Resolution characteristics and a new operation method for a field-emitter image sensor with HARP target

Abstract

A new type of image sensor featuring a unique structure is studied with the aim of achieving both super-high sensitivity and ultrahigh definition. This image sensor combines a field emitter array (FEA) and a high-gain avalanche rushing amorphous photoconductor (HARP) target. We investigated the conditions for improving resolution in a vacuum chamber by inserting a mesh electrode between the FEA and the target. The results indicate that the resolution can be improved by making the accelerating electric field between the FEA gate and the mesh stronger, and by placing the mesh closer to the FEA. We also proposed a new parallel readout operation that is suitable for an ultrahigh-definition image sensor. By dividing the target into multiple segments and reading out signals from each segment simultaneously, the operating frequency can decrease. In our first attempt, a good 60 x 60 pixel image was synthesized from two 30 x 60 pixel segments.