OLED Anode Corrosion Prevention via Inverted Layer Sequence

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Solution Overview

Problem

Conventional OLED display panel manufacturing processes face issues where the size mismatch between the opening in the pixel defining layer and the anode layer can lead to corrosion of the anode layer or reduction in the effective light-illumination area, resulting in a decreased aperture ratio of pixels.

Innovation Solution

The method involves forming a pixel defining layer first, followed by the anode layer, with the anode layer being electrically connected through a through-hole in the planarization layer, and incorporating an upward protruding portion to attach the anode layer to the pixel defining layer, preventing corrosion and ensuring proper light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the opening size in pixel defining layer is increased to prevent anode layer corrosion, then the reliability of anode layer is improved, but the aperture ratio of pixels is reduced due to wrapping of anode layer edge by pixel defining layer

Engineering Contradiction:

Improveanode layer corrosion resistanceVSAvoidaperture ratio of pixels

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

Instead of forming the pixel defining layer first and then the anode layer (conventional approach), this patent inverts the sequence by forming the anode layer first and then the pixel defining layer. This inversion allows the anode layer to be formed with optimal size and shape before the pixel defining layer is added, preventing the wrapping issue while maintaining corrosion protection.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The anode layer is formed in advance before the pixel defining layer is deposited. This preliminary action allows the anode layer to establish its proper dimensions and position first, so that when the pixel defining layer is subsequently formed, it does not wrap around the anode layer edge, thereby maintaining both corrosion resistance and aperture ratio.

Inventive Principle:

Principle #10Preliminary action

2Area of stationary object

If the opening size in pixel defining layer is decreased to increase aperture ratio, then the area of light-illumination is improved, but the anode layer becomes susceptible to corrosion

Engineering Contradiction:

Improveaperture ratio of pixelsVSAvoidanode layer corrosion resistance

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent inverts the conventional manufacturing sequence by forming the anode layer before the pixel defining layer. This allows the anode layer to be formed with precise dimensions that optimize aperture ratio, while the subsequently formed pixel defining layer provides corrosion protection without wrapping around the anode layer.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the mechanical approach of adjusting opening size to balance corrosion protection and aperture ratio with a process sequence substitution. By changing the order of layer formation rather than adjusting dimensions, it achieves both corrosion resistance and high aperture ratio simultaneously.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the pixel defining layer is formed first to establish pixel boundaries, then the manufacturing precision of pixel areas is improved, but the anode layer edge becomes wrapped by pixel defining layer reducing effective light-illumination area

Engineering Contradiction:

Improvepixel area definition accuracyVSAvoideffective light-illumination area

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent inverts the conventional sequence by forming the anode layer first to establish precise pixel boundaries and dimensions, then forming the pixel defining layer afterward. This inversion ensures that the anode layer edge is not wrapped by the pixel defining layer, maintaining full effective light-illumination area while preserving manufacturing precision.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The anode layer is formed in advance as a preliminary step before depositing the pixel defining layer. This preliminary formation of the anode layer establishes the exact pixel boundaries and light-illumination area, preventing subsequent wrapping by the pixel defining layer while maintaining manufacturing precision.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10930717B2Display panel and method for manufacturing same

Publication Date: 2021.02.23 WUHAN CHINA STAR OPTOELECTRONICS SEMICONDUCTOR DISPLAY TECHNOLOGY CO LTD

AI summary

The present disclosure provides a display panel and method for manufacturing same. The method for manufacturing the display panel includes providing an array substrate, wherein a source/drain metal is disposed on the array substrate; sequentially forming a planarization layer and a pixel defining layer on the array substrate, wherein the pixel defining layer comprises a plurality of pixel defining bodies that are spaced apart from each other, and a region located between any two adjacent pixel defining bodies constitutes a pixel area; and forming an anode layer in the pixel area, wherein an edge of the anode layer is attached to the pixel defining layer.