Laser-Via OLED Interconnection for Uniform Light Emission

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Solution Overview

Problem

Conventional methods for forming top-emitting organic light-emitting diodes (OLEDs) face challenges in achieving uniform current distribution and efficient electrical connections, leading to inhomogeneous light emission and device degradation, particularly in large-area applications, due to high resistance in thin conductive layers and complex patterning processes.

Innovation Solution

A method for forming electrical connections through an organic semiconducting layer using laser irradiation, which creates vias between metalized areas without ablating the layers, allowing for simplified production and improved light uniformity without the need for masks or photolithographic patterning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If thin conductive layers are used for electrical connections in large-area OLEDs, then transparency is maintained, but resistance increases causing inhomogeneous light emission and device degradation

Engineering Contradiction:
Improvelight emission uniformityVSAvoiddevice degradation
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent replaces the conventional mechanical/patterning-based approach of creating electrical connections with a laser-based method. Laser irradiation is used to locally modify the organic semiconducting layer and create conductive pathways between metalized areas, substituting traditional photolithography and patterning processes. This allows for precise control of electrical connections without compromising the thin conductive layer structure, thereby maintaining transparency while reducing resistance and improving current distribution uniformity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional patterning methods (photolithography, shadow mask) are used to form electrical connections, then electrical connections can be established, but process complexity increases and production throughput decreases

Engineering Contradiction:
Improveelectrical connection qualityVSAvoidproduction throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts the essential function of creating electrical connections from the complex multi-step patterning process. By using laser irradiation to directly modify the organic semiconducting layer and create conductive pathways, the invention removes the need for photolithography, shadow masks, and multiple deposition steps. This extraction of the core connection-forming function into a single laser-based step dramatically simplifies the process and increases production throughput while maintaining connection quality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces mechanical patterning systems (photolithography equipment, shadow masks) with a laser-based system. The laser directly irradiates the organic semiconducting layer to create conductive pathways, eliminating the need for mechanical mask alignment, photoresist processing, and multiple deposition cycles. This substitution significantly reduces process complexity and enhances production efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Illumination intensity

If additional current supply lines (metal grid) are deposited to lower resistance, then current distribution homogeneity improves, but active area decreases and device efficiency is reduced

Engineering Contradiction:
Improvecurrent distribution homogeneityVSAvoiddevice efficiency
Core Design Contradiction:
Illumination intensityVSProductivity

Solution Approach 1:

The patent introduces laser-irradiated regions of the organic semiconducting layer as an intermediary conductive pathway. Instead of adding a metal grid that blocks light and reduces active area, the laser-modified organic layer serves as a transparent conductive intermediary between the metalized areas. This intermediary provides additional current supply paths to improve homogeneity while maintaining the transparency and active area of the OLED structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 the uniformity of light emission and reduces device degradation by simplifying the production process, enabling the creation of large-area OLEDs with improved efficiency and homogeneity, while minimizing power loss and heating issues associated with conventional electrical connections.

Implementation Method 1

A method for forming electrical connections through an organic semiconducting layer comprises the step of irradiating the organic semiconducting layer with laser light

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

The laser is used to ablate at least one conducting electrode to break the electrical connection

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP2333859B1A method for forming an organic light emitting diode
Publication Date: 2017.09.13 NOVALED GMBH
  • EP2333859B1 patent drawingFigure 1
  • EP2333859B1 patent drawingFigure 2
  • EP2333859B1 patent drawingFigure 3

AI summary

The invention relates to a method of forming a top-emitting organic light emitting diode, the method comprising steps of providing a substrate, fabricating a metalized structure over the substrate, the metalized structure comprising a region A providing a bottom electrode and a region B providing a feed contact for a top electrode, wherein the regions A and B are electrically disconnected from each other, depositing an organic semiconducting layer over the metalized structure, depositing a transparent conducting layer over the organic semiconducting layer thereby providing the top electrode, and forming an electrical short between the top electrode and the feed contact in a connecting area by electrically interconnecting the top electrode with the feed contact through the organic semiconducting layer by irradiating laser light into the connecting area. The invention further relates to a method for forming an electrical interconnection in an electrical device.