Pressure sensor and method of manufacturing the same

Abstract

The application provides a pressure sensor and a preparation method thereof, and comprises the following steps: providing a curved substrate and preparing a laser direct structuring material ink; forming the laser direct structuring material ink on the surface of the curved substrate by spraying, coating or film coating and solidifying to form a first laser direct structuring material layer; forming a first activation area on the first laser direct structuring material layer by using a laser; forming a first electrode layer in the first activation area; forming the laser direct structuring material ink on the surface of the first electrode layer by spraying, coating or film coating and solidifying to form a second laser direct structuring material layer; forming a via hole on the second laser direct structuring material layer; forming a second activation area on the second laser direct structuring material layer by using a laser; forming a second electrode layer in the second activation area; and forming a sensing layer on the surface of the second electrode layer to obtain the pressure sensor.

Description

Technical Field

[0001] This application relates to the field of pressure sensor technology, specifically to a pressure sensor and its fabrication method. Background Technology

[0002] Pressure sensors, as core components that convert pressure signals into measurable electrical signals, are fundamental to cutting-edge applications such as robotic tactile interaction, smart home control, and medical health monitoring. With technological advancements and the continuous deepening of application scenarios, pressure sensors have been widely used in various fields including robotics, smart homes, and medical equipment.

[0003] A typical pressure sensor generally consists of a substrate, connecting lines, electrodes, and sensing materials. Among these, the high-precision fabrication of electrodes and connecting lines on the substrate surface is a key technological step in realizing the sensor's sensing function. Currently, the industry mainly uses traditional processes such as screen printing, inkjet printing, or attaching prefabricated flexible circuit boards to complete this step. However, facing increasingly complex curved surface structures (such as robotic fingers, bionic skin, and wearable device bonding surfaces) and the demand for high-density circuit integration, these existing methods exhibit significant technical limitations. Screen printing struggles to guarantee pattern consistency and resolution on complex curved surfaces; inkjet printing faces challenges in positioning accuracy and adhesion uniformity on curved surfaces; and flexible circuit boards are prone to incomplete conformal attachment when bonded to complex three-dimensional curved surfaces, affecting the reliability of circuit connections. These technical bottlenecks make it difficult to achieve high-density, high-precision circuit distribution on curved surfaces, thus restricting performance improvements in accuracy, spatial resolution, and long-term reliability of curved surface pressure measurement, limiting the development and application of next-generation high-performance curved surface sensing technologies.

[0004] Therefore, developing a novel fabrication process that adapts to complex curved surfaces and enables high-precision, high-density circuit integration has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a pressure sensor and its fabrication method. By locally coating functional materials onto a complex curved substrate, high-precision circuits are formed through laser activation and metallization, and three-dimensional wiring is achieved using a multi-layer stacked structure. This approach overcomes the limitations of specialized materials and molds, significantly improving the accuracy, reliability, and integration density of the curved circuit. Ultimately, the sensor combines the advantages of high spatial resolution sensing, miniaturization, and low cost, broadening its application prospects in flexible electronics and wearable devices.

[0006] To achieve the above objectives, in one aspect, the present invention provides a method for manufacturing a pressure sensor, the method comprising:

[0007] Provide curved substrates and prepare laser direct forming material inks;

[0008] The laser direct forming material ink is formed on the surface of the curved substrate by spraying, coating or film coating and then cured to form a first laser direct forming material layer;

[0009] A first activation region is formed on the first laser-directly formed material layer using a laser.

[0010] A first electrode layer is formed in the first activated region;

[0011] The laser direct forming material ink is formed on the surface of the first electrode layer and cured by spraying, coating or film coating to form a second laser direct forming material layer;

[0012] A via is formed on the second laser direct forming material layer;

[0013] A second activation region is formed on the second laser-directly formed material layer using a laser.

[0014] A second electrode layer is formed in the second activation region;

[0015] A sensing layer is formed on the surface of the second electrode layer to obtain a pressure sensor.

[0016] Optionally, the laser direct forming material ink includes a matrix material, a laser activator, and additives. The matrix material includes at least one of polyetheretherketone, polyphenylene ether, and polyurethane. The laser activator includes copper chromite or copper hydroxyphosphate. The additives include at least one of surfactants, defoamers, roughening agents, antioxidants, dispersants, and leveling agents.

[0017] Optionally, the mass ratio of the matrix material, the laser activator, and the additive is 5:2:3.

[0018] Optionally, the step of forming the laser direct forming material ink on the surface of the curved substrate and curing it by spraying, coating, or film coating to form a first laser direct forming material layer includes:

[0019] The laser direct forming material ink is sprayed onto the surface of the curved substrate at a spraying pressure of 0.25-0.4 MPa, a spraying flow rate of 80-150 mL / min, and a spraying distance of 18-25 cm to obtain the first part.

[0020] The first sample was placed in an oven at 65-75°C for thermosetting for 90-110 minutes to form the first laser-directly formed material layer; and / or,

[0021] The method of forming the laser direct forming material ink on the surface of the first electrode layer and curing it to form the second laser direct forming material layer by means of spraying, coating, or film coating includes:

[0022] The laser direct forming material ink is sprayed onto the surface of the first electrode at a spraying pressure of 0.25-0.4 MPa, a spraying flow rate of 80-150 mL / min, and a spraying distance of 18-25 cm to obtain a second sample.

[0023] The second sample was placed in an oven at 65-75°C for 90-110 minutes to thermally cure it, thereby forming the second laser direct forming material layer.

[0024] Optionally, before forming the laser direct forming material ink on the surface of the curved substrate and curing it by spraying, coating, or laminating to form the first laser direct forming material layer, the method further includes:

[0025] The surface of the substrate is roughened and then cleaned.

[0026] Optionally, forming the first electrode layer in the first activated region includes:

[0027] A copper film, a nickel film, and a gold film are sequentially stacked in the first activation area by electroplating or chemical plating to form a first electrode layer; wherein the thickness of the copper film is 13-15 μm, the thickness of the nickel film is 3-5 μm, and the thickness of the gold film is 5-9 μm.

[0028] Optionally, forming a second electrode layer in the second activation region includes:

[0029] A copper layer, a nickel layer, and a gold layer are sequentially stacked in the second activation region by electroplating or chemical plating to form a second electrode layer; wherein the thickness of the copper layer is 13-15 μm, the thickness of the nickel layer is 3-5 μm, and the thickness of the gold layer is 5-9 μm.

[0030] Optionally, forming a first activation region on the first laser-directly formed material layer using a laser includes:

[0031] The first laser-directly formed material layer is activated using an infrared laser with parameters of 950-1050 mm / min, 35-45 Hz, and 6-8 W to form the first activated region; and / or,

[0032] The method of forming a second activation region on the second laser-directly formed material layer using a laser includes:

[0033] The second laser-directly formed material layer is activated using an infrared laser with parameters of 950-1050 mm / min, 35-45 Hz, and 6-8 W to form the second activated region.

[0034] Optionally, forming a sensing layer on the surface of the second electrode layer includes:

[0035] The sensing layer is formed by spraying or coating a flexible piezoresistive sensitive material onto the surface of the second electrode layer.

[0036] On the other hand, the present invention also provides a pressure sensor prepared by the above method.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention forms a first laser-directly formed material layer and a second laser-directly formed material layer by spraying, coating, or laminating laser-directly formed material ink and then curing it. This eliminates the need for dedicated injection molding materials and molds for overall laser-directly formed materials, which not only reduces manufacturing costs but also significantly broadens the application scope and material adaptability of laser-directly formed technology in pressure sensors and other flexible electronic devices. Furthermore, it enables highly stable, high-density, and high-precision circuit layouts on curved substrates, thereby improving the accuracy and reliability of pressure sensors in curved surface pressure measurement. Attached Figure Description

[0039] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below. For those skilled in the art, other related drawings can be obtained from the above drawings without any creative effort.

[0040] Figure 1 A schematic flowchart illustrating the fabrication method of a pressure sensor provided in an embodiment of the present invention;

[0041] Figure 2 A cross-sectional view of a pressure sensor provided for an embodiment of the present invention;

[0042] Figure 3 A top view of the first electrode layer provided for an embodiment of the present invention;

[0043] Figure 4 A top view of the second electrode layer provided for an embodiment of the present invention. Detailed Implementation

[0044] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0045] This invention provides a method for manufacturing a pressure sensor, such as... Figure 1 and Figure 2 As shown, the preparation method includes:

[0046] S110, Provide a curved substrate 100 and prepare laser direct forming material ink;

[0047] S210. The laser direct forming material ink is formed on the surface of the curved substrate by spraying, coating or film coating and then cured to form a first laser direct forming material layer 200.

[0048] S310. A first activation region is formed on the first laser direct forming material layer 200 using a laser;

[0049] S410. A first electrode layer 300 is formed in the first activated region;

[0050] S510. The laser direct forming material ink is formed on the surface of the first electrode layer 300 and cured by spraying, coating or film coating to form the second laser direct forming material layer 400.

[0051] S610, Form a via 500 on the second laser direct forming material layer;

[0052] S710. A second activation region is formed on the second laser direct forming material layer 400 using a laser.

[0053] S810, A second electrode layer 600 is formed in the second activation region;

[0054] S910, A sensing layer 700 is formed on the surface of the second electrode layer 600 to obtain a pressure sensor 10.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] This invention forms a first laser-directly formed material layer and a second laser-directly formed material layer by spraying, coating, or laminating laser-directly formed material ink and then curing it. This eliminates the need for dedicated injection molding materials and molds for overall laser-directly formed materials, which not only reduces manufacturing costs but also significantly broadens the application scope and material adaptability of laser-directly formed technology in pressure sensors and other flexible electronic devices. Furthermore, it enables highly stable, high-density, and high-precision circuit layouts on curved substrates, thereby improving the accuracy and reliability of pressure sensors in curved surface pressure measurement.

[0057] The working principle of the pressure sensor provided in this embodiment of the invention is as follows: When external pressure is applied to the sensing layer 700, the contact area between the sensing layer 700 and the second electrode layer 600 increases accordingly, causing the contact resistance to decrease; the resistance change signal is transmitted to the signal acquisition circuit through the first electrode layer 300 and the second electrode layer 600, and after signal conditioning and data processing, it is received and analyzed by the host computer, and finally the pressure magnitude and its spatial distribution are visualized and displayed.

[0058] In some embodiments, the laser direct forming material ink includes a matrix material, a laser activator, and additives. The matrix material includes at least one of polyetheretherketone, polyphenylene ether, and polyurethane. The laser activator includes copper chromite or copper hydroxyphosphate. The additives include at least one of surfactants, defoamers, roughening agents, antioxidants, dispersants, and leveling agents.

[0059] In some embodiments, the mass ratio of the matrix material, the laser activator, and the additive is 5:2:3.

[0060] In some embodiments, before forming the laser direct molding material ink on the surface of the curved substrate 100 and curing it by spraying, coating, or film coating to form the first laser direct molding material layer 200, the method further includes:

[0061] The curved substrate 100 is subjected to surface roughening treatment, and the curved substrate 100 after surface roughening treatment is cleaned.

[0062] In some embodiments, the process of forming the laser direct forming material ink on the surface of the curved substrate 100 and curing it to form a first laser direct forming material layer 200 by spraying, coating, or film coating includes:

[0063] The laser direct forming material ink is sprayed onto the surface of the curved substrate 100 at a spraying pressure of 0.25-0.4 MPa, a spraying flow rate of 80-150 mL / min, and a spraying distance of 18-25 cm to obtain the first sample.

[0064] The first sample was placed in an oven at 65-75°C for 90-110 minutes to form the first laser direct forming material layer 200.

[0065] For example, the spraying pressure can be 0.25 MPa, 0.3 MPa, 0.35 MPa, or 0.4 MPa; the spraying flow rate can be 80 mL / min, 90 mL / min, 100 mL / min, 110 mL / min, 120 mL / min, 130 mL / min, 140 mL / min, or 150 mL / min; and the spraying distance can be 18 cm, 20 cm, 22 cm, or 25 cm.

[0066] In some embodiments, the process of forming the laser direct forming material ink on the surface of the first electrode 300 and curing it to form the second laser direct forming material layer 400 by spraying, coating, or film coating includes:

[0067] The laser direct forming material ink is sprayed onto the surface of the curved substrate 100 at a spraying pressure of 0.25-0.4 MPa, a spraying flow rate of 80-150 mL / min, and a spraying distance of 18-25 cm to obtain a second sample.

[0068] The second sample was placed in an oven at 65-75°C for 90-110 minutes to form the second laser direct forming material layer 400.

[0069] For example, the spraying pressure can be 0.25 MPa, 0.3 MPa, 0.35 MPa, or 0.4 MPa; the spraying flow rate can be 80 mL / min, 90 mL / min, 100 mL / min, 110 mL / min, 120 mL / min, 130 mL / min, 140 mL / min, or 150 mL / min; and the spraying distance can be 18 cm, 20 cm, 22 cm, or 25 cm.

[0070] In this embodiment of the invention, the first electrode layer 300 and / or the second electrode layer 600 may be a multilayer metallization layer, including a copper layer as a conductive layer, a nickel layer as an intermediate transition layer, and a gold layer as a surface protective layer; wherein, the nickel layer is used to enhance the bonding force between the copper layer and the gold layer, and the gold layer is used to improve the corrosion resistance and oxidation resistance of the circuit surface.

[0071] In some embodiments, forming the first electrode layer 300 in the first activated region includes:

[0072] A copper film, a nickel film, and a gold film are sequentially stacked in the first activation region by electroplating or chemical plating to form a first electrode layer 300. The copper film has a thickness of 13-15 μm; in an example, the thickness can be 13 μm, 14 μm, or 15 μm. The nickel film has a thickness of 3-5 μm; in an example, the thickness can be 3 μm, 4 μm, or 5 μm. The gold film has a thickness of 5-9 μm; in an example, the thickness can be 5 μm, 6 μm, 7 μm, 8 μm, or 9 μm.

[0073] In some embodiments, forming the second electrode layer 600 in the second activation region includes:

[0074] A copper layer, a nickel layer, and a gold layer are sequentially stacked in the second activation region by electroplating or chemical plating to form a second electrode layer 600. The copper layer has a thickness of 13-15 μm; in an example, the thickness of the copper layer can be 13 μm, 14 μm, or 15 μm. The nickel layer has a thickness of 3-5 μm; in an example, the thickness of the nickel layer can be 3 μm, 4 μm, or 5 μm. The gold layer has a thickness of 5-9 μm; in an example, the thickness of the gold layer can be 5 μm, 6 μm, 7 μm, 8 μm, or 9 μm.

[0075] In embodiments of the present invention, such as Figure 3 and Figure 4 As shown, the first electrode layer 300 includes multiple parallel and spaced first electrodes 310, and the second electrode layer 600 includes multiple parallel and spaced second electrodes 610 and third electrodes 620. The first electrodes 310 and second electrodes 610 are arranged intersectingly, and the third electrodes 620 are arranged parallel to the first electrodes 310. The third electrodes 620 are electrically connected to the first electrodes 310 through corresponding vias 500 to form a cross-grid distribution structure. This structure effectively optimizes the utilization of wiring space, significantly improves the electrode layout density per unit area, and significantly improves the spatial resolution of pressure detection. Combined with the array-type electrode layout and signal acquisition and processing system, accurate measurement and visualization of pressure magnitude, distribution, and changing trends can be achieved.

[0076] It should be noted that, since the first electrode layer 300 is composed of multiple parallel and spaced first electrodes 310, the second laser direct forming material layer 400 is partially stacked on the first electrode 310 and partially stacked on the second laser direct forming material layer 200.

[0077] In some embodiments, forming a first activation region on the first laser-directly formed material layer 200 using a laser includes:

[0078] The first laser-directly formed material layer 200 is activated using an infrared laser with parameters of 950-1050 mm / min, 35-45 Hz, and 6-8 W to form the first activated region.

[0079] Optionally, the laser device that emits infrared lasers can be either a five-axis or a four-axis device.

[0080] In some embodiments, forming a second activation region on the second laser-directly formed material layer 400 using a laser includes:

[0081] The second laser-directly formed material layer 400 is activated using an infrared laser with parameters of 950-1050 mm / min, 35-45 Hz, and 6-8 W to form the second activated region.

[0082] Optionally, the laser device that emits infrared lasers can be either a five-axis or a four-axis device.

[0083] In some embodiments, an infrared laser is used to form a via 500 in a second laser direct forming material layer 400.

[0084] In some embodiments, forming a sensing layer on the surface of the second electrode layer includes:

[0085] The sensing layer is formed by spraying or coating a flexible piezoresistive sensitive material onto the surface of the second electrode layer.

[0086] Furthermore, embodiments of this application also provide a pressure sensor prepared by the above method.

[0087] The specific embodiments of the present invention have been described above. It should be understood that the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for fabricating a pressure sensor, characterized in that, The method includes: Provide curved substrates and prepare laser direct forming material inks; The laser direct forming material ink is formed on the surface of the curved substrate by spraying, coating or film coating and then cured to form a first laser direct forming material layer; A first activation region is formed on the first laser-directly formed material layer using a laser. A first electrode layer is formed in the first activated region; The laser direct forming material ink is formed on the surface of the first electrode layer and cured by spraying, coating or film coating to form a second laser direct forming material layer; A via is formed on the second laser direct forming material layer; A second activation region is formed on the second laser-directly formed material layer using a laser. A second electrode layer is formed in the second activation region; A sensing layer is formed on the surface of the second electrode layer to obtain a pressure sensor; The laser direct forming material ink comprises a matrix material, a laser activator, and additives. The matrix material comprises at least one of polyetheretherketone, polyphenylene ether, and polyurethane. The laser activator comprises copper chromite or copper hydroxyphosphate. The additives comprise at least one of surfactants, defoamers, roughening agents, antioxidants, dispersants, and leveling agents. The process of forming the laser direct forming material ink on the surface of the curved substrate and curing it to form a first laser direct forming material layer by means of spraying, coating, or film coating includes: The laser direct forming material ink is sprayed onto the surface of the curved substrate at a spraying pressure of 0.25-0.4 MPa, a spraying flow rate of 80-150 mL / min, and a spraying distance of 18-25 cm to obtain the first part. The first sample was placed in an oven at 65-75°C for thermosetting for 90-110 minutes to form the first laser-directly formed material layer; and / or, The method of forming the laser direct forming material ink on the surface of the first electrode layer and curing it to form the second laser direct forming material layer by means of spraying, coating, or film coating includes: The laser direct forming material ink is sprayed onto the surface of the first electrode layer at a spraying pressure of 0.25-0.4 MPa, a spraying flow rate of 80-150 mL / min, and a spraying distance of 18-25 cm to obtain a second sample. The second sample was placed in an oven at 65-75°C for 90-110 minutes to thermally cure it, thereby forming the second laser direct forming material layer.

2. The method according to claim 1, characterized in that, The mass ratio of the matrix material, the laser activator, and the additive is 5:2:

3.

3. The method according to claim 1, characterized in that, Before forming the laser direct forming material ink on the surface of the curved substrate by spraying, coating, or laminating and then curing it to form the first laser direct forming material layer, the method further includes: The surface of the substrate is roughened and then cleaned.

4. The method according to claim 1, characterized in that, The formation of the first electrode layer in the first activated region includes: A copper film, a nickel film, and a gold film are sequentially stacked in the first activation area by electroplating or chemical plating to form a first electrode layer; wherein the thickness of the copper film is 13-15 μm, the thickness of the nickel film is 3-5 μm, and the thickness of the gold film is 5-9 μm.

5. The method according to claim 1, characterized in that, The formation of the second electrode layer in the second activation region includes: A copper layer, a nickel layer, and a gold layer are sequentially stacked in the second activation region by electroplating or chemical plating to form a second electrode layer; wherein the thickness of the copper layer is 13-15 μm, the thickness of the nickel layer is 3-5 μm, and the thickness of the gold layer is 5-9 μm.

6. The method according to claim 1, characterized in that, The method of forming a first activation region on the first laser-directly formed material layer using a laser includes: The first laser-directly formed material layer is activated using an infrared laser with parameters of 950-1050 mm / min, 35-45 Hz, and 6-8 W to form the first activated region; and / or, The method of forming a second activation region on the second laser-directly formed material layer using a laser includes: The second laser-directly formed material layer is activated using an infrared laser with parameters of 950-1050 mm / min, 35-45 Hz, and 6-8 W to form the second activated region.

7. The method according to claim 1, characterized in that, The process of forming a sensing layer on the surface of the second electrode layer includes: The sensing layer is formed by spraying or coating a flexible piezoresistive sensitive material onto the surface of the second electrode layer.

8. A pressure sensor, characterized in that, Prepared by the method described in any one of claims 1-7.

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