OLED Encapsulation Structure for Light Efficiency and Color Shift
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Solution Overview
Problem
Current organic light emitting diode (OLED) displays face challenges in achieving optimal light emission efficiency and durability due to issues with refractive index variations and layer thickness in their multilayer structures, which affect optical efficiency and color shift phenomena.
Innovation Solution
The display apparatus incorporates a specific multilayer structure with a first organic layer having a higher refractive index than the first inorganic layer, and a second inorganic layer with a refractive index of 1.7 to 2.0, along with a third inorganic layer, to enhance light emission efficiency and reduce color shift, using silicon oxynitride and silicon nitride layers with varying thicknesses to optimize light path and minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional multilayer structure is used in OLED displays, then the device can be manufactured with standard processes, but light emission efficiency is insufficient and color shift phenomena occur due to refractive index variations
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive indices of different layers (first organic layer: 1.7-1.9, first inorganic layer: 1.60-1.65, second inorganic layer: 1.7-2.0) and their thicknesses to optimize light emission efficiency and eliminate color shift through resonance effects
Solution Approach 2:
The patent uses composite materials by combining multiple layers with different refractive indices (organic and inorganic materials) to create an encapsulation structure that achieves both protection and optical optimization, reducing color shift and improving light emission
2Manufacturing precision
If the thickness of layers is not uniformly controlled, then manufacturing is simpler, but optical efficiency decreases and color shift phenomena occur
Solution Approach 1:
The patent specifies precise thickness parameters for each layer (first organic layer: 500-900 Å, first inorganic layer: 1,000-11,000 Å with varying thickness in different areas, second inorganic layer: 4,500-8,000 Å) to achieve optimal optical performance while providing clear manufacturing guidelines
Solution Approach 2:
The patent applies local quality by having the first inorganic layer with different thickness characteristics in different areas: a first area with uniform thickness over the display region and a second area with decreasing thickness extending to the non-display region, optimizing both optical performance and manufacturing
3Reliability
If refractive index variations are not controlled in the multilayer structure, then material selection is easier, but color shift phenomena occur and display quality decreases
Solution Approach 1:
The patent controls refractive index parameters for each layer (first organic: 1.7-1.9, first inorganic: 1.60-1.65, second inorganic: 1.7-2.0) to prevent color shift and ensure consistent display quality across different viewing conditions
Solution Approach 2:
The patent applies different refractive index requirements to different layers and regions, with the first organic layer having higher refractive index than the first inorganic layer in specific areas, optimizing light emission and preventing color shift in critical display regions
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 configuration improves light emission efficiency by resonance effects and reduces color shift, enhancing the overall performance and reliability of OLED displays by maintaining uniform light emission across the display area.
Implementation Method 1
improves light emission efficiency by resonance effects
Implementation Method 2
The first organic layer has a higher reflective index than the first inorganic layer
Implementation Method 3
refractive index variations and layer thickness in their multilayer structures, which affect optical efficiency and color shift phenomena
Data Source
AI summary
A display apparatus including a base layer including a display region and a non-display region; display elements on the display region and including a first electrode, a light emitting layer, and a second electrode on the light emitting layer; and an upper layer on the display elements, wherein the upper layer includes a first organic layer contacting the second electrode; a first inorganic layer contacting the first organic layer; a second organic layer contacting the first inorganic layer; and a second inorganic layer contacting the second organic layer, wherein the first inorganic layer includes a first and second area, the first area having a refractive index of about 1.60 to about 1.65 with respect to a wavelength of about 633 nm, wherein the first area has a uniform thickness, and wherein a thickness of the second area decreases as a distance from the display region increases.