Temperature and pressure sensing module and preparation method thereof

Abstract

The invention discloses a temperature and pressure sensing module and a preparation method thereof. The sensing module comprises a temperature sensing antenna, a pressure sensing antenna, a resonant antenna and a substrate, the temperature sensing module and the pressure sensing module serve as sensing terminals, the resonance module serves as a wireless transmitting and receiving terminal, and the temperature sensing module, the pressure sensing module and the resonance module are embedded in different layers in the substrate respectively; a temperature sensitive electrode is arranged in the temperature sensing module, and the environment temperature variation is reflected through the capacitance variation of the temperature sensitive electrode; a pressure sensitive electrode is arranged in the pressure sensing module, and the pressure variable quantity is reflected through the capacitance variable quantity of the pressure sensitive electrode; the temperature sensitive electrode, the pressure sensitive electrode and the resonance module are all connected with the control module, and the resonance module supplies power to the control module and sends out temperature and pressure data transmitted from the control module in an electromagnetic resonance mode. The invention has the characteristics of high sensitivity and strong resonant frequency sensing capability.

Description

Technical Field

[0001] The present invention relates to the technical field of passive wireless sensors, and in particular to a temperature and pressure sensing module and a preparation method thereof. Background Art

[0002] With the rapid development of information technology and the increasing requirements and standards for monitoring environments in various fields, the development of multi-parameter integrated measurement, high sensitivity, and high reliability has become an inevitable trend in the development of passive wireless sensors. Currently, passive wireless sensor technology has experienced rapid development in aerospace engine systems, power systems, micro-medical sensors, pipeline monitoring, and other fields. Passive wireless sensors based on SAW (surface acoustic wave), MA (magnetoacoustic), and LC (inductance-capacitance) principles have been developed. However, these sensors all have disadvantages such as high cost, large size, and poor accuracy. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the deficiencies of the existing technology and provide a temperature and pressure sensing module with a compact structure, high sensitivity and strong resonant frequency sensing capability, and a preparation method thereof.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: A temperature and pressure sensing module, comprising: a temperature sensing module, a pressure sensing module, a resonance module, a substrate and a control module; The temperature sensing module and the pressure sensing module both serve as sensing terminals, the resonant module serves as a wireless sending and receiving terminal, and the substrate serves as a carrier. The temperature sensing module, the pressure sensing module, and the resonant module are respectively embedded on different layers inside the substrate; the temperature sensing module is provided with a temperature-sensitive electrode, and the change in the capacitance value of the temperature-sensitive electrode is used to reflect the change in ambient temperature; the pressure sensing module is provided with a pressure-sensitive electrode, and the change in the capacitance value of the pressure-sensitive electrode is used to reflect the change in pressure; the temperature-sensitive electrode, the pressure-sensitive electrode, and the resonant module are all connected to the control module; the resonant module converts wireless microwave signals into electrical energy through electromagnetic resonance coupling, supplies power to the control module, and sends the temperature and pressure data transmitted from the control module out in an electromagnetic resonance manner.

[0005] As a further improvement of the present invention, the temperature sensitive electrodes adopt a planar interdigitated layout, and the two rows of electrode plates of the temperature sensitive electrodes are arranged crosswise in a comb-teeth shape.

[0006] As a further improvement of the present invention, the aspect ratio of the electrode plate is 10:1.

[0007] As a further improvement of the present invention, the pressure sensitive electrode adopts an upper and lower stacked cavity layout, including a planar spiral inductor and a cavity capacitor.

[0008] As a further improvement of the present invention, the pressure sensitive electrode includes a resonant electrode and a reference electrode stacked up and down, and a cavity capacitor is formed between the resonant electrode and the reference electrode.

[0009] As a further improvement of the present invention, the resonant electrode and the reference electrode both adopt a disk structure.

[0010] As a further improvement of the present invention, the resonance module adopts a planar spiral design, and the temperature sensing module and the pressure sensing module are accommodated in the internal space of the resonance module.

[0011] As a further improvement of the present invention, ceramic sheaths are sintered on the peripheries of the temperature sensing module and the pressure sensing module. As a general technical concept, the present invention also provides a method for preparing the temperature and pressure sensing module, comprising the following steps: Step S1: Clean the surface of the substrate produced by the tape casting process, and dry and pre-cure it; Step S2: using a printing and stamping device to open grooves for accommodating silver paste on the surface of the substrate according to the design patterns of the temperature sensing module, the pressure sensing module, and the resonance module; Step S3: using a punching device to open positioning holes, cavity holes, via holes and blind holes on the substrate; Step S4: using a 3D printing device to adopt a laser melting and sintering process to sinter a layer of ceramic sheath around the positioning hole, cavity hole, via hole and the substrate; Step S5: Clean the grooved substrate surface and fill the grooves on the substrate surface with electronic paste using a screen printing device; Step S6: The substrate printed with the electronic paste and the substrate used for isolation are stacked together in the designed number of layers and order, and are evenly hot-pressed using a laminator. They are then transferred to a sintering furnace for co-firing to obtain a temperature and pressure sensing module.

[0012] As a further improvement of the present invention, in step S6, the temperature of the isostatic hot pressing is 120±5° C. and the pressure is 30±1 MPa.

[0013] Compared with the prior art, the advantages of the present invention are: 1. In the temperature and pressure sensing module of the present invention, both the temperature-sensitive electrode and the pressure-sensitive electrode adopt a circular spiral design with a high aspect ratio, which can improve the resonant frequency sensing capability and reduce the parasitic capacitance of the electrodes during operation. In a limited area, it can greatly improve the detection sensitivity and accuracy of ambient temperature and pressure data.

[0014] 2. The present invention's method for preparing a temperature and pressure sensing module uses a 0.16mm thick ultra-thin green ceramic substrate and a large-scale flat spiral design to house the temperature and pressure sensing modules within the internal space. Through specialized processes such as laser grooving, 3D curing, and stacked co-firing, the resulting thin temperature and pressure sensing module is achieved. Compared to a design that uses a 0.5mm thick green ceramic sheet stacked with smaller sensing modules, the present invention reduces the volume of the temperature and pressure sensing module by 68%.

[0015] 3. Compared with the traditional LTCC process route, the temperature and pressure sensing module preparation method of the present invention specifically adds pre-drying and curing and 3D melt sintering process flows. When using an ultra-thin substrate as a substrate for lamination and sintering, it greatly reduces the occurrence of process defects such as delamination, collapse, and edge chipping, thereby improving production efficiency and product yield, thereby reducing production costs and shortening the production cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the planar layout of the temperature and pressure sensing module in a specific embodiment of the present invention; Figure 2 This is a schematic diagram of the cross-sectional structure principle of the temperature and pressure sensing module in a specific embodiment of the present invention; Figure 3 Schematic diagram of the structural principle of the temperature sensing module in a specific embodiment of the present invention; wherein, Figure (a) is a schematic diagram of the planar layout, and Figure (b) is a schematic diagram of the cross-sectional structural principle; Figure 4 Schematic diagram of the structural principle of the pressure sensing module in a specific embodiment of the present invention; wherein, Figure (a) is a schematic diagram of the planar layout, and Figure (b) is a schematic diagram of the cross-sectional structural principle; Figure 5 Schematic diagram of the preparation process of the harmonic temperature and pressure sensing module in a specific embodiment of the present invention; Legend: 1. Temperature sensing module; 2. Pressure sensing module; 3. Resonance module; 4. Substrate; 5. Temperature and pressure sensing module; 6. Temperature sensitive electrode; 7. Pressure sensitive electrode; 71. Resonance electrode; 72. Reference electrode; 8. Punching equipment; 9. Ceramic sheath; 10. Electronic paste; 11. Printing equipment; 12. Laminator; 13. 3D printing equipment; 14. Control module; 15. Sintering furnace. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby.

[0018] In the description of the present invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0019] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0020] Example like Figure 1 and Figure 2 As shown, the temperature and pressure sensing module of the present invention includes: a temperature sensing module 1, a pressure sensing module 2, a resonant module 3, a substrate 4, and a control module 14. The temperature sensing module 1 and the pressure sensing module 2 both serve as sensing terminals, the resonant module 3 serves as a wireless transmitting and receiving terminal, and the substrate 4 serves as a carrier. The temperature sensing module 1, the pressure sensing module 2, and the resonant module 3 are each embedded on different layers within the substrate 4 through a printing and sintering process. A ceramic sheath 9 is sintered around the periphery of each temperature sensing module 1 and the pressure sensing module 2. The temperature sensing module 1 is provided with a temperature-sensitive electrode 6, and changes in the capacitance of the temperature-sensitive electrode 6 reflect changes in ambient temperature. The pressure sensing module 2 is provided with a pressure-sensitive electrode 7, and changes in the capacitance of the pressure-sensitive electrode 7 reflect changes in pressure. Furthermore, the temperature-sensitive electrode 6, the pressure-sensitive electrode 7, and the resonant module 13 are all connected to the control module 14. The resonant module 13 converts wireless microwave signals into electrical energy through electromagnetic resonant coupling, which powers the control module 14. At the same time, the resonance module 13 also transmits the temperature and pressure data transmitted from the control module 14 in a manner of electromagnetic resonance.

[0021] In this embodiment, the substrate 4 serves as a carrier for the temperature sensing module 1, the pressure sensing module 2 and the resonance module 3, and is used to support and protect the temperature sensitive electrode 6 and the pressure sensitive electrode 7. Through the lamination and sintering process, the temperature and pressure sensing module 5 forms a hard whole to protect it from damage and corrosion from external factors.

[0022] Furthermore, the thickness of the substrate 4 is only 0.16 mm. After sintering at about 900°C, the surface hardness of the substrate 4 can reach 634HV. It has high corrosion resistance and structural strength, and can well protect the temperature sensing module 1, pressure sensing module 2 and resonance module 3 inside it.

[0023] like Figure 3 As shown, the temperature-sensitive electrode 6 adopts a planar interdigitated layout, with the two inner rows of electrode plates arranged in a comb-like cross pattern, and the outer rows of electrodes arranged in a spiral pattern. Furthermore, the aspect ratio of the two inner rows of electrode plates is 10:1, achieving high sensitivity and detection accuracy.

[0024] like Figure 4 As shown, the pressure sensitive electrode 7 adopts a large-sized cavity layout with upper and lower layers, and obtains higher sensitivity and detection accuracy through a combination design of a high aspect ratio planar spiral inductor and a large-sized cavity capacitor.

[0025] Furthermore, the pressure-sensitive electrode 7 includes a resonant electrode 71 and a reference electrode 72 stacked one above the other. Both the resonant electrode 71 and the reference electrode 72 have a disc structure. A cavity capacitor is formed between the resonant electrode 71 and the reference electrode 72. Furthermore, a relatively hard ceramic sheath 9 is sintered between the resonant electrode 71 and the reference electrode 72.

[0026] In this embodiment, the resonant module 3 adopts a large-size planar spiral design, accommodating the temperature sensing module 1 and the pressure sensing module 2 in the internal space. While achieving a longer data transmission distance and receiving higher wireless power supply energy, it also has better electromagnetic anti-interference ability.

[0027] like Figure 5 As shown, in this embodiment, a temperature and pressure sensing module applicable to the above-mentioned temperature and pressure sensing module and a preparation method thereof are also provided, comprising the following steps: Step S1: clean the surface of the substrate 4 produced by the tape casting process, and dry and pre-cure it at a temperature of 60°C.

[0028] Step S2 : using a printing and stamping device 11 to open grooves for accommodating silver paste on the surface of the substrate 4 according to the design patterns of the temperature sensing module 1 , the pressure sensing module 2 and the resonance module 3 .

[0029] Step S3: using a punching device 8 to punch positioning holes, cavity holes, via holes and blind holes at appropriate locations on the substrate 4 .

[0030] Step S4: A layer of ceramic sheath 9 is sintered around the positioning holes, cavity holes, via holes and substrate 4 using a laser melting sintering process through a 3D printing device 13 to solidify the hole shape and shape for subsequent positioning and stacking of multiple layers of substrates 4.

[0031] Step S5: Clean the surface of the grooved substrate 4 and fill the grooves on the surface of the substrate 4 with electronic paste 10 using a screen printing device.

[0032] Step S6: The substrate 4 printed with the electronic paste 10 and the substrate 4 used for isolation are stacked together in sequence according to the designed number of layers and order, and are evenly hot-pressed using a laminator 12 at a temperature of 120°C and a pressure of 30 MPa. They are then transferred to a sintering furnace 15 for co-firing to obtain a temperature and pressure sensing module 5 with high protection capabilities.

[0033] In this embodiment, a 0.16mm-thick ultra-thin green ceramic substrate 4 is used, and a large-scale flat spiral design is employed to house the temperature sensing module 1 and the pressure sensing module 2 within the internal space. Furthermore, through specialized processes such as laser grooving, 3D curing, and stacking and co-firing, the resulting thin temperature and pressure sensing module 5 is achieved. Compared to a design that utilizes a 0.5mm-thick green ceramic sheet stacked with smaller sensing modules, the volume of this temperature and pressure sensing module 5 is reduced by 68%.

[0034] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A temperature and pressure sensing module, characterized in that: include: A temperature sensing module (1), a pressure sensing module (2), a resonance module (3), a substrate (4), and a control module (14); The temperature sensing module (1) and the pressure sensing module (2) are both used as sensing terminals, the resonant module (3) is used as a wireless transmitting and receiving terminal, and the substrate (4) is used as a carrier. The temperature sensing module (1), the pressure sensing module (2) and the resonant module (3) are respectively embedded on different layers inside the substrate (4); the temperature sensing module (1) is provided with a temperature sensitive electrode (6), and the change in the capacitance value of the temperature sensitive electrode (6) is used to reflect the change in the ambient temperature; the pressure sensing module (2) is provided with a pressure sensitive electrode (7), and the change in the capacitance value of the pressure sensitive electrode (7) is used to reflect the change in the pressure; the temperature sensitive electrode (6), the pressure sensitive electrode (7) and the resonant module (3) are all connected to the control module (14); the resonant module (3) converts the wireless microwave signal into electrical energy through electromagnetic resonance coupling, supplies power to the control module (14), and sends the temperature and pressure data transmitted from the control module (14) out in the form of electromagnetic resonance.

2. The temperature and pressure sensing module according to claim 1, characterized in that: The temperature sensitive electrodes (6) adopt a planar interdigitated layout, and the two rows of electrode plates of the temperature sensitive electrodes (6) are arranged crosswise in a comb-teeth shape.

3. The temperature and pressure sensing module according to claim 2, characterized in that: The aspect ratio of the electrode plate is 10:

1.

4. The temperature and pressure sensing module according to claim 1, characterized in that: The pressure sensitive electrode (7) adopts an upper and lower stacked cavity layout and includes a planar spiral inductor and a cavity capacitor.

5. The temperature and pressure sensing module according to claim 4, characterized in that: The pressure-sensitive electrode (7) comprises a resonant electrode (71) and a reference electrode (72) stacked up and down, and a cavity capacitor is formed between the resonant electrode (71) and the reference electrode (72).

6. The temperature and pressure sensing module according to claim 5, characterized in that: The resonant electrode (71) and the reference electrode (72) both adopt a disk structure.

7. The temperature and pressure sensing module according to any one of claims 1 to 6, characterized in that: The resonant module (3) adopts a planar spiral design, and the temperature sensing module (1) and the pressure sensing module (2) are accommodated in the internal space of the resonant module (3).

8. The temperature and pressure sensing module according to any one of claims 1 to 6, characterized in that: The outer peripheries of the temperature sensing module (1) and the pressure sensing module (2) are both sintered with ceramic sheaths (9).

9. A temperature and pressure sensing module applicable to any one of claims 1 to 8 and a method for preparing the same, characterized in that: The following steps are involved: Step S1: cleaning the surface of the substrate (4) produced by the tape casting process, and drying and pre-curing the substrate; Step S2: using a printing and pressing device (11) to open a groove for accommodating silver paste on the surface of the substrate (4) according to the design patterns of the temperature sensing module (1), the pressure sensing module (2) and the resonance module (3); Step S3: using a punching device (8) to open positioning holes, cavity holes, via holes and blind holes on the substrate (4); Step S4: using a 3D printing device (13) to sinter a layer of ceramic sheath (9) around the positioning hole, cavity hole, via hole and substrate (4) using a laser melting sintering process; Step S5: cleaning the surface of the grooved substrate (4), and filling the grooves on the surface of the substrate (4) with electronic paste (10) using a screen printing device; Step S6: The substrate (4) printed with the electronic paste (10) and the substrate (4) for isolation are stacked together in sequence according to the designed number of layers and order, and are subjected to balanced hot pressing using a laminator (12), and then transferred to a sintering furnace (15) for co-firing to obtain a temperature and pressure sensing module (5).

10. The preparation method according to claim 9, characterized in that In step S6, the temperature of the isostatic hot pressing is 120±5° C., and the pressure is 30±1 MPa.

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