Hemispherical thin-film transistor passive pixel sensors

Hemispherical image sensors are very promising technology for cameras, surveillance systems and artificial vision. We report on the electrical performance of the hydrogenated amorphous silicon thin-film transistor passive pixel image sensor (PPS) circuits fabricated on a hemispherical substrate using maskless laser-write lithography (LWL). The level-to-level registration and alignment over the curved surface with a high accuracy are demonstrated for the LWL in this work. The obtained results clearly show that it is possible to realize active-matrix PPS with a 150 mu m pixel pitch and a dynamic range of about 40 dB that is suitable for hemispherical image sensors. (C) 2009 Elsevier B.V. All rights reserved.