Image Sensor Optical Black Layout to Block Edge Charge Leakage
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Solution Overview
Problem
The edge portion of the photoelectric conversion layer in imaging devices with organic semiconductor materials is often damaged during processing, leading to electric charges entering the optical black region and hindering its functionality.
Innovation Solution
A common photoelectric conversion layer is used for both effective pixel and optical black regions, with an outer edge electrode positioned to prevent charge leakage into the optical black region, ensuring the optical black region's functionality is not compromised.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common photoelectric conversion layer is used for both effective pixel region and optical black region, then manufacturing complexity is reduced, but edge portion damage during processing causes charge leakage into the optical black region
Solution Approach 1:
A dummy imaging element is introduced as an intermediary component between the optical black region and the effective pixel region. This dummy element acts as a buffer that prevents charge leakage from damaged edge portions of the photoelectric conversion layer from reaching the optical black region, thereby protecting the optical black region's functionality while maintaining the simplicity of using a common photoelectric conversion layer.
Solution Approach 2:
The dummy imaging element is positioned in advance at the boundary between the optical black region and effective pixel region to preemptively block potential charge leakage paths. By preparing this protective structure before edge damage occurs during processing, the optical black region is protected from the anticipated harmful effects of edge portion damage.
2Manufacturing precision
If the photoelectric conversion layer edge is left exposed, then manufacturing precision is improved, but charge leakage occurs at the edge portion during operation
Solution Approach 1:
The dummy imaging element serves as an intermediary barrier that intercepts charges generated at the exposed edge portions of the photoelectric conversion layer. By positioning this dummy element adjacent to the optical black region, it captures and contains edge-generated charges before they can leak into the optical black region, thus eliminating the harmful effect while preserving the manufacturing simplicity of having an exposed edge.
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 effectively prevents charge leakage into the optical black region, maintaining its functionality and improving imaging quality by ensuring the photoelectric conversion layer's integrity.
Implementation Method 1
signal charges generated by photoelectric conversion
Data Source
AI summary
An imaging device includes: an effective pixel region that includes a plurality of imaging elements-A, amplifies signal charges generated by photoelectric conversion, and reads the signal charges into a drive circuit; and an optical black region that includes a plurality of imaging elements-B, surrounds the effective pixel region, and outputs optical black that serves as the reference for black level. In the imaging device, the photoelectric conversion layer forming the plurality of imaging elements-A and the plurality of imaging elements-B is a common photoelectric conversion layer, the common photoelectric conversion layer is located on an outer side of the optical black region, and extends toward an outer edge region surrounding the optical black region, and an outer edge electrode is disposed in the outer edge region.