A Review on Digital Pixel Sensors

TL;DR

This review comprehensively discusses digital pixel sensors, highlighting their advantages, challenges related to pixel pitch, and potential solutions like compact circuits and 3D integration, to advance imaging technology.

Contribution

It provides a detailed categorization, analysis, and comparison of DPS architectures, emphasizing design strategies to overcome pixel pitch limitations.

Findings

DPS offers high speed and image quality compared to analog sensors.

Pixel pitch increase due to ADC integration limits high-density applications.

Strategies like compact circuits and 3D integration can mitigate pixel size issues.

Abstract

Digital pixel sensor (DPS) has evolved as a pivotal component in modern imaging systems and has the potential to revolutionize various fields such as medical imaging, astronomy, surveillance, IoT devices, etc. Compared to analog pixel sensors, the DPS offers high speed and good image quality. However, the introduced intrinsic complexity within each pixel, primarily attributed to the accommodation of the ADC circuit, engenders a substantial increase in the pixel pitch. Unfortunately, such a pronounced escalation in pixel pitch drastically undermines the feasibility of achieving high-density integration, which is an obstacle that significantly narrows down the field of potential applications. Nonetheless, designing compact conversion circuits along with strategic integration of 3D architectural paradigms can be a potential remedy to the prevailing situation. This review article presents a comprehensive overview of the vast area of DPS technology. The operating principles, advantages, and challenges of different types of DPS circuits have been analyzed. We categorize the schemes into several categories based on ADC operation. A comparative study based on different performance metrics has also been showcased for a well-rounded understanding.