Airflow sensor chip test fixture

Abstract

The utility model relates to the field of chip test especially, a kind of airflow sensor chip test fixture.The utility model airflow sensor chip test fixture includes: pedestal;Horizontal displacement platform, fixed in the rear portion of pedestal, it carries out position adjustment in horizontal direction, to drive mounting plate, anvil assembly, probe assembly whole movement;Test platform, fixed in the front portion of pedestal, the middle part is formed with the load-bearing groove of bearing and positioning airflow sensor chip, the load-bearing groove is connected to air hole;Mounting plate, fixed on horizontal displacement platform, extend along vertical direction;Anvil assembly, set on mounting plate, the probe assembly of its drive top end moves along vertical direction, make the probe of probe assembly and the corresponding contact point of airflow sensor chip contact or separate.The utility model effectively avoids the disturbance to sealed cavity in negative pressure test process, to improve the stability and repeatability of airflow sensor chip test result under negative pressure condition.

Description

Technical Field

[0001] This utility model relates to the field of chip testing, and in particular to a test fixture for airflow sensor chips. Background Technology

[0002] As global electronic atomization devices iterate and upgrade towards lightweight and intelligent designs, inhalation detection, as a crucial step in triggering atomization heating, directly determines user experience and product safety. Among numerous detection solutions, capacitive MEMS (Micro-Electro-Mechanical Systems) airflow sensors, with their significant advantages of small size, low power consumption, fast response speed, and high consistency, are gradually replacing traditional microphones or mechanical switches, becoming the mainstream solution in the industry. These sensors typically operate by detecting minute changes in capacitance caused by airflow, and their package size is often on the order of millimeters. Therefore, during the R&D verification and mass production phases, extremely high requirements are placed on the airtightness of the testing environment and the precision of electrode contact.

[0003] However, existing capacitive sensor test fixtures still have significant shortcomings in their structural design, making it difficult to meet the requirements of high-precision testing. First, the alignment accuracy is insufficient: current simple fixtures mostly rely on screw hole gaps (such as 0.5mm-2mm gaps) for rough manual alignment. When facing increasingly miniaturized MEMS chips, this can easily lead to probe misalignment, poor contact, or even damage to the chip pads. Second, the pressing trajectory is unstable: traditional clamping mechanisms often use simple lever or hinge structures (such as L-shaped linkages) for direct pressing. This structure is often accompanied by a small arc displacement component at the moment of closure, causing the probe to laterally slip (sweep) on the contact surface. This not only affects the stability of the electrical connection but also easily causes lateral deformation of the sealing ring, resulting in minor air leakage, which seriously interferes with the accurate measurement of the starting negative pressure (usually at the Pascal level). Summary of the Invention

[0004] I. Technical problems to be solved

[0005] This invention aims to solve at least partially one of the aforementioned technical problems.

[0006] II. Technical Solution

[0007] This utility model provides a test fixture for airflow sensor chips. The test fixture includes: a base; a horizontal displacement platform fixed to the rear of the base, which is horizontally adjustable to move the mounting plate, pressure head assembly, and probe assembly as a whole; a test stage fixed to the front of the base, with a support groove in its center for supporting and positioning the airflow sensor chip, the support groove connecting to an air vent, forming a sealed cavity between the airflow sensor chip and the air vent when the pressure head assembly presses downwards; a mounting plate fixed to the horizontal displacement platform and extending vertically; and a pressure head assembly disposed on the mounting plate, which drives the probe assembly at its top to move vertically, causing the probes of the probe assembly to contact or separate from the corresponding contacts of the airflow sensor chip.

[0008] In some embodiments of this utility model, the pressure head assembly includes: a pressure driving mechanism fixed to the upper part of the mounting plate; a linear guide mechanism disposed at the lower part of the pressure driving mechanism and fixed to the mounting plate; and a pressure rod whose upper end is connected to the pressure driving mechanism, which is guided by the linear guide mechanism under the drive of the pressure driving mechanism, thereby driving the lower probe assembly to lift or press down in the vertical direction.

[0009] In some embodiments of this invention, an upper limit structure and / or a lower limit structure are provided on the movement path of the pressure rod.

[0010] In some embodiments of this utility model, the clamping drive mechanism is an elbow clamp mechanism, which adopts a linkage force amplification and over-dead-point self-locking structure, and maintains a locked state after being pressed past the dead point.

[0011] In some embodiments of this utility model, the linear guide mechanism is a tubular slide rail, the inner diameter of which matches the outer diameter of the corresponding position of the pressure rod, and the pressure rod passes through the tubular slide rail and can slide up and down on its inner side.

[0012] In some embodiments of this utility model, the pressing drive mechanism is an elbow clamp mechanism, which includes: a first arc-shaped connecting rod and a second arc-shaped connecting rod hinged together. The other end of the first arc-shaped connecting rod is hinged to the mounting plate, and the other end of the second arc-shaped connecting rod is hinged to the upper end of the pressure rod. The first arc-shaped connecting rod extends in its middle part in a direction opposite to the end extension direction to form an operating handle. The operating handle controls the rotation of the first arc-shaped connecting rod. Through the movement cooperation of the first arc-shaped connecting rod and the second arc-shaped connecting rod, the pressure rod is driven to move in the vertical direction, and in the closed position, the first arc-shaped connecting rod and the second arc-shaped connecting rod form a dead point state.

[0013] In some embodiments of this utility model, the horizontal displacement platform includes: a displacement platform body comprising a three-layer structure: a lower layer, a middle layer, and an upper layer, wherein the lower layer is fixed to the rear of the base, and a mounting plate is fixed to the upper layer; an X-axis position adjustment mechanism disposed between the middle layer and the lower layer, adjusting the position of the middle layer relative to the lower layer in the X-axis direction; an X-axis locking mechanism, which, when in the adjustment state, allows the position of the middle layer relative to the lower layer in the X-axis direction to be adjustable; and when in the locked state, locks the position of the middle layer relative to the lower layer in the X-axis direction; a Y-axis position adjustment mechanism disposed between the upper layer and the middle layer, adjusting the position of the upper layer relative to the middle layer in the Y-axis direction; and a Y-axis locking mechanism, which, when in the adjustment state, allows the position of the upper layer relative to the middle layer in the Y-axis direction to be adjustable; and when in the locked state, locks the position of the upper layer relative to the middle layer in the Y-axis direction.

[0014] In some embodiments of this utility model, the X-axis position adjustment mechanism is a position adjustment mechanism with micrometer precision; the Y-axis position adjustment mechanism is a position adjustment mechanism with micrometer precision.

[0015] In some embodiments of this utility model, the probe assembly includes: a PCB adapter board, which includes N signal paths, N≥1, and for each signal path, it has an upper surface coarse contact and a lower surface fine contact for electrical signal connection; a fine probe fixing plate, on which N fine probes are fixed, with their upward signal connection to the lower surface fine contact of the PCB adapter board; and a coarse probe fixing plate, on which N coarse probes are fixed, with their downward signal connection to the upper surface coarse contact of the PCB adapter board; wherein, the PCB adapter board is fixed between the fine probe fixing plate and the coarse probe fixing plate; or, the PCB adapter board is embedded in the fine probe adapter board; or, the PCB adapter board is embedded in the coarse probe adapter board.

[0016] In some embodiments of this utility model, the probe assembly is detachably fixed below the pressure head assembly in a modular manner.

[0017] In some embodiments of this invention, one or all of the N fine probes are replaceably fixed to the fine probe fixing plate.

[0018] In some embodiments of this invention, the fine probe fixing plate is replaceably fixed under the PCB adapter board.

[0019] In some embodiments of this invention, one or all of the N coarse probes are replaceably fixed to the coarse probe fixing plate.

[0020] In some embodiments of this invention, the rear electrical signals of the N coarse probes are connected to the test leads.

[0021] In some embodiments of this invention, N=4.

[0022] In some embodiments of this invention, N signal paths are evenly distributed in the middle of the PCB adapter board.

[0023] In some embodiments of this utility model, a reference alignment structure is provided between the horizontal displacement platform and the test stage to define the reference position of the mounting plate and the pressure head assembly relative to the test stage when the horizontal displacement platform is reset.

[0024] In some embodiments of this invention, the test platform is detachably fixed to the front of the base.

[0025] In some embodiments of this utility model, it further includes: a negative pressure tester, whose airflow pipeline is connected to the air vent of the test platform.

[0026] In some embodiments of this utility model, at least a portion of the test platform, mounting plate, and pressure head assembly are made of aluminum.

[0027] In some embodiments of this utility model, an elastic sealing ring is provided at the outer edge of the bearing groove that contacts the airflow sensor chip.

[0028] In some embodiments of this utility model, the airflow sensor chip is a MEMS chip.

[0029] III. Beneficial Effects

[0030] As can be seen from the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0031] (1) In the prior art, alignment is usually achieved by moving the test stage. In this invention, the test stage on which the airflow sensor chip is installed remains fixed, and the upper pressure head assembly and probe system are aligned by the rear horizontal displacement platform. At the same time, a sealed cavity is formed between the chip and the air vent under the pressure state. It can be seen that by keeping the test stage position stable and only adjusting the position of the upper probe system, this invention effectively avoids disturbance to the sealed cavity during the negative pressure test, thereby improving the stability and repeatability of the test results of the airflow sensor chip under negative pressure conditions. At the same time, the upper pressing and probe pressing actions are completed in the same motion path, which helps to shorten the test cycle and improve the overall test efficiency.

[0032] (2) In the prior art, after the horizontal displacement platform is reset, it often relies on manual realignment of the reference. In this invention, a reference alignment structure is set between the horizontal displacement platform and the test stage assembly. Through this reference alignment structure, this invention can quickly restore the predetermined test position when the horizontal displacement platform is reset, reduce repeated adjustment time, and improve test efficiency and consistency.

[0033] (3) In this invention, an elastic sealing ring is provided at the outer edge of the bearing groove that contacts the airflow sensor chip. This elastic seal undergoes elastic deformation during the probe assembly pressing process to compensate for differences in the airflow sensor package height and maintain the airtightness of the sealed cavity.

[0034] (4) In the prior art, the test fixture is roughly manually positioned using the screw hole allowance, which is difficult to meet the precision contact requirements of small-sized high-density pads, and is prone to probe misalignment, resulting in pad damage or poor contact. In this invention, by adjusting the micron-level displacement in the X and Y directions, the electrical connection between the tested electronic cigarette airflow sensor and the probe in the upper part of the fixture can be precisely positioned. At the same time, in order to ensure absolute stability throughout the entire test, a bidirectional locking structure is added to the displacement platform, which can be locked after positioning in the X and Y directions. Fine-tuning can be performed before the test to compensate for clamping deviations, ensuring the repeatability and consistency of the airflow position, pressure point position, and electrode contact, thereby improving the stability and reliability of the test results. The scheme of fine-tuning alignment followed by locking and fixing in this invention is the key to achieving high consistency testing.

[0035] (5) In the prior art, common clamping mechanisms mostly adopt linear push rods or simple lever structures, lacking a clear self-locking mechanism or requiring an additional locking device. In this utility model, the over-dead-point structure formed by the arc-shaped connecting rod enables the clamping action to be automatically maintained after closing, effectively improving the clamping stability; at the same time, the elbow clamp mechanism opens and closes quickly, making it easy to operate and significantly improving the efficiency during batch testing; the integrated design of the operating handle and connecting rod simplifies the structure and improves the ease of operation and mechanical reliability.

[0036] (6) In the prior art, the probe crimping action is mostly achieved through simple hinges or elastic structures, which easily introduces lateral components during the crimping process. In this utility model, the pressure rod mechanism is guided by a linear guide mechanism, which can effectively ensure that the probe assembly moves stably in the vertical direction, reduce the risk of lateral displacement during the crimping process, thereby reducing the adverse effects of probe sweeping on the chip contacts and the sealed cavity, and improving the reliability of the testing process.

[0037] (7) In the prior art, the metal probe is directly connected to the chip, and the probe leads out a wire at the rear end. However, due to the extremely small pads of the MEMS sensor and the extremely small overall probe, there is a risk of the wire falling off or breaking when soldered at the rear end. In addition, during the test, the wire drags the probe, which also poses a risk of contact failure. Maintenance is more complicated than that of the two-segment probe module. In this utility model, the two-segment probe is connected by a PCB adapter board. The upper and lower probes have different thicknesses and functions. The metal probe located on the upper part of the PCB adapter board has a relatively large diameter to accommodate and fix the wire connection point so that it can be easily connected to the external negative pressure tester. It can also withstand the vibration caused by repeated testing and is less prone to wire breakage. Since the size of the capacitive airflow sensor is small, its package is usually in the millimeter range. Therefore, the metal probe located on the lower part of the PCB board adopts a smaller diameter design to improve the positioning accuracy of the electrode contact. The small diameter probe can make more accurate contact with the electrode area of ​​the airflow sensor under test, ensuring the reliability and stability of the electrical connection during the test. Furthermore, if a section of the probe is damaged, it can be replaced individually. The structure, which is thicker at the top and thinner at the bottom, solves the technical contradiction that the single-specification probes of the previous simple fixtures could not simultaneously meet the requirements of connection strength and contact accuracy.

[0038] (8) In this invention, the probe assembly is modularly and detachably fixed below the pressure head assembly. One or all of the fine probes are replaceably fixed to the fine probe fixing plate, which is replaceably fixed below the PCB adapter board. One or all of the N coarse probes are replaceably fixed to the coarse probe fixing plate; the rear electrical signals of the N coarse probes are connected to the test leads. Through the above configuration, fine or coarse probes can be flexibly replaced, improving testing flexibility and greatly reducing usage costs. Attached Figure Description

[0039] Figure 1 , Figure 2 , Figure 3 These are, respectively, the front view, perspective view, and exploded perspective view of the airflow sensor chip testing fixture according to an embodiment of this utility model.

[0040] Figure 4 for Figure 1 The diagram shows a three-dimensional view of the horizontal displacement platform in the airflow sensor chip testing fixture.

[0041] Figure 5 for Figure 1 A three-dimensional view of the probe assembly in the airflow sensor chip test fixture shown. Detailed Implementation

[0042] This invention aims to address the technical challenges of difficult alignment and unstable pressure in chip testing fixtures. By introducing a combined design of a horizontal displacement platform and a linear guide mechanism, it achieves micron-level precise positioning of the airflow sensor under test in the horizontal direction and rigid linear motion of the pressure head assembly in the vertical direction. This not only eliminates human clamping errors and ensures precise contact between the probe and the microelectrode, but also effectively avoids air leakage in the test chamber caused by lateral forces. Consequently, it significantly improves the accuracy and consistency of the airflow sensor's negative pressure test data, meeting the high standards required for R&D and small-batch production.

[0043] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0044] In one exemplary embodiment of the present invention, a test fixture for an airflow sensor chip is provided. Figure 1 , Figure 2 , Figure 3 The figures show a front view, a perspective view, and an exploded perspective view of the airflow sensor chip testing fixture according to an embodiment of this utility model. As shown, the airflow sensor chip testing fixture of this embodiment includes: a base 10; a testing platform 20, fixed to the front of the base, with a support groove 21 formed in the middle to support and position the airflow sensor chip, the support groove being connected to an air vent, and a sealed cavity being formed between the airflow sensor chip and the air vent when the pressure head assembly is pressed down; a horizontal displacement platform 30, fixed to the rear of the base, which is adjusted in the horizontal direction to drive the mounting plate and the pressure head assembly to move as a whole; a mounting plate 40, fixed to the horizontal displacement platform and extending in the vertical direction; and a pressure head assembly 50, disposed on the mounting plate, which drives the probe assembly 60 at its top to move in the vertical direction, so that the probe of the probe assembly contacts or separates from the corresponding contact of the airflow sensor chip.

[0045] The various components of this embodiment will be described in detail below.

[0046] In this embodiment, the airflow sensor chip is a MEMS capacitive sensor chip used in electronic cigarettes. The airflow sensor chip test fixture simulates the airflow changes in an actual electronic cigarette inhalation scenario, applies specific flow rate, pressure, or negative pressure conditions to the MEMS chip, and tests the performance of the MEMS chip under these conditions.

[0047] Overall, the pressure head assembly 50 and probe assembly 60 constitute the upper part of the fixture. The horizontal displacement platform 30 and mounting plate 40 serve as the moving carrier and supporting structure for the upper part of the fixture, respectively. The base 10 forms the foundation for both the horizontal displacement platform 30 and the test stage 20, which are detachably fixed to the rear and front of the base 10, respectively. When the airflow sensor is placed on the test stage 20, the upper part of the fixture presses down, securing the airflow sensor and electrically connecting the metal probe to it. The lower part of the fixture primarily houses the MEMS sensor chip, and an external negative pressure tester can simulate air intake behavior through the vent. The lower test stage can be replaced according to the different models and sizes of airflow sensors required for actual operating conditions.

[0048] It is worth noting that in existing technologies, alignment is typically achieved by moving the test platform. However, in this embodiment, the test platform housing the airflow sensor chip remains fixed. The upper pressure head assembly and probe system are aligned via a rear horizontal displacement platform, simultaneously forming a sealed cavity between the chip and the air vent under pressure. Therefore, this embodiment effectively avoids disturbance to the sealed cavity during negative pressure testing by maintaining a stable test platform position and adjusting only the upper probe system position. This improves the stability and repeatability of the airflow sensor chip's test results under negative pressure conditions. Furthermore, the upper pressing and probe pressing actions are completed within the same motion path, which helps shorten the testing cycle and improve overall testing efficiency.

[0049] In this embodiment, a reference alignment structure is provided between the test stage 20 and the horizontal displacement platform 30 to limit the reference position of the mounting plate 40 and the pressure head assembly 50 relative to the test stage 20 when the horizontal displacement platform 30 is reset.

[0050] It is important to note that in existing technologies, the horizontal displacement platform often relies on manual realignment of the reference after reset. However, in this embodiment, a reference alignment structure is provided between the horizontal displacement platform and the test stage assembly. Through this reference alignment structure, this embodiment can quickly restore the predetermined test position when the horizontal displacement platform is reset, reducing repetitive calibration time and improving test efficiency and consistency.

[0051] As shown in the figure, the test platform 20 is fixed to the front of the base 10, and a support groove 21 is formed in the middle of the platform to support and position the airflow sensor chip. The support groove is connected to the air vent 22. When the pressure head assembly 50 is pressed down, a sealed cavity is formed between the airflow sensor chip and the air vent 22. Furthermore, the test platform adopts a replaceable design. Sensors of different specifications or structures can be installed and positioned simply by replacing the corresponding platform, which greatly improves the versatility and adaptability of the fixture. The test platform 20 is used to support and position the airflow sensor chip under test, providing a stable placement reference surface for the sensor chip and maintaining its fixed posture during testing to avoid measurement deviations caused by vibration, displacement, or installation errors. The air vent 22 is used to guide the airflow output from the external negative pressure tester to the sensitive area of ​​the capacitive airflow sensor under test. Through the air vent 22, specific flow rate, pressure, or negative pressure conditions can be applied to the sensor to simulate airflow changes in actual e-cigarette inhalation scenarios. Furthermore, this test platform is detachably mounted below the pressure head assembly, allowing for platform replacement according to actual working conditions and achieving universality for testing different models of airflow sensors.

[0052] It should be noted that an elastic sealing ring is provided at the outer edge of the support groove that contacts the airflow sensor chip. This elastic seal undergoes elastic deformation during the probe assembly pressing process to compensate for differences in the airflow sensor package height and maintain the airtightness of the sealed cavity.

[0053] Figure 4 for Figure 1 The figure shows a perspective view of the horizontal displacement platform in the airflow sensor chip testing fixture. As shown, the horizontal displacement platform 30 includes: a displacement platform body, which comprises a three-layer structure: a lower layer structure 31, a middle layer structure 32, and an upper layer structure 33. The lower layer structure 31 is fixed to the rear of the base, and the mounting plate is fixed to the upper layer structure; an X-axis position adjustment mechanism 34, disposed between the middle layer structure and the lower layer structure, which adjusts the position of the middle layer structure relative to the lower layer structure in the X-axis direction; an X-axis locking mechanism 35, which, when in the adjustment state, allows the position of the middle layer structure relative to the lower layer structure in the X-axis direction to be adjustable; and when in the locked state, locks the position of the middle layer structure relative to the lower layer structure in the X-axis direction; a Y-axis position adjustment mechanism 36, disposed between the upper layer structure and the middle layer structure, which adjusts the position of the upper layer structure relative to the middle layer structure in the Y-axis direction; and a Y-axis locking mechanism 37, which, when in the adjustment state, allows the position of the upper layer structure relative to the middle layer structure in the Y-axis direction to be adjustable; and when in the locked state, locks the position of the upper layer structure relative to the middle layer structure in the Y-axis direction. Furthermore, both the X-axis position adjustment mechanism 34 and the Y-axis position adjustment mechanism 36 are position adjustment mechanisms with micron precision.

[0054] It is important to note that in existing technologies, test fixtures use screw hole allowances for rough manual positioning, which is insufficient to meet the precision contact requirements of small-sized, high-density pads. This can easily lead to probe misalignment, pad damage, or poor contact. In this embodiment, however, by adjusting the micron-level displacement in the X and Y directions, precise positioning of the electronic cigarette airflow sensor under test and the probes on the upper part of the fixture can be achieved. Simultaneously, to ensure absolute stability throughout the entire testing process, a bidirectional locking structure is incorporated into the displacement platform, allowing it to lock after positioning in the X and Y directions. Fine-tuning can be performed before testing to compensate for clamping deviations, ensuring the repeatability and consistency of the airflow position, pressure point position, and electrode contact, thereby improving the stability and reliability of the test results. This embodiment employs a scheme of fine-tuning alignment followed by locking, which is key to achieving highly consistent testing.

[0055] As shown in the figure, the pressure head assembly 50 includes: a pressure driving mechanism fixed to the upper part of the mounting plate; a linear guide mechanism 54 disposed at the lower part of the pressure driving mechanism and fixed to the mounting plate; and a pressure rod 55, the upper end of which is connected to the pressure driving mechanism. Under the drive of the pressure driving mechanism, the rod is guided by the linear guide mechanism to drive the lower probe assembly to lift or press down in the vertical direction.

[0056] In this embodiment, the clamping drive mechanism is an elbow clamp mechanism. This elbow clamp mechanism adopts a linkage force amplification and over-dead-point self-locking structure, maintaining a locked state after being pressed past the dead point. The elbow clamp mechanism includes: a first arc-shaped connecting rod 51 and a second arc-shaped connecting rod 52 hinged together. The other end of the first arc-shaped connecting rod 51 is hinged to the mounting plate, and the other end of the second arc-shaped connecting rod 52 is hinged to the upper end of the pressure rod. The first arc-shaped connecting rod extends in the middle in a direction opposite to the direction of its end to form an operating handle 53. The operating handle controls the rotation of the first arc-shaped connecting rod. Through the movement cooperation of the first arc-shaped connecting rod and the second arc-shaped connecting rod, the pressure rod is driven to move in the vertical direction, and in the closed position, the first arc-shaped connecting rod and the second arc-shaped connecting rod form an over-dead-point state.

[0057] The elbow clamp mechanism is located above the test fixture and is mainly used to quickly clamp and reliably position the airflow sensor assembly under test. When the handle is pressed down, a clamping force is generated, which makes the upper pressure head assembly firmly hold the airflow sensor under test, thereby avoiding displacement caused by vibration, airflow impact or external force during the test.

[0058] It is worth noting that in existing technologies, common clamping mechanisms often employ linear push rods or simple lever structures, lacking a clear self-locking mechanism or requiring additional locking devices. In this embodiment, however, the over-dead-point structure formed by the arc-shaped connecting rod automatically maintains the clamping action after closure, effectively improving clamping stability. Simultaneously, the elbow clamp mechanism opens and closes rapidly, facilitating operation and significantly improving efficiency during batch testing. The integrated design of the operating handle and connecting rod simplifies the structure, enhancing operational convenience and mechanical reliability.

[0059] As shown in the figure, there is a tubular slide rail below the elbow clamp mechanism. The inner diameter of the tubular slide rail matches the outer diameter of the corresponding position of the pressure rod. The pressure rod passes through the tubular slide rail and can slide up and down on its inner side. The function of the tubular slide rail is to provide stable and controllable linear guidance in the vertical direction for the elbow clamp mechanism and the pressure head assembly it drives, so that the pressure head always moves smoothly in the vertical direction during pressing or lifting, thereby suppressing the lateral displacement of the probe assembly relative to the test stage assembly during pressing or lifting.

[0060] Those skilled in the art should understand that although this embodiment uses a tubular slide rail, the present invention is not limited thereto. In other embodiments of the present invention, other forms of linear guiding mechanisms, such as strip slide rails, can also be used, as long as they can limit the movement of the pressure rod in the vertical direction.

[0061] It is worth noting that in existing technologies, probe crimping is often achieved through simple hinges or elastic structures, which can easily introduce lateral components during the crimping process. In this embodiment, however, a linear guide mechanism guides the crimping rod mechanism, effectively ensuring stable vertical movement of the probe assembly and reducing the risk of lateral displacement during crimping. This reduces the adverse effects of probe sweeping on the chip contacts and the sealed cavity, thereby improving the reliability of the testing process.

[0062] It should be noted that the movement path of the pressure rod 55 is equipped with an upper limit structure and / or a lower limit structure. This limiting mechanism, together with the elbow clamp mechanism and the linear guide mechanism, forms a triple safety structure, limiting the maximum downward stroke of the probe assembly.

[0063] Figure 5 for Figure 1The figure shows a perspective view of the probe assembly in the airflow sensor chip test fixture. As shown, the probe assembly 60 is mounted at the lower end of the pressure head assembly and includes: a PCB adapter board 61, which includes four signal paths, each of which has an upper surface coarse contact and a lower surface fine contact for electrical signal connection; a fine probe fixing plate 62, on which four fine probes 63 are fixed, with their upward signal connection to the lower surface fine contact of the PCB adapter board; and a coarse probe fixing plate 64, on which four coarse probes 65 are fixed, with their downward signal connection to the upper surface coarse contact of the PCB adapter board. The PCB adapter board 61 is embedded in the fine probe adapter board 62.

[0064] Those skilled in the art will understand that in this embodiment, the PCB adapter board 61 is embedded in the fine probe adapter board 62, thereby maximizing the stability and protection of the fine probe. However, this invention is not limited thereto. In some embodiments of this invention, the PCB adapter board can also be embedded in the coarse probe adapter board, or the PCB adapter board can be fixed between the fine probe adapter board and the coarse probe adapter board. Although the protection of the fine probe is not as good as in this embodiment, both can achieve the purpose of this invention.

[0065] Those skilled in the art should understand that the terms "coarse contact on the upper surface," "fine contact on the lower surface," "coarse probe," and "fine probe" are all relative. "Coarse" means that the diameter of the contact or probe on that side is larger than that on the other side, and "fine" means that the diameter of the contact or probe on that side is smaller than that on the other side. The meanings of both are clear to those skilled in the art and will not cause confusion.

[0066] It is important to note that in existing technologies, metal probes are directly connected to the chip, with wires leading out from the rear end of the probe. However, due to the extremely small pads of MEMS sensors and the overall very small probe size, soldering wires to the rear end carries the risk of detachment or breakage. Furthermore, during testing, the wires drag the probe, posing a risk of contact failure. Maintenance is more complex compared to two-segment probe modules. In this embodiment, the two-segment probes are connected via a PCB adapter board. The upper and lower probe segments differ in diameter and function. The metal probe located on the upper PCB adapter board has a relatively large diameter to accommodate and fix the wire connection point, facilitating easy electrical connection with an external negative pressure tester. It can also withstand vibrations from repeated testing and is less prone to wire breakage. Because capacitive airflow sensors are small, with packages typically in the millimeter range, the metal probe located below the PCB board uses a smaller diameter design to improve electrode contact positioning accuracy. The smaller diameter probe allows for more accurate contact with the electrode area of ​​the airflow sensor under test, ensuring reliable and stable electrical connections during testing. Furthermore, if a section of the probe is damaged, it can be replaced individually. The structure, which is thicker at the top and thinner at the bottom, solves the technical contradiction that the single-specification probes of the previous simple fixtures could not simultaneously meet the requirements of connection strength and contact accuracy.

[0067] Furthermore, the probe assembly 60 is modularly and detachably fixed below the pressure head assembly 50. One or all of the fine probes are replaceably fixed to the fine probe mounting plate, which is replaceably fixed below the PCB adapter board. One or all of the N coarse probes are replaceably fixed to the coarse probe mounting plate; the rear electrical signals of the N coarse probes are connected to the test leads. This configuration allows for flexible replacement of fine or coarse probes, improving testing flexibility and significantly reducing operating costs.

[0068] It should be noted that in this embodiment, N=4, meaning that four signal paths are evenly distributed in the center of the PCB adapter board. However, this invention is not limited to this. In other embodiments of this invention, the number of signal paths and their positions on the PCB adapter board can be set according to the needs of the actual device.

[0069] In this embodiment, the external negative pressure tester's lead wire can be electrically connected to the lead wire led out by the metal probe, and the external negative pressure tester's airway can be connected to the air vent of the test platform to simulate the action of inhalation. After the tester is connected to the test fixture, the starting negative pressure of the airflow sensor can be tested. The tester has two air pressure modes: one is the sweep pressure mode, and the other is the constant pressure mode.

[0070] Compared to the acrylic material used in existing testing fixtures, the airflow sensor chip testing fixture in this embodiment is made of all-aluminum alloy, which makes the whole structure robust and durable, and the testing stability high. It can effectively improve the testing accuracy and repeatability of airflow sensors and is suitable for various application scenarios such as R&D verification and mass production testing.

[0071] Those skilled in the art should understand that although this embodiment uses an all-aluminum alloy material, the present invention is not limited thereto. In other embodiments of the present invention, some components such as the base and horizontal displacement platform may be made of metal, while other components may be made of plastic, and the present invention can still be achieved.

[0072] In summary, this embodiment of the airflow sensor chip testing fixture achieves high-precision, stable, and repeatable testing of capacitive airflow sensors through the coordinated operation of the test stage, horizontal displacement platform, pressure head assembly, linear guide, probe assembly, and air vent. Specifically, the test stage and horizontal displacement platform work together to achieve micron-level position adjustment in the planar direction, ensuring that the airflow application position, electrode contact position, and pressure head landing point remain consistent. During the clamping process, the tubular slide rail provides linear guidance, ensuring smooth and uniform force distribution on the pressure head assembly, thereby guaranteeing reliable electrode contact and accurate airflow loading. The quick-locking structure of the elbow clamp mechanism ensures high efficiency during batch testing, while the design of metal probes with different diameters balances the stability of wire lead-outs with the precision of electrode contact, making it suitable for small sensors with millimeter-level packaging.

[0073] This concludes the description of all embodiments of this utility model. Based on the above description, those skilled in the art should have a clear understanding of this utility model.

[0074] It should be noted that for some implementation methods, if they are not key contents of this utility model and are well known to those skilled in the art, they are not described in detail in the accompanying drawings or text due to space limitations. In such cases, relevant prior art can be referred to for understanding.

[0075] The directional terms used in this utility model, such as "center," "lateral," "longitudinal," "top," "bottom," "upper," "lower," "front," "rear," "left," "right," "inner," and "outer," indicate only the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing this utility model and for simplification, 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. Therefore, they should not be construed as limitations on this utility model. Furthermore, throughout the accompanying drawings, the same elements are represented by the same or similar reference numerals. Also, the shapes and dimensions of the components in the drawings do not reflect actual size and proportion, but only illustrate the content of embodiments of this utility model.

[0076] The terms "connected" and "linked" used in this utility model should be interpreted broadly unless otherwise explicitly specified and limited. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the connection of a portion of two components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0077] Those skilled in the art will understand that in the claims and description of this utility model, the word "comprising" does not exclude the presence of elements (or steps) not listed in the claims. The word "a" or "an" preceding an element (or step) does not exclude the presence of a plurality of such elements (or steps).

[0078] Furthermore, the purpose of providing the above embodiments is merely to enable the present invention to meet legal requirements, and the present invention can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein.

[0079] Similarly, it should be understood that, for the sake of brevity, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this approach should not be construed as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, each aspect of the invention comprises fewer than all the features of the preceding single embodiment. Furthermore, embodiments may be used in combination with each other or with other embodiments based on design and reliability considerations; that is, technical features from different embodiments can be freely combined to form more embodiments. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the present invention.

[0080] The above specific embodiments have provided a detailed description of the purpose, technical means, and beneficial effects of this utility model. It should be understood that the purpose of the detailed description is to enable those skilled in the art to understand this utility model more clearly, and it is not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A test fixture for an airflow sensor chip, characterized in that, include: Base; A horizontal displacement platform, fixed to the rear of the base, is adjusted in the horizontal direction to move the mounting plate, pressure head assembly, and probe assembly as a whole. The test stage is fixed to the front of the base, and a support groove is formed in the middle to support and position the airflow sensor chip. The support groove is connected to the air vent. When the pressure head assembly is pressed down, a sealed cavity is formed between the airflow sensor chip and the air vent. Mounting plate, fixed to a horizontal displacement platform, extends vertically; The pressure head assembly, mounted on the mounting plate, drives the probe assembly at its top to move vertically, causing the probe of the probe assembly to contact or separate from the corresponding contact of the airflow sensor chip.

2. The airflow sensor chip testing fixture according to claim 1, characterized in that, The pressure head assembly includes: The clamping drive mechanism is fixed to the upper part of the mounting plate; A linear guide mechanism is located at the lower part of the clamping drive mechanism and fixed to the mounting plate; The pressure rod is connected to the upper end of the pressure drive mechanism. Under the drive of the pressure drive mechanism, it is guided by the linear guide mechanism to drive the lower probe assembly to lift or press down in the vertical direction.

3. The airflow sensor chip testing fixture according to claim 2, characterized in that, The movement path of the pressure rod is provided with an upper limit structure and / or a lower limit structure; and / or, The clamping drive mechanism is an elbow clamp mechanism, which employs a linkage force amplification and over-dead-point self-locking structure to maintain a locked state after being pressed past the dead point; and / or, The linear guide mechanism is a tubular slide rail, the inner diameter of which matches the outer diameter of the corresponding position of the pressure rod. The pressure rod passes through the tubular slide rail and can slide up and down on its inner side.

4. The airflow sensor chip testing fixture according to claim 3, characterized in that, The clamping drive mechanism is an elbow clamp mechanism. The elbow clamp mechanism includes: a first arc-shaped connecting rod and a second arc-shaped connecting rod that are hinged together, the other end of the first arc-shaped connecting rod being hinged to the mounting plate, and the other end of the second arc-shaped connecting rod being hinged to the upper end of the pressure rod. The first arc-shaped connecting rod extends in the middle in a direction opposite to the end extension direction to form an operating handle. The operating handle controls the rotation of the first arc-shaped connecting rod. Through the movement cooperation of the first arc-shaped connecting rod and the second arc-shaped connecting rod, the pressure rod moves in the vertical direction, and in the closed position, the first arc-shaped connecting rod and the second arc-shaped connecting rod form a dead point state.

5. The airflow sensor chip testing fixture according to claim 1, characterized in that, The horizontal displacement platform includes: The displacement platform body comprises a three-layer structure: a lower layer, a middle layer, and an upper layer, wherein the lower layer is fixed to the rear of the base, and the mounting plate is fixed to the upper layer. The X-axis position adjustment mechanism is located between the middle layer structure and the lower layer structure, and its adjustment is the position of the middle layer structure relative to the lower layer structure in the X-axis direction; The X-axis locking mechanism, when in the adjustment state, allows the position of the middle layer structure relative to the lower layer structure in the X-axis direction to be adjustable; when in the locked state, the position of the middle layer structure relative to the lower layer structure in the X-axis direction is locked. The Y-axis position adjustment mechanism is located between the upper structure and the middle structure, and its adjustment is the position of the upper structure relative to the middle structure in the Y-axis direction. The Y-axis locking mechanism allows the position of the upper structure relative to the middle structure to be adjusted in the Y-axis direction when it is in the adjustment state; when it is in the locked state, the position of the upper structure relative to the middle structure is locked in the Y-axis direction.

6. The airflow sensor chip testing fixture according to claim 5, characterized in that, The X-axis position adjustment mechanism is a position adjustment mechanism with micron precision. The Y-axis position adjustment mechanism is a position adjustment mechanism with micrometer precision.

7. The airflow sensor chip testing fixture according to claim 1, characterized in that, The probe assembly includes: The PCB adapter board includes N signal paths, where N≥1. For each signal path, it has coarse contacts on the upper surface and fine contacts on the lower surface for electrical signal connection. A fine probe fixing plate is provided, on which N fine probes are fixed, and their upward signals are connected to the fine contacts on the lower surface of the PCB adapter board. A coarse probe fixing plate is provided, on which N coarse probes are fixed, and their downward signals are connected to the coarse contacts on the upper surface of the PCB adapter board. The PCB adapter board is fixed between the fine probe fixing plate and the coarse probe fixing plate; or, the PCB adapter board is embedded in the fine probe adapter board; or, the PCB adapter board is embedded in the coarse probe adapter board.

8. The airflow sensor chip testing fixture according to claim 7, characterized in that, In the probe assembly: The probe assembly is modularly and detachably fixed below the indenter assembly; and / or, One or all of the N fine probes are replaceably fixed to the fine probe fixing plate; and / or, The fine probe mounting plate can be replaced and fixed below the PCB adapter board; and / or, One or all of the N coarse probes are replaceably fixed to the coarse probe fixing plate; and / or, The electrical signals at the rear ends of the N coarse probes are connected to the test leads; and / or, N=4; and / or, N signal paths are evenly distributed in the middle of the PCB adapter board.

9. The airflow sensor chip testing fixture according to any one of claims 1 to 8, characterized in that, A reference alignment structure is provided between the horizontal displacement platform and the test stage to define the reference position of the mounting plate and the pressure head assembly relative to the test stage when the horizontal displacement platform is reset.

10. The airflow sensor chip testing fixture according to any one of claims 1 to 8, characterized in that, The test platform is detachably fixed to the front of the base; and / or, It also includes: a negative pressure tester, the airflow of which is connected to the vent of the test platform; and / or, At least a portion of the test platform, mounting plate, and indenter assembly is made of aluminum; and / or, An elastic sealing ring is provided at the outer edge of the bearing groove that contacts the airflow sensor chip; and / or, The airflow sensor chip is a MEMS chip.

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