Surface acoustic wave gas-sensitive sensor with three-dimensional nanostructure

Abstract

The utility model discloses a three-dimensional nanostructure surface acoustic wave gas sensor, which comprises a shell, a gas detection mechanism is arranged in the shell, the gas detection mechanism comprises a crystal substrate, a three-dimensional nanostructure plate is fixedly arranged at the top of the crystal substrate, the three-dimensional nanostructure plate is of a U-shaped structure, and the three-dimensional nanostructure plate is fixedly arranged on the top of the crystal substrate. A three-dimensional nano-structure plate is arranged in the shell, a gas-sensitive film is arranged in the three-dimensional nano-structure plate, the gas-sensitive film is attached to the three-dimensional nano-structure plate, two electrode pins are fixedly arranged at the bottom of the shell in a penetrating manner, and the two electrode pins are distributed in a mirror image manner. According to the utility model, the three-dimensional nano-structure plate is of a U-shaped structure, the U-shaped structure can effectively concentrate and guide the propagation of sound waves, reduce the diffusion and loss of energy and improve the detection accuracy, and the three-dimensional nano-structure has huge specific surface area, excellent mechanical properties and excellent optical and electronic properties.

Description

Technical Field

[0001] The utility model relates to the field of surface acoustic wave gas sensors, in particular to a three-dimensional nanostructured surface acoustic wave gas sensor. Background Art

[0002] Surface acoustic wave gas sensor, also known as saw (surface acoustic wave) gas sensor, is the most complex and widely used type of sensor among many sensors. The wave velocity and frequency of surface acoustic wave devices will drift with changes in the external environment. Surface acoustic wave gas sensor uses this property to coat a gas-sensitive film that selectively adsorbs a certain gas on the surface of the piezoelectric crystal. When the gas-sensitive film interacts with the gas to be measured (chemical or biological action, or physical adsorption), the film quality and conductivity of the gas-sensitive film change, causing the surface acoustic wave frequency of the piezoelectric crystal to drift; different gas concentrations will cause different degrees of change in the film quality and conductivity, that is, the changes in the surface acoustic wave frequency will also be different. By measuring the changes in the surface acoustic wave frequency, the changes in gas concentration can be accurately reflected.

[0003] During operation, the existing surface acoustic wave gas sensor converts an input electrical signal into an acoustic signal, which is then converted into an electrical signal for output, thereby realizing the detection of specific gases in the air.

[0004] However, the acoustic signal will be affected by diffusion attenuation, absorption attenuation, scattering attenuation and environmental factors during the transmission process, resulting in energy loss, thereby reducing the accuracy of detection. In addition, the existing gas-sensitive film is attached to the substrate, and there may be a difference in the thermal expansion coefficients between the gas-sensitive film and the substrate. In high or low temperature environments, due to the difference in thermal expansion coefficients, stress or deformation may occur between the film and the substrate, thereby affecting the sensitivity and stability of the gas-sensitive element.

[0005] Therefore, it is necessary to propose a three-dimensional nanostructured surface acoustic wave gas sensor to solve the above problems. Utility Model Content

[0006] The utility model aims to provide a three-dimensional nanostructured surface acoustic wave gas sensor to solve the problem of energy loss caused by diffusion attenuation, absorption attenuation, scattering attenuation and environmental factors during the transmission of acoustic signals.

[0007] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a three-dimensional nanostructured surface acoustic wave gas sensor, comprising a shell, a gas detection mechanism is arranged inside the shell, the gas detection mechanism comprises a crystal substrate, a three-dimensional nanostructured plate is fixedly installed on the top of the crystal substrate, the three-dimensional nanostructured plate is in a U-shaped structure, a gas-sensitive film is arranged inside the three-dimensional nanostructured plate, and the gas-sensitive film is adhered to the three-dimensional nanostructured plate.

[0008] Preferably, an input interdigital transducer and an output interdigital transducer are fixedly mounted on the top of the crystal substrate, the input interdigital transducer is arranged on one side of the three-dimensional nanostructure plate, and the output interdigital transducer is arranged on the other side of the three-dimensional nanostructure plate.

[0009] Preferably, an electrode pin is fixedly provided on the bottom of the housing, two electrode pins are provided, and the two electrode pins are distributed in a mirror image with respect to the crystal substrate.

[0010] Preferably, input wires are fixedly installed at both ends of the input interdigital transducer, and the two input wires are fixedly connected to one of the electrode pins.

[0011] Preferably, output wires are fixedly installed at both ends of the output interdigital transducer, and the two output wires are fixedly connected to another electrode pin.

[0012] Preferably, an insulating pad is fixedly installed inside the shell, the insulating pad is arranged between two electrode pins, and the crystal substrate is fixedly installed on the insulating pad.

[0013] Preferably, an air flow hole is opened on the top of the shell, and a wire mesh cover is fixedly installed in the air flow hole.

[0014] The technical effect of the utility model is that the three-dimensional nanostructured plate is U-shaped, which can effectively concentrate and guide the propagation of sound waves, reduce energy diffusion and loss, and improve the accuracy of detection. At the same time, the three-dimensional nanostructure has a huge specific surface area, excellent mechanical properties, and excellent optical and electronic properties, which improve the accuracy of detection. The utility model adheres the gas-sensitive film to the three-dimensional nanostructured plate, thereby avoiding the different thermal expansion coefficients between the gas-sensitive film and the crystal substrate, which affects the sensitivity and stability of the gas-sensitive element. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the three-dimensional nanostructured surface acoustic wave gas sensor of the utility model.

[0016] Figure 2 This is a cross-sectional view of the structure of the three-dimensional nanostructured surface acoustic wave gas sensor of the utility model.

[0017] Figure 3 This is a schematic diagram of the structure of the gas detection mechanism of the utility model.

[0018] Figure 4 For this utility model Figure 3 A magnified view of the structure in the middle.

[0019] In the figure: 1. outer shell; 2. electrode pins; 3. wire mesh cover; 4. insulating pad; 5. crystal substrate; 6. input interdigital transducer; 7. output interdigital transducer; 8. input wire; 9. three-dimensional nanostructured plate; 10. gas-sensitive film; 11. output wire. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] like Figure 1-Figure 4 As shown, the utility model provides a three-dimensional nanostructured surface acoustic wave gas sensor, including a shell 1, the shell 1 is used to protect and fix the internal components, the top of the shell 1 is provided with an air flow hole, the air flow hole is used for the inflow of gas, so as to detect the concentration or type of specific gas in the gas, and a wire mesh cover 3 is fixedly installed in the air flow hole, the wire mesh cover 3 is used to prevent dust from entering the shell 1.

[0022] The bottom of the housing 1 is fixedly provided with an electrode pin 2, which is used to provide the gas sensor with power required for operation, thereby ensuring that the gas sensor can work normally.

[0023] Furthermore, an insulating pad 4 is fixedly installed inside the housing 1 , and is used to support internal components, reduce electromagnetic interference on the components, and improve the measurement accuracy and stability of the gas sensor. The insulating pad 4 is arranged between the two electrode pins 2 .

[0024] Specifically, a gas detection mechanism is arranged inside the shell 1, and the gas detection mechanism includes a crystal substrate 5, and the crystal substrate 5 is used to propagate surface acoustic waves. An input interdigital transducer 6 and an output interdigital transducer 7 are fixedly installed on the top of the crystal substrate 5. The input interdigital transducer 6 is used to convert an input electrical signal into a surface acoustic signal, and the output interdigital transducer 7 is used to convert a surface acoustic signal into an electrical signal for output. The input interdigital transducer 6 and the output interdigital transducer 7 cooperate to realize the conversion between electrical signals and acoustic signals, so that the surface acoustic wave gas sensor can detect and respond to specific gases.

[0025] A three-dimensional nanostructure plate 9 is fixedly installed on the top of the crystal substrate 5. It should be noted that the three-dimensional nanostructure plate 9 can be made of nanoglass material, but is not limited to nanomaterial glass. The three-dimensional nanostructure refers to a composite material composed of one or more basic structural units in zero dimension, one dimension and two dimension. At the same time, the three-dimensional nanostructure has a huge specific surface area, excellent mechanical properties and excellent optical and electronic properties, which will not be elaborated here.

[0026] A gas-sensitive film 10 is arranged inside the three-dimensional nanostructure plate 9, and the gas-sensitive film 10 is used to chemically react with some specific gases in the air.

[0027] The input IDT 6 is arranged on one side of the three-dimensional nanostructure plate 9 , and the output IDT 7 is arranged on the other side of the three-dimensional nanostructure plate 9 .

[0028] Input wires 8 are fixedly installed at both ends of the input interdigital transducer 6, and the input wires 8 are used to connect an external power supply or signal source to the input interdigital transducer 6 on the crystal substrate 5. Output wires 11 are fixedly installed at both ends of the output interdigital transducer 7, and the output wires 11 are used to transmit the electrical signal generated by the output interdigital transducer 7 on the crystal substrate 5 to an external circuit or processing device.

[0029] There are two electrode pins 2, and the two electrode pins 2 are distributed in a mirror image with respect to the crystal substrate 5, the two input wires 8 are fixedly connected to one of the electrode pins 2, the two output wires 11 are fixedly connected to the other electrode pin 2, and the crystal substrate 5 is fixedly mounted on the insulating pad 4.

[0030] During specific operation, the electrode pin 2 connected to the input wire 8 inputs an electrical signal to the input IDT 6, the input IDT 6 converts the electrical signal into an acoustic signal, the acoustic signal is transmitted through the medium to the output IDT 7, the output IDT 7 converts the acoustic signal into an electrical signal, and the electrical signal is output to the electrode pin 2 connected to the output wire 11 through the output wire 11, thereby realizing the surface acoustic wave gas sensor to detect specific gases in the air.

[0031] When the gas-sensitive film 10 comes into contact with a specific gas in the air and interacts with it (chemical or biological action, or physical adsorption), causing the film mass and conductivity of the gas-sensitive film 10 to change, the surface acoustic wave frequency on the surface of the crystal substrate 5 will drift (it should be noted that the degree of change in the film mass and conductivity will be different for different gas concentrations, that is, the change in the surface acoustic wave frequency will also be different), thereby realizing the detection of the concentration of the specific gas by measuring the surface acoustic wave frequency.

[0032] Taking into account that the acoustic signal will be affected by diffusion attenuation, absorption attenuation, scattering attenuation and environmental factors during the transmission process, resulting in energy loss, thereby reducing the accuracy of detection, the three-dimensional nanostructured plate 9 is formed into a U-shaped structure. The U-shaped structure can effectively concentrate and guide the propagation of sound waves, reduce energy diffusion and loss, and improve the accuracy of detection.

[0033] Taking into account the possible difference in thermal expansion coefficients between the gas-sensitive film 10 and the crystal substrate 5, under high or low temperature environments, due to the difference in thermal expansion coefficients, stress or deformation may be generated between the gas-sensitive film 10 and the crystal substrate 5, thereby affecting the sensitivity and stability of the gas-sensitive element. Therefore, the gas-sensitive film 10 is bonded to the three-dimensional nanostructure plate 9. It should be noted that the material of the three-dimensional nanostructure plate 9 can be selected according to the expansion coefficient of the gas-sensitive film 10, and materials with the same expansion coefficient are selected as much as possible, which will not be elaborated here.

[0034] During operation, the gas-sensitive film 10 is attached to the three-dimensional nanostructured plate 9, thereby avoiding the difference in thermal expansion coefficients between the gas-sensitive film 10 and the crystal substrate 5, which affects the sensitivity and stability of the gas-sensitive element.

Claims

1. A three-dimensional nanostructured surface acoustic wave gas sensor, characterized in that: The invention comprises a shell (1), wherein a gas detection mechanism is arranged inside the shell (1), wherein the gas detection mechanism comprises a crystal substrate (5), wherein a three-dimensional nanostructured plate (9) is fixedly mounted on the top of the crystal substrate (5), wherein the three-dimensional nanostructured plate (9) is in a U-shaped structure, wherein a gas-sensitive film (10) is arranged inside the three-dimensional nanostructured plate (9), and wherein the gas-sensitive film (10) is attached to the three-dimensional nanostructured plate (9).

2. The three-dimensional nanostructured surface acoustic wave gas sensor according to claim 1, characterized in that: An input interdigital transducer (6) and an output interdigital transducer (7) are fixedly mounted on the top of the crystal substrate (5); the input interdigital transducer (6) is arranged on one side of the three-dimensional nanostructure plate (9), and the output interdigital transducer (7) is arranged on the other side of the three-dimensional nanostructure plate (9).

3. The three-dimensional nanostructured surface acoustic wave gas sensor according to claim 1, characterized in that: An electrode pin (2) is fixedly provided on the bottom of the housing (1), two electrode pins (2) are provided, and the two electrode pins (2) are distributed in a mirror image with respect to the crystal substrate (5).

4. The three-dimensional nanostructured surface acoustic wave gas sensor according to claim 2, characterized in that: Input wires (8) are fixedly mounted at both ends of the input interdigital transducer (6), and both input wires (8) are fixedly connected to one of the electrode pins (2).

5. The three-dimensional nanostructured surface acoustic wave gas sensor according to claim 2, characterized in that: Output wires (11) are fixedly mounted at both ends of the output interdigital transducer (7), and the two output wires (11) are fixedly connected to another electrode pin (2).

6. The three-dimensional nanostructured surface acoustic wave gas sensor according to claim 1, characterized in that: An insulating pad (4) is fixedly mounted inside the housing (1); the insulating pad (4) is arranged between two electrode pins (2); and the crystal substrate (5) is fixedly mounted on the insulating pad (4).

7. The three-dimensional nanostructured surface acoustic wave gas sensor according to claim 1, characterized in that: An air flow hole is provided on the top of the housing (1), and a wire mesh cover (3) is fixedly installed in the air flow hole.

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