Imaging Sensor Signal Accumulation Circuit for Dynamic Range Expansion

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Solution Overview

Problem

Existing imaging sensors with global electronic shutters face challenges in signal accumulation and dynamic range expansion, particularly in connecting multiple signal holding units to a single amplification unit, which affects noise component separation and signal output efficiency.

Innovation Solution

The proposed imaging sensor configuration includes multiple sets with photoelectric conversion units, signal holding units, and transfer units, where signals from different accumulation periods are transferred to common input nodes of amplification units, allowing for simultaneous signal accumulation and expanded dynamic range without signal saturation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple signal holding units are connected to separate amplification units, then signal output reliability is improved, but device complexity and circuit area increase

Engineering Contradiction:

Improvesignal output reliabilityVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple signal holding units (first signal holding units and second signal holding units) are connected to a common input node of a single amplification unit through separate transfer paths. This merging approach allows signals from different accumulation periods to be processed by one amplification unit, reducing the total number of amplification units needed while maintaining signal integrity and output reliability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The signal transfer path is segmented into multiple independent routes: one path transfers signals from first signal holding units to the common input node, and another path transfers signals from second signal holding units to the same node. This segmentation allows parallel signal transmission without interference, enabling reliable signal output while sharing a single amplification unit

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If signals from multiple accumulation periods are accumulated simultaneously, then dynamic range is expanded, but signal saturation occurs

Engineering Contradiction:

Improvedynamic rangeVSAvoidsignal saturation

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The accumulation process is divided into separate accumulation periods with dedicated transfer paths. First signal holding units accumulate signals during first accumulation periods, while second signal holding units accumulate signals during second accumulation periods. This temporal segmentation allows the system to handle signals of different intensities without saturation by processing them in separate time windows

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different accumulation modes by controlling the transfer timing. During certain periods, first signal holding units are active; during other periods, second signal holding units are active. This dynamic operation allows the imaging sensor to adapt to varying light conditions and expand dynamic range while preventing signal saturation through timed signal transfer

Inventive Principle:

Principle #15Dynamics

3Device complexity

If one amplification unit processes multiple signal holding units, then device complexity is reduced, but signal transfer control becomes more difficult

Engineering Contradiction:

Improvenumber of amplification unitsVSAvoidsignal transfer control

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The control system divides signal transfer operations into distinct phases: first transfer units transfer signals from photoelectric conversion units to first signal holding units during first accumulation periods, while third transfer units transfer signals to second signal holding units during second accumulation periods. This segmented control approach simplifies the timing and sequencing requirements compared to managing multiple amplification units

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Transfer units serve as intermediary components between photoelectric conversion units and signal holding units, and between signal holding units and the common input node. These intermediaries buffer and manage the signal flow, isolating the amplification unit from complex transfer control requirements while maintaining efficient signal transmission

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enhances the dynamic range by 20 dB, reduces circuit area, and enables efficient noise component separation and signal output, improving the imaging sensor's functionality and accuracy.

Implementation Method 1

a pixel is provided with a photoelectric conversion unit

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS10304894B2Imaging sensor, imaging system, and moving body

Publication Date: 2019.05.28 CANON KK

AI summary

Respective first signal holding units of a plurality of sets are commonly connected to an input node of an amplification unit of one set via a second transfer unit of a set to which the first signal holding unit corresponds, and respective second signal holding units of the plurality of sets are commonly connected to the input node of the amplification unit of one set via a fourth transfer unit of a set to which the second signal holding unit corresponds.