Photoelectric Conversion Apparatus Shading Reduction via Substrate Segmentation

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Solution Overview

Problem

Shading occurs in photoelectric conversion apparatuses due to potential changes in electrically conductive lines, affecting the accuracy of image capture and signal readout, particularly from magnetic noise.

Innovation Solution

The apparatus employs a stacked substrate configuration with specific joints and conductive lines to apply a drive potential, reducing the influence of magnetic noise by supplying the ground potential directly to the readout circuit and pixel array, and using variable capacitance in the AD converter to minimize shading effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ground potential is supplied from a ground line in the pixel array to the readout circuit on another substrate, then the readout circuit can operate, but shading occurs due to potential changes in the electrically conductive line

Engineering Contradiction:
Improvereadout circuit operationVSAvoidimage capture accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent divides the substrate into multiple regions: a first substrate containing the pixel array, a second substrate containing the readout circuit, and a third substrate positioned between them. The third substrate acts as an intermediate layer to supply ground potential independently, segmenting the potential supply path to prevent magnetic noise coupling between the pixel array and readout circuit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The third substrate serves as an intermediary element that mediates the ground potential supply between the first and second substrates. By introducing this intermediate substrate with its own ground potential supply structure, the patent prevents direct coupling that would cause shading, while still enabling proper operation of the readout circuit.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a stacked substrate configuration is used to separate pixel array and readout circuit, then magnetic noise influence is reduced, but device complexity increases

Engineering Contradiction:
Improvesignal readout accuracyVSAvoidsubstrate structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the third substrate: it serves as a structural support layer, a ground potential supply layer, and an electromagnetic shielding layer. By merging these functions into a single intermediate substrate, the overall device complexity is managed while achieving the goal of reducing magnetic noise influence.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The third substrate is designed with multi-functionality, serving simultaneously as a mechanical support structure, an electrical ground potential supply path, and an electromagnetic interference barrier. This universal design approach reduces the need for additional separate components, balancing complexity reduction with performance improvement.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively reduces shading by stabilizing the ground potential and minimizing the impact of magnetic noise, leading to improved image capture and signal readout accuracy across all rows of the pixel array.

Implementation Method 1

a first substrate 10 forming a photoelectric conversion apparatus 1, a second substrate 20 forming a readout circuit 200

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP3745709B1Photoelectric conversion apparatus and equipment
Publication Date: 2022.03.09 CANON KK
  • EP3745709B1 patent drawingFigure 1
  • EP3745709B1 patent drawingFigure 2
  • EP3745709B1 patent drawingFigure 3

AI summary

A photoelectric conversion apparatus includes a first substrate including a pixel array, a second substrate including a readout circuit configured to read out a signal from the pixel array, and a drive terminal to which a drive potential is externally applied. The readout circuit includes a first node to which the drive potential is supplied from the drive terminal via an electrically conductive line arranged in the pixel array, and a second node to which the drive potential is supplied from the drive terminal without going through the pixel array.