All-in-plane image sensors free from readout integrated circuits

TL;DR

This paper presents a novel in-plane image sensor architecture that eliminates the need for electrical readout circuits at each pixel, using impedance tomography for image reconstruction, enabling simpler and miniaturized imaging devices.

Contribution

The authors introduce a new imaging approach with neighbor-connected photoresistive pixels and impedance tomography, validated experimentally for infrared imaging without individual pixel readout circuits.

Findings

Successfully demonstrated infrared imaging with 24 and 264 pixel arrays.

Reconstruction is mathematically stable and robust to pixel variations.

Significantly simplifies imaging device architecture.

Abstract

High resolution image sensors require electrical access to each individual pixel for signal readout. Such access is especially challenging for ultra-miniaturized pixels, for heterogeneously integrated sensing and readout layers in long-wavelength detectors, and for novel light-sensing materials with unestablished integration to silicon chips. Here, we introduce and experimentally validate a novel imaging approach that does not require electrical connections to individual pixels. The sensor matrix involves photoresistive pixels connected neighbor-to-neighbor and packed into a rectangular lattice. The signal readout is based on electrical impedance tomography applied to the photoresistance: the photovoltage is measured at the matrix boundary at various positions of injected bias current, and the image is reconstructed algorithmically. We present experimental validations for moderate-size infrared imagers based on multilayer graphene (24 pixels) and amorphous vanadium oxide (264 pixels). The reconstruction procedure is mathematically stable, sustainable to variations of pixel resistivity and photosensitivity, and its complexity is that of linear system solution. The proposed method enables unprecedented architecture simplification of imaging devices.