Hybrid Concurrent Driving Technique for Large Touch Screen Panels

Abstract

Large interactive touch screen displays are witnessing widespread acceptance among users, while approaching hundreds of Tx/Rx channels and reducing useable bandwidth. This presents several challenges and renders conventional touch detection methods ineffective. For smaller displays, employing concurrent Tx driving methods like Frequency Division Concurrent Driving (FDCD) or Coded Division Concurrent Driving (CDCD) improves SNR and substantially enhances report rate. In larger Touch Screen Panels (TSPs), however, it becomes difficult to drive the entire panel concurrently with either orthogonal frequencies or codes. In this work, a hybrid concurrent driving technique, which combines both FDCD and CDCD, is proposed and evaluated. The proposed driving technique aims to achieve better efficiency in terms of utilizing limited frequency bandwidth and improving the SNR. This work realizes the proposed driving technique by a MATLAB implementation. This paper includes SNR analysis for various scenarios, to evaluate the effectiveness of the proposed technique. The analysis reveals that the proposed method performs reliably under significant amount of noise for all corner cases.