OLED Panel Inorganic Overhang Barriers for Residue-Free Pixel Patterning

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Solution Overview

Problem

Current OLED pixel patterning processes leave behind organic material residues that disrupt performance and limit pixel resolution and panel size, necessitating improved methods for sub-pixel circuit formation.

Innovation Solution

The use of inorganic overhang structures in sub-pixel circuits, combined with evaporation deposition, ensures that OLED material and cathode layers are deposited without contacting residue-forming organic material, allowing for increased pixel density and improved performance by eliminating the need for lift-off procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photo lithography is used to pattern pixels, then pixel resolution can be improved, but organic material residues are left behind that disrupt OLED performance

Engineering Contradiction:

Improvepixel resolutionVSAvoidorganic material residues

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the organic pixel-defining layer after it has served its purpose as a masking layer during evaporation deposition. This extraction eliminates the harmful organic residues that would otherwise remain and disrupt OLED performance, while still allowing photo lithography to achieve high pixel resolution patterning

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The organic pixel-defining layer is deposited beforehand to serve as a temporary masking structure that enables precise photo lithography patterning. After the patterning process completes and achieves the desired pixel resolution, the organic layer is removed since its function is no longer needed

Inventive Principle:

Principle #10Preliminary action

2Productivity

If lift-off procedures are used to remove organic material, then pixel density can be increased, but particle issues arise that disrupt OLED performance

Engineering Contradiction:

Improvepixel densityVSAvoidparticle issues

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the mechanical lift-off procedure with a chemical removal process using oxygen plasma. This substitution eliminates the particle generation associated with mechanical lifting while still achieving the goal of removing organic material to increase pixel density

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Oxygen plasma is used as a strong oxidizing environment to chemically remove the organic pixel-defining layer. This oxidation process cleanly eliminates organic residues without generating particles, thereby increasing pixel density while maintaining OLED performance

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

3Ease of manufacture

If fine metal mask is used for pixel patterning, then manufacturing process can be simplified, but panel size and substrate size are restricted

Engineering Contradiction:

Improvepatterning process simplicityVSAvoidpanel size

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent extracts and removes the organic pixel-defining layer after patterning, which eliminates the need for fine metal masks that restrict panel size. This extraction allows the use of larger substrates while maintaining simplified manufacturing processes

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from using a fine metal mask (a two-dimensional constraint) to using an organic pixel-defining layer that can be deposited and removed in the vertical dimension. This dimensional change allows for larger panel sizes while maintaining the simplicity of the patterning process

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 pixel-per-inch density and improves OLED performance by maintaining inorganic overhang structures during deposition, reducing particle issues and increasing throughput.

Implementation Method 1

depositing the OLED material using evaporation deposition over a substrate

Methodology Applied

Scientific EffectEvaporation deposition: Evaporation

Implementation Method 2

depositing the OLED material using evaporation deposition over a substrate, the OLED material disposed over and in contact with the anode

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS20250234738A1Methods of fabricating OLED panel with inorganic pixel encapsulating barrier

Publication Date: 2025.07.17 APPLIED MATERIALS INC

AI summary

Embodiments described herein relate to sub-pixel circuits and methods of forming sub-pixel circuits that may be utilized in a display such as an organic light-emitting diode (OLED) display. The device includes a plurality of sub-pixels, each sub-pixel of the plurality of sub-pixels defined by adjacent pixel-defining layer (PDL) structures with inorganic overhang structures disposed on the PDL structures, each sub-pixel having an anode, organic light-emitting diode (OLED) material disposed on the anode, and a cathode disposed on the OLED material. The device is made by a process including the steps of: depositing the OLED material and the cathode by evaporation deposition, and depositing an encapsulation layer disposed over the cathode.