ABSTRACT
Thin-film transistors (TFTs) have been widely utilized for flat-panel displays (FPDs). The essential feature of the thin-film technology is that functional devices, such as active-matrix circuits, amplifying circuits, and general circuits, can be fabricated on large and flexible substrates at low temperature at low cost. The outstanding advantage can be employed in sensor applications and maximized when they are integrated in FPDs. The chapter proposes a p/i/n thin-film phototransistor as an excellent thin-film photodevice. It aims to compare two types of temperature sensor, 1-transistor 1-capacitor type and ring oscillator type, whose sensitivities are roughly 1°C. The ring oscillator type temperature sensor is available as a digital device. The digital devices are superior to analog devices from the viewpoint of the onward signal operation. The chapter also proposes a magnetic field sensor using a micro-Hall device, which realizes real-time area sensing of a magnetic field.
