A piezoelectric thin film sensor

Abstract

The present application relates to the technical field of sensor, in particular to a piezoelectric film sensor, which comprises a piezoelectric film, a sensor substrate, upper and lower electrodes respectively arranged on the upper and lower surfaces of the sensor substrate, electrode lead-out structures respectively arranged on the side edges of the upper and lower electrodes, each electrode lead-out structure being located on the same side of the sensor substrate and on the same horizontal plane of the sensor substrate, and a mass block arranged on the piezoelectric film, the piezoelectric film being connected to an external printed circuit board, the mass block being located in a groove of the printed circuit board, and the electrode lead-out structures being connected to the bonding pads of the printed circuit board through connectors; the piezoelectric film sensor can be miniaturized on the printed circuit board, the complexity of the sensor structure is reduced, the limitation on the mounting tolerance and the device tolerance is reduced, and the cost of the device is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensor, in particular to a piezoelectric film sensor. BACKGROUND

[0002] The piezoelectric film, represented by the PVDF flexible piezoelectric film, can sensitively perceive the mechanical deformation in X-Y-Z directions and quantize the mechanical force through the charge output mode. After the charge is converted into the output voltage, it is collected and processed by the MCU or CPU, so as to realize the conversion between the pressure and the digital signal. At the same time, since the piezoelectric film vibration or acceleration sensor is a passive element, it can generate a strong enough charge without power supply, and the signal is easy to collect, thereby saving the power consumption, and it is very suitable for occasions with high environmental sensitivity and low power consumption requirements.

[0003] The piezoelectric film can be made into a vibration or acceleration sensor by using the characteristic of being sensitive to pressure. The principle of making a vibration sensor by using the piezoelectric film in the prior art is to use the cantilever beam principle. When the mass block is impacted by acceleration, the mass block is impacted by the force in the direction of impact, so that the piezoelectric film is deformed. The deformation generates a charge signal, so that the acceleration or vibration is converted into a digital signal for system calling and processing.

[0004] However, in some space-limited or area-limited occasions, it is not possible to place a cantilever beam in a large enough place, and it is not possible to place the cantilever beam and the metal block in an empty space. At the same time, the traditional piezoelectric film vibration or acceleration sensor is often in the form of riveting, and the sensor lead terminal area is too large and thick, which is not suitable for miniaturization and integration with a printed circuit board. SUMMARY

[0005] The present application aims to provide a piezoelectric film sensor to solve the above technical problems.

[0006] A piezoelectric film sensor, comprising,

[0007] The piezoelectric film comprises a sensor substrate, the upper and lower surfaces of the sensor substrate are respectively provided with an upper electrode and a lower electrode, the side edges of the upper electrode and the lower electrode are respectively provided with a first electrode lead-out structure and a second electrode lead-out structure, and the first electrode lead-out structure and the second electrode lead-out structure are located on the same side of the sensor substrate and on the same horizontal plane of the sensor substrate.

[0008] The mass block is arranged on the piezoelectric film, the piezoelectric film is connected to an external printed circuit board, the mass block is located in a groove of the printed circuit board, and the first electrode lead-out structure and the second electrode lead-out structure are connected to the solder pad of the printed circuit board through the connector.

[0009] Preferably, the connector has a plurality of needle bodies, which are clamped with the pads on the printed circuit board.

[0010] Preferably, the diameter of the needle body is less than 1mm.

[0011] Preferably, the printed circuit board has at least two pads, and at least two needle bodies on the connector are clamped with the pads.

[0012] Preferably, the mass block is in a cubic shape, the area of the groove on the printed circuit board is greater than the cross-sectional area of the mass block, and the depth of the groove is greater than the height of the mass block.

[0013] Preferably, the mass block has a certain distance between the outer wall and the inner wall of the groove.

[0014] Preferably, the piezoelectric film further comprises,

[0015] a bottom substrate, and the sensor substrate is arranged on the bottom substrate.

[0016] an upper cover film arranged on the upper electrode.

[0017] Preferably, the piezoelectric film is provided with a sticky glue, and the mass block is arranged on the piezoelectric film through the sticky glue.

[0018] Preferably, the piezoelectric film is an organic high polymer piezoelectric film or an inorganic piezoelectric film.

[0019] Preferably, the first electrode lead-out structure and the second electrode lead-out structure are respectively a positive electrode lead-out structure and a negative electrode lead-out structure.

[0020] The beneficial effects of the present application are: due to the above technical scheme, the piezoelectric film sensor can be miniaturized on the printed circuit board by improving the installation and electrode lead-out mode of the piezoelectric film sensor and the printed circuit board, while reducing the complexity of the sensor structure, reducing the limitation on the installation tolerance and device tolerance, and reducing the cost of the device. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is an exploded view of the piezoelectric film sensor structure in the embodiment of the present application.

[0022] Figure 2 It is an assembly drawing of the piezoelectric film sensor in the embodiment of the present application.

[0023] Figure 3 It is a structural schematic diagram of the printed circuit board in the embodiment of the present application.

[0024] In the drawings: 1, bottom substrate; 2, lower electrode; 21, second electrode lead-out structure; 3, sensor substrate; 4, upper electrode, 41, first electrode lead-out structure; 5, upper layer cover film; 6, adhesive; 7, connector; 8, mass; 9, printed wiring board; 91, groove; 92, solder pad. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0026] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0027] The present application will be further described below with reference to the drawings and specific embodiments, but is not limited by the present application.

[0028] A piezoelectric thin film sensor comprises,

[0029] The piezoelectric thin film comprises a sensor substrate 3, the upper and lower surfaces of the sensor substrate 3 are respectively provided with an upper electrode 4 and a lower electrode 2, the side edges of the upper electrode 4 and the lower electrode 2 are respectively provided with a first electrode lead-out structure 41 and a second electrode lead-out structure 21, the first electrode lead-out structure 41 and the second electrode lead-out structure 21 are located on the same side of the sensor substrate 3 and on the same horizontal plane of the sensor substrate 3.

[0030] The mass 8 is arranged on the piezoelectric thin film, the piezoelectric thin film is connected to an external printed wiring board 9, the mass 8 is located in a groove 91 of the printed wiring board 9, and the first electrode lead-out structure 41 and the second electrode lead-out structure 21 are connected to a solder pad 92 of the printed wiring board 9 through a connector 7.

[0031] In a more preferred embodiment, the connector 7 has a plurality of needle bodies, and the needle bodies are clamped to the solder pads 92 on the printed wiring board 9.

[0032] Specifically, the lead-out electrode form arranged in the prior art often adopts a reverse buckling mode to be connected to the printed wiring board 9, and in this mode, the fixing can only be performed through conductive glue. In the present application, the connection mode is changed, the electrode lead-out structure located on the same side and on the same horizontal plane of the sensor substrate 3 is arranged, and the connection through the connector 7 is realized, so that a simpler structure and more convenient installation are achieved.

[0033] Further preferably, the size of each component of the existing thin film sensor is very small, and errors cannot be overcome during die cutting and subsequent installation, and the cumulative errors of each part affect the consistency of the product, and the present application sets the same side electrode and connects through the connector 7. The error is reduced, and the consistency is higher.

[0034] Further preferably, in the prior art, the bonding method using conductive adhesive must expand the size area of the solder pad 92 in order to ensure the bonding of the bonding surface, and at the same time, in order to meet the accuracy requirements of performance, the size must be controlled very accurately, and the size of the pin body (PIN pin) of the connector 7 can reach 0.2mm, which is much smaller than the 1mm of the bonding surface in the prior art. The electrode structure of the present application is arranged on the same side and can be connected using the connector 7, which reduces the error of each size and the influence of tolerance, and realizes further miniaturization of the device.

[0035] In a preferred embodiment, the diameter of the pin is less than 1mm; specifically, the present application is 0.2mm.

[0036] In a preferred embodiment, the printed circuit board 9 has at least two solder pads 92, and at least two pins on the connector 7 are connected to the solder pads 92.

[0037] In a preferred embodiment, the mass block 8 is a cube, and the area of the groove 91 provided on the printed circuit board 9 is larger than the cross-sectional area of the mass block 8, and the depth of the groove 91 is greater than the height of the mass block 8.

[0038] In a preferred embodiment, the mass block 8 has at least a certain distance between the outer side wall and the inner side wall of the groove 91.

[0039] Specifically, the present application is suitable for vibration sensors or acceleration sensors, and the present application sets a groove 91 with a volume slightly larger than that of the mass block 8 on the printed circuit board 9. The printed circuit board 9 and the piezoelectric film are connected to make the mass block 8 located in the groove 91, and the outer side wall of the mass block 8 and the inner side wall of the groove 91 have at least a certain distance, so that the mass block 8 always stays in a spacious space during the process of shaking caused by acceleration or vibration impact, and is not affected by the surrounding environment.

[0040] In a preferred embodiment, the piezoelectric film further comprises,

[0041] The bottom substrate 1, the sensor substrate 3 is arranged on the bottom substrate 1;

[0042] The upper cover film 5 is arranged on the upper electrode 4.

[0043] In a preferred embodiment, the piezoelectric film is provided with a sticky glue 6, and the mass 8 is provided on the piezoelectric film through the sticky glue 6.

[0044] In a preferred embodiment, the piezoelectric film is an organic polymer piezoelectric film or an inorganic piezoelectric film.

[0045] In a preferred embodiment, the first electrode lead-out structure 41 and the second electrode lead-out structure 21 are respectively a positive electrode lead-out structure and a negative electrode lead-out structure.

[0046] In summary, the piezoelectric film sensor and the printed circuit board 9 are installed and the electrode lead-out mode is improved, the overall structure of the sensor is greatly reduced, and the two lead-out electrodes of the sensor are designed on the same side, which can avoid the strict requirement of the installation size tolerance of the two regions when the lead-out electrodes are respectively located on the two sides, and facilitates the circuit layout design. In addition, the mass 8 is always in an empty space during the shaking process caused by acceleration or vibration impact, and is not affected by the surrounding environment. In appearance, the sensor is also integrated with the printed circuit board 9, without additional increase in the longitudinal height, realizing the same installation process as other electronic components on the printed circuit.

[0047] The above description is only the preferred embodiment of the present application, and does not limit the implementation and protection scope of the present application. Those skilled in the art should realize that any equivalent replacement and obvious changes made according to the description and drawings of the present application should be included in the protection scope of the present application.

Claims

1. A piezoelectric thin-film sensor, characterized in that, include, A piezoelectric thin film includes a sensor substrate, wherein an upper electrode and a lower electrode are respectively provided on the upper and lower surfaces of the sensor substrate, and a first electrode lead-out structure and a second electrode lead-out structure are respectively provided on the side of the upper electrode and the lower electrode. The first electrode lead-out structure and the second electrode lead-out structure are located on the same side of the sensor substrate and are located on the same horizontal plane as the sensor substrate. A mass block is disposed on the piezoelectric film, the piezoelectric film is connected to an external printed circuit board, the mass block is located in the groove of the printed circuit board, and the first electrode lead-out structure and the second electrode lead-out structure are connected to the pads of the printed circuit board through connectors.

2. The piezoelectric thin film sensor according to claim 1, characterized in that, The connector has multiple pins that engage with the pads on the printed circuit board.

3. The piezoelectric thin film sensor according to claim 2, characterized in that, The diameter of the needle body is less than 1 mm.

4. The piezoelectric thin film sensor according to claim 2, characterized in that, The printed circuit board has at least two of the said pads, and at least two of the said pins on the connector engage with the said pads.

5. The piezoelectric thin-film sensor according to claim 1, characterized in that, The mass block is cubic in shape, and the area of ​​the groove on the printed circuit board is larger than the cross-sectional area of ​​the mass block, and the depth of the groove is greater than the height of the mass block.

6. The piezoelectric thin film sensor according to claim 5, characterized in that, There is at least a certain distance between the outer wall of the mass block and the inner wall of the groove.

7. The piezoelectric thin film sensor according to claim 1, characterized in that, The piezoelectric film also includes, The sensor substrate is disposed on the underlying substrate; An upper cover film is disposed on the upper electrode.

8. The piezoelectric thin film sensor according to claim 1, characterized in that, The piezoelectric film is provided with adhesive, and the mass block is attached to the piezoelectric film by the adhesive.

9. The piezoelectric thin film sensor according to claim 1, characterized in that, The piezoelectric film is an organic polymer piezoelectric film or an inorganic piezoelectric film.

10. The piezoelectric thin film sensor according to claim 1, characterized in that, The first electrode lead-out structure and the second electrode lead-out structure are respectively a positive electrode lead-out structure and a negative electrode lead-out structure.

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