ABSTRACT
Thin-film transistors (TFTs) [1,2] have been widely utilized for flat-panel displays (FPDs) [3], such as liquid-crystal displays (LCDs) [4], organic light-emitting diode displays (OLEDs) [5] and electronic papers (EPs) [6]. They have been recently applied to driver circuits, system-on-panel units [7] and general electronics [8], such as information processors [9], integrated beside the FPDs. However, the essential features of the thin-film technology are that functional devices, such as active-matrix circuits, amplifying circuits and general circuits, can be fabricated on large and flexible substrates at low temperature and low cost. These features can be employed not only in the FPDs but also sensor applications because the active-matrix circuits are required for some kinds of area sensors, amplifying circuits are necessary to amplify weak signals from sensor devices, large areas are sometimes needed to improve the sensitivities, and flexible substrates are convenient when they are put anywhere on demand. Therefore, we have studied potential possibilities of the thin-film sensors based on TFT technologies [10].
