Optical panel with full multitouch using patterned indium tin oxide
Wen-Yang Chang, Heng-Ju Lin, Jin-Sheng Chang · Optics Letters · 2011
This study proposes an optical panel with full multitouch using the patterned indium tin oxide (ITO) and an algorithm matrix to avoid ghost points. The patterned ITOs include the virtual high and low impedances. The algorithm matrix with two configurations of equivalent circuits for array scanning is derived using the voltage divider rule. The fabrication process of the multitouch panel is carried out using microelectromechanical systems technology. The optical characteristics of the multitouch panel in the UV, visible, and IR regions are measured using photometric analysis. The multitouch panel, containing sensing pixels of 30×30 arrays, has a pixel size of 2×2 mm2 and a pitch distance of 2 mm. The average values of high and low impedances are 53.23 and 9.3 k Ω, respectively. The maximum transmittance is about 74.2% at the wavelength of 692 nm. The multitouch panel based on high and low impedance patterns has been specifically designed to offer good adjacent touch resolution and sensitivity for reality multitouch applications. In addition, the patterned design and the algorithm matrix provide unlimited multitouch points and avoid ghost points.