Organic EL Display Panel Light-Shielding Structure for High Resolution
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Solution Overview
Problem
As the resolution of display panels increases, the area of each pixel decreases, leading to a reduction in the aperture ratio of the shielding layer, which decreases light emission efficiency and increases glare from external light due to reflective electrodes.
Innovation Solution
An organic EL display panel design featuring a matrix arrangement of pixels with light-reflective pixel electrode layers, column and row banks, light-emitting layers, and light-transmissive opposing electrode layers, along with column and row light-shielding layers that overlap the edge portions of the pixel electrode layers to prevent light leakage and external glare.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shielding layer width is increased to prevent light leakage to adjacent pixels, then color mixing prevention is improved, but aperture ratio decreases and light emission efficiency reduces
Solution Approach 1:
The patent applies different shielding strategies to different regions: a first light-shielding layer is provided at the pixel electrode edge portions where light leakage occurs, while the central light-emitting region maintains high aperture ratio. This localized shielding approach prevents color mixing at boundaries without significantly reducing the overall light emission area.
Solution Approach 2:
The shielding structure is segmented into multiple parts: a first light-shielding layer at the pixel electrode edges, a second light-shielding layer at the bank regions, and a third light-shielding layer at the color filter boundaries. This segmentation allows each shielding component to address specific light leakage paths while minimizing impact on the overall aperture ratio.
2Reliability
If the shielding layer width is increased to prevent light leakage to adjacent pixels, then light leakage prevention is improved, but light emission area per pixel reduces
Solution Approach 1:
The patent provides light-shielding layers specifically at the edge portions of pixel electrodes where light leakage to adjacent pixels occurs, rather than uniformly across the entire pixel structure. This localized approach prevents light leakage at critical boundaries while maintaining large light emission area in the central regions.
Solution Approach 2:
The patent extends light-shielding layers in the vertical dimension by providing multiple shielding layers at different heights and positions (first light-shielding layer at pixel electrode edges, second at banks, third at color filter boundaries), creating a three-dimensional shielding structure that blocks light leakage paths without horizontally encroaching on the light emission area.
3Productivity
If the shielding layer is reduced to increase aperture ratio, then light emission efficiency is improved, but glare from external light increases
Solution Approach 1:
The patent provides light-shielding layers specifically at the edge portions of pixel electrodes where external light reflection and glare occur, while the central light-emitting regions maintain high aperture ratio and efficient light emission. This localized shielding approach addresses glare at boundaries without compromising overall light emission efficiency.
4Measurement precision
If resolution is increased, then display quality is improved, but element area per pixel decreases
Solution Approach 1:
The patent implements a high-resolution display structure where light-shielding layers are concentrated at the narrow edge portions of miniaturized pixel electrodes, allowing the central light-emitting regions to maintain adequate size for efficient light emission even as overall pixel area decreases with increased resolution.
Solution Approach 2:
The patent uses vertical stacking of multiple light-shielding layers at different positions to provide comprehensive light leakage prevention in high-resolution pixels, where horizontal space is limited. This three-dimensional shielding approach effectively blocks light paths without requiring proportional increases in horizontal shielding width that would further reduce the already-small light emission area.
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 light emission efficiency by optimizing the light-shielding structure and reduces glare from external light, maintaining high display contrast and color purity.
Implementation Method 1
pixel electrode layers including a light-reflective material
Implementation Method 2
column light-shielding layers disposed higher than the pixel electrode layers, extending in the column direction, arranged side-by-side in the row direction, and overlapping the row-direction edge portions of the pixel electrode layers
Implementation Method 3
a light-emitting layer that includes an organic light-emitting material... When driven, a voltage is applied between the pair of electrodes, holes are injected to the light-emitting layer from the anode, electrons are injected to the light-emitting layer from the cathode, and the holes and the electrons recombine to emit light
Data Source
AI summary
An organic EL display panel in which pixels are arranged in a matrix, including: light-emitting layers disposed above pixel electrode layers in intervals between adjacent ones of column banks; an opposing electrode layer disposed above the light-emitting layers, the opposing electrode layer including a light-transmissive material; column light-shielding layers disposed higher than the pixel electrode layers, extending in the column direction, arranged side-by-side in the row direction, and overlapping row-direction edge portions of the pixel electrode layers in plan view of a substrate; and row light-shielding layers disposed higher than the pixel electrode layers, extending in the row direction, arranged side-by-side in the column direction, overlapping column-direction edge portions of the pixel electrode layers and partially overlapping contact regions in plan view of the substrate.