OLED Pixel Definition Layer Sidewall Height Compensation
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Solution Overview
Problem
OLED display panels experience significant brightness and color variations at large viewing angles due to differing attenuation rates of light with different wavelengths, leading to color shift issues.
Innovation Solution
The organic light-emitting display panel incorporates a pixel definition layer with varying sidewall heights in its openings, where light-emitting materials of different wavelengths are positioned to compensate for brightness attenuation, with longer wavelength lights having higher sidewalls and shorter wavelength lights having lower sidewalls, to minimize color shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional pixel structure with uniform openings is used, then the manufacturing process is simple, but color shift occurs at large viewing angles due to different brightness attenuation rates of different wavelengths
Solution Approach 1:
The patent applies local quality by creating different sidewall heights in the pixel definition layer for different color sub-pixels. Specifically, red sub-pixels have the highest sidewalls, green sub-pixels have intermediate sidewalls, and blue sub-pixels have the lowest sidewalls. This localized structural differentiation compensates for the wavelength-dependent brightness attenuation at oblique viewing angles, maintaining color consistency without complicating the overall manufacturing process
Solution Approach 2:
The patent changes the geometric parameter of the pixel definition layer openings by varying the sidewall heights according to the emitted light wavelengths. Longer wavelength lights (red) are assigned higher sidewalls, while shorter wavelength lights (blue) are assigned lower sidewalls. This parameter modification adjusts the optical path and attenuation characteristics to compensate for color shift at large viewing angles
2Device complexity
If uniform sidewall heights are used in all pixel openings, then the device structure is simple, but brightness uniformity deteriorates at large viewing angles
Solution Approach 1:
The patent implements local quality by assigning different sidewall heights to different color sub-pixels based on their specific brightness attenuation characteristics. Red sub-pixels with higher sidewalls compensate for greater attenuation of long wavelengths, while blue sub-pixels with lower sidewalls account for less attenuation of short wavelengths. This localized optimization maintains brightness uniformity across viewing angles without requiring complete structural redesign
Solution Approach 2:
The patent modifies the geometric parameters of the pixel definition layer by varying sidewall heights to compensate for wavelength-dependent brightness attenuation. The parameter changes are specifically tailored to each color's optical characteristics, creating a compensated brightness profile that maintains uniformity at large viewing angles
3Stability of the object's composition
If the pixel definition layer has varying sidewall heights for different wavelengths, then color shift is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by differentiating sidewall heights only for different color groups (red, green, blue) rather than requiring precise control for every individual pixel. This approach reduces the number of distinct height levels needed compared to a fully individualized approach, thereby lowering manufacturing precision requirements while still achieving effective color shift compensation
Solution Approach 2:
The patent changes geometric parameters (sidewall heights) in discrete steps corresponding to different color wavelengths. By using a limited number of height levels rather than continuous variation, the patent makes the parameter changes manufacturable with standard precision capabilities while still achieving the desired optical compensation effect
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 effectively reduces color shift and enhances brightness uniformity across viewing angles by scattering and refracting light within the pixel definition layer, ensuring consistent image color at large viewing angles.
Implementation Method 1
This design effectively reduces color shift and enhances brightness uniformity across viewing angles by scattering and refracting light within the pixel definition layer
Implementation Method 2
This design effectively reduces color shift and enhances brightness uniformity across viewing angles by scattering and refracting light within the pixel definition layer
Data Source
AI summary
An organic light-emitting display panel and a display apparatus are provided. An exemplary organic light-emitting display panel includes a substrate; an array layer disposed on the substrate and a display layer disposed on the array layer. The display layer includes an anode layer, a pixel definition layer having a plurality of the openings exposing the anode layer, an organic light-emitting material layer filled in the openings and connecting with the anode layer, and a cathode layer disposed on the organic light-emitting layer. The plurality of openings of the pixel definition layer includes a plurality of first openings and a plurality of second openings. Along a direction perpendicular to the organic light-emitting display panel, a height of a sidewall of at least a portion of a first opening is greater than a height of a sidewall of a second opening.