Compact Optical Sensor Based on Thin-Film Transistors for Large Interactive Displays Using Red/Green/Blue Laser Pointers

A compact thin-film transistor-based (TFT-based) optical sensor is fabricated by combining the processes of hydrogenated amorphous silicon (a-Si:H) and color filters, which are extensively used in liquid crystal displays (LCDs). To increase sensor density of an interactive display and thereby to achieve the accurate detection of the position of optical inputs, the proposed optical sensor combines three sensing structures that respectively detect red, green, and blue light. The three sensing structures use only one ambient light compensation structure, further simplifying the proposed sensor. Measurements demonstrate that red, green, and blue light from 5 mW laser pointers is successfully detected under ambient illumination from 0 lux to 16,000 lux, benefiting the realization of complete optical input functions for large-scale interactive applications.