenient to install and difficult to detect pressure signals. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the first purpose of the present invention is to provide an application of a PI semiconductor material in a pressure sensor. Since the PI semiconductor material has a piezoresistive effect and a high glass transition temperature, and can withstand high temperature, high humidity and high acid environments, the pressure sensor made using the PI semiconductor material as a pressure sensitive element has the advantages of good long-term stability, is suitable for high temperature, high humidity and high acid environments, and has low production costs.

[0007] In order to overcome the shortcomings of the prior art, the second purpose of the present invention is to provide a pressure sensor, which uses PI semiconductor material as a pressure sensitive element, has the advantages of simple structure, small size, ability to withstand high temperature, high humidity and high acid environment, good long-term stability and low production cost.

[0008] In order to achieve the first object of the above invention, the technical solution adopted by the present invention is as follows:

[0009] The present invention provides an application of a PI semiconductor material in a pressure sensor, and adopts the PI semiconductor material as a pressure sensitive element of the pressure sensor.

[0010] Furthermore, the PI semiconductor material includes a polyimide substrate and a conductive substance dispersed in the polyimide substrate, wherein the conductive substance is uniformly dispersed in the polyimide substrate in a physically combined manner, thereby forming the PI semiconductor material.

[0011] Furthermore, the preparation method of the PI semiconductor material is: dibasic acid anhydride, diamine and conductive material are dispersed in an organic solvent to form a stock solution of the PI semiconductor material, and then the stock solution of the PI semiconductor material is brushed or sprayed, and then heated and cured to obtain the PI semiconductor material. The dibasic acid anhydride, diamine and conductive material are uniformly dispersed in an organic solvent to form a stock solution of the PI semiconductor material. When the stock solution of the PI semiconductor material is brushed or sprayed and then heated, the dibasic acid anhydride and the diamine form polyimide through imidization reaction, and the conductive material is uniformly dispersed in the polyimide material. The obtained PI semiconductor material is a film-like material.

[0012] Among them, since the substrate of the PI semiconductor material is polyimide, the glass transition temperature of polyimide is high, the glass transition temperature of the PI semiconductor material prepared by the above preparation method can reach 300°C-450°C, so it has the advantage of high temperature resistance and can be used in high temperature, high humidity and high acid environments.

[0013] Among them, the dibasic acid anhydride is at least one of aromatic dibasic acid anhydride, semi-aromatic dibasic acid anhydride or aliphatic dibasic acid anhydride; or, the dibasic acid anhydride is at least one of pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, dibenzophenonetetracarboxylic dianhydride, hexafluoro dianhydride, octafluorobiphenyl dianhydride, cyclobutanetetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, diphenyl ether tetracarboxylic dianhydride or bisphenol A type dianhydride.

[0014] The diamine is at least one of an aromatic diamine, a semi-aromatic diamine or an aliphatic diamine, or the diamine is at least one of 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-dimethylbenzidine, p-phenylenediamine, 3,3'-diaminodiphenyl sulfone or isophoronediamine.

[0015] Furthermore, the conductive material is at least one of carbon nanotubes, graphene or conductive carbon black.

[0016] Furthermore, the mass percentage of the conductive substance in the dry film of the PI semiconductor material is 2%-20%, and the mass percentage of the conductive substance in the dry film can make the formed material a semiconductor material.

[0017] Furthermore, the molar ratio of the dibasic acid anhydride to the diamine is 1:1, and the solid content of the stock solution of the PI semiconductor material is 5% to 20%; and / or

[0018] The organic solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone; and / or

[0019] The temperature of the heating and curing molding is 300° C. to 400° C., and the time of the heating and curing molding is 5 min to 60 min. The temperature and time can make the PI semiconductor material completely imidized.

[0020] Furthermore, the square resistance of the PI semiconductor material is 500 ohms to 50,000 ohms, so that the PI semiconductor material has a good piezoresistive effect and can be used as a pressure sensitive element.

[0021] The application of a PI semiconductor material in a pressure sensor of the present invention, since the substrate of the PI semiconductor material is polyimide, the conductive material can be evenly dispersed in the polyimide substrate, so that the square resistance uniformity of the PI semiconductor material is relatively good, and the square resistance uniformity fluctuates by about 15%. It has a good piezoresistive effect and a high glass transition temperature, and can withstand high temperature, high humidity and high acid environments. Therefore, the pressure sensor made of the PI semiconductor material as a pressure sensitive element has the advantages of good long-term stability and is suitable for high temperature, high humidity and high acid environments. In addition, as a pressure sensitive element, the PI semiconductor material has good flexibility, is easy to assemble and prepare pressure sensors, has a wide range of applications, and has the advantages of low production costs, compared with the metal resistance strain gauges, ceramic diaphragms, stainless steel diaphragms, and silicon-sapphire semiconductor sensitive elements in the prior art.

[0022] In order to achieve the second purpose of the above invention, the technical solution adopted by the present invention is as follows:

[0023] The present invention provides a pressure sensor, comprising a PI semiconductor diaphragm made of the PI semiconductor material, a pressure sensing circuit arranged on the surface of the PI semiconductor diaphragm, and a CPU chip electrically connected to the pressure sensing circuit.

[0024] Among them, since the PI semiconductor material is a film material formed by dispersing dibasic acid anhydride, diamine and conductive material into an organic solvent to form a stock solution of the PI semiconductor material, and then brushing or spraying the stock solution of the PI semiconductor material, and then heating and curing it, the PI semiconductor material is cut into suitable specifications to obtain a PI semiconductor diaphragm. The substrate of the PI semiconductor diaphragm is polyimide, and the conductive material can be evenly dispersed in the polyimide substrate, so that the square resistance uniformity of the PI semiconductor diaphragm is relatively good, it has a good piezoresistive effect and a high glass transition temperature, and can withstand high temperature, high humidity and high acid environments. Therefore, the pressure sensor prepared has good long-term stability, is suitable for high temperature, high humidity and high acid environments, and has the advantages of low production cost, high precision and fast response.

[0025] In addition, as a pressure sensitive element, the PI semiconductor diaphragm has a piezoresistive effect. When pressure is applied to a certain position of the PI semiconductor diaphragm, the resistance value of that position of the PI semiconductor diaphragm will change due to mechanical deformation. The pressure sensing circuit set on the surface of the PI semiconductor diaphragm is used to sense the change in the resistance value of the PI semiconductor diaphragm. The pressure sensing circuit transmits the sensed resistance change signal to the CPU chip, and the CPU chip calculates the pressure through data conversion, thereby detecting the pressure signal.

[0026] Furthermore, the pressure sensor further includes a signal amplifier, and the pressure sensing circuit is electrically connected to the CPU chip via the signal amplifier. The signal amplifier is used to amplify the resistance value change signal conducted by the pressure sensing circuit and then conduct it to the CPU chip, so that the CPU chip can better receive the resistance value change signal and then calculate the pressure.

[0027] Furthermore, the pressure sensing circuit is a TFT circuit. The TFT circuit is also called a thin film transistor circuit. The TFT circuit is composited on the surface of the PI semiconductor diaphragm and is used to detect the pressure signal on the surface of the PI semiconductor diaphragm. The TFT circuit can detect and locate the change of pressure at each position point on the surface of the PI semiconductor diaphragm.

[0028] Furthermore, the thickness of the PI semiconductor diaphragm is 5μm-80μm. The PI semiconductor diaphragms in this thickness range are easy to realize through brushing or spraying process and curing molding process, and the PI semiconductor diaphragms in this thickness range have good piezoresistive effect and thin thickness, which makes the PI semiconductor diaphragm soft and light, and easy to attach to the surface of the component substrate that needs to detect pressure changes.

[0029] The pressure sensor is used to detect whether the battery is bulging. As long as the PI semiconductor diaphragm is attached to the surface of the battery, it can well detect whether the battery is bulging. Since the PI semiconductor diaphragm has good flexibility and light weight, it is easy to attach to the surface of the battery. In addition, since the PI semiconductor diaphragm has the advantages of high temperature resistance, high humidity resistance and high acid resistance, it can be well applied to detect battery bulging.

[0030] In addition, due to the good flexibility of the PI semiconductor diaphragm, the pressure sensor is also very suitable for use as a pressure sensor at the end of the manipulator, and the PI semiconductor diaphragm is easy to attach to the end of the manipulator. And when the manipulator needs to operate in a high temperature, high humidity, and high acid environment, the application of this pressure sensor has great advantages.

[0031] Therefore, the pressure sensor of the present invention has a good application prospect.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The application of a PI semiconductor material of the present invention in a pressure sensor, the PI semiconductor material has a piezoresistive effect and a high glass transition temperature, and can withstand high temperature, high humidity, and high acid environments. The pressure sensor made by using the PI semiconductor material as a pressure sensitive element has good long-term stability and is suitable for high temperature, high humidity, and high acid environments. In addition, the PI semiconductor material has good flexibility and thin thickness, and is easy to be attached to the surface of a substrate or component as a pressure sensitive element, and has a good application prospect.

[0034] (2) The application of a PI semiconductor material of the present invention in a pressure sensor. Since the substrate of the PI semiconductor material is polyimide, the conductive material can be evenly dispersed in the polyimide substrate, so that the square resistance uniformity of the PI semiconductor material is relatively good, and the square resistance uniformity fluctuates by about 15%. It has a good piezoresistive effect and a high glass transition temperature, and can withstand high temperature, high humidity and high acid environments. Therefore, the pressure sensor made of the PI semiconductor material as a pressure sensitive element has the advantages of good long-term stability and is suitable for high temperature, high humidity and high acid environments. In addition, compared with the metal resistance strain gauges, ceramic diaphragms, stainless steel diaphragms, and silicon-sapphire semiconductor sensitive elements in the prior art, the PI semiconductor material as a pressure sensitive element has good flexibility, is easy to assemble and prepare pressure sensors, has a wide range of applications, and has the advantages of low production costs.

[0035] (3) A pressure sensor of the present invention comprises a PI semiconductor diaphragm made of PI semiconductor material, a pressure sensing circuit arranged on the surface of the PI semiconductor diaphragm, and a CPU chip electrically connected to the pressure sensing circuit. The PI semiconductor diaphragm is obtained by cutting the PI semiconductor material into suitable specifications. The substrate of the PI semiconductor diaphragm is polyimide, and the conductive material can be evenly dispersed in the polyimide substrate, thereby making the square resistance uniformity of the PI semiconductor diaphragm relatively good, having a good piezoresistive effect and a high glass transition temperature, and being able to withstand high temperature, high humidity and high acid environments. Therefore, the obtained pressure sensor has good long-term stability, is suitable for high temperature, high humidity and high acid environments, and has the advantages of low production cost, high precision and fast response. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a structural schematic diagram of a pressure sensor according to Example 7 of the present invention.

[0038] Figure 2 It is a schematic diagram of the decomposed structure of a pressure sensor according to Example 7 of the present invention.

[0039] Figure 3 It is a schematic structural diagram of a pressure sensor according to Example 8 of the present invention.

[0040] Figure 4 It is a schematic diagram of the decomposed structure of a pressure sensor according to Example 8 of the present invention.

[0041] In the figure:

[0042] PI semiconductor diaphragm 1, pressure sensing circuit 2, CPU chip 3, signal amplifier 4. DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. In the present invention, the singular forms "a", "said", "the", "first" and "second" used in the embodiments and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0045] The following describes the invention in conjunction with specific embodiments.

[0046] Example 1

[0047] In the present embodiment, a PI semiconductor material is applied in a pressure sensor, and the PI semiconductor material is used as a pressure sensitive element of the pressure sensor.

[0048] The PI semiconductor material includes a polyimide substrate and a conductive material dispersed in the polyimide substrate.

[0049] The preparation method of the PI semiconductor material is as follows: dispersing pyromellitic anhydride, 4,4'-diaminodiphenyl ether and a conductive material into N,N-dimethylformamide to form a stock solution of the PI semiconductor material, and then brushing or spraying the stock solution of the PI semiconductor material, and then heating it to 350°C and keeping it warm for 30 minutes to solidify and form, so as to obtain the PI semiconductor material. In this embodiment, the molar ratio of pyromellitic anhydride to 4,4'-diaminodiphenyl ether is 1:1, and the solid content of the stock solution of the PI semiconductor material is 10%.

[0050] In this embodiment, the conductive material is carbon nanotubes; the mass percentage of the conductive material in the dry film of the PI semiconductor material is 6%.

[0051] In this embodiment, the sheet resistance of the PI semiconductor material is 20,000 ohms.

[0052] Example 2

[0053] In the present embodiment, a PI semiconductor material is applied in a pressure sensor, and the PI semiconductor material is used as a pressure sensitive element of the pressure sensor.

[0054] The PI semiconductor material includes a polyimide substrate and a conductive material dispersed in the polyimide substrate.

[0055] The preparation method of the PI semiconductor material is as follows: dispersing biphenyltetracarboxylic acid dianhydride, 4,4'-diaminodiphenylmethane and a conductive material into N,N-dimethylacetamide to form a stock solution of the PI semiconductor material, and then brushing or spraying the stock solution of the PI semiconductor material, and then heating it to 300°C for 60 minutes to solidify and form, so as to obtain the PI semiconductor material. In this embodiment, the molar ratio of biphenyltetracarboxylic acid dianhydride to 4,4'-diaminodiphenylmethane is 1:1, and the solid content of the stock solution of the PI semiconductor material is 12%.

[0056] In this embodiment, the conductive material is graphene; the mass percentage of the conductive material in the dry film of the PI semiconductor material is 20%.

[0057] In this embodiment, the sheet resistance of the PI semiconductor material is 500 ohms.

[0058] Example 3

[0059] In the present embodiment, a PI semiconductor material is applied in a pressure sensor, and the PI semiconductor material is used as a pressure sensitive element of the pressure sensor.

[0060] The PI semiconductor material includes a polyimide substrate and a conductive material dispersed in the polyimide substrate.

[0061] The preparation method of the PI semiconductor material is as follows: dispersing benzophenone tetracarboxylic acid dianhydride, 2,2'-bis(trifluoromethyl)benzidine and a conductive material into N-methylpyrrolidone to form a stock solution of the PI semiconductor material, and then brushing or spraying the stock solution of the PI semiconductor material, and then heating it to 400°C for 5 minutes to solidify and form, thereby obtaining the PI semiconductor material. In this embodiment, the molar ratio of benzophenone tetracarboxylic acid dianhydride to 2,2'-bis(trifluoromethyl)benzidine is 1:1, and the solid content of the stock solution of the PI semiconductor material is 8%.

[0062] In this embodiment, the conductive material is conductive carbon black; the mass percentage of the conductive material in the dry film of the PI semiconductor material is 2%.

[0063] In this embodiment, the sheet resistance of the PI semiconductor material is 50,000 ohms.

[0064] Example 4

[0065] In the present embodiment, a PI semiconductor material is applied in a pressure sensor, and the PI semiconductor material is used as a pressure sensitive element of the pressure sensor.

[0066] The PI semiconductor material includes a polyimide substrate and a conductive material dispersed in the polyimide substrate.

[0067] Among them, the preparation method of PI semiconductor material is: hexafluorodianhydride, octafluorobiphenyldianhydride, 3,3'-dimethylbenzidine, p-phenylenediamine and conductive material are dispersed in a composition of N,N-dimethylformamide and N,N-dimethylacetamide to form a stock solution of PI semiconductor material, and then the stock solution of PI semiconductor material is brushed or sprayed, and then heated to 320°C and kept warm for 45 minutes to solidify and form, that is, the PI semiconductor material is obtained. In this embodiment, the molar ratio of dibasic acid anhydride (composition of 3,3'-dimethylbenzidine and p-phenylenediamine) and diamine (composition of 3,3'-dimethylbenzidine and p-phenylenediamine) is 1:1, and the solid content of the stock solution of PI semiconductor material is 10%.

[0068] In this embodiment, the conductive material is carbon nanotubes; the mass percentage of the conductive material in the dry film of the PI semiconductor material is 16%.

[0069] In this embodiment, the sheet resistance of the PI semiconductor material is 5000 ohms.

[0070] Example 5

[0071] In the present embodiment, a PI semiconductor material is applied in a pressure sensor, and the PI semiconductor material is used as a pressure sensitive element of the pressure sensor.

[0072] The PI semiconductor material includes a polyimide substrate and a conductive material dispersed in the polyimide substrate.

[0073] Among them, the preparation method of the PI semiconductor material is: cyclobutanetetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, 3,3'-diaminodiphenyl sulfone and a conductive material are dispersed in N,N-dimethylformamide to form a stock solution of the PI semiconductor material, and then the stock solution of the PI semiconductor material is brushed or sprayed, and then heated to 380°C for 15 minutes to solidify and form, that is, the PI semiconductor material is obtained. In this embodiment, the molar ratio of the dibasic acid anhydride (a composition of cyclobutanetetracarboxylic acid dianhydride and naphthalenetetracarboxylic acid dianhydride) and 3,3'-diaminodiphenyl sulfone is 1:1, and the solid content of the stock solution of the PI semiconductor material is 12%.

[0074] In this embodiment, the conductive material is a combination of carbon nanotubes and graphene; the mass percentage of the conductive material in the dry film of the PI semiconductor material is 9%.

[0075] In this embodiment, the sheet resistance of the PI semiconductor material is 10,000 ohms.

[0076] Example 6

[0077] In the present embodiment, a PI semiconductor material is applied in a pressure sensor, and the PI semiconductor material is used as a pressure sensitive element of the pressure sensor.

[0078] The PI semiconductor material includes a polyimide substrate and a conductive material dispersed in the polyimide substrate.

[0079] Among them, the preparation method of the PI semiconductor material is: diphenyl ether tetracarboxylic dianhydride, bisphenol A dianhydride, isophorone diamine and a conductive material are dispersed in N-methylpyrrolidone to form a stock solution of the PI semiconductor material, and then the stock solution of the PI semiconductor material is brushed or sprayed, and then heated to 360°C and kept warm for 20 minutes to solidify and form, that is, the PI semiconductor material is obtained. In this embodiment, the molar ratio of the dibasic acid anhydride (a composition of diphenyl ether tetracarboxylic dianhydride and bisphenol A dianhydride) and isophorone diamine is 1:1, and the solid content of the stock solution of the PI semiconductor material is 20%.

[0080] In this embodiment, the conductive material is a combination of carbon nanotubes and conductive carbon black; the mass percentage of the conductive material in the dry film of the PI semiconductor material is 5%.

[0081] In this embodiment, the sheet resistance of the PI semiconductor material is 30,000 ohms.

[0082] Example 7

[0083] A pressure sensor of this embodiment, please refer to Figure 1 and Figure 2 , including a PI semiconductor diaphragm 1 made of PI semiconductor material, a pressure sensing circuit 2 arranged on the surface of the PI semiconductor diaphragm 1, and a CPU chip 3 electrically connected to the pressure sensing circuit 2. Among them, the PI semiconductor diaphragm 1, as a pressure sensitive element, has a piezoresistive effect. When a certain position of the PI semiconductor diaphragm 1 is subjected to pressure, the resistance value of this position of the PI semiconductor diaphragm 1 will change due to mechanical deformation. The pressure sensing circuit 2 arranged on the surface of the PI semiconductor diaphragm 1 is used to sense the change in the resistance value of the PI semiconductor diaphragm 1. The pressure sensing circuit 2 transmits the sensed resistance value change signal to the CPU chip 3, and the CPU chip 3 calculates the pressure through data conversion, thereby detecting the pressure signal.

[0084] In this embodiment, the pressure sensing circuit 2 is a TFT circuit. In this embodiment, the TFT circuit is arranged in a matrix structure of multiple rows and multiple columns interlaced with each other, thereby being able to better detect the pressure change at each position on the surface of the PI semiconductor diaphragm 1.

[0085] In this embodiment, the thickness of the PI semiconductor diaphragm is 30 μm. The PI semiconductor diaphragm 1 of this thickness has a good piezoresistive effect and is thin, so that the PI semiconductor diaphragm 1 is flexible, light, and easy to attach to the surface of the component substrate that needs to detect pressure changes.

[0086] Example 8

[0087] A pressure sensor of this embodiment, please refer to Figure 3 and Figure 4 , including a PI semiconductor diaphragm 1 made of PI semiconductor material, a pressure sensing circuit 2 arranged on the surface of the PI semiconductor diaphragm 1, a signal amplifier 4 electrically connected to the pressure sensing circuit 2, and a CPU chip 3 electrically connected to the signal amplifier 4.

[0088] Among them, the PI semiconductor diaphragm 1 is a pressure sensitive element with a piezoresistive effect. When a certain position of the PI semiconductor diaphragm 1 is subjected to pressure, the resistance value of the position of the PI semiconductor diaphragm 1 will change due to mechanical deformation. The pressure sensing circuit 2 arranged on the surface of the PI semiconductor diaphragm 1 is used to sense the change in the resistance value of the PI semiconductor diaphragm 1. The pressure sensing circuit 2 transmits the sensed resistance value change signal to the signal amplifier 4. The signal amplifier 4 is used to amplify the resistance value change signal transmitted by the pressure sensing circuit 2 and then transmit it to the CPU chip 3, so that the CPU chip 3 can better receive the resistance value change signal and then calculate the pressure, thereby realizing the detection of the pressure signal.

[0089] In this embodiment, the pressure sensing circuit 2 is a TFT circuit. In this embodiment, the TFT circuit is arranged in a matrix structure of multiple rows and multiple columns interlaced with each other, thereby being able to better detect the pressure change at each position on the surface of the PI semiconductor diaphragm 1.

[0090] In this embodiment, the thickness of the PI semiconductor diaphragm 1 is 20 μm. The PI semiconductor diaphragm 1 of this thickness has a good piezoresistive effect and is thin, so that the PI semiconductor diaphragm 1 is flexible, light, and easy to attach to the surface of the component substrate that needs to detect pressure changes.

[0091] Example 9

[0092] A pressure sensor of this embodiment, please refer to Figure 3 and Figure 4 The difference between this embodiment and embodiment 8 is that, in this embodiment, the thickness of the PI semiconductor diaphragm 1 is 5 μm. The PI semiconductor diaphragm 1 of this thickness is lighter and thinner, and has a better piezoresistive effect, which makes the PI semiconductor diaphragm 1 soft and light, and easy to attach to the surface of the substrate of the component that needs to detect pressure changes.

[0093] Example 10

[0094] A pressure sensor of this embodiment, please refer to Figure 3 and Figure 4 The difference between this embodiment and Embodiment 8 is that, in this embodiment, the thickness of the PI semiconductor diaphragm 1 is 80 μm. The PI semiconductor diaphragm 1 of this thickness has a good piezoresistive effect and is thin, which makes the PI semiconductor diaphragm 1 soft and light, and easy to attach to the surface of the substrate of the component that needs to detect pressure changes.

[0095] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An application of PI semiconductor material in a pressure sensor, characterized in that: PI semiconductor material is used as the pressure sensitive element of the pressure sensor.

2. The use of a PI semiconductor material in a pressure sensor as claimed in claim 1, characterized in that: The PI semiconductor material includes a polyimide substrate and a conductive substance dispersed in the polyimide substrate.

3. The use of a PI semiconductor material in a pressure sensor according to claim 1, characterized in that: The preparation method of the PI semiconductor material is: dispersing dibasic acid anhydride, diamine and conductive material in an organic solvent to form a stock solution of the PI semiconductor material, then brushing or spraying the stock solution of the PI semiconductor material, and then heating and curing the solution to obtain the PI semiconductor material.

4. The use of a PI semiconductor material in a pressure sensor as claimed in claim 2 or 3, characterized in that: The conductive material is at least one of carbon nanotubes, graphene or conductive carbon black; and / or The mass percentage of the conductive substance in the dry film of the PI semiconductor material is 2%-20%.

5. The use of a PI semiconductor material in a pressure sensor as claimed in claim 3, characterized in that: The molar ratio of the dibasic acid anhydride to the diamine is 1:1, and the solid content of the stock solution of the PI semiconductor material is 5% to 20%; and / or The organic solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone; and / or The temperature of the heating and curing molding is 300° C. to 400° C., and the time of the heating and curing molding is 5 min to 60 min.

6. The use of a PI semiconductor material in a pressure sensor according to claim 1, characterized in that: The square resistance of the PI semiconductor material is 500 ohms to 50,000 ohms.

7. A pressure sensor, characterized in that: The invention comprises a PI semiconductor diaphragm made of the PI semiconductor material, a pressure sensing circuit arranged on the surface of the PI semiconductor diaphragm, and a CPU chip electrically connected to the pressure sensing circuit.

8. A pressure sensor as claimed in claim 8, characterized in that: It also includes a signal amplifier, and the pressure sensing circuit is electrically connected to the CPU chip through the signal amplifier.

9. A pressure sensor as claimed in claim 7, characterized in that: The pressure sensing circuit is a TFT circuit.

10. A pressure sensor as claimed in claim 7, characterized in that: The thickness of the PI semiconductor film is 5 μm-80 μm.

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