阅读说明：本技术 一种分体式压电传感器 (Split type piezoelectric sensor ) 是由 单华锋 王家冬 曹凯敏 韩秀萍 李红文 陈磊 于 2020-04-01 设计创作，主要内容包括：本发明公开了一种分体式压电传感器,涉及压电传感领域,包括第一电路板和第二电路板；第一电路板包括分板、压电薄膜和第一连接头；分板和第一电路板位于同一平面,分板位于第一电路板的镂空区域内并与第一电路板内的一端相连,令分板以第一电路板内的一端为支点产生位移；压电薄膜贴覆于分板并与分板电连接；第一连接头与压电薄膜同侧设置,第一连接头与第一电路板电连接；第二电路板包括信号处理单元和与信号处理单元电连接的第二连接头；第二连接头与第一连接头相对并可拆卸的连接,第二连接头支撑第一电路板。本发明的技术效果在于分离了压电薄膜和运算处理单元,并且压电薄膜可随时拆卸并测试,实现了压电薄膜电路板的复用。(The invention discloses a split type piezoelectric sensor, which relates to the field of piezoelectric sensing and comprises a first circuit board and a second circuit board; the first circuit board comprises a sub board, a piezoelectric film and a first connector; the branch board and the first circuit board are positioned on the same plane, the branch board is positioned in the hollow area of the first circuit board and is connected with one end in the first circuit board, and the branch board generates displacement by taking one end in the first circuit board as a fulcrum; the piezoelectric film is attached to the sub-plate and electrically connected with the sub-plate; the first connector is arranged on the same side of the piezoelectric film and is electrically connected with the first circuit board; the second circuit board comprises a signal processing unit and a second connector electrically connected with the signal processing unit; the second connector is opposite to and detachably connected with the first connector, and the second connector supports the first circuit board. The invention has the technical effects that the piezoelectric film and the operation processing unit are separated, and the piezoelectric film can be detached and tested at any time, thereby realizing the multiplexing of the piezoelectric film circuit board.)

1. A split type piezoelectric sensor is characterized by comprising a first circuit board and a second circuit board;

the first circuit board comprises a sub board, a piezoelectric film and a first connector; the branch board and the first circuit board are positioned on the same plane, the branch board is positioned in the hollow area of the first circuit board and is connected with one end in the first circuit board, and the branch board is enabled to generate displacement by taking one end in the first circuit board as a fulcrum; the piezoelectric film is attached to the sub-plate and electrically connected with the sub-plate; the first connector and the piezoelectric film are arranged on the same side, and the first connector is electrically connected with the first circuit board;

the second circuit board comprises a signal processing unit and a second connector electrically connected with the signal processing unit; the second connector with first connector is relative and detachable connects, the second connector supports first circuit board.

2. The split piezoelectric sensor according to claim 1, wherein a surface of the second circuit board on a side where the second connector is provided is plated with copper.

3. The split piezoelectric sensor according to claim 1, wherein the first connector and the second connector are plural, and the first connector surrounds the hollow area.

4. The split piezoelectric sensor according to claim 1, further comprising: an elastic pad disposed between the piezoelectric film and the second circuit board.

5. The split piezoelectric sensor according to any one of claims 1 to 4, wherein a shield is provided on a side of the first circuit board opposite to the piezoelectric film, and the shield surrounds the hollowed-out region.

6. The split piezoelectric sensor of claim 5, wherein the shield comprises a through hole.

Technical Field

The invention relates to the field of piezoelectric sensing, in particular to a split type piezoelectric sensor.

Background

The piezoelectric film is a novel high molecular polymer type flexible transduction material, can be processed into a vibration sensor or an accelerometer with high efficiency, reliability and low cost, and can also be combined with a proper circuit to form a wireless detection and monitoring system. Due to the advantages of the piezoelectric film sensor, the piezoelectric film sensor is widely applied to many fields such as buildings, speed and acceleration measurement, medical physiological signal acquisition, vehicle theft prevention and the like.

Present piezoelectric film sensor is mostly the cantilever type, and piezoelectric film pastes and covers the inboard at the cantilever, and when the sensor received the outside longitudinal stress who applys this moment, can produce great stress on horizontal, produce deformation and signal of telecommunication, after the signal processing unit conversion to obtain concrete measurement parameter.

The cantilever beam structure of the existing piezoelectric film sensor is generally two types: the piezoelectric film is attached to one side (generally the inner side) of the suspension beam with an electrode, the attached piezoelectric film is located on the same circuit board with a signal processing unit and is easily affected by heat of the circuit board, the attached piezoelectric film cannot be tested independently and is difficult to overhaul, and a sensor can be replaced integrally after the piezoelectric film is damaged, so that the cost is high.

The other type is a welding or riveting type, a metal plate or a ceramic plate and the like are selected as a suspension beam, the metal plate or the ceramic plate attached with a piezoelectric film is installed on a bottom plate with a signal processing unit by a welding or riveting method, the riveting or welding end has the functions of connection and signal transmission, however, as the piezoelectric film is used as a high polymer material, the piezoelectric film is not high in temperature resistance, the piezoelectric film can be damaged or the performance of the piezoelectric film is degraded in the welding process, and the adhesion quality of the film is not easy to detect. In addition, the welding or riveting mode is not beneficial to the disassembly of the sensor, and particularly, the riveting mode can only adopt a destructive disassembly mode, thus being not beneficial to the maintenance and the reuse of the piezoelectric film plate.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a split piezoelectric sensor, which can flexibly replace and test the performance of a piezoelectric film.

In order to achieve the above object, the present invention provides a split type piezoelectric sensor, including a first circuit board and a second circuit board;

the first circuit board comprises a sub board, a piezoelectric film and a first connector; the branch board and the first circuit board are positioned on the same plane, the branch board is positioned in the hollow area of the first circuit board and is connected with one end in the first circuit board, and the branch board is enabled to generate displacement by taking one end in the first circuit board as a fulcrum; the piezoelectric film is attached to the sub-plate and electrically connected with the sub-plate; the first connector and the piezoelectric film are arranged on the same side, and the first connector is electrically connected with the first circuit board;

the second circuit board comprises a signal processing unit and a second connector electrically connected with the signal processing unit; the second connector with first connector is relative and detachable connects, the second connector supports first circuit board.

Furthermore, the surface of the second circuit board, which is provided with the second connector, is plated with copper.

Furthermore, the first connector and the second connector are multiple, and the first connector surrounds the hollow area.

Further, still include: an elastic pad disposed between the piezoelectric film and the second circuit board.

Furthermore, a shielding cover is arranged on the surface, opposite to the piezoelectric film, of the first circuit board, and the shielding cover surrounds the hollow area.

Further, the shield can includes a through hole.

The invention has the technical effects that the piezoelectric film and the operation processing unit are separated, the piezoelectric film can be detached at any time and is easy to test, and the multiplexing of the piezoelectric film circuit board is realized.

The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

FIG. 1 is a bottom view of a first circuit board according to the present invention;

FIG. 2 is a schematic structural diagram of a second circuit board according to the present invention;

FIG. 3 is a top view of a first circuit board according to the present invention;

fig. 4 is a perspective view of a first circuit board according to the present invention.

Description of reference numerals: 100-a first circuit board; 101-a piezoelectric film; 102-a first connector; 103-splitting the plate; 104-metal shield welding spot; 105-a metal shield; 106-a via; 200-a second circuit board; 201-a second connector; 202-elastic cushion.

Detailed Description

The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.

In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. The thickness of the components may be exaggerated where appropriate in the figures to improve clarity.

Fig. 1 shows an inner structure of the first circuit board 100. The first circuit board 100 is hollow, and the sub-board 103 is located in the hollow area inside the first circuit board 100, and is connected to one end inside the first circuit board 100 and located on the same plane. The sub-board 103 is further coated with a piezoelectric film 101 electrically connected thereto, and a first connection terminal 102 is further provided on the same side as the piezoelectric film 191.

The sub-board 103 may be bent according to a direction of a compressive stress when the sub-board is subjected to the compressive stress by using an end connected to the first circuit board 100 as a fulcrum, and may be cyclically moved due to an elastic action when the compressive stress is released.

The material of the piezoelectric film 101 may be a piezoelectric material commonly used at present, such as polyvinylidene fluoride (PVDF), Polydimethylsiloxane (PDMS), and the like, and is not limited herein. When the sub-board 103 is deformed by the compressive stress, the piezoelectric film 101 is driven to deform together to generate an electrical signal, and the electrical signal generated by the piezoelectric film 101 is transmitted to the first connector 102 disposed on the same side as the piezoelectric film 101 through the circuit on the first circuit board 100.

Of course, in order to generate the cyclic and reciprocal displacement, the ends of the sub-board 103 are not connected to the circuit board, and in addition, a part of space needs to be reserved between the first circuit board 100 and the second circuit board 200 to provide enough space for the displacement of the sub-board 103.

Fig. 2 shows a schematic structural diagram of a second circuit board 200, which is provided with a second connecting head 201 and an elastic pad 202. The second circuit board 200 also integrates a signal processing unit (not shown in the figure).

The second connector 201 is opposite to the first connector 102 and detachably connected to the first connector 102, the second connector 201 receives the electrical signal transmitted from the first connector 102 and transmits the electrical signal to the signal processing unit, and the signal processing unit responds to the electrical signal and processes the electrical signal to obtain a detection result. During operation of the sensor, the second connector 201 supports the first circuit board 100, so that it deforms when the sub-board 103 is subjected to a compressive stress, and the piezoelectric film 101 generates a sufficient amount of detectable electrical signals.

In order to make the support of the first circuit board 100 more stable, the first connectors 102 and the second connectors opposite to the first connectors may be two or more, and are disposed around the hollow area outside the sub-board 103.

In this embodiment, the first connector 102 and the second connector 201 are inserted board-to-board connectors, and have a certain height. When the first circuit board 100 and the second circuit board 200 are connected, a certain gap is formed between the two, and the distance between the two boards is nominally 0.98 mm.

The elastic pad 202 is disposed in the gap and should be in contact with the sub-plate 103 and the piezoelectric film 101 for alleviating vibration interference caused by the overall motion of the external sensor, and also can support the sub-plate 103 and the piezoelectric film 101 and contribute to the generation of pre-stress. In this embodiment, the elastic pad 202 is made of soft silicone, and the thickness of the soft silicone is 1mm, and the thickness of the soft silicone will also vary according to the height of the connector between boards. The hardness of the soft silica gel can be selected from 20 to 40 Shore hardness, and can be adjusted according to the pressure stress to be measured. In addition, the elastic pad 202 can press the piezoelectric film 101 to prevent the piezoelectric film from falling off accidentally.

Further, the surface of the second circuit board 200 near the first circuit board 100 is copper-clad for grounding and has the function of shielding the environmental electromagnetic noise.

Fig. 3 and 4 show the outer structure of the first circuit board 100, and the outer side of the hollow area has a metal shielding cover 105, and the metal shielding cover 105 surrounds the sub-board 103 to suppress the environmental electromagnetic noise and avoid the power frequency electromagnetic interference, which is generally an alloy of zinc, copper and nickel.

The metal shielding cover 105 is provided with a through hole 106, when the sensor is used, a salient point of an external device to be tested can pass through the through hole to generate compressive stress on the first circuit board, any position of the sub-board 103 can be selected at the through hole, and only the sub-board 103 needs to generate corresponding deformation when being subjected to the compressive stress. The pressure stress to be measured can be adjusted according to the size range of the pressure stress to be measured, for example, when the pressure stress to be measured is small, the through holes can be arranged at the tail ends of the sub-plates 103, and the sensor is more sensitive; in contrast, when the compressive stress to be measured is large, the through holes can be arranged at the middle end of the sub-plate 103 or at the connecting end of the sub-plate 103.

In one embodiment, the sensor is operated with the piezoelectric film 101 sandwiched between two shielding layers, with the upper side shielded by the metal shield 105 and the lower side shielded by the copper plating of the second circuit board 200, together suppressing environmental interference.

Further, the first circuit board 100 and the second circuit board 200 both use conventional circuit board material FR-4 (epoxy resin glass fiber laminate), and may also use other circuit board materials that can be designed with circuit, such as composite substrate single-sided half-glass fiber board 22F, single-sided glass fiber board CEM-1, double-sided half-glass fiber board CEM-3, or metal substrate.

When the sensor is manufactured, firstly, a connector and a metal shielding cover 105 between the boards are welded on the first circuit board 100 and the second circuit board 200 respectively, then the piezoelectric film 101 is pasted at normal temperature, the first circuit board 100 and the second circuit board 200 are tested respectively, and after the test is finished, the first circuit board 100 is directly inserted on the second circuit board 200, so that the complete piezoelectric sensor can be formed. During maintenance, the first circuit board 100 is directly detached, faults can be tested independently, the piezoelectric film 101 can be replaced conveniently, high-temperature operation under the condition that the piezoelectric film exists is avoided, and damage to the piezoelectric film caused by high temperature is prevented.

Further, the elastic pad 202 may not be provided in the gap between the first circuit board 100 and the second circuit board 200, and the sensor may be used as an acceleration sensor. When the sensor is vibrated, the sub-plate 103 is vibrated along with the vibration of the elastic pad 202, so that the piezoelectric film 101 is driven to deform, and the current acceleration value can be accurately obtained by arranging the signal processing unit.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.