LED Display Planarization and Moat Structure for Light Extraction
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Solution Overview
Problem
Light emitting element display devices face issues with luminance differences between front and side surfaces, asymmetry in luminance orientation, and reduced light extraction efficiency due to absorption by adjacent banks.
Innovation Solution
A light emitting diode display device is designed with a substrate, adhesive layer, first and second planarization layers of different refractive indices, and a moat surrounding the light emitting diode, along with a reflective plate over the moat's side surface to enhance light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional light emitting diode structure is used, then the device is simple to manufacture, but light extraction efficiency is reduced due to absorption by adjacent banks
Solution Approach 1:
The patent introduces a moat structure that segments the space around the light emitting diode, separating it from adjacent banks. This segmentation prevents light absorption by banks while maintaining manufacturing feasibility through standard semiconductor fabrication processes
Solution Approach 2:
The patent introduces a reflective plate as an intermediary element between the light emitting diode and the surrounding environment. This reflective plate redirects laterally emitted light toward the front surface, improving light extraction efficiency without complicating the manufacturing process
2Device complexity
If no moat structure is provided, then the device structure is simple, but light emitted from the light emitting diode is absorbed in adjacent banks
Solution Approach 1:
The moat structure acts as a spatial separator that divides the device into distinct regions. This segmentation creates a light extraction pathway that prevents bank absorption while adding minimal structural complexity to the overall device design
3Device complexity
If lateral light is not redirected, then the device structure is simple, but front luminance is reduced
Solution Approach 1:
The reflective plate serves as an intermediary optical element that redirects laterally emitted light toward the front surface. This intermediary structure improves front luminance by utilizing light that would otherwise be lost, without requiring complex active control mechanisms
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
The solution improves front luminance and light extraction efficiency by refracting lateral light to the front surface and reflecting it using the reflective plate, increasing total light output by up to 31%.
Implementation Method 1
a first planarization layer provided over the adhesive layer and configured to cover a side surface of the light emitting diode and to have a first refractive index
Implementation Method 2
a first reflective plate provided over at least a portion of the side surface of the moat
Data Source
AI summary
Disclosed is a display device comprising a substrate, a first layer provided over the substrate, a light emitting element provided over the first layer, a first planarization layer over the first layer and covering a side surface of the light emitting element and having a first refractive index, a second planarization layer over the first planarization layer and having a second refractive index, and a bank over the second planarization layer, wherein the first planarization layer has a moat spaced apart from the light emitting element and surrounds at least a portion of the light emitting element.