Due to changes in the form factor of display panels and touch screen panels in various devices, capacitive touch systems have evolved to address various issues such as low power consumption, noise immunity, and small chip size. Furthermore, some devices have applications that use a stylus. Since the stylus operates similarly to a finger touch, it encounters similar issues. Recent research trends focus on addressing key issues such as noise, which is primarily caused by the self-capacitor formed between the display cathode and the touch screen panel. In this paper, Various research papers discussing methods to eliminate external noise will be reviewed. These advancements enhance noise immunity in touch systems, making it easier to use thinner and more flexible panels. These progress make touch technology more versatile and reliable in various applications.

A study on capacitive characteristics of stylus pen for touch panel are progressed in this paper. Also the main factors for capacitive sensitivity are studied. Namely, highly sensitive stylus pen which can be applied to capacitive touch panel are studied based on the analysis of materials and process conditions regardless of pattern shapes. Stylus pen was made of PDMS(Poly-Di-Methyl-Siloxane) and conductive metal powders which does not damage the touch panel surface. We tried to get the advantages of both the properties of soft PDMS and conductive metal powders. We found that potential difference of capacitance change with conductivity of the composite materials(PDMS + metal powders) it implies that during touch process, large voltage difference can be caused by the high conductive materials of stylus pen. Stylus pen made by PDMS with mixed with Ag powders which has large conductivity shows more capacitance change of 1 pF than PDMS with other materials of Ni or C powders.