Display Device Capping Layer Porous Structure Warping
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Solution Overview
Problem
Display devices face the challenge of substrate warping due to stress, which affects the quality and reliability of liquid-crystal display (LCD) devices, particularly in maintaining accurate color reproduction and panel flatness.
Innovation Solution
A display device structure incorporating a first substrate with a wavelength conversion layer, a capping layer featuring a porous layer with a higher thermal expansion coefficient than the inorganic layer, and a polarizing layer, which helps to mitigate stress-induced warping by reducing thermal expansion coefficient differences between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional multi-layer structure is used in LCD devices, then color reproduction quality can be improved, but substrate warping occurs due to stress from thermal expansion coefficient differences between layers
Solution Approach 1:
The patent applies parameter changes by modifying the thermal expansion coefficient of the capping layer through creating a porous structure. The porous layer has a thermal expansion coefficient of 2.5-5.0 ppm/K, which is specifically tuned to match or closely approximate the thermal expansion coefficient of the wavelength conversion layer (5-7 μm thickness). This parameter matching eliminates the stress that causes substrate warping while maintaining the multi-layer structure needed for color reproduction quality.
Solution Approach 2:
The patent uses composite materials by combining a porous layer with inorganic materials (silicon nitride, silicon oxide, or silicon oxynitride) to create a capping layer with tailored properties. The porous structure provides the necessary thermal expansion characteristics, while the inorganic material components maintain structural integrity and optical performance. This composite approach allows simultaneous achievement of substrate flatness and color reproduction quality.
2Adaptability or versatility
If layers with different thermal expansion coefficients are stacked, then functional requirements can be met, but stress accumulates causing warping
Solution Approach 1:
The patent changes the thermal expansion parameter of the capping layer by introducing a porous structure with controlled porosity. The porous layer's thermal expansion coefficient (2.5-5.0 ppm/K) is specifically designed to match the wavelength conversion layer's thermal expansion characteristics. This parameter optimization reduces thermal stress accumulation while maintaining the functional versatility of the multi-layer structure for color conversion and optical control.
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 proposed solution effectively prevents substrate warping, enhancing the stability and color reproduction capabilities of LCD devices by managing thermal expansion and maintaining panel flatness.
Implementation Method 1
The porous layer may have a thermal expansion coefficient larger than that of the first inorganic layer. The porous layer may have a thermal expansion coefficient of 2.5 ppm/K to 5.0 ppm/K.
Data Source
AI summary
Provided are display device and method for fabricating the same. According to an aspect of the present disclosure, there is provided a display device comprising: a first substrate; at least one wavelength conversion layer disposed on the first substrate; a capping layer disposed on the wavelength conversion layer and comprising a porous layer; and a first polarizing layer disposed on the capping layer.