Patterned Priming Layer for Contained Liquid Deposition in OLEDs

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Solution Overview

Problem

Current methods for producing full-color OLEDs face challenges in preventing ink spreading and color mixing, leading to reduced emissive area and quality issues due to the need for containment structures and surface tension discontinuities, which restrict continuous coating processes.

Innovation Solution

A process involving a fluorinated material layer with a photoinitiator, treated with an aromatic amine priming layer and exposed to activating radiation to create a patterned surface energy pattern, allowing for controlled liquid deposition of subsequent layers without spreading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If containment structures (pixel wells, banks) are used to prevent ink spreading, then color mixing is prevented, but the emissive area is reduced and quality uniformity deteriorates

Engineering Contradiction:

Improvecolor mixing preventionVSAvoidemissive area

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

A surfactant layer is introduced as an intermediary between the pixel well structure and the emissive ink. This surfactant layer modifies the surface energy distribution to create surface tension discontinuities that confine the ink within the pixel region without requiring the ink to wet the containment structure walls, thereby preserving emissive area and maintaining uniform thickness.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface energy parameters of the containment structure are modified by applying a surfactant layer. This changes the surface tension characteristics from high surface energy (causing ink wetting and spreading) to low surface energy (preventing wetting and confining ink), thus resolving the contradiction between containment effectiveness and emissive area preservation.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If all layers are printed to maintain containment, then ink spreading is prevented, but productivity decreases and equipment cost increases

Engineering Contradiction:

Improveink spreading preventionVSAvoidproduction throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The surfactant layer enables continuous coating processes for non-emissive layers without interruption or re-patterning. The surface tension discontinuities created by the surfactant persist through subsequent coating steps, maintaining ink containment while allowing high-speed continuous deposition methods to be used, thereby improving productivity.

Inventive Principle:

Principle #20Continuity of useful action

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

Enables continuous coating of layers with improved yield and reduced equipment costs by maintaining containment and preventing ink spreading, enhancing the quality and efficiency of OLED production.

Implementation Method 1

forming the first layer comprising a fluorinated material and a photoinitiator; exposing the priming layer patternwise with activating radiation

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

treating the first layer with a priming layer consisting essentially of an aromatic amine compound; the patterned priming layer has a second surface energy that is higher than the first surface energy

Methodology Applied

Scientific EffectSurface tension discontinuity: Surface Tension

Implementation Method 3

forming the second layer by liquid deposition on the patterned priming layer; preventing the spreading of the liquid colored materials

Methodology Applied

Scientific EffectWetting: Wetting

Data Source

PatentUS9312485B2Process and materials for making contained layers and devices made with same

Publication Date: 2016.04.12 LG CHEM LTD

AI summary

There is provided a process for forming a contained second layer over a first layer, including the steps:forming the first layer including a fluorinated material and a photoinitiator, and having a first surface energy;treating the first layer with a priming layer including an aromatic amine compound;exposing the priming layer patternwise with activating radiation, resulting in exposed areas and unexposed areas;developing the priming layer to effectively remove the priming layer from the unexposed areas resulting in a first layer having a patterned priming layer, wherein the patterned priming layer has a second surface energy that is higher than the first surface energy; andforming the second layer by liquid deposition on the patterned priming layer on the first layer.