Capacitive pressure sensor and preparation method thereof, and pulse detector

Abstract

The present application discloses a capacitive pressure sensor, a method for preparing the same, and a pulse detector. The capacitive pressure sensor comprises a first flexible substrate, a first electrode layer located on the surface of the first flexible substrate, a first dielectric layer located on the surface of the first electrode layer, a second dielectric layer opposite the first dielectric layer, a second electrode layer located on the surface of the second dielectric layer, and a second flexible substrate located on the surface of the second electrode layer; wherein the first electrode layer is a microstructured electrode layer, and the second electrode layer is a printed electrode layer. The technical solution disclosed in the present application provides a flexible capacitive pressure sensor for pulse detection, so that it can be directly attached to the wrist for pulse detection. The first electrode layer is configured as a microstructured electrode layer to ensure the sensitivity and accuracy of the sensor, thereby achieving highly sensitive pulse detection. The sensor has a simple structure, a compact size, low cost, and high detection sensitivity, making it easy to apply and promote on a large scale.

Description

Technical Field

[0001] The present application relates to the field of pulse detection technology, and more specifically, to a capacitive pressure sensor and a preparation method thereof, and a pulse detector. Background Art

[0002] Traditional Chinese Medicine (TCM) uses pulse diagnosis as a primary basis for clinical diagnosis. Doctors can use the speed and strength of the pulse to identify a patient's heart rate and treat conditions like atrial fibrillation. With the rapid development of modern medicine, the equipment used to detect pulse diagnosis in TCM is also rapidly developing.

[0003] Currently, pulse diagnosis equipment primarily consists of large-scale hospital-based devices and home-use pulse diagnostic instruments. Large-scale hospital-based pulse diagnostic instruments are complex and require professional assistance and guidance. While they can acquire relatively accurate pulse signals, they are difficult to use conveniently. Existing home-use pulse diagnostic instruments typically consist of a base, sleeve, and pneumatic / air pressure device, resulting in a relatively complex structure and high cost.

[0004] In summary, how to reduce the structural complexity and cost of pulse detection equipment and achieve high-sensitivity pulse detection is a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a capacitive pressure sensor and its preparation method, and a pulse detector, which are used to reduce the structural complexity and cost of the pulse detection equipment and achieve high-sensitivity pulse detection.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] A capacitive pressure sensor includes a first flexible substrate, a first electrode layer located on a surface of the first flexible substrate, a first dielectric layer located on a surface of the first electrode layer, a second dielectric layer opposite the first dielectric layer, a second electrode layer located on a surface of the second dielectric layer, and a second flexible substrate located on a surface of the second electrode layer; wherein the first electrode layer is a microstructured electrode layer, and the second electrode layer is a printed electrode layer.

[0008] Preferably, the first electrode layer includes a PDMS microstructure layer located on the surface of the first flexible substrate and a conductive layer located on the surface of the PDMS microstructure layer.

[0009] Preferably, the conductive layer includes Ti disposed on the surface of the PDMS microstructure layer and Au disposed on the surface of Ti.

[0010] Preferably, the first electrode layer is a trapezoidal microstructure electrode layer or a pyramid microstructure electrode layer.

[0011] Preferably, the dielectric constants of the first dielectric layer and the second dielectric layer are both greater than a preset value.

[0012] Preferably, the first dielectric layer and the second dielectric layer are both Al2O3 layers.

[0013] Preferably, the first flexible substrate and the second flexible substrate are both PET layers.

[0014] Preferably, the second electrode layer is Ag.

[0015] A pulse detector, comprising:

[0016] A capacitive pressure sensor as described in any one of the above items, adapted to be attached to a wrist;

[0017] The processor connected to the capacitive pressure sensor is used to detect the capacitance signal of the capacitive pressure sensor and obtain the pulse signal according to the capacitance signal.

[0018] A method for preparing a capacitive pressure sensor, for preparing any of the capacitive pressure sensors described above, comprising:

[0019] Disposing a first electrode layer on a surface of a first flexible substrate, and depositing a first dielectric layer on a surface of the first electrode layer;

[0020] providing a second electrode layer on the surface of the second flexible substrate, and depositing a second dielectric layer on the surface of the second electrode layer;

[0021] The first dielectric layer and the second dielectric layer are arranged opposite to each other and packaged to obtain a capacitive pressure sensor;

[0022] Wherein, the first electrode layer is a microstructure electrode layer, and the second electrode layer is a printed electrode layer.

[0023] The present application provides a capacitive pressure sensor and a preparation method thereof, and a pulse detector, wherein the capacitive pressure sensor includes a first flexible substrate, a first electrode layer located on the surface of the first flexible substrate, a first dielectric layer located on the surface of the first electrode layer, a second dielectric layer opposite to the first dielectric layer, a second electrode layer located on the surface of the second dielectric layer, and a second flexible substrate located on the surface of the second electrode layer; wherein the first electrode layer is a microstructured electrode layer, and the second electrode layer is a printed electrode layer.

[0024] The above technical solution disclosed in the present application utilizes a first flexible substrate, a first electrode layer located on the first flexible substrate, a first dielectric layer located on the surface of the first electrode layer, a second dielectric layer opposite to the first dielectric layer, and a second flexible substrate located on the surface of the second dielectric layer to constitute a flexible capacitive pressure sensor for pulse detection, so as to facilitate direct attachment to the wrist for pulse detection, and the first electrode layer is set as a microstructured electrode layer to ensure the sensitivity and accuracy of the capacitive pressure sensor, thereby achieving high-sensitivity pulse detection, and the second electrode layer is set as a printed electrode layer to ensure the flexibility and simplicity of preparation of the capacitive pressure sensor. Among them, after the capacitive pressure sensor provided by the present application is attached to the wrist, the beating of the pulse will cause the spacing between the first electrode layer and the second electrode layer to change, and the dielectric constant of the composite dielectric layer composed of the first dielectric layer, the second dielectric layer and the air between the two will also change, thereby causing the capacitance of the capacitive pressure sensor to change. Therefore, the pulse characteristics can be reflected by the capacitance change rate of the capacitive pressure sensor. From the above, it can be seen that the capacitive pressure sensor for pulse detection provided by this application does not require complex structural design and numerous devices. It has a simple structure, small size, low cost, and high detection sensitivity. Since pulse detection can be performed by simply attaching it to the wrist, it can be used conveniently and is easy to apply and promote on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0026] Figure 1 A schematic structural diagram of a capacitive pressure sensor provided in an embodiment of the present application;

[0027] Figure 2 A schematic structural diagram of a microstructured electrode layer in a capacitive pressure sensor provided in an embodiment of the present application;

[0028] Figure 3 A schematic structural diagram of a printed electrode layer in a capacitive pressure sensor provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of attaching a capacitive pressure sensor to a human wrist to detect pulse according to an embodiment of the present application;

[0030] Figure 5 A characteristic diagram of a periodic pulse detected by a capacitive pressure sensor provided in an embodiment of the present application;

[0031] Figure 6 The capacitive pressure sensor provided in the embodiment of the present application detects a single pulse waveform. DETAILED DESCRIPTION

[0032] The core of this application is to provide a capacitive pressure sensor and its preparation method, and a pulse detector, which are used to reduce the structural complexity and cost of pulse detection equipment and achieve high-sensitivity pulse detection.

[0033] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0034] See also Figures 1-4 ,in, Figure 1 FIG. 1 shows a schematic structural diagram of a capacitive pressure sensor provided in an embodiment of the present application. Figure 2 FIG2 shows a schematic structural diagram of a microstructure electrode layer in a capacitive pressure sensor provided in an embodiment of the present application. Figure 3 FIG. 1 shows a schematic structural diagram of a printed electrode layer in a capacitive pressure sensor provided in an embodiment of the present application. Figure 4 The schematic diagram of the embodiment of the present application showing the capacitive pressure sensor attached to the human wrist to detect pulse is shown, wherein Figure 4 In the figure, 10 represents the capacitive pressure sensor provided by the present application, and 20 represents a human arm. A capacitive pressure sensor provided in an embodiment of the present application may include a first flexible substrate 1, a first electrode layer 2 located on the surface of the first flexible substrate 1, a first dielectric layer 3 located on the surface of the first electrode layer 2, a second dielectric layer 4 opposite to the first dielectric layer 3, a second electrode layer 5 located on the surface of the second dielectric layer 4, and a second flexible substrate 6 located on the surface of the second electrode layer 5; wherein the first electrode layer 2 is a microstructured electrode layer, and the first electrode layer 2 is a printed electrode layer. The present application provides a flexible, conformable capacitive pressure sensor, which can be used to detect pulse signals.

[0035] Specifically, the capacitive pressure sensor includes a first flexible substrate 1, a first electrode layer 2 located on one side surface of the first flexible substrate 1, a first dielectric layer 3 located on the surface of the first electrode layer 2 (the surface of the first electrode layer 2 here specifically refers to the side surface of the first electrode layer 2 facing away from the first flexible substrate 1), a second dielectric layer 4 arranged opposite to the first dielectric layer 3 (the relative arrangement here specifically refers to the second dielectric layer 4 being arranged opposite to the side surface of the first dielectric layer 3 facing away from the first electrode layer 2), a second electrode layer 5 on the surface of the second dielectric layer 4 (the surface of the second dielectric layer 4 here specifically refers to the side surface of the second dielectric layer 4 facing away from the first dielectric layer 3), and a second flexible substrate 6 located on the surface of the second electrode layer 5 (the surface of the second electrode layer 5 here specifically refers to the side surface of the second electrode layer 5 facing away from the second dielectric layer 4). The first dielectric layer 3 and the second dielectric layer 4 are both deposited on the surfaces of the first electrode layer 2 and the second electrode layer 5 by atomic deposition. Therefore, the structure of the first dielectric layer 3 is the same as that of the first electrode layer 2, and the structure of the second dielectric layer 4 is the same as that of the second electrode layer 5. Figure 1 Taking the direction shown as an example, the capacitive pressure sensor provided by the present application comprises, from bottom to top, a first flexible substrate 1, a first electrode layer 2, a first dielectric layer 3, a second dielectric layer 4, a second electrode layer 5, and a second flexible substrate 6. The first flexible substrate 1 and the second flexible substrate 6 not only support the corresponding first electrode layer 2 and the first dielectric layer 3, the second electrode layer 5, and the second dielectric layer 4, respectively, but also provide the capacitive pressure sensor with good flexibility, so that the capacitive pressure sensor can be well fitted on the wrist for pulse detection.

[0036] In the capacitive pressure sensor provided in the present application, the first electrode layer 2 is a microstructured electrode layer (the microstructured electrode layer can be prepared on a silicon wafer mold by a MEMS (Microfabrication Process, a general term for microstructure processing technology from nanometer scale to millimeter scale) process, and the specific preparation method can be referred to in the subsequent detailed description). Correspondingly, the dielectric layer (i.e., the first dielectric layer 3) located on the surface of the microstructured electrode layer is also a microstructured shape (i.e., the dielectric layer is a microstructured dielectric layer). This design can improve the sensitivity of the capacitive pressure sensor, that is, the capacitive pressure sensor can sensitively sense external pressure, so that when the capacitive pressure sensor is attached to the wrist, the pulse can be sensitively sensed, thereby improving the sensitivity and accuracy of pulse detection. It should be noted that in order to ensure the flexibility and conformability of the microstructured electrode layer, the microstructured electrode layer can specifically include a base layer arranged on the surface of the flexible substrate (the base layer has good flexibility and is bendable, and the base layer is a microstructured shape), and a conductive layer arranged on the surface of the base layer (the conductive layer is also a microstructured shape). In the capacitive pressure sensor provided in the present application, the second electrode layer 5 is a printed electrode layer (specifically, it can be prepared by printing on the second flexible substrate 6 through a screen printing process), so that while the sensitivity of the capacitive sensor is ensured by the microstructure electrode layer, the flexibility and simplicity of preparation of the capacitive pressure sensor are ensured by the printed electrode layer (the preparation of the printed electrode layer is simpler than that of the microstructure electrode layer), so as to reduce the preparation cost of the capacitive pressure sensor.

[0037] In addition, in the capacitive sensor provided in the present application, the first dielectric layer 3, the second dielectric layer 4 and the air therebetween form a composite dielectric layer, which has an obvious capacitive response to pressure and has good sensitivity and dynamic response.

[0038] When using a capacitive pressure sensor for pulse detection, it is only necessary to place the capacitive pressure sensor on the wrist, and the pulse signal can be collected through signal acquisition. No professional training is required, and the pulse signal can be accurately collected anytime and anywhere. Its working principle is: when there is pressure on the surface of the capacitive pressure sensor, the distance between the first electrode layer 2 and the second electrode layer 5 of the capacitive pressure sensor will decrease under the action of pressure. At the same time, the dielectric constant of the composite dielectric layer composed of the first dielectric layer 3, the second dielectric layer 4 and the air between the two will also increase under pressure deformation. The combined influence of the two factors causes the capacitance of the capacitive pressure sensor to change. When the capacitive pressure sensor is attached to the wrist, the beating of the pulse will cause the deformation of the capacitive pressure sensor. The pressure of waveforms with different characteristics is different. Therefore, the different characteristics of the pulse can be reflected by the capacitance change rate of the capacitive pressure sensor. For details, please refer to Figure 5 and Figure 6 ,in, Figure 5 shows a periodic pulse characteristic diagram detected by the capacitive pressure sensor provided in an embodiment of the present application, Figure 6 The figure shows a single pulse waveform detected by the capacitance pressure sensor provided by the embodiment of the present application, wherein: Figure 5 and Figure 6 The horizontal axis is time (in seconds), and the vertical axis is the capacitance change rate (specifically △C / C, where △C is the capacitance change). Figure 4 and Figure 5 It can be seen that the collected pulse signal shows stable consistency and periodicity, and can clearly show the three characteristic peaks of the pulse: the main wave (P), the pre-dicrotic wave (T), and the dicrotic wave (D).

[0039] From the above, it can be seen that the capacitive pressure sensor for pulse detection provided by this application has the characteristics of flexibility and conformability, high detection sensitivity and accuracy, and high convenience. It also has a simple structure, does not require complex devices, and is low in cost, making it easy to promote and apply on a large scale.

[0040] The above technical solution disclosed in the present application utilizes a first flexible substrate, a first electrode layer located on the first flexible substrate, a first dielectric layer located on the surface of the first electrode layer, a second dielectric layer opposite to the first dielectric layer, and a second flexible substrate located on the surface of the second dielectric layer to constitute a flexible capacitive pressure sensor for pulse detection, so as to facilitate direct attachment to the wrist for pulse detection, and the first electrode layer is set as a microstructured electrode layer to ensure the sensitivity and accuracy of the capacitive pressure sensor, thereby achieving high-sensitivity pulse detection, and the second electrode layer is set as a printed electrode layer to ensure the flexibility and simplicity of preparation of the capacitive pressure sensor. Among them, after the capacitive pressure sensor provided by the present application is attached to the wrist, the beating of the pulse will cause the spacing between the first electrode layer and the second electrode layer to change, and the dielectric constant of the composite dielectric layer composed of the first dielectric layer, the second dielectric layer and the air between the two will also change, thereby causing the capacitance of the capacitive pressure sensor to change. Therefore, the pulse characteristics can be reflected by the capacitance change rate of the capacitive pressure sensor. From the above, it can be seen that the capacitive pressure sensor for pulse detection provided by this application does not require complex structural design and numerous devices. It has a simple structure, small size, low cost, and high detection sensitivity. Since pulse detection can be performed by simply attaching it to the wrist, it can be used conveniently and is easy to apply and promote on a large scale.

[0041] In a capacitive pressure sensor provided by an embodiment of the present application, the first electrode layer 2 may include a PDMS microstructure layer 21 located on a surface of a first flexible substrate 1 and a conductive layer 22 located on a surface of the PDMS microstructure layer 21 .

[0042] In the present application, the first electrode layer 2 may include a PDMS (Polydimethylsiloxane) microstructure layer 21 located on the surface of the first flexible substrate 1 (the PDMS microstructure layer 21 is the base layer of the first electrode layer 2) and a conductive layer 22 located on the surface of the PDMS microstructure layer 21 (the conductive layer 22 is also in a microstructure shape, that is, the conductive layer 22 is specifically a microstructure conductive layer). The conductive layer 22 can be specifically provided on the surface of the PDMS microstructure layer 21 by evaporation.

[0043] PDMS has the characteristics of flexibility, bendability, and good elasticity. Using it in a capacitive pressure sensor can ensure that the conductive layer 22 has good ductility thereon and make the electrode layer have good flexibility, thereby facilitating the improvement of the flexibility of the capacitive pressure sensor and improving the user experience.

[0044] In a capacitive pressure sensor provided by an embodiment of the present application, the conductive layer 22 may include Ti disposed on the surface of the PDMS microstructure layer and Au disposed on the surface of the Ti.

[0045] In the present application, the conductive layer 22 in the first electrode layer 2 can specifically include Ti (titanium) arranged on the surface of the PDMS microstructure layer (specifically, a Ti layer arranged on the surface of the PDMS microstructure layer) and Au (gold) arranged on the Ti surface (specifically, an Au layer arranged on the surface of the Ti layer).

[0046] Ti serves as a bridge between the PDMS microstructure layer and Au. Au is relatively soft and has good conductivity, making the capacitive pressure sensor more flexible and conformable.

[0047] In a capacitive pressure sensor provided by an embodiment of the present application, the first electrode layer 2 is a trapezoidal microstructure electrode layer or a pyramid microstructure electrode layer.

[0048] In the present application, the first electrode layer 2 can be a trapezoidal microstructure electrode layer or a pyramidal microstructure electrode layer, so that the capacitive pressure sensor has high sensitivity, thereby improving the precision and accuracy of pulse detection. Figure 1 and Figure 2 In the embodiment, the first electrode layer 2 is shown as a trapezoidal microstructure electrode layer. Of course, the first electrode layer 2 can also be set as a microstructure electrode layer of other shapes, such as a rectangular microstructure electrode layer, etc., and this application does not limit this.

[0049] In the capacitive pressure sensor provided by the embodiment of the present application, the dielectric constants of the first dielectric layer 3 and the second dielectric layer 4 are both greater than a preset value.

[0050] In the present application, the dielectric constant of the first dielectric layer 3 and the dielectric constant of the second dielectric layer 4 can both be greater than a preset value (the preset value can be set according to actual conditions, for example, the dielectric constant of air is used as the preset value), that is, the first dielectric layer 3 and the second dielectric layer 4 are both dielectric layers with high dielectric constants, so that the composite dielectric layer formed by the first dielectric layer 3, the second dielectric layer 4 and the air therebetween has a very obvious capacitive response to pressure, thereby making the capacitive pressure sensor have good sensitivity and dynamic response, so as to accurately detect pulse.

[0051] It should be noted that the materials of the first dielectric layer 3 and the second dielectric layer 4 can be the same, so as to reduce the types of materials and thus reduce the cost and manufacturing complexity of the capacitive pressure sensor.

[0052] In a capacitive pressure sensor provided by an embodiment of the present application, the first dielectric layer 3 and the second dielectric layer 4 are both Al2O3 layers.

[0053] In this application, aluminum oxide (Al2O3) can be used as the first dielectric layer 3 and the second dielectric layer 4 of the capacitive pressure sensor. Al2O3 not only has a high dielectric constant (its dielectric constant is 6.5), but also can form a dense thin film on the electrode layer after atomic deposition, thereby improving the performance of the capacitive pressure sensor.

[0054] In a capacitive pressure sensor provided by an embodiment of the present application, the first flexible substrate 1 and the second flexible substrate 6 are both PET layers.

[0055] In the present application, PET (Polyethylene terephthalate) can be selected as the first flexible substrate 1 and the second flexible substrate 6 of the capacitive pressure sensor. It has good flexibility, and therefore can ensure the flexibility of the capacitive pressure sensor, making it flexible and fit on the wrist and low in cost.

[0056] In an embodiment of the present application, a capacitive pressure sensor is provided, wherein the second electrode layer is Ag.

[0057] In this application, Ag (silver) can be used as the printed electrode layer in the capacitive pressure sensor (specifically, the Ag layer disposed on the surface of the second dielectric layer). Ag is relatively soft and has good conductivity. Therefore, the capacitive pressure sensor can be made more flexible and conformable.

[0058] The present application also provides a pulse detector, which may include:

[0059] A capacitive pressure sensor such as any of the above, adapted to fit on the wrist;

[0060] The processor connected to the capacitive pressure sensor is used to detect the capacitance signal of the capacitive pressure sensor and obtain the pulse signal according to the capacitance signal.

[0061] The pulse detector provided by the embodiment of the present application can include any of the above-mentioned capacitance pressure sensors, which is used to be fitted on the wrist and used to detect the pulse signal (specifically converting the pulse signal into a capacitance signal corresponding to the capacitance pressure sensor). The pulse detector can also include a processor connected to the capacitance pressure sensor, which can detect the capacitance signal of the capacitance pressure sensor and obtain the pulse signal based on the capacitance signal so that the user can intuitively obtain the pulse signal.

[0062] In addition, the pulse detector can also include a wristband and a display screen, wherein the wristband makes it easy for the user to fix the pulse detector on the wrist and prevents the pulse detector from being lost; the display screen can display the pulse signal obtained by the processor.

[0063] The present application also provides a method for preparing a capacitive pressure sensor, which is used to prepare any of the above-mentioned capacitive pressure sensors and may include:

[0064] Disposing a first electrode layer on the surface of the first flexible substrate, and depositing a first dielectric layer on the surface of the first electrode layer;

[0065] Disposing a second electrode layer on the surface of the second flexible substrate, and depositing a second dielectric layer on the surface of the second electrode layer;

[0066] The first dielectric layer and the second dielectric layer are arranged opposite to each other and packaged to obtain a capacitive pressure sensor;

[0067] The first electrode layer is a microstructure electrode layer, and the second electrode layer is a printed electrode layer.

[0068] The present application also provides a method for preparing a capacitive pressure sensor, which can be specifically provided with a first electrode layer on the surface of a first flexible substrate, and a first dielectric layer is deposited on the surface of the first electrode layer; a second electrode layer is provided on the surface of a second flexible substrate, and a second dielectric layer is deposited on the surface of the second electrode layer; the first dielectric layer and the second dielectric layer are arranged relative to each other and packaged to obtain a capacitive pressure sensor. The first electrode layer is a microstructure electrode layer, and the microstructure electrode layer can be prepared on a silicon wafer mold using a MEMS process. Specifically, a microstructured silicon wafer mold can be prepared in advance, and then a base layer can be spin-coated on the microstructured silicon wafer mold, and the first flexible substrate can be covered on the base layer, and then cured. After curing, the base layer covering the first flexible substrate is torn off from the microstructured silicon wafer mold, and then a conductive layer is provided on the base layer to obtain a microstructured electrode. The second electrode layer is a printed electrode layer, and the printed electrode layer can be prepared by printing on the second flexible substrate using a screen printing process.

[0069] The manufacturing process of the capacitive sensor mentioned above is as follows:

[0070] S1: A microstructure is prepared on a silicon wafer mold through processes such as development, photolithography, and wet etching. Among them, the preparation method of the trapezoidal microstructure mold is as follows: the microstructure mold is prepared based on the MEMS process, specifically using a 285nm SiO2 silicon wafer as the substrate. First, a rectangular mask for the preparation of the trapezoidal microstructure is drawn on CAD, and the silicon wafer is patterned by photolithography. Then, the exposed SiO2 is corroded with hydrofluoric acid, and the silicon wafer is ultrasonically cleaned with deionized water for 10 minutes. The silicon wafer is corroded with potassium hydroxide solution to form a trapezoidal microstructure, and finally the residual SiO2 is etched again with hydrofluoric acid and ultrasonically cleaned with deionized water for 10 minutes.

[0071] S2: Based on the microstructured silicon mold obtained in S1, PDMS with a curing agent and main agent ratio of 1:10 is spin-coated on its surface, and a flexible PET substrate is covered on it.

[0072] S3: Peel the flexible PET described in S2 from the silicon wafer, and evaporate titanium / gold (Ti / Au) electrodes on the surface of the trapezoidal microstructure. For S2 and S3, specifically, the preparation of the trapezoidal microstructure electrode is as follows: spin-coat a curing agent and a main agent of 1:10 PDMS on the trapezoidal microstructure silicon wafer mold prepared above, and cover the PDMS with a layer of 25μm PET, and then evacuate the PDMS in a vacuum box for 20 minutes to remove bubbles. Next, heat it at 100°C for 3 hours to cure the PDMS, and then tear it off from the silicon wafer mold to obtain a trapezoidal microstructure with PDMS on the PET. Finally, the PET with the PDMS trapezoidal microstructure is placed in an evaporator to prepare a continuous microstructure titanium / gold (Ti / Au) electrode on the trapezoidal microstructure.

[0073] S4: Prepare flexible printed electrodes using a screen printing process, using conductive silver paste as the electrode substrate. Specifically, the printed electrodes are prepared by drawing the electrode shape in CAD, and then processing a screen for printing the electrodes based on the processed shape. A 1000-mesh screen ensures good electrode precision. The conductive silver paste is then applied to the screen, and a scraper is used to penetrate the screen onto the 25μm PET. Finally, the printed electrodes are transferred to an oven to dry the conductive silver paste and cured by heating at 80°C for 3 hours.

[0074] S5: depositing a layer of high dielectric constant aluminum oxide (Al2O3) film on the surface of the microstructured electrodes and printed electrodes prepared in S3 and S4; specifically, preparation of the composite dielectric layer: depositing high dielectric constant aluminum oxide (Al2O3) on the surface of the above-mentioned microstructured electrodes and printed electrodes by atomic deposition method.

[0075] S6: The microstructure electrode layer and the printed electrode layer obtained in S5 are packaged and combined to obtain a capacitive pressure sensor; this step is assembly. Specifically, the microstructure electrode and the printed electrode layer after deposition are aligned up and down and packaged to prepare a flexible and conformable capacitive pressure sensor.

[0076] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device comprising a series of elements are inherent to the elements. In the absence of further restrictions, the elements limited by the statement "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device comprising the elements. In addition, the above-mentioned technical solutions provided in the embodiments of the present application are not described in detail in accordance with the corresponding technical solutions in the prior art to achieve the same principle, so as to avoid excessive elaboration.

[0077] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A capacitive pressure sensor, characterized in that: The present invention comprises a first flexible substrate, a first electrode layer located on a surface of the first flexible substrate, a first dielectric layer located on a surface of the first electrode layer, a second dielectric layer opposite to the first dielectric layer, a second electrode layer located on a surface of the second dielectric layer, and a second flexible substrate located on a surface of the second electrode layer; wherein the first electrode layer is a microstructured electrode layer, and the second electrode layer is a printed electrode layer; the structure of the first dielectric layer is the same as that of the first electrode layer, and the structure of the second dielectric layer is the same as that of the second electrode layer; the first dielectric layer and the second dielectric layer are both Al2O3 layers; and the first dielectric layer, the second dielectric layer, and the air therebetween form a composite dielectric layer.

2. The capacitive pressure sensor according to claim 1, wherein: The first electrode layer includes a PDMS microstructure layer located on the surface of the first flexible substrate and a conductive layer located on the surface of the PDMS microstructure layer.

3. The capacitive pressure sensor according to claim 2, characterized in that: The conductive layer includes Ti arranged on the surface of the PDMS microstructure layer and Au arranged on the surface of Ti.

4. The capacitive pressure sensor according to claim 1, wherein: The first electrode layer is a trapezoidal microstructure electrode layer or a pyramidal microstructure electrode layer.

5. The capacitive pressure sensor according to claim 1, wherein: The first flexible substrate and the second flexible substrate are both PET layers.

6. The capacitive pressure sensor according to claim 1, wherein: The second electrode layer is Ag.

7. A pulse condition detector, characterized in that: include: The capacitive pressure sensor according to any one of claims 1 to 6, adapted to be attached to a wrist; The processor connected to the capacitive pressure sensor is used to detect the capacitance signal of the capacitive pressure sensor and obtain the pulse signal according to the capacitance signal.

8. A method for preparing a capacitive pressure sensor, characterized in that: For preparing the capacitive pressure sensor according to any one of claims 1 to 6, comprising: Disposing a first electrode layer on a surface of a first flexible substrate, and depositing a first dielectric layer on a surface of the first electrode layer; providing a second electrode layer on the surface of the second flexible substrate, and depositing a second dielectric layer on the surface of the second electrode layer; The first dielectric layer and the second dielectric layer are arranged opposite to each other and packaged to obtain a capacitive pressure sensor; Wherein, the first electrode layer is a microstructure electrode layer, and the second electrode layer is a printed electrode layer.

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