Nondestructive continuous detection method and device for accelerated airtightness test of metal / glass sealing structure

Abstract

The invention discloses a nondestructive continuous detection method and device for an air tightness acceleration test of a metal / glass sealing structure, and belongs to the technical field of air tightness measurement. The objective of the invention is to solve the three technical defects of microcrack propagation caused by destructive detection, incapability of continuously acquiring water vapor data through single detection, and disjunction of leakage rate criterion and airtight failure physical mechanism in the existing helium mass spectrum backpressure method. The method comprises the steps that S1, a temperature and humidity sensor is packaged into a metal / glass insulator sealing structure through an FPC sensor circuit board, a test cavity is constructed, and temperature and humidity electric signals in the test cavity are transmitted to an external signal group control board through lead columns; s2, putting the test cavity into an acceleration cavity for an accelerated life test, and simultaneously applying three stresses of temperature, humidity and pressure difference to the test cavity in the accelerated life test process; s3, the signal group control board calculates the water vapor content IV in the test cavity in real time, and when IV is larger than or equal to 5000 ppm for three continuous times, airtightness failure is judged.

Description

Technical Field

[0001] The present invention belongs to the field of airtightness measurement technology, and specifically relates to a method and device for non-destructive continuous monitoring of electronic component sealing structures in accelerated life tests. The method and device are particularly suitable for airtightness failure detection of metal / glass insulator sealing structures (such as sealed relays). Background Art

[0002] The main failure modes of electronic components include, but are not limited to, open circuits, short circuits, functional failures, electrical parameter drift, and unstable failures. Based on existing research and analysis, water vapor plays a secondary role in the airtight failure of sealed relays. Multi-stress coupling is a major factor affecting the propagation of microcracks in glass insulators and further leading to water vapor leakage. There are many methods for measuring airtightness, and the airtightness testing of electronic components is divided into fine leak testing and coarse leak testing. Coarse leak testing uses various solution bubble methods, weighing methods, and dyeing methods. Fine leak testing methods include helium mass spectrometry backpressure leak testing, radioactive isotope leak testing, and optical leak testing.

[0003] The most commonly used method for leak detection of components is helium mass spectrometry back pressure leak detection. However, since the helium mass spectrometry back pressure method also has a certain degree of impact on glass insulators when the helium tank pressurizes the workpiece, there are several disadvantages in using a helium mass spectrometer:

[0004] 1. Discontinuity: A single test cannot obtain the dynamic change data of water vapor under multi-stress coupling, and it is difficult to establish a failure evolution model. The destructive test results in a single water vapor detection data point and is unable to conduct multi-stress coupling research, resulting in its unsustainability. The present invention is based on failure physics, rather than statistical physics. It does not fit data equations through a large number of data points, but instead uses failure modes to combine temperature, humidity, and pressure difference to accelerate the analysis of the airtight failure of sealed relays. In the present invention, each stress point in the accelerated life test can extend the water vapor data of the device failure at different times. Since airtight failure cannot be predicted, it can only be predicted through previous data and experience. Once the water vapor content inside the sealed relay does not reach the failure water vapor content, the sealed relay is tested using a helium mass spectrometer, the experiment is terminated, and the atmosphere inside the relay housing is exchanged with the outside world, resulting in a change in its internal water vapor content, making it impossible to perform accurate and effective analysis.

[0005] 2. Destructive testing: This detection method is destructive. During the leak rate detection process, a helium mass spectrometer applies high pressure and then evacuates the metal / glass insulator seal. This high pressure is often much higher than normal atmospheric pressure, and even significantly higher than the limit pressure difference of the accelerated life test. This damages the glass insulator in a short period of time. This damage will not cause through-hole cracks in the glass insulator, which means that no significant change in the leak rate can be observed during short-term leak rate testing. However, during longer storage or accelerated life testing, if the microcracks in the glass insulator absorb water vapor, it will significantly accelerate the expansion of the microcracks and cause the metal / glass insulator seal to fail. Due to its hidden nature, this is often overlooked during the use of helium mass spectrometers.

[0006] 3. Inaccurate criteria: While leak rate testing may pass, the internal water vapor content may have exceeded the standard (due to residual water vapor or increased microcracks). Airtightness failure is actually caused by excessive water vapor content, which directly triggers contact failure and other faults. This leak rate testing method results in lax airtightness testing of the metal / glass insulator sealing structure. Leak rate testing using a helium mass spectrometer can result in passing the leak rate test but exceeding the internal water vapor content standard. This is partly due to excessive residual water vapor caused by processes such as packaging, and partly due to increased microcracks in the glass insulator due to lead stud climbing and applied high voltage. This can lead to excessive internal water vapor content even when the leak rate remains within the standard. The various failures that actually cause device failure, including electrical contact failure and contact bonding, stem from airtightness failure caused by excessive internal water vapor content.

[0007] In summary, the defects of the existing helium mass spectrometry backpressure method are that destructive detection leads to microcrack expansion, a single detection cannot continuously obtain water vapor data, and the leak rate judgment is disconnected from the physical mechanism of airtight failure, which ultimately leads to inaccurate sealing structure failure assessment. Summary of the Invention

[0008] In order to address the three major technical defects of the existing helium mass spectrometry backpressure method, namely, destructive detection leading to microcrack propagation, the inability to continuously obtain water vapor data in a single detection, and the disconnection between the leak rate criterion and the physical mechanism of airtight failure, the present invention provides a non-destructive continuous detection method and device for accelerated airtightness testing of metal / glass sealing structures.

[0009] In one aspect, the present invention provides a non-destructive continuous testing method for accelerated airtightness testing of a metal / glass sealing structure, the method comprising the following steps:

[0010] S1. Encapsulate the temperature and humidity sensor into a metal / glass insulator sealed structure through an FPC sensor circuit board to construct a test cavity. The temperature and humidity electrical signals inside the test cavity are transmitted to an external signal group control board through lead pins.

[0011] S2. placing the test cavity into an accelerating cavity to perform an accelerated life test, during which three stresses of temperature, humidity, and pressure difference are simultaneously applied to the test cavity;

[0012] S3. The signal group control board calculates the water vapor content IV inside the test chamber in real time. When IV is ≥5000 ppm for three consecutive times, it is determined that the airtightness has failed.

[0013] Preferably, the water vapor content IV inside the test cavity in step S3 is obtained as follows:

[0014]

[0015] Where,

[0016] To test the real-time relative humidity inside the chamber during the accelerated life test;

[0017] To test the real-time temperature inside the chamber during the accelerated life test;

[0018] is the saturated vapor pressure of water vapor at the current temperature;

[0019] To test the initial pressure of the cavity, set it to normal pressure;

[0020] To test the initial temperature inside the cavity before the accelerated life test;

[0021] It is the pressure difference between the acceleration chamber and the test chamber during the accelerated life test.

[0022] Preferably, the process of applying humidity stress to the test chamber during the accelerated life test in step S2 is: pre-adding a trace amount of liquid water to the acceleration chamber, and the amount of the trace liquid water added is calculated according to the following formula to ensure that all liquid water is in the form of water vapor after the accelerated life test is carried out:

[0023]

[0024] Where, is the gas constant, is the molar mass of water, To accelerate the water vapor content inside the cavity during the accelerated life test.

[0025] Preferably, the process of applying pressure differential stress to the test cavity during the accelerated life test in step S2 is as follows: after adding a trace amount of liquid water, the acceleration cavity is pressurized or depressurized according to the preset pressure differential stress of the experiment, and the amount of pressure added or depressurized is calculated according to the following formula:

[0026]

[0027] Where, Is the charging pressure or extraction pressure, positive value represents charging pressure, negative value represents extraction pressure;

[0028] It is the initial air pressure of the acceleration chamber before the accelerated life test.

[0029] Preferably, the process of applying temperature stress to the test cavity during the accelerated life test in step S2 is: after applying the pressure differential stress, the acceleration cavity is placed in a constant temperature box, and the temperature stress is applied by using the constant temperature box. The temperature of the entire device is increased by the constant temperature box, and a small amount of liquid water is pre-added inside the acceleration cavity and vaporized to reach the preset temperature, humidity, and pressure differential; the temperature and humidity sensor arranged in the acceleration cavity detects the temperature and humidity data in real time and transmits it to the signal group control board.

[0030] Preferably, in the accelerated test, any one of the stress factors of temperature stress, humidity stress and pressure difference stress has at least 2 levels.

[0031] In another aspect, the present invention provides a non-destructive continuous detection device for accelerated testing of airtightness of a metal / glass sealing structure, the device comprising a test cavity, an acceleration cavity, and a control unit; the test cavity is placed in the acceleration cavity, and the acceleration cavity provides temperature stress, humidity stress, and pressure difference stress for the test cavity;

[0032] Control unit: includes FPC signal transmission board 10 and signal group control board 14;

[0033] The test chamber includes a temperature and humidity sensor 7, an FPC sensor circuit board 8, and a metal / glass insulator sealing structure 9. The first temperature and humidity sensor 7 is sealed into the metal / glass insulator sealing structure 9 via the FPC sensor circuit board 8 to construct the test chamber. The temperature and humidity electrical signals of the test chamber are transmitted to the signal group control board 14 via the FPC signal transmission board 10.

[0034] The acceleration chamber includes a pressure vessel cover 3, a silicone rubber sealing structure 4, a flanged pressure vessel 5, a second temperature and humidity sensor 6, a thermostat 13, and a pressure differential stress loading unit. The flanged pressure vessel 5 is placed in the thermostat 13. The pressure vessel cover 3 seals the upper opening of the flanged pressure vessel 5 via the silicone rubber sealing structure 4. The second temperature and humidity sensor 6 is sealed inside the acceleration chamber.

[0035] The pressure differential stress loading unit includes a flange pressure transmitter 1, a stainless steel three-way valve 2, a sealing ball valve 11, a micro air pump 12 and an explosion-proof plug 15. The pressure vessel tank top cover 3 has a central through hole, and the sealing ball valve 11 is installed at the central through hole. The sealing ball valve 11 is externally connected to an interface of the stainless steel three-way valve 2, and the other two interfaces of the stainless steel three-way valve 2 are respectively connected to the flange pressure transmitter 1 and the micro air pump 12. The micro air pump 12 inflates or exhausts air into the acceleration cavity to increase or decrease the air pressure in the acceleration cavity, and the flange pressure transmitter 1 monitors the internal pressure of the acceleration cavity in real time. When the preset pressure differential stress is reached, the sealing ball valve 11 is closed, the flange pressure transmitter 1, the stainless steel three-way valve 2 and the micro air pump 12 are disassembled, and the explosion-proof plug 15 is installed on the external interface of the sealing ball valve 11.

[0036] Preferably, the thickness of the FPC signal transmission board 10 is not less than 100 μm, and the bending radius is ≥5 mm. One end of the FPC signal transmission board 10 is connected to the temperature and humidity sensor packaged in the test chamber by soldering packaging; the other end of the FPC signal transmission board 10 passes through the side wall of the acceleration chamber to be electrically connected to the external signal group control board 14;

[0037] The connection between the FPC signal transmission board 10 and the side wall of the acceleration chamber is sealed with silicone rubber. The sealing method is: first, the FPC signal transmission board is passed through the silicone rubber sealing ring at the connection, and the silicone rubber sealing ring is fixed to the groove of the pressure vessel tank top cover 3. Then, liquid silicone rubber with a thickness of not less than 4 mm is applied on both sides of the silicone rubber sealing ring for sealing protection, and vacuum silicone grease is applied on the contact surface between the FPC signal transmission board 10 and the silicone rubber sealing ring.

[0038] Preferably, a groove for covering the tank body is provided on the lower surface of the pressure vessel tank top cover 3, and a silicone rubber ring is placed in the groove. When the tank body is covered, the groove is squeezed and liquid silicone rubber is applied to the connection. Vacuum silicone grease is applied to the contact surface between the tank body and the silicone rubber ring to maintain a sealed structure on all sides.

[0039] Preferably, the acceleration chamber provides humidity stress in the following manner: before installing the sealing ball valve 11, a small amount of liquid water is added into the interior through the central through hole of the pressure vessel tank top cover 3, so that it is completely vaporized and reaches a preset humidity during the accelerated life test.

[0040] The present invention has the following beneficial effects: It provides a method for non-destructively and continuously detecting the internal water vapor content of a metal / glass insulator seal under accelerated life test conditions of high temperature, high humidity, and high pressure. This method overcomes the numerous problems of traditional leak rate detection methods, including helium mass spectrometers, such as the inability to perform non-destructive and continuous detection, and the lack of rigorous judgment criteria. By fully considering the effect of internal water vapor content on microcracks in the glass insulator within the metal / glass insulator seal from the perspective of failure physics, the method can non-destructively, continuously, and accurately determine when the metal / glass insulator seal fails. Specifically, the method includes the following points:

[0041] 1. Breakthrough of the bottleneck of non-destructive continuous monitoring:

[0042] Built-in temperature and humidity sensors utilize the lead pins and other structures of the metal / glass insulator seal structure to transmit the sensor's electrical signals, avoiding the destructive operation of traditional helium mass spectrometry and enabling continuous collection of water vapor data throughout the life cycle. This eliminates the problem of multiple test stops and inspections during accelerated life testing, which can damage the metal / glass insulator seal structure. It effectively reduces the impact of other factors on accelerated life testing, effectively shortening the airtightness accelerated life testing cycle of metal / glass insulator seals from months or even years to just over a month.

[0043] 2. Multi-layer sealing design ensures stable signal transmission in high-pressure / high-temperature environments; the contradiction between signal transmission and cavity sealing in high-pressure environments is resolved through the FPC circuit board + silicone rubber sealing assembly. The FPC material ensures corrosion resistance under high-temperature and high-humidity conditions. At the same time, sufficient structural strength and bending resistance ensure that there is no obvious deformation when the flange is fixed, which can ensure a sealing performance of no less than 2 times the atmospheric pressure.

[0044] While ensuring the sealing of the accelerated life test device, the electrical signals of the temperature and humidity sensors are transmitted stably and accurately. With the help of the water vapor and pressure control device, the water vapor and pressure inside the acceleration cavity are accurately controlled by evaporating a small amount of liquid water and pre-pressurizing and pumping. At the same time, the problem that the overall structure needs to measure pressure during the accelerated life test is solved, thereby avoiding the problem that the water vapor and pressure control structure is difficult to take into account the simultaneous stability of trace water vapor and pressure. The water vapor content and leakage status inside different cavities during the accelerated life test can be detected non-destructively and continuously.

[0045] 3. Scientificity and acceleration of failure criteria:

[0046] Using water vapor content ≥5000 ppm as the criterion, it closely follows the physical nature of failure and reflects the physical mechanism of failure more directly than leak rate detection.

[0047] Compared with traditional high-temperature and high-humidity accelerated life tests, the three-stress coupling acceleration (temperature / humidity / pressure difference) introduces the ultimate pressure difference that the metal / glass insulator sealing structure can withstand, which is expected to shorten the test cycle by more than 80%.

[0048] 4. Support online early warning, the host computer software displays data in real time and triggers alarms (such as IV exceeding the threshold). BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a flow chart of the non-destructive continuous testing method for the accelerated air tightness test of the metal / glass sealing structure of the present invention;

[0050] Figure 2 This is a schematic structural diagram of the nondestructive continuous testing device for the accelerated air tightness test of the metal / glass sealing structure of the present invention, which is equipped with a flange-type pressure transmitter 1, a stainless steel three-way valve 2, a sealing ball valve 11 and a micro air pump 12;

[0051] Figure 3 It is a structural schematic diagram of the nondestructive continuous detection device for the accelerated test of the air tightness of the metal / glass sealing structure of the present invention. The flange pressure transmitter 1, the stainless steel three-way valve 2, the sealing ball valve 11, and the micro air pump 12 are disassembled and the explosion-proof plug is installed. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0053] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0054] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0055] Specific implementation method 1: Figures 1 to 3 This embodiment describes a nondestructive continuous detection device for an accelerated airtightness test of a metal / glass sealing structure, comprising a test chamber, an acceleration chamber, and a control unit. The test chamber is placed within the acceleration chamber, and the acceleration chamber provides temperature stress, humidity stress, and pressure differential stress for the test chamber.

[0056] Control unit: includes FPC signal transmission board 10 and signal group control board 14; signal group control board 14 is the data interaction and logic control center of the entire device, and its main functions are: collecting sensor data such as temperature and humidity, and realizing the calculation and visualization of airtightness parameters.

[0057] Test chamber: The test chamber structure is the core packaging unit of the tested sealed relay. Its main functions are to achieve real-time collection of temperature and humidity inside the seal, ensure the internal structure is sealed and can withstand high temperature, high humidity and high pressure environments, and communicate with the external data system through an integrated flexible circuit. It includes the following components:

[0058] Built-in No. 1 temperature and humidity sensor 7: responsible for real-time monitoring of the temperature and humidity data inside the test chamber;

[0059] FPC sensor circuit board 8: provides fixation and connection support for the above sensors;

[0060] Metal / glass insulator sealed structure 9: Encapsulates the sealed structure under test, with lead posts and glass insulators, and has a complete sealed physical structure;

[0061] FPC signal transmission board 10: It is responsible for the circuit connection between the signal acquisition sensor and the external signal group control board. It also has high temperature and flexibility characteristics and is suitable for complex installation environments.

[0062] The combination of the above components ensures that internal signal acquisition and transmission are completed without damaging the seal.

[0063] The first temperature and humidity sensor 7 is sealed into the metal / glass insulator sealing structure 9 with the help of the FPC sensor circuit board 8 to construct a test cavity; the temperature and humidity electrical signals of the test cavity are transmitted to the signal group control board 14 through the FPC signal transmission board 10; the metal / glass insulator sealing structure 9 includes but is not limited to any sealing device that can maintain the internal atmosphere and the external atmosphere independently and realize the transmission of internal and external electrical signals, especially a sealed relay, which is sealed by a metal shell and a glass insulator and realizes the transmission of electrical signals between the FPC sensor circuit board and the FPC signal transmission board through lead pins; the electrical signal transmission of the temperature and humidity sensor is realized through the FPC signal transmission board 10, which is used to detect the temperature and water vapor in the acceleration cavity and detect whether there is gas leakage based on the change of water vapor; the temperature and humidity sensor 8 encapsulated in the test cavity is used to detect the temperature and water vapor content in the test cavity. Since the degree of gas leakage in the test cavity is very low, the total amount of gas leaked into the test cavity when the internal water vapor content reaches the failure criterion of 5000ppm is far less than the gas content of the test cavity itself, so the test cavity does not need to detect pressure;

[0064] Acceleration chamber: The acceleration chamber structure is used to build a controlled accelerated life test environment. Its main function is to apply stress conditions such as temperature, humidity, and air pressure to the outside of the test chamber to achieve environmental control and sealing during the test, and support pressurization and air intake operations. It includes the following components:

[0065] Flange pressure vessel tank 5: provides a controlled sealed environment and carries the test cavity;

[0066] Silicone rubber sealing structure 4: forms a reliable seal at multiple connection interfaces and sealing parts to prevent gas leakage;

[0067] Sealing ball valve 11, stainless steel three-way valve 2: realize the control of air intake and exhaust of the acceleration chamber;

[0068] Explosion-proof plug 15: ensures safe discharge under overpressure conditions;

[0069] Constant temperature box 13: provides a stable and controllable temperature environment for the cavity;

[0070] Flange type pressure transmitter 1: used to detect the pressure change inside the cavity;

[0071] Micro air pump 12: cooperates with the air circuit system to complete the process of pumping or pressurizing.

[0072] Specifically, it includes a pressure vessel tank cover 3, a silicone rubber sealing structure 4, a flanged pressure vessel tank 5, a second temperature and humidity sensor 6, a constant temperature box 13, and a pressure differential stress loading unit; the flanged pressure vessel tank 5 is placed in the constant temperature box 13, and the pressure vessel tank cover 3 seals the upper opening of the flanged pressure vessel tank 5 through the silicone rubber sealing structure 4, accelerating the sealing of the second temperature and humidity sensor 6 inside the cavity;

[0073] The pressure differential stress loading unit includes a flange pressure transmitter 1, a stainless steel three-way valve 2, a sealing ball valve 11, a micro air pump 12 and an explosion-proof plug 15. The pressure vessel tank top cover 3 has a central through hole, and the sealing ball valve 11 is installed at the central through hole. The sealing ball valve 11 is externally connected to an interface of the stainless steel three-way valve 2, and the other two interfaces of the stainless steel three-way valve 2 are respectively connected to the flange pressure transmitter 1 and the micro air pump 12. The micro air pump 12 inflates or exhausts air into the acceleration cavity to increase or decrease the air pressure in the acceleration cavity, and the flange pressure transmitter 1 monitors the internal pressure of the acceleration cavity in real time. When the preset pressure differential stress is reached, the sealing ball valve 11 is closed, the flange pressure transmitter 1, the stainless steel three-way valve 2 and the micro air pump 12 are disassembled, and the explosion-proof plug 15 is installed on the external interface of the sealing ball valve 11.

[0074] An airtight connection is achieved between the three components: a test chamber sealed with a temperature and humidity sensor, a heated, humidified and pressurized acceleration chamber for accelerated life testing, and an FPC signal transmission board 10. The connecting component that achieves the airtight connection between the three components is a silicone rubber sealing structure, which includes but is not limited to a silicone rubber sealing ring that can pass through the circuit board, liquid silicone rubber, high-airtightness sealant, vacuum silicone grease, etc.

[0075] The FPC sensor circuit board 8, FPC signal transmission board 10, and sealing ball valve 11 must ensure that their physical properties and electrical signal transmission performance are not damaged or changed under the extreme acceleration stress applied during the accelerated life test until the entire accelerated life test is completed. This is especially true for corrosion caused by high temperature and high humidity, and bending caused by high voltage. The FPC signal transmission board is a multi-layer composite copper foil structure with an EMI anti-interference layer and upper and lower insulating protective films. The thickness of the FPC signal transmission board 10 is not less than 100μm, and the bending radius is ≥5mm. One end of the FPC signal transmission board 10 is connected to the temperature and humidity sensor encapsulated in the test chamber using a soldering package. The other end of the FPC signal transmission board 10 is electrically connected to the external signal group control board 14 through the side wall of the acceleration chamber.

[0076] The connection between the FPC signal transmission board 10 and the side wall of the acceleration chamber is sealed with silicone rubber. The sealing method is: first, the FPC signal transmission board is passed through the silicone rubber sealing ring at the connection, and the silicone rubber sealing ring is fixed to the groove of the pressure vessel tank top cover 3. Then, liquid silicone rubber with a thickness of not less than 4 mm is applied on both sides of the silicone rubber sealing ring for sealing protection, and vacuum silicone grease is applied on the contact surface between the FPC signal transmission board 10 and the silicone rubber sealing ring.

[0077] The lower surface of the pressure vessel tank top cover 3 is provided with a groove for covering the tank body. A silicone rubber ring is placed in the groove. When the cover is closed, it is squeezed and liquid silicone rubber is applied to the connection. Vacuum silicone grease is applied to the contact surface between the tank body and the silicone rubber ring to maintain a sealed structure on all sides.

[0078] The acceleration chamber provides humidity stress by adding a small amount of liquid water through the central through-hole of the pressure vessel's top cover 3 before installing the sealing ball valve 11. This is done by completely vaporizing the water during the accelerated life test and reaching the preset humidity. This is achieved using micro-injectors (pipettes) of various specifications.

[0079] The internal volume of the test chamber must accommodate the temperature and humidity sensor and be airtight. The sealed relay itself can serve as the test chamber; the acceleration chamber itself must be airtight. Temperature and humidity sensor sealing method: Use methods including but not limited to soldering and reflow soldering to complete the sealing of the temperature and humidity sensor to the metal / glass insulator sealing structure, and transmit electrical signals through the lead posts wrapped by the glass insulator. In particular, when the temperature and humidity sensor must be connected or fixed by reflow soldering, a reflow soldering process is required. Ensure that the sealing process does not affect the airtightness of the metal / glass insulator sealing structure, and ensure that the sealing process does not affect the sensor's electrical signal transmission and test accuracy.

[0080] Specific embodiment 2: This embodiment describes a non-destructive continuous detection method for accelerated airtightness testing of a metal / glass sealing structure, the method comprising the following steps:

[0081] S1. Encapsulate the temperature and humidity sensor into a metal / glass insulator sealed structure through an FPC sensor circuit board to construct a test cavity. The temperature and humidity electrical signals inside the test cavity are transmitted to an external signal group control board through lead pins.

[0082] S2. placing the test cavity into an accelerating cavity to perform an accelerated life test, during which three stresses of temperature, humidity, and pressure difference are simultaneously applied to the test cavity;

[0083] S3. The signal group control board calculates the water vapor content IV inside the test chamber in real time. When IV is ≥5000 ppm for three consecutive times, it is determined that the airtightness has failed.

[0084] The acceleration chamber features temperature, humidity, and air pressure control. It utilizes a heating and pressurization system, and precisely calculates and adds water to create an accelerated aging environment. The chamber structure utilizes a flanged metal tank with sealing grooves, and utilizes liquid silicone rubber, vacuum silicone grease, and other materials for multi-layer sealing. A seal-enhanced silicone ring is also included to maintain a stable seal under long-term pressure. A temperature and humidity sensor is encapsulated within the acceleration chamber structure to monitor the humidity status of the chamber in real time. Any sudden changes in humidity or abnormal rate of change can be detected, promptly signaling abnormalities in the chamber's airtightness.

[0085] This technology encapsulates a micro temperature and humidity sensor inside a sealed relay cavity, and then places the relay in an accelerated cavity for accelerated life testing with heating, humidification, and pressurization. The sensor continuously monitors the changing trend of internal water vapor, thereby evaluating changes in sealing performance. Due to the coupling mechanism between microcrack expansion and water vapor leakage, the change trend of the humidity curve measured by the sensor can be used to infer the degree of damage to the relay glass insulator, thereby achieving non-destructive continuous testing. By analyzing the humidity-leakage rate pattern of relay samples after microcrack expansion, the microscopic mechanism of seal airtight failure under humidity stress can be revealed. The sensor needs to be calibrated before packaging, and then encapsulated inside the sealed relay, and the test data is output through the FPC signal transmission board to ensure data transmittance and system integrity under the premise of cavity sealing.

[0086] The water vapor content IV inside the test cavity in step S3 is calculated based on the relative humidity transmitted from the test cavity, specifically:

[0087]

[0088] Where,

[0089] To test the real-time relative humidity inside the chamber during the accelerated life test;

[0090] To test the real-time temperature inside the chamber during the accelerated life test;

[0091] is the saturated vapor pressure of water vapor at the current temperature; the saturated vapor pressure of water vapor at any temperature can be obtained by looking up the table, which is a known quantity.

[0092] To test the initial pressure of the cavity, set it to normal pressure;

[0093] This is the initial temperature inside the test chamber before the accelerated life test; the initial temperature must be higher than the dew point temperature of the test chamber.

[0094] This is the pressure differential between the acceleration chamber and the test chamber during the accelerated life test. The pressure inside the acceleration chamber, measured by flange-mounted pressure transmitter 1, is the preset pressure, while the pressure inside the test chamber can be considered the initial pressure. The pressure differential between the two can be calculated using the preset and initial pressures.

[0095] The process of applying humidity stress to the test cavity during the accelerated life test in step S2 is as follows: a trace amount of liquid water is pre-added to the acceleration cavity. The amount of the trace liquid water added is calculated according to the following formula to ensure that all liquid water is in the form of water vapor after the accelerated life test is carried out:

[0096]

[0097] Where, is the gas constant, is the molar mass of water, To accelerate the water vapor content inside the cavity during the accelerated life test.

[0098] The process of applying pressure differential stress to the test cavity during the accelerated life test in step S2 is as follows: after adding a trace amount of liquid water, the acceleration cavity is pressurized or depressurized according to the preset pressure differential stress of the experiment, and the amount of pressure added or depressurized is calculated according to the following formula:

[0099]

[0100] Where, Is the charging pressure or extraction pressure, positive value represents charging pressure, negative value represents extraction pressure;

[0101] It is the initial air pressure of the acceleration chamber before the accelerated life test.

[0102] The process of applying temperature stress to the test cavity during the accelerated life test in step S2 is as follows: after applying the pressure differential stress, the acceleration cavity is placed in a constant temperature box, and the temperature stress is applied by using the constant temperature box. The temperature of the entire device is increased by the constant temperature box, and a small amount of liquid water is pre-added inside the acceleration cavity and vaporized to reach the preset temperature, humidity, and pressure differential; the temperature and humidity sensor set in the acceleration cavity detects the temperature and humidity data in real time and transmits it to the signal group control board.

[0103] In the accelerated test, any one of the stress factors including temperature stress, humidity stress and pressure difference stress shall have at least 2 levels.

[0104] Take level 3 as an example:

[0105] For temperature stress: the levels can be 85°C, 105°C, 125°C.

[0106] For humidity stress: the level can be 2.4×10 5 ppm, 2.6×10 5 ppm, 2.8×10 5 ppm.

[0107] For differential pressure stress: the levels can be 50 kPa, 70 kPa, 90 kPa.

[0108] Temperature and humidity sensors packaged in the accelerated chamber should be continuously tested at a temperature no lower than the saturated vapor pressure of the accelerated chamber. This means that the trace amount of liquid water added to the accelerated chamber must be in the form of water vapor after the accelerated life test. Temperature and humidity sensors packaged in the test chamber can be tested simultaneously with the accelerated chamber temperature, or when the test chamber is lowered to the initial temperature before the accelerated life test. If the temperature and humidity sensors packaged in the test chamber are tested at the initial temperature before the accelerated life test, the temperature and humidity sensors packaged in the test chamber must complete at least one heating and cooling cycle. During the accelerated life test, the heating and cooling rates must not exceed 5°C / min to avoid introducing additional temperature shock factors. The heating temperature should be consistent with the temperature of the accelerated life test and maintained at the highest temperature for 1 hour to ensure that the temperature and humidity sensors do not absorb additional water vapor before the accelerated life test.

[0109] Here is a complete working process:

[0110] Phase 1: sensor packaging and preprocessing;

[0111] 1. Cover plate leakage rate detection;

[0112] 2. Reflow solder the temperature and humidity sensor 7 to the lead pins through the FPC sensor circuit board 8;

[0113] 3. Clean the welding area with anhydrous ethanol;

[0114] 4. The cover is pressed together with the housing (not sealed);

[0115] 5. Dry at 110℃ for 8 hours (to reduce residual moisture);

[0116] 6. Vacuum and fill with dry inert gas;

[0117] 7. Metal / glass sealing;

[0118] Phase 2: Acceleration chamber pre-test preparation;

[0119] 8. Bake the accelerated chamber at 80°C for ≥8h (drying treatment);

[0120] 9. Install the test chamber to the flanged pressure vessel tank 5;

[0121] 10. Silicone rubber sealing structure 4 multi-layer sealing:

[0122] 10.1 The FPC signal transmission board 10 passes through the opening of the silicone rubber ring;

[0123] 10.2 Coated with ≥4mm liquid silicone rubber;

[0124] 10.3 Curing ≥ 48h;

[0125] 10.4 Covered with high airtight sealant + vacuum silicone grease;

[0126] 11. A small amount of liquid water is injected into the acceleration chamber:

[0127] 11.1 Calculate the required water volume m;

[0128] 11.2 Add deionized water using a pipette;

[0129] 12. Pressure pre-adjustment:

[0130] 12.1 Install the pressure components (sealed ball valve 11 / flange pressure transmitter 1 / stainless steel three-way valve 2 / micro air pump 12);

[0131] 12.2 Calculation of required air pressure ;

[0132] 12.3 The air pump pressure is adjusted to the target value;

[0133] Phase 3: Accelerated life test execution;

[0134] 13. Remove the pressure assembly, close the sealing ball valve 11, and install the explosion-proof plug 15;

[0135] 14. The constant temperature box 13 is heated to the target temperature (85 / 105 / 125°C);

[0136] 15. Start real-time monitoring:

[0137] The loop begins:

[0138] 15.1 Collect temperature and humidity data to ensure that at least one cycle of testing is completed every hour, that is, each sensor outputs at least one set of data every hour to ensure the continuity of the accelerated life test data.

[0139] 15.2 Calculate the internal water vapor content IV:

[0140] 15.3 Data Transfer:

[0141] The FPC signal transmission board 10 converts I²C to RS485 protocol;

[0142] The signal group control board 14 displays and stores data in real time;

[0143] 15.4 Failure determination:

[0144] Yes (IV ≥ 5000 ppm for three consecutive times) → 16. Determine airtight failure;

[0145] No → return to the beginning of the loop;

[0146] 16. Terminate the test and sound an alarm;

[0147] Phase 4: Post-trial verification;

[0148] 17. Helium mass spectrometer retest leak rate (verification failure criterion);

[0149] 18. Data Analysis:

[0150] Quantify the effect of humidity / pressure differential on failure time;

[0151] Establish a microcrack growth model.

[0152] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in conjunction with other described embodiments.

Claims

1. A non-destructive continuous testing method for accelerated airtightness testing of metal / glass sealing structures, characterized in that: The method comprises the following steps: S1. Encapsulate the temperature and humidity sensor into a metal / glass insulator sealed structure through an FPC sensor circuit board to construct a test cavity. The temperature and humidity electrical signals inside the test cavity are transmitted to an external signal group control board through lead pins. S2. placing the test cavity into an accelerating cavity to perform an accelerated life test, during which three stresses of temperature, humidity, and pressure difference are simultaneously applied to the test cavity; S3. The signal group control board calculates the water vapor content IV inside the test chamber in real time. When IV is ≥5000 ppm for three consecutive times, it is determined that the airtightness has failed.

2. The non-destructive continuous detection method for accelerated airtightness testing of a metal / glass sealing structure according to claim 1, characterized in that: In step S3, the water vapor content IV inside the test cavity is obtained as follows: Where, To test the real-time relative humidity inside the chamber during the accelerated life test; To test the real-time temperature inside the chamber during the accelerated life test; is the saturated vapor pressure of water vapor at the current temperature; To test the initial pressure of the cavity, set it to normal pressure; To test the initial temperature inside the cavity before the accelerated life test; It is the pressure difference between the acceleration chamber and the test chamber during the accelerated life test.

3. The non-destructive continuous detection method for accelerated airtightness testing of a metal / glass sealing structure according to claim 2, characterized in that: The process of applying humidity stress to the test cavity during the accelerated life test in step S2 is as follows: a trace amount of liquid water is pre-added to the acceleration cavity. The amount of the trace liquid water added is calculated according to the following formula to ensure that all liquid water is in the form of water vapor after the accelerated life test is carried out: Where, is the gas constant, is the molar mass of water, To accelerate the water vapor content inside the cavity during the accelerated life test.

4. The non-destructive continuous detection method for accelerated airtightness testing of a metal / glass sealing structure according to claim 3, characterized in that: The process of applying pressure differential stress to the test cavity during the accelerated life test in step S2 is as follows: after adding a trace amount of liquid water, the acceleration cavity is pressurized or depressurized according to the preset pressure differential stress of the experiment, and the amount of pressure added or depressurized is calculated according to the following formula: Where, Is the charging pressure or extraction pressure, positive value represents charging pressure, negative value represents extraction pressure; It is the initial air pressure of the acceleration chamber before the accelerated life test.

5. The non-destructive continuous detection method for accelerated airtightness testing of a metal / glass sealing structure according to claim 4, characterized in that: The process of applying temperature stress to the test cavity during the accelerated life test in step S2 is as follows: after applying the pressure differential stress, the acceleration cavity is placed in a constant temperature box, and the temperature stress is applied by using the constant temperature box. The temperature of the entire device is increased by the constant temperature box, and a small amount of liquid water is pre-added inside the acceleration cavity and vaporized to reach the preset temperature, humidity, and pressure differential; the temperature and humidity sensor set in the acceleration cavity detects the temperature and humidity data in real time and transmits it to the signal group control board.

6. The non-destructive continuous detection method for accelerated airtightness testing of a metal / glass sealing structure according to claim 1, characterized in that: In the accelerated test, any one of the stress factors including temperature stress, humidity stress and pressure difference stress shall have at least 2 levels.

7. A non-destructive continuous detection device for accelerated airtightness testing of metal / glass sealing structures, the device being used to implement the method described in any one of claims 1 to 6, characterized in that: The device includes a test cavity, an acceleration cavity and a control unit; the test cavity is placed in the acceleration cavity, and the acceleration cavity provides temperature stress, humidity stress and pressure difference stress for the test cavity; Control unit: including an FPC signal transmission board (10) and a signal group control board (14); The test cavity comprises a temperature and humidity sensor (7), an FPC sensor circuit board (8) and a metal / glass insulator sealing structure (9), wherein the first temperature and humidity sensor (7) is sealed into the metal / glass insulator sealing structure (9) with the aid of the FPC sensor circuit board (8) to construct the test cavity; the temperature and humidity electrical signals of the test cavity are transmitted to the signal group control board (14) via the FPC signal transmission board (10); The acceleration chamber comprises a pressure vessel tank top cover (3), a silicone rubber sealing structure (4), a flanged pressure vessel tank (5), a No. 2 temperature and humidity sensor (6), a constant temperature box (13), and a pressure differential stress loading unit; the flanged pressure vessel tank (5) is placed in the constant temperature box (13), the pressure vessel tank top cover (3) seals the upper opening of the flanged pressure vessel tank (5) through the silicone rubber sealing structure (4), and the No. 2 temperature and humidity sensor (6) is sealed inside the acceleration chamber; The pressure differential stress loading unit comprises a flange-type pressure transmitter (1), a stainless steel three-way valve (2), a sealing ball valve (11), a micro air pump (12) and an explosion-proof plug (15). The pressure vessel tank top cover (3) has a central through hole, and the sealing ball valve (11) is installed at the central through hole. The sealing ball valve (11) is externally connected to an interface of the stainless steel three-way valve (2), and the other two interfaces of the stainless steel three-way valve (2) are respectively connected to the flange-type pressure transmitter (1) and the micro air pump (12). The micro air pump (12) inflates or deflates the acceleration chamber to increase or decrease the air pressure in the acceleration chamber, and the flange-type pressure transmitter (1) monitors the internal pressure of the acceleration chamber in real time. When the preset pressure differential stress is reached, the sealing ball valve (11) is closed, the flange-type pressure transmitter (1), the stainless steel three-way valve (2) and the micro air pump (12) are disassembled, and the explosion-proof plug (15) is installed on the external interface of the sealing ball valve (11).

8. The non-destructive continuous testing device for accelerated airtightness testing of metal / glass sealing structures according to claim 7, characterized in that: The thickness of the FPC signal transmission board (10) is not less than 100 μm, and the bending radius is ≥5 mm. One end of the FPC signal transmission board (10) is connected to the temperature and humidity sensor packaged in the test cavity by soldering packaging; the other end of the FPC signal transmission board (10) passes through the side wall of the acceleration cavity and is electrically connected to the external signal group control board (14); The connection between the FPC signal transmission board (10) and the side wall of the acceleration chamber is sealed with silicone rubber. The sealing method is as follows: first, the FPC signal transmission board (10) is passed through the silicone rubber sealing ring at the connection, and the silicone rubber sealing ring is fixed to the groove of the pressure vessel tank top cover (3). Then, liquid silicone rubber with a thickness of not less than 4 mm is applied on both sides of the silicone rubber sealing ring for sealing protection, and vacuum silicone grease is applied on the contact surface between the FPC signal transmission board (10) and the silicone rubber sealing ring.

9. The non-destructive continuous testing device for accelerated airtightness testing of metal / glass sealing structures according to claim 7, characterized in that: The lower surface of the pressure vessel tank top cover (3) is provided with a groove for covering the tank body, and a silicone rubber ring is placed in the groove. When the cover is closed, the groove is squeezed and liquid silicone rubber is applied to the connection. Vacuum silicone grease is applied to the contact surface between the tank body and the silicone rubber ring, thereby maintaining a sealed structure on all sides.

10. The non-destructive continuous testing device for accelerated airtightness testing of metal / glass sealing structures according to claim 7, characterized in that: The acceleration chamber provides humidity stress in the following manner: before installing the sealing ball valve (11), a small amount of liquid water is added into the interior through the central through hole of the pressure vessel tank top cover (3), so that it is completely vaporized and reaches a preset humidity during the accelerated life test.

Images