Deposition Mask Layout for Low-Resistance Transparent Cathodes

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Solution Overview

Problem

The challenge lies in balancing the resistance and planar dimension of the cathode in electronic devices like organic EL displays, where a larger planar dimension improves electrical resistance but reduces light transmittance.

Innovation Solution

A deposition mask group is used to form electrodes with a second layer that extends between adjacent elements, increasing the thickness and reducing resistance between adjacent electrodes while maintaining light transmittance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the planar dimension of the cathode is increased to reduce electrical resistance, then the electrical properties improve, but the light transmittance of the device decreases

Engineering Contradiction:
Improveelectrical resistanceVSAvoidlight transmittance
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The cathode structure transitions from a single-layer planar configuration to a multi-layer stacked configuration. By adding a second cathode layer that overlaps with the first cathode layer in the vertical dimension, the invention reduces electrical resistance through increased conductive path length without increasing the horizontal planar dimension, thereby preserving light transmittance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The second cathode layer is positioned to overlap with and nest within the horizontal projection of the first cathode layer. This nested arrangement allows the cathode structure to achieve enhanced electrical connectivity through vertical stacking while maintaining a compact horizontal footprint that does not obstruct light transmission paths.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If the planar dimension of the cathode is increased to improve electrical conductivity, then the conductivity improves, but the light transmittance of the device decreases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidlight transmittance
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The invention addresses the conductivity-transmittance contradiction by moving from two-dimensional planar expansion to three-dimensional vertical stacking. The second cathode layer is deposited over the first layer, creating a stacked architecture that enhances conductivity through increased vertical conductive paths while maintaining the same or reduced horizontal footprint, thus preserving light transmittance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention merges the functionality of multiple cathode layers into a single integrated structure where the first and second cathode layers work together to provide enhanced electrical conductivity. This merged multi-layer cathode structure achieves superior conductivity without requiring proportional increases in planar dimension, thereby maintaining optimal light transmittance.

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 enhances electrical conductivity between adjacent electrodes while preserving the light transmittance of the device, addressing the trade-off between resistance and transmittance.

Implementation Method 1

a conductive material is deposited onto the organic layer via the through holes of the deposition mask to form a cathode on the organic layer

Methodology Applied
Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentEP3919649B1Deposition mask group and method for manufacturing electronic device
Publication Date: 2026.03.04 DAI NIPPON PRINTING CO LTD
  • EP3919649B1 patent drawingFigure 1~2
  • EP3919649B1 patent drawingFigure 3~4
  • EP3919649B1 patent drawingFigure 5~6

AI summary

A deposition mask group includes a first deposition mask having two or more first through holes arranged along two different directions, a second deposition mask having two or more second through holes arranged along two different directions and a third deposition mask having two or more third through holes. The first through hole and the second through hole or the third through hole partly overlap when the first deposition mask, the second deposition mask and the third deposition mask are overlapped.