Thin Film Transistor Barrier Layer Refractive Index Matching
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Solution Overview
Problem
Existing thin film transistor array panels face challenges in preventing moisture penetration and maintaining high light transmittance, particularly due to refractive index differences between the barrier layer and the base substrate, which can lead to light reflection and reduced display performance.
Innovation Solution
A thin film transistor array panel design featuring a barrier layer with alternately stacked transparent material layers having compressive and tensile residual stress, made of silicon oxynitride, closely matched to the refractive index of the base substrate, along with a buffer layer and interlayer insulating layer of the same material, to minimize refractive index differences and enhance light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer is added to prevent moisture penetration, then moisture resistance is improved, but light transmittance deteriorates due to refractive index differences causing reflection
Solution Approach 1:
The barrier layer is constructed as a composite structure with multiple transparent material layers having different refractive indices. By combining materials such as silicon oxynitride, silicon oxide, and silicon nitride in specific sequences, the layer achieves both effective moisture barrier properties and optimized optical characteristics to reduce reflection.
Solution Approach 2:
The refractive indices of the transparent material layers are carefully controlled to fall within specific ranges (1.46-1.74 for first layer, 1.46-2.05 for second layer, 1.46-2.30 for third layer). By adjusting these optical parameters and the thickness of each layer, the structure minimizes light reflection while maintaining moisture barrier functionality.
2Stress or pressure
If transparent material layers with different residual stresses are stacked, then stress on the base substrate is reduced, but device complexity increases
Solution Approach 1:
The barrier layer is divided into multiple transparent material layers (first, second, and third layers) with different residual stress characteristics. By segmenting the single barrier function into multiple layers with complementary stress properties, the overall stress on the base substrate is reduced while maintaining the necessary barrier performance.
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 reduces moisture penetration and light reflection, improving light transmittance and reducing stress on the base substrate, thereby enhancing the performance and durability of the display panel.
Implementation Method 1
a difference between a refractive index of the barrier layer and a refractive index of the base substrate is within about 6%
Data Source
AI summary
A thin film transistor array panel device comprises: a base substrate; a barrier layer disposed over the base substrate and comprising a plurality of transparent material layers; and an array of thin film transistors disposed over the barrier layer. A difference between a refractive index of the barrier layer and a refractive index of the base substrate may be within about 6%. The transparent material layers may be arranged such that the transparent material layers having compressive residual stress and the transparent material layers having tensile residual stress are alternately stacked. Each of the transparent material layers may comprise silicon oxynitride (SiON).