Image Sensor Grid Driving Line Architecture for Shutter Delay Reduction

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Solution Overview

Problem

Image sensors face delays in shutter switching due to parasitic resistance and capacitance, especially when using high-frequency drive signals for high-speed continuous shots or 3D imaging, leading to incomplete charge transfer and operational inefficiencies.

Innovation Solution

The implementation of a grid-shaped driving line system with multiple driving buffers applied at opposite ends of each driving line, reducing resistance and increasing driving force, allowing for high-speed switching of shutters without delays, even with high-frequency drive signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a high-frequency drive signal is applied to the shutter for high-speed continuous shots or 3D imaging, then the shutter switching speed is improved, but delay occurs due to parasitic resistance and capacitance causing incomplete charge transfer

Engineering Contradiction:
Improveshutter switching speedVSAvoidcharge transfer completeness
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The pixel array is divided into multiple blocks, with each block containing multiple pixels that share common driving lines. This segmentation allows for localized optimization of driving signals and reduces the impact of parasitic effects on the entire array, enabling high-speed switching while maintaining charge transfer reliability in each block

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Transfer electrodes are introduced as intermediary elements between the shutters and the charge storage regions. These transfer electrodes act as mediators that facilitate complete charge transfer by providing an additional controllable interface, ensuring that high-frequency drive signals can effectively control charge movement without loss due to parasitic effects

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the shutter is opened sufficiently for a short time to obtain high quality images, then image quality is improved, but the shutter must switch extremely quickly which exacerbates delay problems

Engineering Contradiction:
Improveimage qualityVSAvoidshutter switching delay
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The shutter is opened sufficiently for a short time to obtain high quality images, but the shutter must switch extremely quickly which exacerbates delay problems

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Different drive signals with varying frequencies and waveforms are applied to different blocks of pixels. This allows optimization of the drive signal parameters for each specific application scenario, enabling precise control of shutter timing to achieve both high image quality and minimal switching delay

Inventive Principle:
Principle #35Parameter changes

3Force

If multiple driving buffers are applied at opposite ends of each driving line in a grid shape, then resistance is reduced and driving force is increased, but device complexity increases

Engineering Contradiction:
Improvedriving forceVSAvoiddriving line structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The pixel array is divided into multiple blocks, with each block containing multiple pixels that share common driving lines. This segmentation allows for localized optimization of driving signals and reduces the impact of parasitic effects on the entire array, enabling high-speed switching while maintaining charge transfer reliability in each block

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple driving buffers are applied at opposite ends of each driving line in a grid shape, then resistance is reduced and driving force is increased, but device complexity increases

Inventive Principle:
Principle #5Merging (Combining)

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 significantly reduces delay and rise times, enabling normal operation of shutters with high-frequency signals, improving charge transfer efficiency and image quality, particularly in high-resolution and 3D imaging applications.

Implementation Method 1

Each pixel is provided with a photoelectric conversion device such as a photodiode that performs photoelectric conversion

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP2879376B1Image sensor and method of driving image sensor
Publication Date: 2018.07.25 SAMSUNG ELECTRONICS CO LTD
  • EP2879376B1 patent drawingFigure 1~2
  • EP2879376B1 patent drawingFigure 3
  • EP2879376B1 patent drawingFigure 4

AI summary

An image sensor includes a pixel array. The image sensor may include a photoelectric conversion device generating electric charges according to photoelectric conversion in each of a plurality of pixels, a shutter of each of the plurality of pixels controlling movements of the generated electric charges according to a drive signal, a driving line connecting the shutters of all of the plurality of pixels of the pixel array, through which the drive signal is transmitted, and a plurality of driving buffers applying the drive signal to the driving line.