Diffused silicon pressure sensor

Abstract

The utility model provides a kind of diffusion silicon pressure sensor, comprising: pedestal, metal needle is provided on the pedestal;Process joint, including first end and second end, installation cavity is provided in the second end of process joint, pressure sensitive chip is provided in installation cavity, the pressure sensitive chip is blocked in the pedestal by the pedestal, the pressure sensitive chip is electrically connected between the metal needle;Metal diaphragm, set in the first end of process joint, for inserting measured medium, and measured medium pressure is transferred to the pressure sensitive chip;The circumference of the metal diaphragm is welded between the first end of process joint and seals.This scheme solves the frost heaving failure problem that has long plagued diffusion silicon pressure sensor in the way of simple and efficient, brings significant improvement in reliability, cost, process and application range etc.

Description

Technical Field

[0001] This utility model relates to the field of pressure detection technology, and in particular to a diffused silicon pressure sensor. Background Technology

[0002] In traditional diffused silicon pressure sensors, the outer edge of the metal diaphragm is typically fixed to a weld ring using methods such as laser welding or electron beam welding, forming a sealed oil-filled cavity. However, this structure inevitably introduces a tiny annular weld gap (or capillary gap) between the outer edge of the metal diaphragm and the weld ring. When the sensor is used in environments containing moisture or liquid water (such as humid air, water treatment, refrigeration systems, food processing, and outdoor environments), moisture may penetrate into this tiny weld gap through capillary action or pressure, affecting the lifespan and accuracy of the diffused silicon pressure sensor. Summary of the Invention

[0003] This invention provides a diffused silicon pressure sensor to solve the above-mentioned problems.

[0004] This utility model provides a diffused silicon pressure sensor, the diffused silicon pressure sensor comprising:

[0005] A base, on which a metal pin is provided;

[0006] A process connector includes a first end and a second end. The second end of the process connector is provided with a mounting cavity, and a pressure-sensitive chip is disposed in the mounting cavity. The base seals the pressure-sensitive chip in the base, and the pressure-sensitive chip is electrically connected to the metal pin.

[0007] A metal diaphragm is disposed at the first end of the process connector for extending into the measured medium and transmitting the pressure of the measured medium to the pressure-sensitive chip; the circumference of the metal diaphragm is welded and sealed to the first end of the process connector.

[0008] In one embodiment of the present invention, an oil-filled cavity is formed between the base and the inner wall of the mounting cavity, and the oil-filled cavity is filled with silicone oil.

[0009] In one embodiment of this utility model, ceramic is disposed within the oil-filled cavity.

[0010] In one embodiment of this utility model, the process connector is provided with threads on its circumference.

[0011] In one embodiment of the present invention, an oil filling hole is provided on the base, and the oil filling hole is used to fill the oil filling cavity with silicone oil.

[0012] In one embodiment of this utility model, a sealing element for sealing after the oil filling hole is completed is provided inside the oil filling hole.

[0013] In one embodiment of the present invention, from the first end to the second section of the process connector, the process connector includes a sealing part, an extension part, a connecting part and a mounting part arranged in sequence, the diameters of the extension part, the connecting part and the mounting part increase in sequence, the diameter of the sealing part is larger than that of the extension part, and the metal diaphragm is mounted on the end face of the sealing part.

[0014] In one embodiment of the present invention, a central groove is provided on the end face of the sealing part, the central groove is connected to the mounting cavity, and the metal diaphragm covers the central groove and then seals the sealing part circumferentially.

[0015] In one embodiment of the present invention, from the first end to the second end of the process connector, the mounting cavity includes a first mounting section and a second mounting section. The diameter of the first mounting section is smaller than that of the second mounting section. The pressure-sensitive chip is installed in the first mounting section, and the base is installed in the second mounting section and seals the mounting cavity.

[0016] In one embodiment of the present invention, the silicone oil fills the central groove and the second mounting section.

[0017] The beneficial effects of this utility model: The diffused silicon pressure sensor proposed in this utility model, by completely eliminating the traditional solder ring and adopting innovative design and packaging processes (e.g., seamless welding or integral molding of the metal diaphragm edge directly to the process connector), brings the following significant beneficial effects:

[0018] (1) Complete elimination of the risk of freeze-thaw failure: The most significant advantage lies in the complete elimination of the tiny annular gap between the outer edge of the metal diaphragm and the welding ring. With this gap eliminated, moisture in the measured medium loses its space to remain, fundamentally preventing the possibility of moisture freezing and expanding within the gap. Therefore, in applications involving low-temperature, water-containing, or humid environments, the diffused silicon pressure sensor completely avoids the failure modes caused by diaphragm deformation, rupture, and subsequent silicone oil leakage due to ice compression, significantly improving product reliability and service life.

[0019] (2) Simplified structure and reduced cost: As an independent component in the traditional structure, the welding ring requires cost for its manufacturing, procurement and assembly. This application reduces the number of parts and simplifies the sensor structure by eliminating the welding ring, thereby reducing material costs and assembly complexity, and improving production efficiency and economic benefits.

[0020] (3) Improve process consistency and yield: In the traditional structure, the welding between the solder ring and the diaphragm is a key process step that generates tiny gaps. It is difficult to control the precision and is prone to introducing defects. The new structure avoids this high-precision welding step that is prone to gaps, simplifies the key packaging process, and helps to improve product consistency and manufacturing yield.

[0021] (4) Expanding the scope of application: Since the problem of frost heave has been fundamentally solved, diffused silicon pressure sensors can be applied more safely and reliably to previously limited harsh environments, such as refrigeration systems, chillers, outdoor weather monitoring, water treatment (especially low temperature environments), food processing, and any industrial site that may be exposed to low temperature, humid or water-containing media, which greatly expands the market application potential of the product.

[0022] In summary, this solution, through fundamental structural innovation, solves the long-standing problem of freeze-thaw failure in diffused silicon pressure sensors in a simple and efficient manner, resulting in significant improvements in reliability, cost, manufacturability, and application scope. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0024] In the attached diagram:

[0025] Figure 1 Exploded view of a diffused silicon pressure sensor provided in an embodiment of the present invention;

[0026] Figure 2 This is a cross-sectional view provided in one embodiment of the present invention.

[0027] The attached figures are labeled as follows:

[0028] Metal diaphragm 101, process connector 102, pressure sensitive chip 103, ceramic 104, base 105, oil filling hole 105a, metal pin 106, binding wire 107, sealing steel ball 108, sealing part 1021, extension part 1022, connecting part 1023, mounting part 1024. Detailed Implementation

[0029] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0030] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0031] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0032] Please see Figure 1 and Figure 2 As shown, a diffused silicon pressure sensor provided in one embodiment of the present invention includes:

[0033] Base 105, on which a metal pin 106 is provided;

[0034] The process connector 102 includes a first end and a second end. The second end of the process connector 102 is provided with a mounting cavity. A pressure-sensitive chip 103 is provided in the mounting cavity. The base 105 seals the pressure-sensitive chip 103 inside the base 105. The pressure-sensitive chip 103 is electrically connected to the metal pin 106.

[0035] A metal diaphragm 101 is disposed at the first end of the process connector 102 for extending into the measured medium and transmitting the pressure of the measured medium to the pressure-sensitive chip 103; the circumference of the metal diaphragm 101 is welded and sealed to the first end of the process connector 102.

[0036] It should be noted that in existing technologies, the welding ring is pressed onto the metal diaphragm 101. To eliminate the influence of the deformation stress of the metal diaphragm 101 itself on the diffused silicon pressure sensor, most metal diaphragms 101 have corrugated surfaces. This inevitably leads to a small gap (or capillary gap) between the welding ring and the metal diaphragm 101. When the diffused silicon pressure sensor is applied to environments containing water vapor or liquid water (such as humid air, water treatment, refrigeration systems, food processing, outdoor environments, etc.), moisture may penetrate into this tiny welding gap through capillary action or pressure penetration. When the ambient temperature changes periodically (especially when it drops below freezing), the moisture trapped in the gap will freeze. Because water expands in volume when it freezes (approximately 9%), and this small gap is extremely limited and restricted, the enormous compressive force generated by the expansion of the ice crystals will directly act on the edge region of the metal diaphragm 101, generating continuous and repeated compressive stress on the metal diaphragm 101. Under this compressive stress, the following consequences are likely to occur:

[0037] (1) Plastic deformation or rupture of metal diaphragm 101: The edge of metal diaphragm 101 undergoes irreversible deformation under the repeated action of ice expansion force, and may even produce cracks or perforations.

[0038] (2) Silicone oil leakage: Once the metal diaphragm 101 is ruptured or the welded seal fails due to deformation, the silicone oil in the cavity will leak to the outside or be invaded by contaminated media.

[0039] (3) Complete failure of diffused silicon pressure sensor: Silicon oil leakage will destroy the pressure transmission path, causing abnormal output, drift, or even permanent damage to diffused silicon pressure sensor. Media intrusion will directly corrode the sensitive silicon chip.

[0040] To alleviate the above problems, methods such as filling the gaps with special sealants, optimizing the welding process to reduce the gaps, or using materials that are more resistant to low-temperature impact are commonly used. However, these methods are often costly and complex, and cannot fundamentally eliminate the gaps and the resulting risk of freeze-thaw cycles, resulting in limited improvement in reliability. Therefore, in this embodiment, the traditional welded ring structure is eliminated. The outer edge of the metal diaphragm 101 is directly connected to the upper surface of the process joint 102 via laser welding to achieve a full circumferential gapless connection, completely eliminating capillary gaps and blocking the path of moisture intrusion.

[0041] In this embodiment, by completely eliminating the traditional solder ring and employing innovative design and packaging processes (e.g., seamless welding or integral molding of the metal diaphragm 101 edge directly to the process connector 102), the following significant benefits are achieved:

[0042] (1) Complete elimination of the risk of freeze-thaw failure: The most significant advantage lies in the complete elimination of the tiny annular gap between the outer edge of the metal diaphragm 101 and the welding ring. With this gap eliminated, moisture in the measured medium loses its space to remain, fundamentally preventing the possibility of moisture freezing and expanding within the gap. Therefore, in applications involving low-temperature, water-containing, or humid environments, the diffused silicon pressure sensor completely avoids the failure modes caused by diaphragm deformation, rupture, and subsequent silicone oil leakage due to ice compression, significantly improving product reliability and service life.

[0043] (2) Simplified structure and reduced cost: As an independent component in the traditional structure, the welding ring requires cost for its manufacturing, procurement and assembly. This application reduces the number of parts and simplifies the sensor structure by eliminating the welding ring, thereby reducing material costs and assembly complexity, and improving production efficiency and economic benefits.

[0044] (3) Improve process consistency and yield: In the traditional structure, the welding between the solder ring and the diaphragm is a key process step that generates tiny gaps. It is difficult to control the precision and is prone to introducing defects. The new structure avoids this high-precision welding step that is prone to gaps, simplifies the key packaging process, and helps to improve product consistency and manufacturing yield.

[0045] (4) Expanding the scope of application: Since the problem of frost heave has been fundamentally solved, diffused silicon pressure sensors can be applied more safely and reliably to previously limited harsh environments, such as refrigeration systems, chillers, outdoor weather monitoring, water treatment (especially low temperature environments), food processing, and any industrial site that may be exposed to low temperature, humid or water-containing media, which greatly expands the market application potential of the product.

[0046] In summary, this embodiment solves the long-standing problem of freeze-thaw failure in diffused silicon pressure sensors in a simple and efficient manner through fundamental structural innovation, resulting in significant improvements in reliability, cost, manufacturability, and application scope.

[0047] For example, a metal pin 106 penetrates the base 105 to facilitate the output of electrical signals.

[0048] In one exemplary embodiment, an oil-filled cavity is formed between the base 105 and the inner wall of the mounting cavity, and the oil-filled cavity is filled with silicone oil.

[0049] It is worth noting that the pressure of the measured medium is transmitted to the silicone oil through the metal diaphragm 101, and then to the pressure-sensitive chip 103 through the silicone oil to achieve pressure detection.

[0050] In one exemplary embodiment, a ceramic 104 is disposed within the oil-filled cavity.

[0051] It is worth noting that the ceramic 104 is used to reduce the volume of the oil-filled cavity and reduce the impact of temperature on the expansion of silicone oil.

[0052] In one exemplary embodiment, the process connector 102 is provided with threads on its circumference.

[0053] For example, the threads on process connector 102 are used to mount a diffused silicon pressure sensor.

[0054] In an exemplary embodiment, an oil filling hole 105a is provided on the base 105, and the oil filling hole 105a is used to fill the oil filling cavity with silicone oil.

[0055] In this embodiment, an oil filling hole 105a is provided on the base 105 to facilitate silicone oil filling.

[0056] In one exemplary embodiment, a sealing element is provided in the oil filling hole 105a for sealing after oil filling is completed.

[0057] For example, the sealing element is a sealing steel ball 108, used to seal the oil filling hole 105a to prevent silicone oil leakage after filling. Compared with using a cylindrical plug to seal the oil filling hole 105a, using the sealing steel ball 108 to seal the oil filling hole 105a has lower requirements for the size precision of the sealing steel ball 108. However, if a cylindrical plug is used for sealing, the cylindrical plug must be close to the diameter of the oil filling hole 105a, which requires higher machining precision from the cylindrical plug.

[0058] In an exemplary embodiment, from the first end to the second section of the process connector 102, the process connector 102 includes a sealing portion 1021, an extension portion 1022, a connecting portion 1023 and a mounting portion 1024 arranged sequentially. The diameters of the extension portion 1022, the connecting portion 1023 and the mounting portion 1024 increase sequentially. The diameter of the sealing portion 1021 is larger than that of the extension portion 1022. A metal diaphragm 101 is mounted on the end face of the sealing portion 1021.

[0059] For example, threads are provided on the connection portion 1023 for mounting the diffused silicon pressure sensor.

[0060] In this embodiment, the sealing portion 1021 is provided for mounting the metal diaphragm 101. The extension portion 1022 is provided to increase the distance between the metal diaphragm 101 and the pressure-sensitive chip 103, so that the metal diaphragm 101 can be inserted into the measured medium after the diffused silicon pressure sensor is installed.

[0061] In an exemplary embodiment, a central groove is provided on the end face of the sealing part 1021, and the central groove communicates with the mounting cavity. After the metal diaphragm 101 covers the central groove, it seals the sealing part 1021 circumferentially.

[0062] In this embodiment, a connection is provided between the central groove and the mounting cavity to facilitate pressure transmission of the silicone oil.

[0063] In one exemplary embodiment, from the first end to the second end of the process connector 102, the mounting cavity includes a first mounting section and a second mounting section. The diameter of the first mounting section is smaller than that of the second mounting section. The pressure-sensitive chip 103 is mounted in the first mounting section, and the base 105 is mounted in the second mounting section and seals the mounting cavity.

[0064] It should be noted that the diameter of the first mounting section is smaller than that of the second mounting section. This is partly to match the shape and specifications of the base 105, and partly to limit the position of the base 105 during assembly, ensuring the accuracy of the assembly position.

[0065] In one exemplary embodiment, silicone oil fills the central groove and the second mounting section.

[0066] In this embodiment, ceramic 104 is provided in the second mounting section to reduce the remaining space in the second mounting section and reduce the amount of silicone oil filling.

[0067] For example, the second mounting section of the pressure-sensitive chip 103 is also provided with a bonding wire 107, which is a gold wire or an aluminum wire, for connecting the pressure-sensitive chip 103 and the metal pin 106.

[0068] For example, the base 105 is made of an insulating material, such as alumina ceramic 104.

[0069] For example, the sealing steel ball 108 is laser-sealed to the oil filling hole 105a of the base 105 to achieve permanent sealing of the cavity.

[0070] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A diffused silicon pressure sensor, characterized in that, include: A base, on which a metal pin is provided; A process connector includes a first end and a second end. The second end of the process connector is provided with a mounting cavity, and a pressure-sensitive chip is disposed in the mounting cavity. The base seals the pressure-sensitive chip in the base, and the pressure-sensitive chip is electrically connected to the metal pin. A metal diaphragm is disposed at the first end of the process connector for extending into the measured medium and transmitting the pressure of the measured medium to the pressure-sensitive chip; the circumference of the metal diaphragm is welded and sealed to the first end of the process connector.

2. The diffused silicon pressure sensor according to claim 1, characterized in that, An oil-filled cavity is formed between the base and the inner wall of the mounting cavity, and the oil-filled cavity is filled with silicone oil.

3. The diffused silicon pressure sensor according to claim 2, characterized in that, The oil-filled cavity is lined with ceramics.

4. The diffused silicon pressure sensor according to any one of claims 1 to 3, characterized in that, The process connector has threads on its circumference.

5. The diffused silicon pressure sensor according to claim 2, characterized in that, The base is provided with an oil filling hole, which is used to fill the oil filling cavity with silicone oil.

6. The diffused silicon pressure sensor according to claim 5, characterized in that, The oil filling hole is equipped with a sealing element for sealing after oil filling is completed.

7. The diffused silicon pressure sensor according to claim 2, characterized in that, From the first end to the second section of the process connector, the process connector includes a sealing part, an extension part, a connecting part and a mounting part arranged in sequence. The diameters of the extension part, the connecting part and the mounting part increase in sequence. The diameter of the sealing part is larger than that of the extension part. The metal diaphragm is mounted on the end face of the sealing part.

8. The diffused silicon pressure sensor according to claim 7, characterized in that, A central groove is provided on the end face of the sealing part, and the central groove is connected to the mounting cavity. After the metal diaphragm covers the central groove, it seals the sealing part circumferentially.

9. The diffused silicon pressure sensor according to claim 8, characterized in that, From the first end to the second end of the process connector, the mounting cavity includes a first mounting section and a second mounting section. The diameter of the first mounting section is smaller than that of the second mounting section. The pressure-sensitive chip is installed in the first mounting section, and the base is installed in the second mounting section and seals the mounting cavity.

10. The diffused silicon pressure sensor according to claim 9, characterized in that, The silicone oil fills the central groove and the second mounting section.

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