Laser Repair of OLED Bright Spot Defects
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Solution Overview
Problem
Existing methods for repairing organic electroluminescence (EL) display apparatuses are inefficient in stably darkening bright spot defective elements, often causing deterioration in electrode quality and incomplete repair due to laser beam application.
Innovation Solution
A method involving a laser beam application to the upper electrode of bright spot defective elements, creating a closed line and unirradiated area along the partition wall edges, which transforms the upper electrode and electron transmission layer, thereby increasing resistance and darkening the defective area without short-circuiting other layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laser beam is applied to repair bright spot defective elements in organic EL display apparatuses, then the defective elements can be darkened, but the repair is unstable and may cause deterioration in electrode quality
Solution Approach 1:
The patent divides the repair process into two distinct stages: first applying a laser beam to transform the upper electrode and electron transmission layer, then applying a second laser beam to transform the organic layer. This segmentation allows each laser application to have a specific function, improving repair stability while preventing electrode deterioration. The first stage creates a transformed area that prevents short-circuiting, while the second stage completes the darkening effect.
Solution Approach 2:
The patent performs preliminary transformation of the upper electrode and electron transmission layer before transforming the organic layer. This preliminary action creates a stable foundation that prevents electrode quality deterioration while preparing the structure for complete darkening. The transformed area in the electrode layers acts as a barrier that prevents subsequent organic layer transformation from affecting electrode integrity.
2Reliability
If the laser beam transforms the upper electrode and electron transmission layer, then the transformed area enlarges and prevents short-circuiting, but the process may leave emitting areas outside the partition walls
Solution Approach 1:
The patent applies laser beams with different parameters to different local areas: the first laser beam transforms the upper electrode and electron transmission layer in a controlled area, while the second laser beam transforms the organic layer in a slightly larger area that extends to the partition walls. This local quality differentiation ensures short-circuit prevention in the electrode layers while maintaining precise control over the emitting area boundaries in the organic layer.
Solution Approach 2:
The patent uses partial action by applying the second laser beam only after the first transformation is complete, and only in the organic layer region. The transformed area from the first laser beam serves as a boundary that prevents excessive transformation. This partial action approach ensures that the emitting area is precisely controlled and does not extend beyond the partition walls while still achieving complete darkening of the defective element.
3Ease of manufacture
If existing repair methods are used, then the process is simple, but the repair is incomplete and electrode quality deteriorates
Solution Approach 1:
The patent segments the repair process into two sequential laser beam applications with distinct functions. The first laser beam transforms the electrode and electron transmission layer to prevent short-circuiting, while the second laser beam transforms the organic layer to complete the darkening. This segmentation maintains operational simplicity while achieving complete and reliable repair, unlike existing single-step methods that are either incomplete or cause electrode deterioration.
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 method effectively and stably darkens bright spot defective elements without leaving emitting areas outside the partition walls, ensuring reliable repair and maintaining electrode integrity.
Implementation Method 1
applying a laser beam to an area of the upper electrode in the bright spot defective element, to draw a closed line... transforming the upper electrode and an electron transmission layer by focusing the laser beam on the upper electrode
Implementation Method 2
transforming the upper electrode and an electron transmission layer by focusing the laser beam on the upper electrode, and in step (b-1), an area that is transformed in the electron transmission layer is enlarged by application of the laser beam
Data Source
AI summary
A method includes: (a) preparing the organic electroluminescence display apparatus including: plural elements in which a reflective anode, an organic layer including an emission layer, and a transparent cathode are stacked; and partition walls, in which at least one of the picture elements is a bright spot defective element that always lights or blinks and (b) applying a laser beam to an area of the transparent cathode in the bright spot defective element, to draw a closed line and to have an unirradiated area along a periphery of the area, the area reflecting an emitting part. Step (b) includes (b-1) transforming the transparent cathode and an electron transmission layer by focusing the laser beam on the transparent cathode. In step (b-1), an area transformed in the electron transmission layer is enlarged by application of the laser beam.