Display Apparatus Inclined Electrode Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light-emitting display apparatuses face issues with light extraction efficiency due to unemitted light and require numerous process steps and masks for connecting light-emitting elements and thin-film transistors, leading to increased costs and process complexity, along with potential disconnection issues at contact holes.
Innovation Solution
A display apparatus design featuring a second protective layer with openings and inclined electrodes to enhance light reflection and reduce process complexity by overlapping contact holes, preventing undercut and disconnection, and optimizing electrode thickness for improved light extraction and connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional multi-layer protective structure with separate contact holes is used, then connection reliability between light-emitting elements and thin-film transistors is improved, but manufacturing process complexity and costs increase due to numerous process steps and masks
Solution Approach 1:
The patent merges the first and second contact holes into a single integrated contact hole structure that passes through both the first and second protective layers. This consolidation reduces the number of separate masking and etching processes required, thereby simplifying the manufacturing process while maintaining reliable electrical connection between the light-emitting element and thin-film transistor.
Solution Approach 2:
The integrated contact hole structure serves multiple functions simultaneously: it provides electrical connection through both protective layers, defines the emission area boundary, and prevents undercut formation. This multi-functionality eliminates the need for separate structural elements, reducing process complexity while ensuring connection reliability.
2Loss of energy
If the first electrode is extended to the emission area to improve light extraction efficiency, then light extraction efficiency increases, but undercut formation and disconnection risks increase at the boundary of contact holes
Solution Approach 1:
The patent applies different structural characteristics to different regions: the first electrode has an inclined surface in the emission area to maximize light extraction, while the integrated contact hole provides vertical sidewalls at the boundary regions to prevent undercut formation. This localized differentiation allows the electrode to achieve high light extraction efficiency without compromising connection reliability.
Solution Approach 2:
The integrated contact hole structure is designed with sufficient width and proper positioning before electrode deposition to prevent undercut formation during subsequent processing steps. This proactive design ensures that even when the first electrode is extended to the emission area, the boundary regions maintain structural integrity and prevent disconnection.
3Object-generated harmful factors
If the first electrode is made thinner to prevent short circuiting, then electrical isolation is improved, but connection reliability and light extraction efficiency decrease
Solution Approach 1:
The patent transitions from controlling electrode thickness alone to utilizing the third dimension (vertical profile) through inclined surfaces. The first electrode has an inclined surface that allows sufficient thickness at the boundaries for reliable connection and short circuit prevention, while maintaining thinner regions in the emission area for optimal light extraction. This dimensional approach resolves the contradiction between electrical isolation and connection reliability.
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
The design increases light extraction efficiency, reduces manufacturing costs and complexity, and prevents connection failures between light-emitting elements and thin-film transistors, while maintaining high luminance with low power consumption.
Implementation Method 1
configuring the first electrode to have an inclined portion at an edge of the emission area, thereby allowing light emitted from an emission layer to be reflected by the inclined portion of the first electrode
Data Source
AI summary
A display apparatus according to embodiments of the present specification may include a thin-film transistor disposed on a substrate, a first protective layer disposed on the thin-film transistor and including a first contact hole configured to expose a connection electrode of the thin-film transistor, a second protective layer disposed on the first protective layer and including an opening configured to expose the first protective layer and a second contact hole configured to expose the first contact hole, and a light-emitting element disposed on the opening. A first electrode of the light-emitting element may be disposed in an area including the opening and the first and second contact holes and connected to the connection electrode through the first and second contact holes.