Research On Cloth-based Flexible And Stretchable Circuit System Based On Wrinkled Structure

With the improvement of people’s living standards,especially concerned about their own health,more and more flexible electronic devices and systems are required to be integrated into traditional textiles to realize intelligent wearable electronic platform to monitor,feed back and analyze various physiological signals and health status of human body in real time.Due to the inherent soft,porous and stretchable properties of textiles,it is a great challenge to integrate electrically stable and functionally reliable electronic systems on their surfaces.In view of this,this paper proposes to construct folded electrodes on the surface of elastic fabrics by combining laser cutting and heat transfer printing methods,and designs and studies the driving circuit of fabric based(stretchable alternating current electroluminescence S-ACEL)devices and the digital tube application based on electroluminescence devices.Finally,combined with the design of Wrinkled structures,The driving circuit of silver based Wrinkled structure AC driven electroluminescent devices based on fabric is prepared.The main work is as follows:(1)Research on laser cutting-heat transfer to fabric electrode: the control circuit diagram of AC driven electroluminescent devices is designed by using CAD(Computer Aided Design)software,and the control circuit of cloth based AC driven electroluminescent devices is prepared by means of UV laser cutting and heat transfer to the fabric.The circuit shows excellent mechanical flexibility and functionality.The surface morphology of the circuit and the conductivity of the conductor are studied.It is found that the minimum line width of the circuit is 0.5 mm,the resistance is about0.2 Ω,and the circuit adhered firmly to the fabric substrate.Finally,the digital tube is fabricated on the basis of AC driven electroluminescent devices,and it is driven and controlled by FPGA(Field Programmable Gate Array)and seven AC driven electroluminescent device driving circuits,which shows the compatibility and great application prospect of this work in fabric electronic system.(2)Research on stretchable fabric electrode with Wrinkled structure: Ag/TPU conductive paste film is prepared by scraping process.The cut Silver conductive film is heat transferred to the pre-stretched fabric substrate to prepare the fabric electrode(0.5 cm*10 cm in size)with wrinkle structure.Through the characterization of the micro morphology of the folded structure electrode,it is found that the electrode has a periodic folded structure and is attached to the surface of the fabric substrate,and the initial resistance of the electrode is 0.2 Ω.Then the fabric substrate was pre-stretched in different degrees,and the relationship between the resistance change rate and the stretching distance was tested.The results shows that the tensile properties of the electrode increased with the increase of the pre-stretching range.When the electrode is stretched to its original length(structure stretching stage),the resistance value of the electrode basically does not change.In the essential stretching stage of the electrode,the resistance of the electrode increases with the increase of the stretching range,and the increase is larger and larger.Finally,the 100% pre-stretched electrode(0.2 cm*5 cm in size)is tested for tensile stability(repeated stretching for1000 times),washing resistance(washing for 6 h)and high temperature and high humidity resistance(double 85 high temperature and high humidity).It is found that the resistance value remained about 0.4 Ω before and after the test.The peel test shows that the electrode had a very strong adhesion strength on the fabric,with a value of more than 1000 N/m.(3)Research on flexible stretchable circuit system: the application of the control circuit of cloth AC driven electroluminescent devices is expanded to realize that the control circuit(prepared at 80% pre-stretching)is within 55% stretching range,and the circuit still retains its functionality.By adding the non-deformable region,the electronic components can be prevented from shifting during the stretching process.The minimum width of the conductor adhered to the fabric substrate is only 1 mm.It is found that the appearance of wrinkled structure can significantly improve the tensile performance of the circuit system(the circuit remains in normal working state within 55% of the tensile range),indicating the importance of the resistance stability of the stretchable electrode,which provides a theoretical basis and design reference for the application of stretchable fabric electronics.In this paper,the method of laser cutting and heat transfer printing to the fabric substrate is used as the electrode graphic technology.The design of the control circuit of the AC driven electroluminescent device is realized concisely and efficiently,and it is controlled by the traditional FPGA development board to realize the display of the number of code tubes of the electroluminescent device;Then,by means of laser cutting and heat transfer printing to the pre-stretched fabric substrate,a stretchable silver based electrode with wrinkled structure is realized.The electrode has the characteristics of both wrinkled structure and essential stretching,which greatly improves the stretchability of the silver conductive film;Finally,combined with the graphic technology and the preparation of wrinkled structure electrode,the control circuit of AC driven electroluminescent devices with wrinkled structure is realized on the elastic band.The appearance of pleated structure significantly improves the stretchability of the circuit system,and provides a design reference for the application of stretchable fabric electronics.