| In recent years,the miniaturization technology represented by MEMS technology drives the rapid growth of sensor manufacturing technology.The sensor has the advantages of high performance,miniaturization,high integration,low cost and mass production.However,with the emerging applications in various fields such as wearable electronics,mobile communication,structural health monitoring and intelligent health monitoring,higher requirements for MEMS sensors have been put forward.These sensors can convert physical information into electrical signals.Among them,the response to mechanical stimuli such as strain and pressure is the most studied.The sensors used to measure the strain caused by the deformation of objects are collectively referred to as strain sensors.In wearable devices,for example,strain sensors are typically integrated into clothing,glasses and watches,or directly attached to human skin to collect physical,chemical and biological signals generated by humans or their surroundings.In the process of natural bending,stretching,pressing or twisting of human tissues,joints or organs,strain sensors can convert mechanical deformation into output signals to characterize the movement of the body.In this paper,PZT piezoelectric thick film was used as piezoelectric functional layer material,and 50-?m-thick PZT thin film was prepared by chemical mechanical polishing(CMP)process.By optimizing the rigid substrate material and copper wire lead technology of beryllium bronze substrate array strain sensor,we used flexible polyimide(PI)film as the substrate,20-?m-thick stainless steel foil as the support layer,combined low temperature epoxy bonding technology and water-dissolvent tape transferring technology,and prepared a 3×3 piezoelectric strain sensor array based on flexible PI substrate.The stainless steel foil as the bottom electrode wire was cut to form the island structure,which was connected by 100-?m-wide serpentine wires.The sensor array didn't interfere with each other in the strain measurement and had certain extensibility and stability.Mechanical analysis and experimental calibration of the sensor were also carried out.The sensor performance was tested on a tension-compression platform.The strain of the stainless steel sheet was changed by controlling the displacement during compression,and the linear relationship between the output voltage of the array sensor and the strain was drawn.The sensitivity was up to 1.88mv/??.In addition,this study also tested the relationship between the output voltage of the sensor and the compression speed of the clamp.When the compression speed increased,the work done by the clamp to the sensor increased,and the output voltage of the sensor increased.The sensitivity of the sensor to the compression speed was 137.8mv/(mm·s-1).The3×3 sensors array can be tightly attached to the surface of a curved structure such as a plastic balloon and simultaneously measure the strain at nine points.In the future,the flexible piezoelectric strain sensor array is expected to be applied to multi-point strain measurement on the surface of skin,heart and other organs,and has broad application prospects in the fields of medicine,bionic robot and electronic skin. |
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