Electroluminescent Display Sub-Pixel Area Segmentation
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Solution Overview
Problem
Existing OLEDs face challenges in achieving uniform lifetime and improving the opening ratio due to the limitations of shadow mask technology, which restricts the density and size of sub-pixel regions, and the blue light-emitting layer has the shortest lifetime among red, green, and blue light-emitting elements.
Innovation Solution
The electroluminescent display features sub-pixel regions with varying areas, where a single color light-emitting layer can be used across multiple sub-pixel regions, allowing for adjustment of the arrangement and area of sub-pixel regions to increase density and improve resolution, and the area of blue light-emitting regions is optimized to extend the lifetime by reducing operation voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional shadow mask technology is used to fabricate organic light-emitting elements, then the manufacturing process is simple and well-established, but the minimum distance between openings limits the density and area of sub-pixel regions
Solution Approach 1:
The invention divides each pixel region into multiple sub-pixel regions with different areas (first, second, and third sub-pixel regions). This segmentation allows different color light-emitting layers to be positioned in different area configurations, enabling increased overall density while maintaining sufficient spacing for shadow mask fabrication. The varied sub-pixel areas optimize the use of available space without requiring reduction of minimum opening distances.
Solution Approach 2:
Different sub-pixel regions within the same pixel are assigned different areas to accommodate the specific characteristics of different color light-emitting layers. This local differentiation allows optimization of each color's positioning and area based on its lifetime characteristics and light-emitting properties, while maintaining uniform manufacturing constraints across the entire display.
2Illumination intensity
If the operating current is increased to improve brightness, then the light output increases, but the lifetime of organic light-emitting elements is shortened
Solution Approach 1:
Different color light-emitting layers are positioned in sub-pixel regions with different areas. Since the blue light-emitting layer has the shortest lifetime, it can be positioned in smaller area regions, while red and green layers with longer lifetimes occupy larger areas. This local differentiation in area allocation compensates for the lifetime differences of different colors, achieving more uniform overall display lifetime without requiring reduced operating current.
3Illumination intensity
If the area of blue light-emitting regions is increased to improve brightness, then the light output increases, but the lifetime problem of blue light elements is exacerbated
Solution Approach 1:
The blue light-emitting layer is positioned specifically in the first sub-pixel regions which have smaller areas compared to other sub-pixel regions. This local area differentiation allows the blue light-emitting elements to operate at lower effective currents due to their smaller total area, thereby extending their lifetime while still providing sufficient blue light output when combined with the other color layers.
4Manufacturing precision
If multiple shadow masks are used to fabricate different color light-emitting layers, then each color can be precisely positioned, but the manufacturing complexity and number of process steps increase
Solution Approach 1:
By segmenting each pixel into sub-pixel regions with different areas and strategically positioning different color light-emitting layers in these segmented regions, the invention enables precise color positioning to be achieved through area differentiation rather than requiring separate shadow masks for each color. This segmentation strategy reduces the number of shadow masks needed while maintaining positioning precision.
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 enhances the overall resolution and extends the lifetime of the display by allowing a single color light-emitting layer to be applied to multiple sub-pixel regions, ensuring uniform lifetimes for blue, green, and red organic light-emitting elements while overcoming the limitations of traditional shadow mask technology.
Implementation Method 1
electrons and holes can be recombined in the light-emitting layer 22 of the organic light-emitting element 20 to produce light
Data Source
AI summary
An electroluminescent display comprises a substrate with a plurality of pixel regions, wherein each pixel region has a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region. Pluralities of first color light-emitting layers, second color light-emitting layers, and third color light-emitting layers are formed on the substrate. Each first color light-emitting layer is disposed in one first sub-pixel region, and each second color light-emitting layer is disposed in two adjacent second sub-pixel regions. The area of the first sub-pixel region is larger than the area of the second sub-pixel region in a single pixel region.