OLED Pixel Definition Layer Asymmetric Inclination
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Solution Overview
Problem
Current OLED technologies face challenges in achieving high resolution and uniformity of film layers due to issues with pixel definition layer structures, leading to color blending and short circuits between the cathode and anode, and breakage of the cathode during the manufacturing process.
Innovation Solution
The pixel definition layer is designed with opening regions having a cross-section that is either regular or inverted trapezoidal, with an upper surface formed from a hydrophobic material and an inclination surface from a hydrophilic material, ensuring the light emitting material is evenly filled and preventing residue and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pixel definition layer uses a conventional structure with vertical or simple inclined walls, then the manufacturing process is simple, but the film layer uniformity is poor leading to color blending and short circuits
Solution Approach 1:
The pixel definition layer employs an asymmetric cross-sectional structure where the inclination surfaces have different angles relative to the base substrate. Specifically, at least one inclination surface forms a smaller angle with the base substrate compared to conventional structures, creating an asymmetric profile that optimizes film layer deposition uniformity while preventing color blending between adjacent pixels.
Solution Approach 2:
The pixel definition layer features locally varied surface properties through different inclination angles at different regions. The inclination surfaces are designed with specific angle ranges (e.g., 10-45 degrees) to control material deposition locally, ensuring uniform film formation in critical areas while maintaining manufacturing feasibility.
2Measurement precision
If the opening regions have a narrow width to achieve high resolution, then the resolution improves, but the aperture ratio decreases reducing light emission efficiency
Solution Approach 1:
The patent transitions from considering only the planar dimensions of opening regions to incorporating the vertical dimension through inclined surfaces. By designing inclination surfaces that angle toward the center of adjacent opening regions, the effective light emission area is increased without compromising the narrow planar width needed for high resolution, thus improving aperture ratio while maintaining resolution.
3Use of energy by moving object
If the pixel definition layer has a wide opening to improve light emission, then the aperture ratio improves, but the resolution decreases due to color blending
Solution Approach 1:
The inclination surfaces are designed with curved or rounded profiles rather than sharp straight lines. The inclination surfaces extend from the top surface of the pixel definition layer down to the base substrate, creating a smooth transitional geometry that guides material deposition and prevents sharp edges that would cause color blending, thereby maintaining resolution while allowing wider openings for improved light emission.
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 design enhances the uniformity of the film layers and improves light emitting performance by preventing color blending and short circuits, while avoiding breakage of the cathode pattern.
Implementation Method 1
the pixel definition layer has an upper surface formed from a hydrophobic material, and an inclination surface of the pixel definition layer corresponding to each of the opening regions is formed from a hydrophilic material
Implementation Method 2
the pixel definition layer has an upper surface formed from a hydrophobic material, and an inclination surface of the pixel definition layer corresponding to each of the opening regions is formed from a hydrophilic material
Data Source
Figure 1a~1b
Figure 2a~3
Figure 4~5
AI summary
An organic electroluminescent display panel, its manufacturing method and a display device are disclosed. In the organic electroluminescent display panel, a pixel definition layer (200) provided therein has opening regions (300) corresponding to pixel areas in the OLED, and each of the opening regions (300) has an opening larger than a bottom surface of the opening region (300). An upper surface (a) of the pixel definition layer (200) is formed from a hydrophobic material, and an inclination surface (b) of the pixel definition layer (200) corresponding to each of the opening regions (300) is formed from a hydrophilic material. The above OLED can assure the uniformity of the film layers formed after the pixel definition layer (200) can be guaranteed to improve the light emitting performance of the OLED.