Stacked Imaging Element Layout to Prevent Charge Blooming
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Solution Overview
Problem
In imaging elements with a stacked configuration, charge generated by photoelectric conversion can flow into adjacent elements, leading to blooming and degradation of image quality.
Innovation Solution
Incorporating a charge storage electrode separated from the first electrode by an insulating layer, with a potential difference that attracts charges strongly to the storage region, preventing flow into adjacent elements, and using a charge movement control electrode to control the electric field and potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stacked configuration with photoelectric conversion units is used, then color imaging capability is improved, but charge may flow into adjacent elements causing blooming
Solution Approach 1:
The photoelectric conversion layer is divided into multiple independent photoelectric conversion units, each with its own charge storage electrode and insulating layer. This segmentation isolates charge carriers within each unit, preventing charge blooming between adjacent elements while maintaining color imaging capability through the stacked configuration of multiple units sensitive to different wavelengths.
Solution Approach 2:
An insulating layer is introduced as an intermediary between the photoelectric conversion layer and the charge storage electrode. This insulating layer acts as a barrier that prevents charge from flowing into adjacent elements, thereby suppressing blooming while still allowing the stacked configuration to function for color imaging.
2Reliability
If a charge storage electrode is added to prevent blooming, then image quality is improved, but device complexity increases
Solution Approach 1:
The charge storage electrode serves multiple functions: it stores photoelectrically generated charge, prevents charge blooming to adjacent elements, and maintains the electric field necessary for charge collection. This multi-functionality improves image quality without proportionally increasing device complexity, as a single component achieves multiple objectives.
Solution Approach 2:
The charge storage electrode is positioned beneath the photoelectric conversion layer, creating a nested structure where the charge storage function is integrated within the existing photoelectric conversion unit architecture. This nesting approach adds the necessary charge storage capability while minimizing additional structural complexity.
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 suppresses kTC noise and prevents charge blooming, maintaining image quality by ensuring charges are stored and transferred efficiently within the intended pixel.
Implementation Method 1
a photoelectric conversion layer (313) including an organic material... The first photoelectric conversion unit 311 photoelectrically converts, for example, green light
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An imaging element includes a photoelectric conversion unit including a first electrode 11, a photoelectric conversion layer 13, and a second electrode 12 that are stacked, in which the photoelectric conversion unit further includes a charge storage electrode 14 arranged apart from the first electrode 11 and arranged to face the photoelectric conversion layer 13 through an insulating layer 82, and when photoelectric conversion occurs in the photoelectric conversion layer 13 after light enters the photoelectric conversion layer 13, an absolute value of a potential applied to a part 13C of the photoelectric conversion layer 13 facing the charge storage electrode 14 is a value larger than an absolute value of a potential applied to a region 13B of the photoelectric conversion layer 13 positioned between the imaging element and an adjacent imaging element.