Packaging structure for gas sensor

Abstract

The utility model provides a packaging structure for a gas sensor. The packaging structure for the gas sensor comprises a circuit board and a sensor chip, wherein the circuit board is of a U-shaped structure so as to form a flow channel of gas to be detected; the sensor chip is packaged on the circuit board and located on the inner side of the U-shaped structure, the sensor chip is provided with a detection area capable of making direct contact with the flow channel, and a gap is formed between the detection area and the circuit board facing the detection area. The packaging structure for the gas sensor can be placed in a detection space in the use process, and the U-shaped structure of the circuit board can play a supporting role, so that gas to be detected sequentially passes through the flow channel and the gap to be in contact with a detection area of the sensor chip, the detection area is prevented from being shielded, and the environmental suitability is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of gas sensing devices, in particular to a packaging structure for a gas sensor. Background Art

[0002] A hydrogen sensor is a detection device that can monitor the hydrogen concentration in the environment in real time, and its working principle is based on physical and chemical technologies. At present, hydrogen sensors are mainly divided into types such as electrochemical type and semiconductor type. These sensors have high sensitivity and reliability and can work stably under complex and changeable environmental conditions, providing a strong guarantee for the safe application of hydrogen energy. The detection scenarios of hydrogen are diverse and complex. The existing hydrogen sensors in the prior art can adapt to the scenarios under large-space rings, but for some special application scenarios, such as narrow spaces, there is a problem that the detection part of the sensor is easily blocked. Summary of the Utility Model

[0003] In view of this, embodiments of the utility model provide a packaging structure for a gas sensor to eliminate or improve one or more defects existing in the prior art.

[0004] The utility model provides a packaging structure for a gas sensor, including a circuit board and a sensor chip;

[0005] Wherein, the circuit board is of a U-shaped structure to form a flow channel for the gas to be measured;

[0006] The sensor chip is packaged on the circuit board and is located inside the U-shaped structure. The sensor chip has a detection area that can directly contact the flow channel, and there is a gap between the detection area and the circuit board facing it.

[0007] In some embodiments of the utility model, the circuit board is a rigid circuit board or a flexible circuit board; when the circuit board is a flexible circuit board, the packaging structure for the gas sensor further includes a fixing member, the fixing member is arranged at the end or a position close to the end of the circuit board, and the fixing member is fixedly connected to the circuit board.

[0008] In some embodiments of the utility model, the sensor chip includes any one or more of a hydrogen sensor chip, a carbon monoxide sensor chip, a sulfur dioxide sensor chip, a hydrogen sulfide sensor chip, a chlorine sensor chip, and a formaldehyde sensor chip.

[0009] In some embodiments of the utility model, the packaging structure for the gas sensor further includes a conducting wire and a protective layer;

[0010] Wherein, two ends of the conducting wire are respectively connected to the circuit board and the sensor chip;

[0011] The protective layer is fixedly arranged on the circuit board, and the protective layer covers at least the conductive wire, the connection part between the conductive wire and the sensor chip, and the connection part between the conductive wire and the circuit board; ventilation holes are arranged on the protective layer so that the detection area can contact the gas to be detected.

[0012] In some embodiments of the present invention, the conductive wire is a gold wire with a diameter of 0.2 - 0.5 mm; and / or, the protective layer includes a cofferdam structure formed by epoxy resin.

[0013] In some embodiments of the present invention, the fixing member is connected to the circuit board by means of bonding, welding, clamping, bolt connection or riveting; and / or,

[0014] The fixing member includes pin headers, and both ends of the pin headers have shoulder structures, and both ends of the circuit board are fixedly connected to the shoulder structures respectively; and / or,

[0015] The fixing member includes a fixing clip for clamping both ends of the circuit board.

[0016] In some embodiments of the present invention, reinforcing plates are fixedly connected to both ends of the circuit board, the reinforcing plates are located on the side of the circuit board away from the shoulder structures, and the thickness of the reinforcing plates is 0.2 - 0.5 mm.

[0017] In some embodiments of the present invention, a backing plate is fixedly arranged on the circuit board, the backing plate is located on the side of the circuit board facing away from the sensor chip, and the backing plate corresponds to the position of the sensor chip.

[0018] In some embodiments of the present invention, the circuit board is a multi-layer structure, and the circuit board includes a first polyimide layer, a first copper foil layer, a second polyimide layer, a second copper foil layer and a third polyimide layer which are stacked in sequence.

[0019] In some embodiments of the present invention, the circuit board is a strip-like structure; and / or,

[0020] The end of the sensor chip is arranged away from the circuit board.

[0021] The packaging structure for a gas sensor of the present invention can be placed in a detection space during use. The U-shaped structure of the circuit board can play a supporting role, enabling the gas to be detected to contact the detection area of the sensor chip through the flow channel and the gap in sequence, preventing the detection area from being blocked, and improving the environmental adaptability.

[0022] Additional advantages, objects, and features of the present utility model will be partially described below, and will become partially apparent to those of ordinary skill in the art after studying the following text, or may be learned from the practice of the present utility model. The objects and other advantages of the present utility model can be realized and obtained by the structures specifically pointed out in the specification and the drawings.

[0023] Those skilled in the art will understand that the objects and advantages that can be achieved by the present utility model are not limited to those specifically described above, and the above and other objects that the present utility model can achieve will be more clearly understood according to the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present utility model, form a part of this application, and do not limit the present utility model. The components in the drawings are not drawn to scale, but are only for showing the principles of the present utility model. For the convenience of showing and describing some parts of the present utility model, the corresponding parts in the drawings may be enlarged, that is, may become larger relative to other components in the exemplary device actually manufactured according to the present utility model. In the drawings:

[0025] Figure 1 is a schematic structural diagram of a packaging structure for a gas sensor in an embodiment of the present utility model.

[0026] Figure 2 is a top view of a packaging structure for a gas sensor in an embodiment of the present utility model.

[0027] Figure 3 is an exploded structural diagram of a packaging structure for a gas sensor in an embodiment of the present utility model.

[0028] Reference numerals: 1, first reinforcing plate; 2, backing plate; 3, circuit board; 4, sensor chip; 5, conductive wire; 6, protective layer; 61, ventilation hole; 7, second reinforcing plate; 8, pin. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] In order to make the objects, technical solutions, and advantages of the present utility model clearer, the present utility model will be further described in detail below in conjunction with the embodiments and the drawings. Here, the illustrative embodiments and descriptions thereof of the present utility model are used to explain the present utility model, but do not limit the present utility model.

[0030] Here, it should also be noted that in order to avoid obscuring the present utility model due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present utility model are shown in the drawings, and other details less related to the present utility model are omitted.

[0031] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0032] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0034] In order to solve the problem in the prior art that the detection area of the packaging structure for gas sensors is easily blocked, an embodiment of the utility model provides a packaging structure for a gas sensor. The U-shaped structure of the packaging structure for the gas sensor plays a supporting role, and the flow channel and the gap can enable the gas to be detected to contact the sensor chip, preventing the detection area from being blocked, thereby improving environmental adaptability.

[0035] Reference Figure 1 The embodiment of the utility model provides a packaging structure for a gas sensor, including a circuit board 3 and a sensor chip 4. The circuit board 3 is a U-shaped structure to form a flow channel for the gas to be measured. The sensor chip 4 is packaged on the circuit board 3 and is located on the inner side of the U-shaped structure. The sensor chip 4 has a detection area that can directly contact the flow channel, and there is a gap between the detection area and the circuit board 3 facing it.

[0036] Specifically in the above embodiment, the circuit board 3 can be a circuit board, which can be bent 180 degrees to form a U-shaped structure, but it is necessary to ensure that the circuit board 3 does not break inside, or the bending is less than 180 degrees, and the two ends of the circuit board 3 are U-shaped structures with horns tilted, or the bending is greater than 180 degrees, and the two ends of the circuit board 3 are U-shaped structures that fit each other. In the process of using the packaging structure for the gas sensor of this embodiment, the packaging structure for the gas sensor is placed in the detection space, and the U-shaped structure of the circuit board 3 can play a supporting role, so that the gas to be detected contacts the detection area of the sensor chip 4 through the flow channel and the gap in turn, preventing the detection area from being blocked, and improving environmental adaptability.

[0037] For example, in the usage scenario of a narrow space, the encapsulation structure for a gas sensor is placed inside the narrow space. The U-shaped structure of the circuit board 3 can contact the wall surface inside the narrow space. The gas to be detected can enter the flow channel from the middle of the U-shaped structure and then contact the detection area through the gap, preventing the detection area of the sensor chip 4 from being blocked by the structures or objects inside the narrow space. The encapsulation structure for a gas sensor in this embodiment can not only be applied to the usage scenario of a narrow space, but also to the usage scenarios with vibration, a lot of dust and debris. Based on the same principle, the U-shaped structure of the encapsulation structure for a gas sensor can prevent the displacement of obstacles caused by vibration from blocking the detection area and the blocking of the detection area by dust and debris.

[0038] It should be noted that the circuit board 3 with a U-shaped structure can also play the role of fixing the overall encapsulation structure for a gas sensor. For example, in the usage scenario of a narrow space, when the width of the gap is basically the same as the thickness of the encapsulation structure for a gas sensor, after the U-shaped structure is squeezed by the side walls of the gap, it will generate a certain amount of resilience, thus pressing tightly against the side walls of the gap and fixing the encapsulation structure for a gas sensor in the gap, which is convenient for the installation of the encapsulation structure for a gas sensor.

[0039] In some embodiments, the circuit board 3 is a rigid circuit board or a flexible circuit board or a combination of a rigid circuit board and a flexible circuit. When the circuit board 3 is a rigid circuit board, the circuit board 3 can adopt a double-layer combination method or the circuit board 3 can be processed and manufactured through a mold. The circuit board 3 can be integrally formed, having the advantages of uniform quality and high strength. When the circuit board 3 is a flexible circuit board, the encapsulation structure for a gas sensor further includes a fixing member, and the fixing member is arranged at the end or near the end of the circuit board 3. The fixing member is fixedly connected to the circuit board 3. The fixing member is used to fix the circuit board 3 so that the flexible circuit board 3 maintains a U-shaped structure. This setting can well reduce costs. The flexible circuit board can be bent and has a resilient property, which is convenient for processing. Flexible circuit boards with different length specifications can be set according to the application scenario and can be applied to gas detection in various narrow gaps. When the circuit board 3 is a combination of a rigid circuit board and a flexible circuit, the bent part of the U-shaped structure can be selected as a flexible circuit board, and the remaining positions can be selected as rigid circuit boards. This setting can take into account the advantages of low cost and high strength. In addition, the overall encapsulation structure for a gas sensor can be replaced as a consumable as a whole, which is convenient for maintenance.

[0040] In some embodiments, the sensor chip 4 can be a silicon-based semiconductor chip, which includes any one or more of a hydrogen sensor chip, a carbon monoxide sensor chip, a sulfur dioxide sensor chip, a hydrogen sulfide sensor chip, a chlorine sensor chip, and a formaldehyde sensor chip. The sensor chip 4 in this embodiment can specifically be a sensor chip for detecting different gases. Sensor chips equipped with different gases can detect different gases and are applied to different gas detection scenarios. Refer to Figure 2 , with the bent side of the circuit board 3 as the right side and the other side as the left side, the sensor chip 4 can be arranged at a position 5 - 15 mm to the right of the middle of the circuit board 3. The sensor chip 4 can be connected to the gold-plated pads of the circuit board 3 by using the technology of ultrasonic gold wire ball bonding to achieve the electrical connection of the chip.

[0041] Specifically, taking the hydrogen sensor chip as an example, with the urgent global demand for clean energy, hydrogen energy, as an efficient and environmentally friendly energy form, is gradually becoming an important direction for energy transformation. Hydrogen energy has advantages such as zero carbon emissions and high energy density and is widely used in fields such as fuel cell vehicles, industrial production, and energy storage. However, there are certain safety hazards during the storage, transportation, and use of hydrogen, such as leakage or explosion. To ensure the safe application of hydrogen energy, the research and development and use of hydrogen sensors are particularly important.

[0042] During the application process of hydrogen energy, hydrogen sensors play a crucial role. First of all, in the links of hydrogen storage and transportation, the sensor can monitor the hydrogen concentration in real time and detect leakage in a timely manner, thus avoiding the occurrence of safety accidents. In addition, in hydrogen fuel cell vehicles, hydrogen sensors can monitor the hydrogen content and purity in real time to ensure the safe and efficient operation of the vehicle. With the continuous development of hydrogen energy technology, the application fields of hydrogen sensors are also constantly expanding. In environmental monitoring, hydrogen sensors can accurately detect the hydrogen concentration in the air and provide guarantee for environmental protection and human health. In industrial production, hydrogen sensors can monitor the hydrogen concentration in the production process in real time to prevent leakage accidents.

[0043] In short, as an important technical means in the application process of hydrogen energy, the research and development and application of hydrogen sensors are of great significance. The hydrogen sensor in this embodiment has the characteristics of higher sensitivity, smaller volume, lower power consumption, and more intelligence, providing a more solid safety guarantee for the wide application of hydrogen energy.

[0044] In some embodiments, the packaging structure for the gas sensor further includes a conductive wire 5 and a protective layer 6. The conductive wire 5 is used to connect the circuit board 3 and the sensor chip 4. The protective layer 6 serves to protect the conductive wire 5 and the sensor chip 4, and at the same time enables the detection area of the sensor chip 4 to come into contact with the gas to be measured. Among them, the two ends of the conductive wire 5 are respectively connected to the circuit board 3 and the sensor chip 4. The protective layer 6 is fixedly arranged on the circuit board 3. The protective layer 6 at least covers the conductive wire 5, the connection part between the conductive wire 5 and the sensor chip 4, and the connection part between the conductive wire 5 and the circuit board 3. The protective layer 6 plays a role of fixing and protecting, ensuring that the conductive wire 5 will not break and be exposed to the air. An air vent 61 is provided on the protective layer 6, so that the detection area can come into contact with the gas to be measured. The detection area can be set at the center position of the sensor chip 4.

[0045] In some embodiments, the conductive wire 5 is a gold wire with a diameter of 0.1 - 0.5 mm. The gold wire is conducive to the implementation of the ultrasonic ball bonding process. Other materials of conductive wires 5 can also be used, such as silver wires and copper wires. The protective layer 6 includes a cofferdam structure formed by epoxy resin. The encapsulation of the epoxy resin can be completed by a dispensing machine. Refer to Figure 3 , the epoxy resin can be arranged in a square frame shape, and the detection area of the sensor chip 4 is avoided during the dispensing process to form a window structure for the detection area, which plays a role in protecting and fixing the gold wire and ensures gas fluidity.

[0046] In some embodiments, the fixing member is connected to the circuit board 3 by means of bonding, welding, bolt connection or riveting. For example, the fixing member includes a pin header 8. Both ends of the pin header 8 have shoulder structures. The two ends of the circuit board 3 are respectively fixedly connected at the shoulder structures. Refer to Figure 2 , the middle part of the pin header 8 is a prismatic structure, and the two ends are cylindrical structures. A shoulder structure is formed at the junction of the prism and the cylinder. The end of the circuit board 3 has a pin hole, and the pin hole is sleeved on the cylindrical structure. Soldering can be carried out at the pin hole by means of soldering with solder wire to ensure that the circuit board 3 is in a bent U-shaped structure; the output mode of the circuit board 3 can be carried out by soldering with a solder wire pad or inserting the pin header 8.

[0047] In some other embodiments, the fixing member includes a fixing clip for clamping the two ends of the circuit board 3. The two ends of the circuit board 3 can be clamped together by means of clamping to play a fixing role.

[0048] In some embodiments, reinforcing plates are fixedly connected to both ends of the circuit board 3. The reinforcing plates are located on the side of the circuit board 3 away from the shoulder structure, and the thickness of the reinforcing plates is 0.2 - 0.5 mm. The reinforcing plates can be made of the same material as the circuit board 3, such as polyimide material. Refer to Figure 1Specifically, the reinforcing plate includes a first reinforcing plate 1 and a second reinforcing plate 7. The first reinforcing plate 1 and the second reinforcing plate 7 are respectively located at the two ends of the circuit board 3. The reinforcing plate can adopt a square structure to strengthen the welding strength between the pin hole and the pin 8 to avoid damage to the pad during welding.

[0049] In some embodiments, a pad 2 is fixedly disposed on the circuit board 3, and the pad 2 is located on the side of the circuit board 3 away from the sensor chip 4, and the pad 2 corresponds to the position of the sensor chip 4. The pad 2 can be made of 304 stainless steel sheet, and the pad 2 enhances the hardness of the circuit board 3 to ensure that the circuit board 3 will not be deformed due to excessive pressure during ultrasonic ball welding, and at the same time avoid the situation where the ball welding machine cannot bind the sensor chip 4.

[0050] In some embodiments, the circuit board 3 is a multi-layer structure, and the circuit board 3 includes a first polyimide layer, a first copper foil layer, a second polyimide layer, a second copper foil layer, and a third polyimide layer stacked in sequence. The circuit board 3 is a circuit board substrate with polyimide as a substrate and copper foil as a conductive material. The imide substrate plays an insulating role, and the two layers of copper foil increase the circuit integration.

[0051] In some embodiments, the circuit board 3 is a strip-shaped structure, and the sensor chip 4 is arranged away from the end of the circuit board 3. Such an arrangement allows the sensor chip 4 to be located on one side of the overall packaging structure for the gas sensor. The packaging structure for the gas sensor can extend into a narrow space, making it easier for the sensor chip 4 to contact the gas to be measured at the far end of the narrow space.

[0052] The packaging structure for the gas sensor in the above embodiment has the following technical effects:

[0053] 1. The U-shaped structure of the circuit board 3 can play a supporting role, so that the gas to be detected can contact the detection area of the sensor chip 4 through the flow channel and the gap in turn, preventing the detection area from being blocked, improving environmental adaptability, and can be used in narrow spaces, vibrations, dust and debris.

[0054] 2. The flexible circuit board is bendable, has resilience and is easy to process. Flexible circuit boards of different lengths can be set according to application scenarios and can be used for gas detection in various narrow gaps.

[0055] 3. The protective layer 6 includes a cofferdam structure formed by epoxy resin, which plays a role in protecting and fixing the gold wire. During the dispensing process, the detection area of the sensor chip 4 is avoided to ensure gas flow.

[0056] It should be clear that the present utility model is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present utility model is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present utility model.

[0057] In the present utility model, features described and / or illustrated for one embodiment can be used in the same or a similar manner in one or more other embodiments, and / or combined with the features of other embodiments or replace the features of other embodiments.

[0058] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, various changes and modifications can be made to the embodiments of the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A packaging structure for a gas sensor, characterized in that, It includes a circuit board (3) and a sensor chip (4); Among them, the circuit board (3) is of a U-shaped structure to form a flow channel for the gas to be measured; The sensor chip (4) is encapsulated on the circuit board (3) and is located inside the U-shaped structure. The sensor chip (4) has a detection area that can directly contact the flow channel, and there is a gap between the detection area and the circuit board (3) facing it.

2. The encapsulation structure for a gas sensor according to claim 1, characterized in that, The circuit board (3) is a rigid circuit board or a flexible circuit board; in the case where the circuit board (3) is a flexible circuit board, the packaging structure for the gas sensor further includes a fixing member, and the fixing member is arranged at the end or a position close to the end of the circuit board (3), and the fixing member is fixedly connected to the circuit board (3).

3. The encapsulation structure for a gas sensor according to claim 1, wherein, The sensor chip (4) includes any one or more of a hydrogen sensor chip, a carbon monoxide sensor chip, a sulfur dioxide sensor chip, a hydrogen sulfide sensor chip, a chlorine sensor chip, and a formaldehyde sensor chip.

4. The encapsulation structure for a gas sensor according to claim 1, wherein The packaging structure for the gas sensor further includes a conductive wire (5) and a protective layer (6); Among them, both ends of the conductive wire (5) are respectively connected to the circuit board (3) and the sensor chip (4); The protective layer (6) is fixedly arranged on the circuit board (3), and the protective layer (6) at least covers the conductive wire (5), the connection part between the conductive wire (5) and the sensor chip (4), and the connection part between the conductive wire (5) and the circuit board (3); a ventilation hole (61) is arranged on the protective layer (6) so that the detection area can contact the gas to be measured.

5. The encapsulation structure for a gas sensor according to claim 4, wherein, The conductive wire (5) is a gold wire with a diameter of 0.1 - 0.5 mm; and / or, the protective layer (6) includes a cofferdam structure formed by epoxy resin.

6. The encapsulation structure for a gas sensor according to claim 2, wherein, The fixing member is connected to the circuit board (3) by bonding, welding, clamping, bolt connection or riveting; and / or, The fixing member includes a pin header (8), and both ends of the pin header (8) have shoulder structures, and both ends of the circuit board (3) are respectively fixedly connected at the shoulder structures; and / or, The fixing member includes a fixing clip for clamping both ends of the circuit board (3).

7. The encapsulation structure for a gas sensor according to claim 6, characterized in that, Reinforcing plates are fixedly connected to both ends of the circuit board (3), the reinforcing plates are located on the side of the circuit board (3) away from the shoulder structures, and the thickness of the reinforcing plates is 0.2 - 0.5 mm.

8. The encapsulation structure for a gas sensor according to claim 1, wherein A backing plate (2) is fixedly arranged on the circuit board (3), the backing plate (2) is located on the side of the circuit board (3) facing away from the sensor chip (4), and the backing plate (2) corresponds to the position of the sensor chip (4).

9. The encapsulation structure for a gas sensor according to claim 1, characterized in that, The circuit board (3) is a multi-layer structure, and the circuit board (3) includes a first polyimide layer, a first copper foil layer, a second polyimide layer, a second copper foil layer, and a third polyimide layer stacked in sequence.

10. The encapsulation structure for a gas sensor according to claim 1, characterized in that, The circuit board (3) is of a strip structure; and / or, The end of the sensor chip (4) is arranged away from the circuit board (3).

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