Image Sensor Shielding Layout for Stable Peripheral Circuits
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Solution Overview
Problem
In stacked image sensors, the voltage applied to transparent electrodes can cause instability in control circuits due to adverse effects on peripheral circuit operations, leading to unstable circuit performance.
Innovation Solution
The imaging device incorporates a pixel section with a photoelectric conversion film, top and bottom electrodes, and a first light-shielding film electrically connected to the top electrode, along with a peripheral circuitry section including a second light-shielding film that overlaps the circuitry, ensuring the two light-shielding films are separated to prevent potential fluctuations from affecting the peripheral circuitry, thereby stabilizing circuit operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first light-shielding film is electrically connected to the top electrode to control potential, then photoelectric conversion efficiency is improved, but potential fluctuations adversely affect peripheral circuit operations
Solution Approach 1:
The light-shielding film is divided into two separate films: the first light-shielding film electrically connected to the top electrode for photoelectric conversion control, and the second light-shielding film covering the peripheral circuitry for electrical shielding. This segmentation isolates potential fluctuations in the pixel section from the peripheral circuitry, preventing interference while maintaining photoelectric conversion efficiency.
Solution Approach 2:
The second light-shielding film acts as an intermediary shielding layer between the peripheral circuitry and the first light-shielding film. It blocks electrical interference and potential fluctuations from affecting the peripheral circuit operations, while allowing the first light-shielding film to maintain its electrical connection for photoelectric conversion control.
2Device complexity
If a single light-shielding film is used for both photoelectric conversion and peripheral circuit shielding, then device complexity is reduced, but circuit operation stability deteriorates
Solution Approach 1:
The light-shielding function is segmented into two independent films with distinct roles: the first film serves photoelectric conversion by being electrically connected to the top electrode, while the second film provides electrical shielding for the peripheral circuitry. This segmentation resolves the conflict between simplicity and stability by using two specialized components instead of one multi-functional component.
Solution Approach 2:
Different regions of the device receive different light-shielding treatments: the pixel section receives controlled potential management through the first light-shielding film, while the peripheral circuitry section receives electrical interference protection through the second light-shielding film. This local differentiation optimizes performance for each specific function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration stabilizes the operation of peripheral circuitry by isolating the potential fluctuations of the first light-shielding film from the second light-shielding film, ensuring the imaging device maintains stable circuit performance and reduces image quality deterioration.
Implementation Method 1
photodetecting elements for generating electrical signals corresponding to the amounts of incident light
Implementation Method 2
a first light-shielding film that overlaps part of the photoelectric conversion film in a plan view
Data Source
AI summary
An imaging device includes a pixel section and a peripheral circuitry section provided around the pixel section. The pixel section includes: a photoelectric conversion film; a top electrode located above the photoelectric conversion film; bottom electrodes that face the top electrode, with the photoelectric conversion film being disposed between the top electrode and the bottom electrodes; and a first light-shielding film that overlaps part of the photoelectric conversion film in a plan view and that is electrically connected to the top electrode. The first light-shielding film has electrical conductivity. The peripheral circuitry section includes peripheral circuitry and a second light-shielding film that overlaps at least part of the peripheral circuitry in the plan view. The first light-shielding film and the second light-shielding film are separated from each other.