Asymmetric Potential Barriers in Photoelectric Conversion Elements
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Solution Overview
Problem
In imaging apparatuses, differences in sensitivity among photoelectric conversion elements can lead to saturation issues, causing charge leakage and a decrease in focus-ranging precision, especially when trying to maintain high subject luminance in one direction parallel to the imaging plane.
Innovation Solution
The structure includes photoelectric conversion units with varying potential barriers between elements, where the height of the barrier between elements in one direction is less than in another direction, preventing charge leakage to adjacent elements in the direction of higher luminance, thus maintaining focus-ranging precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the potential barrier between photoelectric conversion elements is lowered to obtain proper signals despite sensitivity differences, then signal quality improves, but charge leakage increases and focus-ranging precision decreases
Solution Approach 1:
The patent applies local quality by creating asymmetric potential barriers between adjacent photoelectric conversion elements. Specifically, the potential barrier in the first direction (where high luminance subjects are imaged) is made higher than in the second direction, allowing selective charge confinement where needed while permitting controlled charge sharing in other directions. This resolves the contradiction by maintaining focus-ranging precision in the critical direction without sacrificing signal quality overall.
Solution Approach 2:
The patent implements asymmetry by designing different potential barrier heights in different spatial directions. The barrier between elements in the first direction is configured to be higher than barriers in the second direction, creating an asymmetric charge confinement structure. This asymmetric design allows the system to maintain precision in the direction of highest importance (first direction) while accepting controlled charge leakage in less critical directions, thereby resolving the technical contradiction.
2Illumination intensity
If photoelectric conversion elements are made highly sensitive to capture high subject luminance, then luminance capture improves, but saturation occurs causing charge leakage to adjacent elements
Solution Approach 1:
The patent applies local quality by implementing direction-dependent potential barriers that adapt to the imaging requirements. In the first direction where high luminance subjects are captured, higher potential barriers prevent saturation-induced charge leakage, maintaining focus-ranging precision. In the second direction, lower barriers allow controlled charge sharing. This resolves the contradiction between capturing high luminance and maintaining precision by making the barrier height locally adaptive to directional requirements.
Solution Approach 2:
The patent applies preliminary anti-action by pre-configuring asymmetric potential barriers before charge saturation can occur. The higher barriers in the first direction are established in advance to prevent the harmful effect of charge leakage that would otherwise occur during saturation. This preemptive measure allows the elements to handle high luminance without losing focus-ranging precision, resolving the contradiction before it manifests.
3Measurement precision
If uniform potential barriers are used between all adjacent photoelectric conversion elements, then manufacturing simplicity is maintained, but focus-ranging precision cannot be optimized for specific directions
Solution Approach 1:
The patent applies local quality by making the potential barrier structure directionally dependent rather than uniform. The barrier height varies based on the spatial direction, being higher in the first direction for precision-critical applications and lower in the second direction. This localized differentiation resolves the contradiction by optimizing precision where needed while accepting increased structural complexity only to the extent necessary for directional optimization.
Solution Approach 2:
The patent implements asymmetry in the potential barrier configuration, creating a deliberately non-uniform structure where barriers differ in height depending on direction. This asymmetric design resolves the contradiction between precision optimization and manufacturing simplicity by accepting controlled complexity only in the dimensions that matter for the primary imaging function, while maintaining simplicity in less critical aspects.
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 approach allows for high focus-ranging precision in one direction while allowing charge leakage in another direction, enabling focus ranging up to higher subject luminance without compromising precision.
Implementation Method 1
the height of a potential barrier produced at a region between plural photoelectric conversion elements against signal charges
Implementation Method 2
signals produced by plural photoelectric conversion elements are processed as one pixel signal
Data Source
AI summary
An imaging apparatus includes a micro lens, a second photoelectric conversion element that is located adjacent to a first photoelectric conversion element in a first direction, and a third photoelectric conversion element that is located adjacent to the first photoelectric conversion in a second direction intersecting with the first direction, wherein the height of a potential barrier produced at a region between the first and third photoelectric conversion elements against a signal charge is less than the height of a potential barrier produced at a region between the first and second photoelectric conversion elements against a signal charge.