A highly integrated temperature sensor for deep-sea applications and its production and packaging process

Abstract

The present invention relates to the field of ocean observation technology, and discloses a highly integrated temperature sensor for deep-sea applications, including a temperature sensor housing, a temperature sensitive element, a signal processing circuit board, and a digital signal transmission cable. The temperature sensitive element and the signal processing circuit board are packaged in the temperature sensor housing, and the digital signal transmission cable connects the signal processing circuit board to the main circuit board of the device. The present invention also discloses a production and packaging process for a highly integrated temperature sensor for deep-sea applications. The various parts of the entire temperature sensor of the present invention are integrated into a whole, which simplifies the structure while improving the measurement accuracy and anti-interference ability of the temperature sensor.

Description

Technical Field

[0001] The present invention relates to the field of ocean observation technology, and in particular to a highly integrated temperature sensor for deep-sea applications and a production and packaging process thereof. Background Art

[0002] Temperature data is a basic parameter for physical ocean observations and a basic element of ocean dynamics. It is an essential factor for calculating other physical parameters such as salinity, density, and speed of sound. Therefore, it is widely used in various detection instruments, motion platforms, operating equipment, sailing ships, aquaculture, and even military weapons and equipment. Therefore, the measurement accuracy of temperature sensors for routine physical ocean observations and providing meaningful data support for marine science is generally required to be within ±0.01 degrees Celsius. The better equipment made internationally can achieve a measurement accuracy of ±0.003 degrees Celsius. Common working modes of temperature sensors are generally divided into the following categories.

[0003] 1. The temperature sensor is the main body, working independently and self-contained. During the working process, it does not exchange data with the outside. All working data is stored inside. When the work is completed, it is salvaged manually and connected to the computer using a communication cable to export all historical data. The data of this sensor has poor real-time performance.

[0004] 2. Directly attach the finished product of the external temperature sensor, use physical reinforcement to tie the sensor to the main body, and use a watertight cable between the two to achieve interactive communication of commands and data. This method occupies a large volume.

[0005] 3. Using embedded integration to integrate the shell structure of the temperature sensor with its own shell structure can achieve higher integration, more reliable connection effects, better fluid characteristics, and a more beautiful appearance.

[0006] Although the embedded temperature sensor is integrated with the main device in terms of structure, achieving the miniaturization of the overall volume, the sensor circuit still needs to be placed. Generally speaking, the temperature sensitive part of the temperature sensor is encapsulated in a separate shell, and this shell is installed on the instrument body. The signal processing circuit board is independent of the temperature sensitive part and is installed in the instrument main circuit, and the two are connected by a cable.

[0007] The problems brought by this form are: first, it increases the difficulty of the entire instrument design. The instrument main circuit board needs to open up a separate space for the temperature sensor circuit board, and for the temperature circuit board, an appropriate number of mounting holes are required to fix it. Between the two circuit boards, there is also a need for board-to-board connectors to realize signal communication. Therefore, the space of the entire system cannot be made very small, which increases the design difficulty for some systems with limited space and compact structure. At the same time, due to the need for structural installation reinforcement, reliability is reduced. For some routine monitoring experiments, such as impact vibration, additional consideration is required in this area, otherwise the circuit board is likely to fall off during future use. In addition, for the instrument equipment, it is necessary to consider the relevant integrated installation issues at the beginning of the design, which increases the difficulty of instrument design. Secondly, the sensor sensitive signal is easily interfered, and the measurement accuracy is affected. Because it is separated in structure, the front-end sensitive element and the circuit board need to be connected with wires to connect the signal of the sensitive element to the processing circuit. In some applications, the length of this wire will be relatively long, and it may pass through areas with harsh electrical environments, such as motor modules and radio frequency modules. Therefore, the analog signal of the sensitive element is transmitted in this wire, and the signal strength is very weak, which is easily affected by the length of the wire, the size of the contact resistance, and the strength of the electromagnetic interference in space. In the application process of some instruments, the measurement accuracy of the sensor is seriously affected, or even cannot be used. Thirdly, it increases the difficulty of using and managing the sensor. The sensitive component part of the sensor is installed separately from the signal processing circuit board, so that a device is disassembled into two parts instead of a whole. During use and storage, they must be placed in a one-to-one combination to ensure the correspondence between the sensitive component part and the processing circuit board, and their order cannot be disrupted. This increases the difficulty of management. Finally, the structure of the sensitive component part is uncertain, resulting in a variety of structural sizes in various application scenarios, which makes the temperature sensor unable to be universal. Summary of the invention

[0008] 1. Problem Solving

[0009] In view of the deficiencies in the prior art, the present invention provides a highly integrated temperature sensor for deep-sea applications. The various parts of the entire temperature sensor are integrated into a whole, which simplifies the structure while improving the measurement accuracy and anti-interference ability of the temperature sensor.

[0010] (II) Technical solution

[0011] In order to achieve the above-mentioned practical use effect of adding a temperature probe, the present invention provides the following technical solutions:

[0012] A highly integrated temperature sensor for deep-sea applications comprises a temperature sensor housing, a temperature sensitive element, a signal processing circuit board, and a digital signal transmission cable, wherein the temperature sensitive element and the signal processing circuit board are encapsulated in the temperature sensor housing, and the digital signal transmission cable connects the signal processing circuit board with a device circuit mainboard; the temperature sensor housing comprises a signal processing circuit board compartment, a mounting portion, and a temperature sensor probe, wherein the mounting portion is arranged between the signal processing circuit board compartment and the temperature sensitive element accommodating cavity, the signal processing circuit board compartment is filled with potting glue, and the interior of the temperature sensor probe is filled with a curable heat-conductive medium in the upper half and potting glue in the lower half.

[0013] Furthermore, the outer surface of the signal processing circuit board compartment is provided with threads, and the threads are in the form of watertight connectors.

[0014] Furthermore, the mounting portion is hexagonal.

[0015] Furthermore, an O-ring groove for placing an O-ring is provided on the outer surface of the connection between the signal processing circuit board compartment and the mounting portion.

[0016] Furthermore, the temperature sensitive element is composed of a temperature sensitive resistor and two metal guide wires, a shielding protective sleeve is provided outside the metal guide wire, and the temperature sensitive resistor is arranged at the top inside the temperature sensor probe.

[0017] Furthermore, the signal processing circuit board includes an analog signal processing part, a digital signal processing part, a logic function processing part, a temperature sensitive element interface, and a digital communication interface.

[0018] The present invention also discloses a production and packaging process for a highly integrated temperature sensor for deep-sea applications, comprising the following steps:

[0019] 1) Perform an appearance inspection on the processed temperature sensor housing to prevent material defects or processing errors;

[0020] 2) Clean the temperature sensor housing with ultrasonic cleaning, then rinse it with clean water and put it in an oven to dry;

[0021] 3) Connect the digital communication interface of the digital signal transmission cable to the signal processing circuit board, and solder the four signal wires in the cable to the relevant solder joints of the circuit board;

[0022] 4) Cut the metal wire of the temperature sensitive component to an appropriate length so that after welding, when the signal processing circuit board is placed in the circuit board compartment, the temperature sensitive resistor is just on top of the temperature probe;

[0023] 5) Install a shielding protective cover on the outside of the metal guide wire of the temperature sensitive component;

[0024] 6) Weld the two metal guide wires in the processed temperature sensitive element to the signal processing circuit board to ensure that the temperature sensitive element is in a straight state;

[0025] 7) Use a needle to absorb the heat-conducting medium and push it to the temperature sensor probe part;

[0026] 8) Place the signal processing circuit board with the temperature sensitive component into the circuit board compartment, and at the same time make the temperature sensitive resistor enter the top of the temperature sensor probe and be completely immersed in the heat conductive medium;

[0027] 9) Store in an upside-down position for at least 24 hours until the performance of the thermal conductive medium is stable;

[0028] 10) Use a needle to absorb the potting glue and push it into the signal processing circuit board compartment, and control the flow of the potting glue to completely soak the circuit board and part of the communication cable;

[0029] 11) Leave and store for at least 24 hours until the potting glue is completely cured.

[0030] Furthermore, the sheathing method of step 5) is to first sheath a thinner shielding protective sheath on one of the wires, then put the two wires together, and sheath a thicker shielding protective sheath on the outside as a whole. The shielding protective sheath needs to extend to the root of the temperature sensitive resistor.

[0031] Furthermore, the heat-conducting medium in step 7) is pre-vacuumed.

[0032] Furthermore, the potting glue in step 10) is pre-vacuumed.

[0033] (III) Beneficial effects

[0034] Compared with the prior art, the present invention provides a highly integrated temperature sensor for deep-sea applications, which has the following beneficial effects:

[0035] 1. All parts of the temperature sensor are integrated into a whole. The installation of the sensor only needs to screw the sensor onto the instrument housing and connect the cable to the instrument main circuit board. There are no more components of other parts. The structure is simple and the installation is convenient.

[0036] 2. Since the sensor integrates the signal processing circuit inside, no additional circuit board is required outside. Therefore, the instrument does not need to provide space for circuit board installation, and only a communication interface is required, which reduces the complexity of the overall design of the instrument;

[0037] 3. No need for the instrument to provide circuit board installation space, which can further reduce the volume of the entire instrument and make miniaturization design easier;

[0038] 3. Reduce the number of structural components of the system, reduce the structural installation work, improve the reliability of the equipment as a whole, and reduce the risk of overall failure;

[0039] 4. Since the temperature sensor integrates the signal processing circuit inside the sensor, the temperature sensitive element is very close to the processing circuit, and the metal guide wire is always inside the metal shell of the sensor, so the weak signal on the guide wire is not easily interfered by the outside world. It has better performance in terms of measurement accuracy;

[0040] 5. Improved the anti-interference ability of the sensor. The cables that the sensor finally provides to the instrument and equipment only contain power supply and digital communication lines. They have strong anti-interference ability, the communication process is not easily affected by environmental electronic interference, and the length of the communication cable can also be greatly increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of the present invention;

[0042] Figure 2 It is a structural schematic diagram of the temperature sensor housing of the present invention;

[0043] Figure 3 It is a schematic diagram of the structure of the temperature sensitive element of the present invention;

[0044] Figure 4 It is a structural schematic diagram of the signal processing circuit board of the present invention;

[0045] Figure 5 is a schematic diagram of a signal processing circuit board of the present invention;

[0046] Figure 6 It is a structural schematic diagram of the digital signal transmission cable of the present invention;

[0047] Figure 7 It is a structural schematic diagram of the present invention connected with marine instruments and equipment.

[0048] Among them, 1 temperature sensor probe, 2 temperature sensitive element, 3 mounting part, 4 signal processing circuit board, 5 signal processing circuit board compartment, 6 digital signal transmission cable, 7 potting glue, 8 thermal conductive medium, 9 thread, 10 O-ring, 11 O-ring groove, 12 temperature sensitive resistor, 131 thin shielding protective cover, 132 thick shielding protective cover, 14 metal guide wire, 15 sensor end interface, 16 signal transmission cable body, 17 device end interface, 18 device circuit main board, 19 highly integrated temperature sensor. DETAILED DESCRIPTION

[0049] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0050] Embodiment 1:

[0051] A highly integrated temperature sensor for deep sea applications, such as Figure 1-7 shown.

[0052] The entire sensor is generally divided into four parts: a temperature sensor housing, a temperature sensitive element 2 , a signal processing circuit board 4 , and a digital signal transmission cable 6 .

[0053] The temperature sensor housing includes a temperature sensor probe 1, a hexagonal mounting structure 3, and a signal processing circuit board compartment 5. The hexagonal mounting structure 3 is disposed between the temperature sensor probe 1 and the signal processing circuit board compartment 5. One side of the hexagonal mounting structure 3 is a sensor support surface. The outer surface of the signal processing circuit board compartment 5 is provided with a plurality of turns of fixed threads 9, and adopts a watertight connector commonly used in marine instruments. The outer surface of the connection between the signal processing circuit board compartment 5 and the hexagonal mounting structure 3 is also provided with an O-ring groove 11 for accommodating an O-ring 10.

[0054] The temperature sensitive element 2 is composed of a temperature sensitive resistor 12, a metal wire 14, and an insulating sheath. There are two metal wires 14, one of which is now equipped with a thinner shielding protective sheath 131, and then the two metal wires are combined, and a thicker shielding protective sheath 132 is installed on the outside as a whole. The shielding protective sheath extends from one end of the temperature sensitive resistor 12 to the root of the metal wire, and a part of the other end is left.

[0055] The digital signal processing circuit board 4 includes an analog signal processing part, a digital signal processing part, a logic function processing part, a temperature sensitive element interface, and a digital communication interface.

[0056] Compared with the original independent circuit, the miniaturized circuit system adopts highly integrated microchips, high-density wiring methods, multi-layer circuit board design, and double-sided surface mount. At the same time, a proprietary bootloader is established inside the processor, so that the program burning and updating use the working interface instead of occupying a separate connector, reducing space occupancy. Finally, the volume of the entire temperature signal processing circuit is reduced to 6mm*22mm*3mm (W*L*H), which can be embedded in a very small space.

[0057] The circuit system is generally divided into a digital part and an analog part, and the two are electrically isolated to ensure the accuracy of signal acquisition. The digital part includes the MCU processor, which is responsible for information processing, mathematical calculations, task management, etc. The digital interface circuit converts the information of the processor into common RS232, RS485 or TTL level protocols, and communicates with the outside through communication cables. The digital power supply part is responsible for providing energy to different digital modules. The analog part includes a signal conditioning circuit, which is directly connected to the temperature sensitive element, drives and obtains the weak signal of the temperature sensitive element, and optimizes and conditions it. The AD analog-to-digital conversion module receives the conditioned analog signal and converts it into a digital signal for transmission to the MCU processor. The analog power management provides energy to different modules of the analog part, ensures the stability of voltage and current, and reduces noise introduction.

[0058] The digital signal transmission cable is composed of a sensor end interface 15, a cable body 16, and a device end interface 17, wherein the cable body contains four wires.

[0059] The temperature sensitive resistor 12 of the temperature sensitive element is located at the inner top of the sensor probe 1, and two metal wires 14 are connected to the temperature sensitive element interface part of the signal processing circuit board 4. The space where the temperature sensitive resistor is located is filled with a curable heat-conducting medium 8. The upper half of the space where the metal wires 14 are located is filled with a curable heat-conducting medium, and the lower half is filled with a hard potting glue. The signal processing circuit board is located inside the circuit board compartment of the sensor housing, and a part of the transmission cable extends into the circuit board compartment and is connected to the digital communication interface part of the signal processing circuit board. The entire internal space of the circuit board compartment is filled with a hard potting glue 7.

[0060] The threaded part of the sensor housing adopts the watertight connector form commonly used in marine instruments. As long as the marine instrument equipment has a standard watertight connector position, the temperature sensor can be directly integrated and used.

[0061] The various parts of the temperature sensor are integrated into a whole, rather than separate parts. When in use, the entire temperature sensor 19 is directly installed in the mounting hole reserved in the instrument and tightened to ensure the watertightness of the equipment. Inside the instrument, the transmission cable 6 of the temperature sensor 19 can be directly connected to the instrument main body circuit board 18 without the need for other matching circuit structures. At the same time, the power signal and digital signal transmitted in the transmission cable 6 have strong anti-interference performance, the length of the transmission cable is greatly increased, and it can cross areas with complex electrical environments.

[0062] Embodiment 2:

[0063] A production and packaging process for a highly integrated temperature sensor for deep-sea applications comprises the following steps:

[0064] 1) Perform an appearance inspection on the processed temperature sensor housing to prevent material defects or processing errors;

[0065] 2) Place the temperature sensor housing in an ultrasonic cleaning box and add an oil cleaning agent to perform ultrasonic cleaning on the temperature sensor housing for half an hour. After cleaning it with clean water, place it in an oven for drying.

[0066] 3) Connect the digital communication interface of the sensor end of the communication cable to the signal processing circuit board, and solder the four signal wires in the cable to the relevant solder joints of the circuit board;

[0067] 4) Cut the metal wire of the temperature sensitive component to an appropriate length so that after welding, when the signal processing circuit board is placed in the circuit board compartment, the temperature sensitive resistor is just on top of the temperature probe;

[0068] 5) Install a shielding sheath on the outside of the metal wire of the temperature sensitive element. The shielding sheath is installed by first putting a thinner sheath on one of the wires, then putting the two wires together, and planting a thicker sheath on the outside of the whole. The sheath needs to extend to the root of the temperature sensitive resistor, leaving only a small section at the other end;

[0069] 6) Solder the two metal wires exposed from the processed temperature sensitive element to the signal processing circuit board to ensure that the temperature sensitive element is in a straight state;

[0070] 7) Prepare the heat-conducting medium in the container, put it into the vacuum tank and evacuate it for half an hour, and finally take the heat-conducting medium out of the vacuum tank;

[0071] 8) Use a needle to absorb the processed thermal conductive medium and push it to the temperature sensor probe part;

[0072] 9) Carefully place the signal processing circuit board with the temperature sensitive component into the circuit board compartment, and allow the sensitive resistor of the temperature sensitive component to enter the top of the temperature probe and be completely immersed in the heat conductive medium;

[0073] 10) Place it in an upside-down position and store it for 24 hours to wait for the performance of the heat transfer medium to stabilize;

[0074] 11) Prepare the potting glue in another container, put it into a vacuum tank and evacuate it for half an hour, and finally take the potting glue out of the vacuum tube;

[0075] 12) Use a needle to absorb the potting glue and push it into the circuit board compartment of the temperature sensor housing. Control the flow of the potting glue to completely soak the circuit board and part of the communication cable;

[0076] 13) Place it in a suitable position and store it for 24 hours, waiting for the potting glue to completely solidify;

[0077] 14) The entire temperature sensor is now assembled.

[0078] The purpose of cleaning the entire sensor housing is to remove metal debris, cutting fluid, etc. that remain during the processing. These substances may block the probe part, damage the temperature sensitive components, affect the flow of thermal conductive media and potting glue, and hinder the adhesion of potting glue to the metal housing.

[0079] The function of the shielding sheath is to prevent the metal wires of the two temperature sensitive elements from being connected to each other, to prevent the metal wires from being connected to the metal casing of the sensor, and to merge the two metal wires into one.

[0080] Filling the temperature sensor probe with a heat-conducting medium is to increase the heat conduction rate of the sensor probe, so that the outside temperature enters the thermistor part of the temperature sensitive element more quickly, shorten the time constant of the entire sensor, and improve the response rate of the sensor.

[0081] Filling the temperature sensor circuit board compartment with potting glue is to stabilize the various components inside the sensor and prevent them from moving during use; it also seals the heat-conducting medium in the probe part to prevent it from flowing; it also seals the electrical part of the entire temperature sensor, allowing the entire sensor to be immersed in a constant temperature water tank for experiments, preventing liquid from entering the circuit board and damaging the circuit.

[0082] Before filling the thermal conductive medium and potting glue, the vacuum operation is performed to precipitate the gas in the sensor, ensuring that the thermal conductive medium and potting glue are pushed into the sensor without bubbles and with uniform texture. When the pressure of the liquid decreases, the volume of the dissolved gas will precipitate, expand, rise to the surface and rupture.

[0083] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A production and packaging process for a highly integrated temperature sensor for deep-sea applications, wherein the sensor comprises a temperature sensor housing, a temperature sensitive element, a signal processing circuit board, and a digital signal transmission cable, wherein the temperature sensitive element and the signal processing circuit board are packaged in the temperature sensor housing, and the digital signal transmission cable connects the signal processing circuit board with the device circuit board; the temperature sensor housing comprises a signal processing circuit board compartment, a mounting portion, and a temperature sensor probe, wherein the mounting portion is disposed between the signal processing circuit board compartment and the temperature sensitive element accommodating cavity, the signal processing circuit board compartment is filled with potting glue, the upper half of the interior of the temperature sensor probe is filled with a curable heat-conducting medium, and the lower half is filled with potting glue, characterized in that: The following steps are involved: 1) Perform an appearance inspection on the processed temperature sensor housing to prevent material defects or processing errors; 2) Clean the temperature sensor housing with ultrasonic cleaning, then rinse it with clean water and put it in an oven to dry; 3) Connect the digital communication interface of the digital signal transmission cable to the signal processing circuit board, and solder the four signal wires in the cable to the relevant solder joints of the circuit board; 4) Cut the metal wire of the temperature sensitive component to an appropriate length so that after welding, when the signal processing circuit board is placed in the circuit board compartment, the temperature sensitive resistor is just on top of the temperature probe; 5) Install a shielding protective cover on the outside of the metal wire of the temperature sensitive component; 6) Weld the two metal guide wires in the processed temperature sensitive element to the signal processing circuit board to ensure that the temperature sensitive element is in a straight state; 7) Use a needle to absorb the heat-conducting medium and push it to the temperature sensor probe part; 8) Place the signal processing circuit board with the temperature sensitive component into the circuit board compartment, and at the same time make the temperature sensitive resistor enter the top of the temperature sensor probe and be completely immersed in the heat conductive medium; 9) Store in an upside-down position for at least 24 hours until the performance of the thermal conductive medium is stable; 10) Use a needle to absorb the potting glue and push it into the signal processing circuit board compartment, and control the flow of the potting glue to completely soak the circuit board and part of the communication cable; 11) Leave and store for at least 24 hours until the potting glue is completely cured.

2. The production and packaging process of a highly integrated temperature sensor for deep-sea applications according to claim 1, characterized in that: The encapsulation method of step 5) is to first encapsulate a thinner shielding protective cover on one of the wires, then put the two wires together, and encapsulate a thicker shielding protective cover on the outside as a whole. The shielding protective cover needs to extend to the root of the temperature sensitive resistor.

3. The production and packaging process of a highly integrated temperature sensor for deep-sea applications according to claim 1, characterized in that: The heat-conducting medium in step 7) is pre-vacuumed.

4. The production and packaging process of a highly integrated temperature sensor for deep-sea applications according to claim 1, characterized in that: The potting glue in step 10) is pre-vacuumed.

5. The production and packaging process of a highly integrated temperature sensor for deep-sea applications according to any one of claims 1 to 4, characterized in that: The outer surface of the signal processing circuit board compartment is provided with threads, and the threads are in the form of watertight connectors.

6. A production and packaging process for a highly integrated temperature sensor for deep-sea applications according to any one of claims 1 to 4, characterized in that: The mounting portion is hexagonal.

7. A production and packaging process for a highly integrated temperature sensor for deep-sea applications according to any one of claims 1 to 4, characterized in that: An O-ring groove for placing an O-ring is also provided on the outer surface of the connection between the signal processing circuit board compartment and the mounting portion.

8. The production and packaging process of a highly integrated temperature sensor for deep-sea applications according to any one of claims 1 to 4, characterized in that: The temperature sensitive element is composed of a temperature sensitive resistor and two metal guide wires. A shielding protective sleeve is arranged outside the metal guide wire. The temperature sensitive resistor is arranged at the top of the temperature sensor probe.

9. A production and packaging process for a highly integrated temperature sensor for deep-sea applications according to any one of claims 1 to 4, characterized in that: The signal processing circuit board comprises an analog signal processing part, a digital signal processing part, a logic function processing part, a temperature sensitive element interface, and a digital communication interface.

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