Solid-State Image Sensor Charge Merging for Faster Pixel Readout
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Solution Overview
Problem
Existing solid-state imaging devices face challenges in effectively adding signal electric charges across multiple pixels, limiting their performance and flexibility in imaging applications.
Innovation Solution
The implementation of a solid-state imaging device with a photoelectric conversion film, a first electrode, a second electrode, a first electric charge accumulation section, a reset transistor, and an electric potential generator that applies a specific electric potential (VPD) to pixels, allowing signal electric charges to be accumulated and read out efficiently across both readout and non-readout pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal electric charges are accumulated in each pixel separately, then measurement precision is improved, but device complexity increases due to requiring separate readout circuits for each pixel
Solution Approach 1:
Multiple pixels share a common first electric charge accumulation section (floating diffusion region) where signal electric charges from different pixels are accumulated together. This merging approach allows simultaneous accumulation of signals from multiple pixels while using a single readout circuit, thereby reducing device complexity while maintaining measurement precision through the shared accumulation mechanism
Solution Approach 2:
The first electric charge accumulation section serves multiple functions: it accumulates signal electric charges from multiple different pixels, acts as a shared storage node, and enables simultaneous readout of multiple pixel signals through a single readout circuit. This multi-functionality reduces the overall number of components needed in the imaging device
2Productivity
If readout is performed from every pixel, then productivity is improved, but loss of time increases due to sequential readout requirements
Solution Approach 1:
Signal electric charges from multiple pixels are merged into a single first electric charge accumulation section, enabling simultaneous readout of multiple pixel signals through one readout circuit. This eliminates the need for sequential access to individual pixel circuits, significantly reducing readout time while maintaining high productivity through efficient batch processing of multiple pixel signals
3Manufacturing precision
If electric potential is applied to all pixels during accumulation, then manufacturing precision is improved, but use of energy increases
Solution Approach 1:
Electric potential is applied selectively only to specific pixels that require signal accumulation during the accumulation period, rather than uniformly to all pixels. This localized approach maintains precise control over charge accumulation in active pixels while minimizing energy consumption by leaving other pixels in a low-power state, thereby resolving the contradiction between manufacturing precision and energy usage
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 enables the efficient accumulation and reading out of signal electric charges, enhancing the imaging device's ability to add charges across pixels, reducing noise, and allowing for flexible arrangement of readout and non-readout pixels, while maintaining high conversion efficiency and speed.
Implementation Method 1
A solid-state imaging device has been developed which uses a compound semiconductor such as InGaAs, for example, as a photoelectric conversion film
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
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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 that accumulates signal electric charges which are generated in the photoelectric conversion film and are moved via the first electrode, a reset transistor that is provided to each pixel and applies a reset electric potential to the first electric charge accumulation section, 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 out of the plurality of 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 between the first electrode and the second electrode when the reset electric potential is applied to the first electrode.