A printed proximity-sensing surface based on organic pyroelectric sensors and organic thin-film transistor electronics
In this work is presented for the first time a large-area proximity sensing surface fabricated by printing organic materials and featuring distributed Analog Frontend Electronics (AFE) based on Organic Thin-Film Transistors (OTFTs). The sensor foil enables detecting the presence of approaching heat sources (like humans or moving machines) at a distance. This development is expected to play an important role to increase the level of security, improve the interaction modalities and reduce the costs in Human-Robot-Interaction (HRI) applications. The core of the sensing surface is a 5x10 matrix of Long Wavelength Infra-Red (LWIR) organic pyroelectric sensors (frontplane) laminated with the OTFT AFE (backplane). Both front and backplane foils are fabricated using printing techniques. The AFE provides sensor signal amplification and unambiguous pixel addressing in order to maximize the detection distance and reduce the pixel crosstalk. The matrix backplane electronics achieves an average yield of 82% fully working pixels over 200 measured ones and a maximum foil yield of 96%, corresponding to 768 defect-free devices: this is the largest reported circuit complexity achieved by a printed OTFT circuit to-date. Proximity detections of human hand approaches from different directions and position tracking of a movable heat source have been successfully demonstrated with the proposed system-on-foil up to a distance of ∼ 0.4 m and at a readout speed of 100 frames/s.
To reference this document use:
Thin film circuits
Thin film transistors
Analog front end
Organic thin film transistors
Nature Electronics, 5 (5), 289-299