Conductive Inorganic Layer Extension in OLED Pixel Defining

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Solution Overview

Problem

In organic light-emitting display devices, the deposition process with substrates and masks in close contact can damage the pixel defining layer, leading to insufficient or separated conductive inorganic layers, which affects display quality and increases thickness due to the need for additional spacer processes.

Innovation Solution

The implementation of a display device design where the conductive inorganic layer extends beyond the intermediate layer's end by 0.5 μm or more, with a convex portion structure that increases adhesion to the pixel defining layer, preventing peeling and ensuring uniform light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a deposition process is conducted with a substrate and a mask in close contact, then manufacturing precision is improved, but the pixel defining layer is damaged

Engineering Contradiction:

Improvedeposition precisionVSAvoidmask damage to pixel defining layer

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The conductive inorganic layer serves as an intermediary protective layer between the mask and the pixel defining layer. During the deposition process, the mask is positioned in close contact with the conductive inorganic layer rather than directly with the pixel defining layer, preventing mechanical damage while maintaining deposition precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The conductive inorganic layer is formed in advance on the intermediate layer before the final deposition process. This preliminary formation creates a protective surface that receives mask contact during subsequent deposition, preventing damage to the underlying pixel defining layer.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a spacer is arranged on the pixel defining layer to prevent damage, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveprotection of pixel defining layerVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective function is merged with the conductive inorganic layer that is already required for electrical functionality. Instead of adding a separate spacer layer, the conductive inorganic layer serves dual purposes: providing electrical conduction and protecting the pixel defining layer during deposition processes.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The conductive inorganic layer performs multiple functions simultaneously: it provides electrical conductivity for device operation and serves as a protective barrier during mask-based deposition processes, eliminating the need for dedicated protective spacers.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a spacer is arranged on the pixel defining layer to prevent damage, then reliability is improved, but device thickness increases

Engineering Contradiction:

Improveprotection of pixel defining layerVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

4Ease of manufacture

If the conductive inorganic layer is formed only on the intermediate layer, then ease of manufacture is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improvedeposition process simplicityVSAvoidconductive inorganic layer coverage

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The conductive inorganic layer is extended from a single-plane deposition on the intermediate layer to a multi-dimensional structure that wraps around and extends onto the pixel defining layer. This dimensional extension ensures complete coverage and prevents peeling while maintaining a relatively simple deposition process.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The pixel defining layer is prepared with a specific surface structure in advance that facilitates the extension and adhesion of the conductive inorganic layer. This preliminary preparation ensures that when the conductive inorganic layer is deposited, it naturally extends onto the pixel defining layer with good adhesion, improving coverage without complicating the deposition process.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10325970B2Display device

Publication Date: 2019.06.18 SAMSUNG DISPLAY CO LTD

AI summary

A display device including a first pixel electrode and a second pixel electrode disposed adjacent to each other on a substrate; a pixel defining layer including a first opening corresponding to the first pixel electrode, a second opening corresponding to the second pixel electrode, and a first convex portion arranged adjacent to the first opening; a first intermediate layer arranged on the first pixel electrode to correspond to the first opening and including a first emission layer; and a first conductive inorganic layer arranged on the first intermediate layer to correspond to the first opening. At least one end of the first conductive inorganic layer extends beyond an end of the first intermediate layer and is disposed on the pixel defining layer between the first opening and the second opening.