Laser-Formed Pixel Openings for Reliable High-Resolution Displays
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Solution Overview
Problem
Existing display devices face challenges in maintaining high resolution and reliability due to issues with the thickness and formation of holes in the pixel-defining layer, which can lead to defects and increased resistance in the sub-pixel electrode and opposite electrode contact areas.
Innovation Solution
A method involving the use of a laser beam to precisely remove portions of the pixel-defining layer and intermediate layer on the sub-pixel electrode, forming a hole with controlled thickness and length to ensure effective contact between the sub-pixel and opposite electrodes, while minimizing damage to the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pixel-defining layer is made thicker to improve manufacturing robustness, then manufacturing stability is improved, but the hole formation precision and electrode contact reliability deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the pixel-defining layer thickness to a specific range (100-2000 Å) and controlling the laser beam intensity (200 mJ/cm² or less) to achieve both manufacturing stability and hole formation precision. This parameter optimization resolves the contradiction by finding the optimal balance point where the layer is thick enough for stable manufacturing but thin enough for precise hole formation.
Solution Approach 2:
The patent uses partial action by selectively removing only the necessary portion of the pixel-defining layer to form holes, rather than removing the entire layer. The laser beam is applied with controlled intensity (200 mJ/cm² or less) to achieve just enough removal for proper electrode contact while preserving the remaining layer structure for manufacturing stability.
2Reliability
If the hole in the pixel-defining layer is made larger to improve electrode contact area, then electrical conductivity is improved, but the resolution and pixel density deteriorate
Solution Approach 1:
The patent resolves this contradiction by optimizing the hole dimensions and pixel-defining layer thickness parameters. The controlled hole size, achieved through precise laser processing, provides sufficient contact area for reliable electrode connection while maintaining small overall pixel dimensions for high resolution and density.
Solution Approach 2:
The patent applies segmentation by creating discrete, precisely-controlled holes in the pixel-defining layer rather than using a continuous structure. This segmentation allows for optimized local contact areas while maintaining the overall pixel structure integrity and resolution.
3Productivity
If the laser beam intensity is increased to improve hole formation efficiency, then productivity is improved, but the damage to the display panel increases
Solution Approach 1:
The patent applies parameter changes by optimizing the laser beam intensity to a maximum of 200 mJ/cm². This parameter setting achieves sufficient hole formation efficiency for productive manufacturing while remaining below the threshold that would cause damage to the display panel, thus resolving the contradiction between productivity and panel safety.
Solution Approach 2:
The patent converts the potentially harmful high-intensity laser effect into a beneficial controlled process. By carefully controlling the laser intensity at 200 mJ/cm² or less, the process that could otherwise damage the panel is transformed into a precise, efficient hole-forming method that improves productivity without causing harm.
4Manufacturing precision
If the pixel-defining layer thickness is reduced to improve hole formation and electrode contact, then manufacturing precision is improved, but the structural stability and defect prevention deteriorate
Solution Approach 1:
The patent resolves this contradiction through parameter optimization, setting the pixel-defining layer thickness within the range of 100-2000 Å. This optimized thickness provides sufficient precision for hole formation and electrode contact while maintaining adequate structural stability to prevent manufacturing defects, balancing both requirements simultaneously.
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 reliability and quality of the display device by reducing resistance and preventing defects, while maintaining high resolution and ensuring efficient power distribution through the sub-pixel circuit.
Implementation Method 1
forming a hole by irradiating a laser beam to a pixel-defining layer and an intermediate layer above an upper surface of a sub-pixel electrode
Data Source
AI summary
A display device includes a substrate, a sub-pixel electrode above the substrate, a pixel-defining layer partially above the sub-pixel electrode, an intermediate layer partially above the pixel-defining layer, and defining a hole exposing at least a portion of the sub-pixel electrode, and an opposite electrode partially above the intermediate layer, wherein a first side surface defining the hole, which is adjacent to an edge portion of the sub-pixel electrode, includes a side surface of the pixel-defining layer and a side surface of the intermediate layer.