Solid-State Image Sensor Charge Sharing for Low-Noise Pixel Readout
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Solution Overview
Problem
Existing solid-state imaging devices face challenges in efficiently adding signal electric charges across multiple pixels, leading to limitations in noise reduction, flexibility in pixel arrangement, and photoelectric conversion efficiency.
Innovation Solution
The implementation of a solid-state imaging device with a photoelectric conversion film and an electric potential generator that applies a specific electric potential VPD to non-readout pixels, allowing signal electric charges to move to readout pixels for accumulation and readout, thereby enhancing charge addition and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal electric charges are accumulated in separate pixel circuits for each pixel, then measurement precision is improved, but device complexity increases and productivity decreases
Solution Approach 1:
Multiple pixel circuits are merged into a single integrated circuit structure where signal electric charges from multiple pixels are accumulated in a shared first electric charge accumulation section. This consolidation reduces device complexity while maintaining the ability to accurately accumulate and measure signal charges from multiple pixels simultaneously.
Solution Approach 2:
The first electric charge accumulation section serves as a universal accumulation node for signal electric charges from multiple pixels, rather than requiring separate accumulation sections for each pixel. This multi-functional design improves productivity and reduces complexity while preserving measurement precision through the shared accumulation mechanism.
2Adaptability or versatility
If readout pixels are distributed across the pixel array, then adaptability is improved, but signal electric charge addition efficiency deteriorates
Solution Approach 1:
A transfer electrode is introduced as an intermediary component between the photoelectric conversion film and the first electric charge accumulation section. This transfer electrode efficiently collects signal electric charges from multiple distributed pixels and transports them to the accumulation section, maintaining high addition efficiency regardless of pixel arrangement flexibility.
Solution Approach 2:
The pixel array is segmented into multiple independent pixels with individual first electrodes, allowing flexible arrangement of readout and non-readout pixels. Meanwhile, the charge accumulation function is segmented into a separate first electric charge accumulation section, enabling efficient charge collection from all pixels without being constrained by pixel distribution.
3Productivity
If electric potential difference is increased to improve charge collection speed, then productivity is improved, but loss of energy increases
Solution Approach 1:
The electric potential generator applies an electric potential VPD to the first electrode before signal electric charges need to be collected, preparing the electric field in advance. This preliminary action enables efficient charge collection when needed without requiring continuous high energy input, thus improving productivity while reducing overall energy loss.
Solution Approach 2:
The electric potential VPD is applied periodically or as needed rather than continuously, with the electric potential generator activating only when charge collection is required. This periodic application maintains high charge collection speed when active while significantly reducing energy consumption during inactive periods.
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 enables efficient addition of signal electric charges across pixels, reduces noise, and maintains high photoelectric conversion efficiency while allowing flexible arrangement of readout and non-readout pixels, improving imaging performance.
Implementation Method 1
a photoelectric conversion film provided over a plurality of pixels
Implementation Method 2
an electric potential generator that applies, during a period in which the signal electric charges are accumulated in the first electric charge accumulation section, an electric potential VPD to the first electrode of each of at least one or more pixels
Data Source
AI summary
A solid-state imaging device including a photoelectric conversion film provided over a plurality of pixels, a first electrode electrically coupled to the photoelectric conversion film and provided to each pixel, a second electrode opposed to the first electrode, the photoelectric conversion film being interposed between the second electrode and the first electrode, a first electric charge accumulation section, a reset transistor that is provided to each pixel, and an electric potential generator that applies, during a period in which the signal electric charges are accumulated in the first electric charge accumulation section, an electric potential VPD to the first electrode of each of at least one or more pixels, an electric potential difference between the first electrode and the second electrode when the electric potential VPD is applied to the first electrode being smaller than an electric potential difference when a reset electric potential is applied to the first electrode.