Light-Blocking Opening Geometry for Low-Banding OLED Displays
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Solution Overview
Problem
Conventional light emitting display devices face challenges in maintaining a high aperture ratio while minimizing reflective color bands when a polarizer is not formed on the entire surface, which can lead to reduced display quality and shortened LED lifespan.
Innovation Solution
The implementation of a light blocking member with specific opening structures, including red, blue, and green openings, each with a hybrid structure of straight and curved lines, and optimized Gaussian filter full widths at half maximum, to reduce reflective color bands and enhance aperture ratio, along with a reflection adjustment layer and color filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a polarizer is not formed on the entire surface to improve optical sensor efficiency, then optical sensor efficiency is improved, but reflective color bands increase and display quality deteriorates
Solution Approach 1:
The patent applies local quality by forming openings with specific geometric characteristics (maximum minimum distance ratios) only in the light blocking member regions corresponding to sub-pixels, rather than uniformly across the entire display. This localized approach with varying opening shapes for different colors (red, green, blue) selectively addresses reflective color bands in specific areas while maintaining optical sensor efficiency in other regions.
Solution Approach 2:
The patent employs asymmetry by designing openings with different maximum minimum distance ratios for different colors (red: 1.02-1.15, green: 1.32-1.38, blue: 1.05-1.20). These asymmetric geometric parameters are specifically tailored to reduce reflective color bands for each color channel, preventing symmetric reflection patterns that cause color banding artifacts.
2Object-affected harmful factors
If the aperture ratio is increased to improve display quality, then display quality is improved, but reflective color bands become more prominent
Solution Approach 1:
The patent changes geometric parameters of openings by controlling the maximum minimum distance ratio within specific ranges (red: 1.02-1.15, green: 1.32-1.38, blue: 1.05-1.20). These parameter variations optimize the balance between aperture ratio and reflective color band reduction, allowing larger openings that improve display quality while maintaining geometric characteristics that suppress color banding.
Solution Approach 2:
The patent introduces curvature by forming openings with rounded corners instead of sharp angles. This curvature modifies light reflection patterns, reducing the formation of reflective color bands while maintaining adequate aperture ratio for display quality.
3Illumination intensity
If LED current is increased to improve brightness, then brightness is improved, but LED lifespan is shortened
Solution Approach 1:
The patent applies partial action by forming openings with optimized geometric parameters that provide sufficient light transmission for required brightness levels without excessive aperture ratios. This moderate approach allows adequate brightness while avoiding conditions that would accelerate LED degradation, thus extending LED lifespan.
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 effectively minimizes reflective color bands and secures a high aperture ratio, thereby improving display quality and extending the lifespan of the light emitting diodes.
Implementation Method 1
a light blocking member positioned on the encapsulation layer and including a red opening, a blue opening, and a green opening
Implementation Method 2
The light emitting display device may further include color filters of different colors that may be positioned in the red opening, the blue opening, and the green opening
Implementation Method 3
The light emitting display device may further include a reflection adjustment layer filling the red opening, the blue opening, and the green opening and formed on the light blocking member
Data Source
AI summary
In a light emitting display device, a light blocking member is positioned on an encapsulation layer and includes a red opening, a blue opening, and a green opening. The red opening, the blue opening, and the green opening have a mass center, a first position closest to the mass center, and a second position furthest from the mass center. In case that a ratio of a distance from the mass center to the second position to a distance from the mass center to the first position is referred to as a maximum minimum distance ratio, the red opening has a value of about 1.02 or more and about 1.15 or less, the blue opening has a value of about 1.05 or more and about 1.2 or less, and the green opening has a value of about 1.32 or more and about 1.38.