Signal Pad Corrosion Protection in OLED Displays

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Solution Overview

Problem

The top emission type organic light emitting display apparatus faces challenges with signal pad corrosion and increased process complexity due to exposure and the need for additional masking steps to prevent corrosion and damage during manufacturing.

Innovation Solution

The solution involves a two-layer structure for the signal pad and pad electrode, using materials with enhanced corrosion resistance, and a simplified masking process to minimize additional processes and prevent corrosion, with the signal pad and pad electrode formed using the same material to reduce oxidation rates and exposure vulnerabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the top of the signal pad is exposed to connect to external driving circuit, then electrical connection is achieved, but corrosion resistance deteriorates

Engineering Contradiction:
Improveelectrical connectionVSAvoidcorrosion resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent transitions from a two-dimensional planar exposure to a three-dimensional protective structure by forming side surfaces that extend vertically from the signal pad. These side surfaces create a protective barrier that blocks corrosive substances from reaching the pad while maintaining electrical connectivity through the top surface.

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

Solution Approach 2:

The patent employs thin film structures as protective barriers. The side surfaces are formed as thin film structures that cover and protect the signal pad from corrosion while allowing the top surface to remain exposed for electrical connection. This thin film approach provides effective protection without adding significant complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

2Ease of operation

If a separate hole formation process is performed after anode electrode patterning to expose signal pad, then signal pad exposure is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvesignal pad exposureVSAvoidnumber of processes
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into a single integrated structure. The same pattern formation process that defines the anode electrode also defines the signal pad exposure area. The side surfaces serve dual purposes: they protect the signal pad from corrosion and simultaneously define the exposure area, eliminating the need for separate hole formation processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The side surfaces perform multiple functions simultaneously: they act as protective barriers against corrosion, define the exposure area for electrical connection, and serve as structural elements of the overall device architecture. This multi-functionality reduces the total number of manufacturing steps required.

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

Data Source

PatentEP3107130B1Organic light emitting display apparatus and method of manufacturing the same
Publication Date: 2021.05.12 LG DISPLAY CO LTD
  • EP3107130B1 patent drawingFigure 1~2
  • EP3107130B1 patent drawingFigure 3~4A
  • EP3107130B1 patent drawingFigure 4B~4C

AI summary

Disclosed is an organic light emitting display apparatus in which an anode electrode (180, 200), an organic emission layer (240), a cathode electrode (250), and an auxiliary electrode (190, 210) connected to the cathode electrode (250) and disposed on the same layer as that of the anode electrode (180, 200) are disposed in an active area (AA) of the substrate (100), a signal pad (300) and a pad electrode (400) connected to the signal pad (300) and covering a top of the signal pad (300) are disposed in a pad area (PA) of the substrate (100), and a top of the pad electrode (400) is lower in oxidation rate than the top of the signal pad (300).