Miniaturized gas sensor and gas sensor array

Abstract

The utility model relates to the technical field of gas sensor, disclose a kind of miniaturization gas sensor and gas sensor array, including substrate and package shell, wherein in the substrate surface integration several micro hot plate realizes the compact structure of sensor, it is convenient to install and use in limited space.Second, signal electrode and heating electrode coplanar setting in micro hot plate surface, simplify the preparation process of sensor, ensure that sensor work has high stability and sensitivity.Then sputtering gas sensitive layer on signal electrode upper surface, improve sensor response speed and detection precision.In addition, substrate center is integrated with signal processing circuit, and respectively with each micro hot plate electrode connection, realized the centralized processing of signal, effectively reduced line interference, improved data processing efficiency and accuracy.In order to protect the internal structure of sensor, substrate periphery is coated with package shell, effectively prevent the interference of external environment, thereby prolong the service life of sensor.

Description

Technical Field

[0001] This utility model belongs to the field of gas sensor technology, specifically relating to a miniaturized gas sensor and a gas sensor array. Background Technology

[0002] Gas sensors are devices used to detect the concentration of specific gases in an environment, and are widely used in air quality monitoring, industrial process control, and the detection of flammable and explosive gases. Traditional gas sensors are typically large and consume a lot of power, making them difficult to meet the needs of modern portable devices and Internet of Things (IoT) applications. With the development of microelectromechanical systems (MEMS) technology and nanomaterials, the miniaturization of gas sensors has become possible.

[0003] Existing miniature gas sensors still have shortcomings in terms of sensitivity, selectivity and stability, and their manufacturing process is complex and costly. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned problems and provide a miniaturized gas sensor and gas sensor array, which has the characteristics of small size, high sensitivity, fast response speed and low power consumption.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a miniaturized gas sensor, including a substrate, wherein a plurality of micro-hot plates are integrated on the surface of the substrate, and each micro-hot plate is provided with a signal electrode and a heating electrode on its surface, the signal electrode and the heating electrode being arranged on the same plane, and a gas-sensitive layer is sputtered on the upper surface of the signal electrode;

[0007] The substrate has a signal processing circuit integrated at its center. The signal processing circuit is connected to the signal electrode and heating electrode on each micro-hot plate. The substrate is surrounded by an encapsulation shell.

[0008] A further improvement of this invention is that the substrate is a flat plate structure made of silicon material using MEMS technology.

[0009] A further improvement of this invention is that the signal electrode is a T-type Pt electrode with an electrode width of 100-120 μm; the heating electrode is a C-type Pt electrode, and the signal electrode and the heating electrode are arranged in a nested annular structure.

[0010] A further improvement of this utility model is that four micro-hot plates are provided, and the four micro-hot plates are arranged in a 2×2 matrix.

[0011] A further improvement of this invention is that the gas-sensitive layer is a CuO nanoflower structure layer with a three-dimensional flower-like morphology on its surface and a thickness of 100-500 nm.

[0012] A further improvement of this invention is that the signal electrode and the heating electrode are connected to the electrode pins, the electrode pins are connected to the signal processing circuit through metal wires, and the electrode pins are fixedly mounted on the micro-hot plate through a cantilever beam structure.

[0013] A further improvement of this invention is that the electrode pins are electrically connected to the signal processing circuit, the signal electrode, and the heating electrode.

[0014] A further improvement of this invention is that the micro-hot plate is provided with isolation holes, which are microporous structures arranged in a ring.

[0015] A further improvement of this utility model is that the encapsulation shell is made of ceramic, and the encapsulation shell is connected to the substrate and the substrate and the micro-hot plate by welding.

[0016] Secondly, this utility model also provides a gas sensor array, which is formed by integrating several miniaturized gas sensors arranged in an array on a circuit board.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention provides a miniaturized gas sensor. By integrating several micro-hot plates on the substrate surface, the sensor's structure is compacted, facilitating installation and use within limited space. Secondly, the signal electrode and heating electrode are coplanarly disposed on the micro-hot plate surface, simplifying the sensor's fabrication process and promoting efficient signal and heating energy transmission, ensuring high stability and sensitivity during sensor operation. Then, a gas-sensitive layer is sputtered onto the upper surface of the signal electrode, enabling the sensor to detect gas changes more quickly and accurately, improving the sensor's response speed and detection accuracy. Furthermore, a signal processing circuit is integrated at the center of the substrate and connected to each micro-hot plate electrode, achieving centralized signal processing, effectively reducing circuit interference, and improving data processing efficiency and accuracy. To protect the sensor's internal structure, the substrate is encapsulated in a shell, effectively preventing interference from the external environment and extending the sensor's lifespan.

[0019] Furthermore, the T-type signal electrode and the C-type heating electrode are arranged in a nested ring structure, which makes the heating area highly overlap with the sensing area, thereby improving the sensor's response speed and sensitivity.

[0020] Furthermore, the gas-sensitive layer is a CuO nanoflower structure layer with a three-dimensional flower-like morphology on its surface. The CuO nanoflower structure gas-sensitive layer has a large specific surface area and abundant active sites, which is conducive to the adsorption and reaction of gas molecules and improves the sensor's sensitivity and selectivity to gases.

[0021] Furthermore, the electrode pins are fixedly mounted on the micro-hot plate via a cantilever beam structure. The cantilever beam connection structure reduces the impact of thermal stress on the micro-hot plate and extends the service life of the sensor. Attached Figure Description

[0022] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the present invention and do not specifically limit the shapes and proportions of the components of the present invention.

[0023] Figure 1 This is a schematic diagram of the overall packaging structure of the miniaturized gas sensor of this utility model;

[0024] Figure 2 This is a schematic diagram of the substrate planar structure of the miniaturized gas sensor of this utility model;

[0025] Figure 3 This is a schematic diagram of the planar structure of the micro-hot plate of the miniaturized gas sensor of this utility model;

[0026] Figure 4 This is a schematic diagram of the overall structure of the miniaturized gas sensor testing device of this utility model;

[0027] Figure 5 This is a diagram of the miniaturized gas sensor array of this utility model.

[0028] The components include: 1. Substrate; 2. Encapsulation shell; 3. Micro-hot plate; 4. Signal processing circuit; 5. Signal electrode; 6. Heating electrode; 7. Gas sensitive layer; 8. Electrode pins; 9. Isolation hole; 10. Air pump; 11. Humidifier; 12. Power supply; 13. Data acquisition unit; 14. Air injection port; 15. Fan; 16. Sensor test platform. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of the embodiments of this utility model, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use, they are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the utility model. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of the embodiments of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0035] The present invention will now be described in further detail with reference to the accompanying drawings:

[0036] An embodiment of this utility model provides a miniaturized gas sensor, including a substrate 1, an encapsulation shell 2, a micro-hot plate 3, a signal processing circuit 4, a signal electrode 5, a heating electrode 6, a gas sensitive layer 7, electrode pins 8, and an isolation hole 9; wherein four micro-hot plates 3 are integrated on the surface of the substrate 1, and the four micro-hot plates 3 are arranged in a 2×2 matrix. Each micro-hot plate 3 is provided with a signal electrode 5 and a heating electrode 6 on its surface. The signal electrode 5 and the heating electrode 6 are coplanar. A gas sensitive layer 7 is sputtered on the upper surface of the signal electrode 5. The signal processing circuit 4 is integrated at the center of the substrate 1. The signal processing circuit 4 is connected to the signal electrode 5 and the heating electrode 6 on each micro-hot plate 3 respectively. The substrate 1 is surrounded by an encapsulation shell 2.

[0037] The substrate 1 is a flat plate structure made of silicon material using MEMS technology. Specifically, the substrate 1 is made of single-crystal silicon material and is processed and prepared using microelectromechanical systems manufacturing process. The surface of the substrate 1 is oxidized to form a silicon dioxide insulating layer, which is used to provide electrical insulation performance.

[0038] The micro-hot plate 3 is made of a low thermal conductivity material, specifically silicon nitride. The micro-hot plate 3 has a square structure and is formed as a suspended structure on the substrate 1 using MEMS technology, creating a thermal insulation cavity between the micro-hot plate 3 and the substrate 1. The micro-hot plate 3 integrates a signal processing circuit 4, including a signal amplifier, an analog-to-digital converter, and a temperature compensation circuit. The signal processing circuit 4 can analyze and process the electrical signal generated by the gas-sensitive layer 7 and perform temperature compensation to improve the sensor's measurement accuracy.

[0039] The signal electrode 5 is a T-shaped Pt electrode with a width of 100-120 μm, deposited on the surface of the micro-hot plate 3 by magnetron sputtering, and is used to collect electrical signals. The T-shaped structure includes a transverse electrode and a longitudinal electrode. The T-shaped structure design of the signal electrode 5 increases the contact area with the gas-sensitive layer 7, thereby improving the signal acquisition efficiency.

[0040] The heating electrode 6 is a C-type Pt electrode. Pt has good conductivity and a linear temperature coefficient of resistance, making it suitable not only as a heating resistor but also as a temperature sensing electrode for precise temperature control. The signal electrode 5 and the heating electrode 6 are arranged in a nested ring structure. The heating electrode 6, also fabricated using magnetron sputtering, is used to regulate the operating temperature of the gas-sensitive layer 7. The C-type structure of the heating electrode 6 allows it to surround the signal electrode 5, forming a uniform heating area. The signal electrode 5 and the heating electrode 6 are coplanarly positioned on the surface of the micro-hot plate 3, providing better thermal uniformity and electrical isolation through a silicon dioxide insulating layer.

[0041] The gas-sensitive layer 7 is a CuO nanoflower structure layer with a three-dimensional flower-like morphology on its surface and a thickness of 100-500 nm. The gas-sensitive layer 7 is deposited on the surface of the signal electrode 5 using radio frequency magnetron sputtering technology. It is used to adsorb target gas molecules and generate changes in electrical signals. This nanoflower structure has a large specific surface area, which is beneficial for the adsorption and reaction of gas molecules, thus improving the sensitivity of the sensor.

[0042] Signal electrode 5 and heating electrode 6 are connected to electrode pin 8, which is connected to signal processing circuit 4 via metal wires. Electrode pin 8 comprises four symmetrically distributed pin units, each group including a heating pin and a signal pin. The four groups are located at the four corners of the micro-hot plate 3, symmetrically distributed at 90°. In each group, the heating pin is connected to heating electrode 6, and the signal pin is connected to signal electrode 5. Electrode pin 8 is connected to signal processing circuit 4 via metal wires. The heating pin provides heating current, and the signal pin transmits the electrical signal generated by gas-sensitive layer 7.

[0043] The electrode pin 8 is fixed to the micro-hot plate 3 through a cantilever beam connection structure. One end of the cantilever beam is connected to the signal electrode 5 or the heating electrode 6, and the other end is connected to the electrode pin 8. The electrode pin 8 is fixed to the micro-hot plate 3. The cantilever beam forms a flexible support structure, which reduces the impact of thermal stress on the micro-hot plate 3.

[0044] The micro-hot plate 3 is provided with isolation holes 9, which are arranged in a ring. The isolation holes 9 can effectively reduce the conduction of heat to the substrate 1, improve the thermal isolation effect of the micro-hot plate 3, and reduce the power consumption of the sensor.

[0045] The encapsulation housing 2 is made of ceramic. The encapsulation housing 2 is connected to the substrate 1 and the substrate 1 and the micro-hot plate 3 by welding. A gas passage is provided on the top. The encapsulation housing 2 can effectively protect the internal structure of the sensor, and at the same time, the gas to be measured is allowed to enter the sensor and contact the gas sensitive layer 7 through the gas passage on the top.

[0046] This invention also provides a gas sensor array, which is formed by integrating several miniaturized gas sensors arranged in an array on a circuit board.

[0047] As a preferred solution, miniaturized gas sensors are integrated on a single circuit board in a 3×3 array arrangement to form a multi-channel gas sensor array, which greatly reduces the size and cost of the sensors and enables high-density sensor array arrangement in a limited space.

[0048] Another embodiment of this utility model provides an overall testing device for a miniaturized gas sensor, including an air pump 10, a humidifier 11, a power supply 12, a data acquisition unit 13, an air injection port 14, a fan 15, and a sensor testing platform 16. The miniaturized gas sensor is placed on the sensor testing platform 16, which is itself a test circuit board connected to the power supply 12 and the data acquisition unit 13. The power supply 12 provides power, and the data acquisition unit 13 uses an STM32F103RET6 microprocessor as its main control chip. At the start of the test, the power supply 12 is turned on, and the micro-heat plate 3 is heated to a specified temperature of 300°C. The humidifier 11 and air pump 10 are then turned on to control the humidity between 35% and 65%. Test gas is injected through the air injection port 14, and the fan 15 is turned on to accelerate gas diffusion. When the miniaturized gas sensor on the sensor testing platform 16 detects the gas, it sends a signal to the data acquisition unit 13, which then transmits it to a computer.

[0049] Working principle

[0050] When the sensor is operating, current is supplied to the micro-hot plate 3 via the heating electrode 6, raising the temperature of the micro-hot plate 3 to the optimal operating temperature of the gas-sensitive layer 7, which is 300°C. The gas to be measured enters the sensor through the gas vent at the top of the encapsulation housing 2 and comes into contact with the gas-sensitive layer 7. Gas molecules undergo adsorption and redox reactions on the surface of the CuO nanoflower structure, causing a change in the resistance value of the gas-sensitive layer 7. This change in resistance is detected by the signal electrode 5 and amplified and processed by the signal processing circuit 4.

[0051] Considering the STM32 chip's operating voltage range of 2.0~3.6V, this system uses a uniform 3.3V as its power supply voltage. Additionally, a 5V power supply is required to meet the heating requirements of the sensor. To address these different power needs, a 9V power adapter is used as the main power input. Two power conversion circuits are integrated into the system to convert the 9V power to the required 5V and 3.3V. The 5V power supply uses the MP1584EN DC-DC step-down regulator. For the 3.3V power supply, an AMS1117-3.3 linear regulator is selected to simplify the circuit and improve efficiency. The ADS1015 is used as the core converter for data acquisition, converting analog signals to digital signals for subsequent digital processing and analysis. An EC800N-CN module is used as the 4G communication module, and the STM32 microprocessor is used as the system's main control chip, responsible for receiving data from the volatile organic compound (VOC) gas sensor and communicating with the EC800N-CN module through an appropriate interface. Once the data is ready, the STM32 will send the data to the EC800N-CN module, which will then upload the data to the Alibaba Cloud server via 4G signal.

[0052] Many embodiments and applications beyond the examples provided will be apparent to those skilled in the art upon reading the foregoing description. Therefore, the scope of this teaching should not be determined by reference to the foregoing description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed utility model subject matter.

[0053] The above content provides a further detailed description of this utility model. It should not be considered that the specific embodiments of this utility model are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of this utility model, and all such deductions or substitutions should be considered to fall within the scope of protection of this utility model as defined by the submitted claims.

Claims

1. A miniaturized gas sensor, characterized in that, Includes a substrate (1), on which four micro-hot plates (3) are integrated, the four micro-hot plates (3) are arranged in a 2×2 matrix, and each micro-hot plate (3) is provided with a signal electrode (5) and a heating electrode (6) on its surface. The signal electrode (5) and the heating electrode (6) are arranged on the same plane, and a gas sensitive layer (7) is sputtered on the upper surface of the signal electrode (5). The signal electrode (5) is a T-type Pt electrode with an electrode width of 100-120 μm; the heating electrode (6) is a C-type Pt electrode, and the signal electrode (5) and the heating electrode (6) are arranged in a nested ring structure. The substrate (1) has a signal processing circuit (4) integrated at its center. The signal processing circuit (4) is connected to the signal electrode (5) and heating electrode (6) on each micro-hot plate (3). The signal electrode (5) and heating electrode (6) are connected to the electrode pin (8), the electrode pin (8) is connected to the signal processing circuit (4) through a metal wire, and the electrode pin (8) is fixed on the micro-hot plate (3) through a cantilever beam structure; The micro-hot plate (3) is provided with isolation holes (9), which are microporous structures arranged in a ring. The substrate (1) is surrounded by a packaging shell (2).

2. The miniaturized gas sensor according to claim 1, characterized in that, The substrate (1) is a flat plate structure made of silicon material using MEMS technology.

3. A miniaturized gas sensor according to claim 1, characterized in that, The gas-sensitive layer (7) is a CuO nanoflower structure layer with a three-dimensional flower-like morphology on its surface and a thickness of 100-500 nm.

4. A miniaturized gas sensor according to claim 1, characterized in that, The electrode pin (8) is electrically connected to the signal processing circuit (4), the signal electrode (5), and the heating electrode (6).

5. A miniaturized gas sensor according to claim 1, characterized in that, The encapsulation shell (2) is made of ceramic. The encapsulation shell (2) is connected to the substrate (1) and the substrate (1) is connected to the micro-hot plate (3) by welding.

6. A gas sensor array, characterized in that, The miniaturized gas sensors according to any one of claims 1-5 are integrated on a circuit board in a plurality of array arrangements.

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