Image Pickup Device Electric Potential Adjusting Electrode Uniformity

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Solution Overview

Problem

Stacked-type image pickup devices suffer from image unevenness due to the structure of the pixel electrodes and photoelectric conversion layers, leading to poor image quality and sensitivity issues.

Innovation Solution

The introduction of an electric potential adjusting electrode and a signal reading portion configured to maintain uniform electric charge collection across all pixel electrodes, using a conductive material for the opposing electrode to allow light incidence and applying a voltage to create an electric field for charge collection, while the electric potential adjusting portion ensures the electric potential of the electric potential adjusting electrode remains within a predetermined range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a stacked-type image pickup device structure is used to improve light use efficiency and sensitivity, then light use efficiency and sensitivity are improved, but image unevenness occurs due to the structure of pixel electrodes and photoelectric conversion layers

Engineering Contradiction:
Improvelight use efficiencyVSAvoidimage uniformity
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

An electric potential adjusting electrode is introduced as an intermediary component between the pixel electrode and the opposing electrode. This mediator adjusts the electric potential distribution in the gap region, preventing image unevenness while maintaining the stacked-type structure's high light use efficiency and sensitivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electric potential adjusting electrode is selectively positioned only in regions where image unevenness occurs (typically at the edges or specific areas of the pixel), allowing local adjustment of electric potential without affecting the entire pixel structure. This maintains overall image quality while addressing specific uniformity issues.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the electric potential of the electric potential adjusting electrode is not controlled, then the structure is simple, but electric charge overflow occurs and adjacent pixel electrodes are influenced

Engineering Contradiction:
Improvestructure complexityVSAvoidelectric charge control
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The electric potential adjusting electrode is connected to a potential controlling portion that provides feedback control. The controlling portion monitors the electric potential of the adjusting electrode and adjusts it to maintain a predetermined potential level, preventing charge overflow and interference with adjacent pixels while keeping the overall structure relatively simple.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The potential controlling portion maintains the electric potential of the adjusting electrode at a predetermined level, creating an equipotential region that prevents charge overflow and eliminates electric field disturbances that could affect adjacent pixel electrodes. This ensures reliable charge collection without increasing structural complexity.

Inventive Principle:
Principle #12Equipotentiality

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 image quality by ensuring uniform signal levels across all pixels, reducing image unevenness and improving sensitivity, and maintaining stable electric potential to prevent overflow and influence on adjacent pixel electrodes.

Implementation Method 1

an organic layer 13 including a photoelectric conversion layer 12 which generates electric charge in accordance with light received

Methodology Applied
Scientific EffectPhotoelectric conversion: Photovoltaic Effect

Implementation Method 2

by applying an electric field between the opposing electrode 4 and the pixel electrode 5, the electric charge (electrons or holes) generated in the photoelectric conversion layer 3 moves to the pixel electrode 5

Methodology Applied
Scientific EffectElectric field: Electric Field

Data Source

PatentEP2290694B1Image pickup device and image pickup apparatus
Publication Date: 2019.07.10 FUJIFILM CORP
  • EP2290694B1 patent drawingFigure 1
  • EP2290694B1 patent drawingFigure 2~3
  • EP2290694B1 patent drawingFigure 4~6

AI summary

An image pickup device includes a plurality of first electrodes, a second electrode, a third electrode, a photoelectric conversion layer, a plurality of signal reading portions, at least one of electric potential adjusting portions. The plurality of first electrodes is arranged on an upper side of a substrate in two dimensions with a predetermined gap interposed between one of the first electrodes and another first electrode adjacent to the one of the first electrode. The second electrode is arranged next to the first electrodes arranged on an outermost side of the first electrodes with the predetermined gap interposed between the first electrodes arranged on the outermost side and the second electrode. The third electrode faces both of the plurality of first electrodes and the second electrode. The photoelectric conversion layer is disposed between the plurality of first electrodes and the second electrode and the third electrode. The plurality of signal reading portions is connected to the plurality of first electrodes and reads out signals corresponding to electric charge that is generated in the photoelectric conversion layer and moved to the plurality of first electrodes. The at least one of plurality electric potential adjusting portions that is connected to the second electrode and adjusts electric potential of the second electrode such that the electric potential of the second electrode determined in accordance with electric charge that is generated in the photoelectric conversion layer and moved to the second electrode is not beyond a predetermined range.