Rectangular Wave Pixel Electrodes Prevent Particle Short-Circuits

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Solution Overview

Problem

In organic EL display devices, the difference in etch rates between metal and transparent conductive films can lead to particle generation, causing short-circuits between adjacent pixel electrodes, resulting in malfunction and reduced reliability.

Innovation Solution

The pixel electrodes are designed with a specific shape, such as a rectangular wave shape, where the maximum length of their sides is shorter than the minimum distance between them, preventing particles from straddling between electrodes and thus avoiding short-circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If pixel electrodes are arranged adjacent to each other with small spacing, then the display area is increased, but particles generated during etching can straddle between electrodes causing short-circuits

Engineering Contradiction:

Improvedisplay areaVSAvoidrisk of short-circuit between electrodes

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The pixel electrodes are designed with a rectangular wave shape where each side is divided into multiple segments. The maximum length of each side is made shorter than the minimum distance between adjacent electrodes, segmenting the electrode structure to prevent continuous particle bridges between neighboring electrodes while maintaining high display area utilization.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the maximum length of electrode sides is reduced, then particles cannot straddle between electrodes, but the electrode area may be reduced

Engineering Contradiction:

Improveprevention of short-circuitVSAvoidelectrode area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The pixel electrodes are given a rectangular wave shape with curved or angled transitions rather than sharp 90-degree corners. This curved geometry allows the electrode to maintain compact side lengths that prevent particle bridging while optimizing the enclosed area for light emission, balancing reliability and display area.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Loss of energy

If a highly reflective metal material is used for the anode, then luminous efficiency is increased, but etch rate difference with transparent conductive film causes particle generation

Engineering Contradiction:

Improveluminous efficiencyVSAvoidparticle generation during etching

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent acknowledges the etch rate difference between metal and transparent conductive films as an inevitable phenomenon, but converts this potential harm into a benefit by designing electrode shapes that leverage the selective etching behavior. The rectangular wave shape with controlled side lengths utilizes the etching process to define precise electrode boundaries while preventing particle-related short-circuits.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11276740B2Semiconductor device and display device

Publication Date: 2022.03.15 MAGNOLIA WHITE CORP

AI summary

The semiconductor device includes: a first conductor pattern disposed on an insulating surface; and a second conductor pattern disposed on the insulating surface and spaced apart from the first conductor pattern, wherein, in a planar view, a first side of the first conductor pattern and a second side of the second conductor pattern are each formed of a plurality of sides, the first side and the second side face each other, and each of a maximum length of a plurality of sides constituting the first side and a maximum length of a plurality of sides constituting the second side is shorter than the minimum distance between the first side and the second side.