LED Capping Layer Thickness Control for Display Reflectance
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Solution Overview
Problem
Conventional display devices face challenges in achieving high luminous efficiency and low reflectance of external light, leading to issues such as color bleeding and reduced display quality, particularly in smaller, lighter, and more portable devices.
Innovation Solution
A display device design featuring light emitting diodes with specific capping layers and a thin film encapsulation structure, including inorganic and organic layers, to optimize light emission and reduce external light reflectance, with capping layer thicknesses between 540 angstroms and 640 angstroms for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional display device structure is used, then the device can be manufactured with standard processes, but the external light reflectance is high causing color bleeding and reduced display quality
Solution Approach 1:
The patent applies parameter changes by precisely controlling the capping layer thickness to 540-640 angstroms, which is a specific parameter range optimized to reduce external light reflectance. This thickness control creates destructive interference for reflected light waves, thereby minimizing color bleeding while maintaining manufacturability through standard semiconductor processing techniques.
Solution Approach 2:
The patent employs composite materials by combining the capping layer with specific underlying layers and encapsulation structures. The capping layer is formed as part of a multi-layer composite structure that includes inorganic and organic encapsulation layers, where each material contributes specific optical and protective properties to collectively reduce external light reflectance and prevent color bleeding.
2Object-affected harmful factors
If the capping layer thickness is increased to reduce external light reflectance, then color bleeding is reduced, but the luminous efficiency decreases
Solution Approach 1:
The patent optimizes the capping layer thickness to a specific range of 540-640 angstroms, which represents a critical parameter change. This precise thickness control achieves the optimal balance where the layer is thick enough to create sufficient destructive interference for reflected light (reducing color bleeding) but thin enough to allow maximum light transmission from the LED, thereby maintaining high luminous efficiency.
3Weight of moving object
If the display device is made smaller and lighter for portability, then the device becomes more portable, but the display quality and light emission performance deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the capping layer thickness to 540-640 angstroms, which enhances light extraction efficiency from the LED. This parameter optimization increases the luminous intensity per unit area, allowing smaller display devices to maintain or improve light emission performance despite reduced overall size and weight.
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 effectively increases display quality by reducing external light reflectance and enhancing luminous efficiency, minimizing color bleeding and improving image display in portable devices.
Implementation Method 1
a first capping layer disposed on the first light emitting diode and that has a thickness of about 540 angstroms to about 640 angstroms
Data Source
AI summary
A display device includes a substrate, a light emitting diode disposed on the substrate and that emits light that has a preset color, a capping layer disposed on the light emitting diode and that has a thickness of about 540 angstroms to about 640 angstroms, and a thin film encapsulation layer disposed on the capping layer. As the capping layer has a predetermined thickness, a reflectance of external light is reduced, a color bleeding phenomenon is reduced, and the luminous efficiency of the light emitting diode is increased.