Research On Transparent Touch Screen Driving Circuit Based On Thin Film Transistor

With the continuous development of human social science and technology,touch technology,as the basic form of human-computer interaction,is increasingly used in people's lives.Touch technology,as one of the main ways of human-computer interaction,can be divided into resistive touch,capacitive touch,inductive touch,electromagnetic touch,and optical touch,etc.LCD touch screens based on thin film transistor liquid crystal display technology dominate the market.Similarly,the driving design of a thinfilm transistor-based touch screen is one of the key technologies that affect the operation of the touch screen.In the face of the current wide variety of touch screen types,different touch screen structures often require different driving circuit design concepts.A transparent touch screen driving circuit based on thin film transistors is designed in this paper using printed circuit board(PCB).The design can be divided into four parts.Firstly,based on the characteristics and working methods of the new thin film transistor device,determine the basic structure of the driving circuit for the thin-film transistor in a single touch point to work normally,and then design a 5 by 5 mesh format touch screen.The required driving voltage in the driving circuit is determined according to the switching characteristics of the thin film transistor integrated in the transparent touch screen obtained from the actual test;Secondly,design the transparent touch screen driving circuit.The transparent touch screen driving circuit mainly consists of six kinds of functional modules: a buck module,a data selection module,a boost module,a negative voltage module,a positive and negative voltage selection module and an FPC30 module.The appropriate chip design is selected separately corresponding circuit,and then the entire design of the driving circuit system is presented in the form of a printed circuit board(PCB);Thirdly,in order to better verify the working effect of the transparent touch screen driving circuit,this paper also designs the corresponding data collection platform to detect the touch effect of the transparent touch screen,including touch sensing circuit and corresponding graphical interface.And the touch sensing circuit will also be presented as a printed circuit board(PCB).Finally,verify the function of the transparent touch screen driving circuit.The transparent touch screen driving circuit and touch sensing circuit will operate normally under the control of the microprocessor controller,and the touch data of the transparent touch screen will be transmitted to the computer and displayed dynamically by the graphical interface.The designed transparent touch screen driving circuit outputs a positive voltage of 15 V and a negative voltage of-5V.In order to control the conduction and the cut-off state of the thin film transistor integrated in the transparent touch screen to achieve the purpose of controlling touch points,it can selectively output two voltages under the control of an external microprocessor.And the driving circuit can selectively control the working states of some touch points individually.Although the transparent touch screen driving circuit in this study can only drive 24 touch points at the same time,its structure is extensible and can be expanded according to the change of the number of touch points.