Display Electrode Layout With Local ITO Thickness Control
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Solution Overview
Problem
Existing display devices face challenges in enhancing light transmittance and reducing line resistance while protecting contact electrodes from etchant damage during the etching process.
Innovation Solution
The display device incorporates a substrate with specific electrode configurations and contact electrodes made of crystalline ITO, along with an insulating layer that exposes certain areas to form a first pattern, allowing for improved light transmittance and reduced line resistance by increasing the thickness of conductive layers in contact with light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of conductive layers is increased to reduce line resistance, then line resistance decreases, but light transmittance deteriorates
Solution Approach 1:
The patent applies different thicknesses of the same conductive material (ITO) in different regions: thicker ITO layers are used in line areas where electrical conductivity is critical, while thinner ITO layers are used in contact areas where light transmittance is critical. This local differentiation resolves the contradiction by optimizing each region for its primary function.
Solution Approach 2:
The patent introduces a vertical dimension variation by creating multi-layer ITO structures with different thicknesses at different heights. The conductive layer is configured to have varying thickness profiles, allowing simultaneous optimization of electrical conductivity (thicker regions) and optical transmittance (thinner regions) within the same conductive path.
2Manufacturing precision
If etching process is used to form patterns, then manufacturing precision improves, but contact electrode damage occurs
Solution Approach 1:
The patent introduces a protective film as an intermediary layer between the etchant and the contact electrode during the etching process. This protective film prevents direct contact between the etchant and the contact electrode, thereby preventing damage while allowing the etching process to proceed with high precision for pattern formation.
Solution Approach 2:
The protective film is formed on the contact electrode before the etching process begins. This preliminary protective action ensures that when the etchant is applied subsequently, the contact electrode is already shielded and cannot be damaged by the etchant, allowing precise pattern formation without harm.
3Illumination intensity
If transparent conductive material is used for contact electrodes, then light transmittance improves, but line resistance increases
Solution Approach 1:
The patent uses transparent conductive material (ITO) with locally varied thickness: thinner regions in contact areas for optimal light transmittance, and thicker regions in line areas for optimal electrical conductivity. This spatial variation in thickness allows the same material to satisfy both optical and electrical requirements in different locations.
Solution Approach 2:
The conductive structure is formed as a composite of multiple ITO layers with different thicknesses, effectively creating a composite conductive system. The multi-layer structure combines the advantages of both thin (high transmittance) and thick (low resistance) regions within a single integrated conductive path.
Data Source
AI summary
A display device and a method of fabricating a display device are provided. The display device includes a substrate comprising a contact area and a line area, a first electrode that extends in a first direction on the substrate, a first electrode pattern that extends in the first direction and is spaced apart from the first electrode on the substrate, a second electrode that extends in the first direction and is between the first electrode and the first electrode pattern on the substrate, a second electrode pattern that extends in the first direction and is between the first electrode and the second electrode on the substrate, and a first light-emitting element between the first electrode and the second electrode pattern in the contact area.