Low‐Cost Fabrication Method for Thin, Flexible, and Transparent Touch Screen Sensors

• Published in: Advanced materials technologies Vol. 5; no. 9
• Main Authors: Kim, Seong‐jun, Phung, Thanh Huy, Kim, Seora, Rahman, Md. Khalilur, Kwon, Kye‐Si
• Format: Journal Article
• Language: English
• Published: 01.09.2020
• Subjects: capacitive touch panel; laser sintering; near‐field electrospinning; PET substrates; transparent flexible electrodes
• ISSN: 2365-709X; 2365-709X
• DOI: 10.1002/admt.202000441

This study presents a new fabrication method for touch screen sensors using inexpensive, flexible, and transparent polyethylene terephthalate (PET) films. In the proposed method, a transparent capacitive touch sensor array is implemented with two independent axes of invisible electrodes consisting of indium tin oxide (ITO) patterns and bridge electrodes. A low‐cost implementation of the bridge electrodes is achieved by using near‐field electrospinning (NFES) method for the conductive lines with linewidth of 3–5 µm. Then, the printed bridge electrode is sintered using green laser without damaging the PET film. It is demonstrated that two transparent electrodes deposited on a single sheet of PET film can detect the touch location by scanning the driving signal while simultaneously measuring the capacitances from the sensing lines connected via bridge electrodes. Invisible bridge electrodes are printed by using near‐field electrospinning (NFES) of Ag paste ink on a single sheet of indium tin oxide (ITO)‐patterned polyethylene terephthalate (PET) film. Green laser light is used to sinter the printed patterns without damaging PET film. Flexible and transparent touch sensors are demonstrated based on two axes of invisible electrodes of ITO pattern and bridge electrodes.