Development And Application Of Tension Control System For Roll-to-roll Atomic Layer Deposition Equipment

The roll-to-roll atomic layer deposition equipment is an industrial thin film preparation equipment based on spatial atomic layer deposition technology.It is widely used in the fields of national defense,aerospace,flexible display and semiconductor due to its advantages of high yield,low cost and large-scale thin film preparation.Tension control,as one of the key technologies in roll-to-roll atomic layer deposition equipment,directly or indirectly affects the efficient preparation of thin film products.However,the existing system cannot guarantee the precise control of tension and lacks the ability of data monitoring.Therefore,this paper aims to independently research and develop a set of tension control system with low cost,easy operation and on-line monitoring ability of data visualization,and to effectively improve the quality of thin film products and the reliability of the preparation process through the precise control of tension.First of all,combined with the volume of the composition of atomic layer deposition equipment characteristics,the overall tension closed-loop control scheme was put forward,and through analysis,selection and design of the interactive system,tension detection and amplification components,drive components and tension control algorithm,the overall technical solution was established,which takes upper computer software as interactive method,embedded system as control unit,the cylinder as driving device,tension control algorithm based on PID method as control strategy.In the hardware part,through the function analysis of the control system circuit,eight functional modules,such as power module,main control module,communication and interaction module,debugging output module and signal sampling module,were determined.And through the design and manufacture of the schematic diagram and the circuit board,the realization of the control system circuit hardware was completed.In the software part,the software scheme based on embedded real-time operating system（RTOS）is adopted,and the functions of data acquisition,storage,control and communication of the lower computer were realized by combining the analysis and design of logic block diagram.Based on the development environment of Qt Creator,the upper computer interaction software with the functions of connection,communication,waveform display and one-button parameter setting were designed and completed.The software has the characteristics of perfect function,beautiful user interface and simple interaction.The tension control system was tested,and the results show that the steady error of tension can reach the minimum of less than 5% under the static condition,and the fluctuation rate can reach the minimum of less than 15% under the moving condition,which can meet the use requirements.Through the analysis of the film deposition experiment results under different tension setting conditions,it is found that when the tension setpoint is set at 25 N and 35 N,the vibration of the equipment,the growth of the film and other processes are significantly improved,which is of great significance for the efficient preparation of the film.