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Proceedings Paper

TFT active image sensor with current-mode readout circuit for digital x-ray fluoroscopy
Author(s): Nader Safavian; G. R. Chaji; A. Nathan; J. A. Rowlands
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Paper Abstract

In this paper, an innovative current-programmed, current-output active TFT image sensor suitable for real time x-ray imaging (fluoroscopy) using hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) technology coupled with a transimpedance feedback column amplifier for pixel signal readout is presented. Simulation results show that this new TFT circuit can successfully compensate for variations in a-Si:H TFT characteristics under prolonged gate voltage stress. The readout is fast enough to fulfill the timing requirements of digital fluoroscopy. Dynamic effects such as charge injection, charge feed-through and drain-source voltage variation as well as additive noise of the pixel TFTs induce error on the output current of the pixel. To explore the dependence of this error on pixel parameters, concise analytical expressions are derived which can be used to reduce the amount of the output current error by proper pixel design.

Paper Details

Date Published: 13 October 2005
PDF: 9 pages
Proc. SPIE 5969, Photonic Applications in Biosensing and Imaging, 596929 (13 October 2005); doi: 10.1117/12.629811
Show Author Affiliations
Nader Safavian, Univ. of Waterloo (Canada)
G. R. Chaji, Univ. of Waterloo (Canada)
A. Nathan, Univ. of Waterloo (Canada)
J. A. Rowlands, Univ. of Toronto (Canada)

Published in SPIE Proceedings Vol. 5969:
Photonic Applications in Biosensing and Imaging
Brian C. Wilson; Richard I. Hornsey; Warren C. W. Chan; Ulrich J. Krull; Robert A. Weersink; Kui Yu, Editor(s)

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