Array Substrate Coating Layer for Light Transmission
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Solution Overview
Problem
The existing array substrates for liquid crystal display screens suffer from a multi-layer reflection phenomenon due to the significant difference in refractive indices between the base substrate and the transparent conductive oxide film layer, leading to a low light transmission rate, which is further limited by manufacturing constraints on the thickness of the transparent conductive oxide film layer.
Innovation Solution
Incorporating a coating layer between the base substrate and the transparent conductive oxide film layer with a refractive index intermediate to both, thereby reducing the multi-layer reflection and enhancing light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent conductive oxide film layer is applied directly on the base substrate, then the electrical conductivity is improved, but the light transmission rate deteriorates due to multi-layer reflection
Solution Approach 1:
An intermediate coating layer with refractive index 1.6-1.8 is introduced between the base substrate (refractive index 1.5) and the transparent conductive oxide film layer (refractive index 1.92-2.05). This intermediary layer acts as a refractive index bridge, reducing the abrupt refractive index difference and thereby minimizing multi-layer reflection, which improves light transmission rate while maintaining the electrical conductivity function of the TCO layer.
Solution Approach 2:
The patent optimizes the refractive index parameter of the coating layer to be within 1.6-1.8, which is higher than the base substrate (1.5) but lower than the TCO layer (1.92-2.05). This parameter optimization creates a gradual refractive index transition, reducing reflection at interfaces and improving light transmission while preserving electrical conductivity.
2Reliability
If the thickness of the transparent conductive oxide film layer is increased to improve conductivity, then the electrical resistivity is reduced, but the light transmission rate is further limited by manufacturing constraints
Solution Approach 1:
The coating layer serves as an optical intermediary that decouples the relationship between TCO layer thickness and light transmission. By providing a refractive index transition zone, it allows the TCO layer to be optimized for electrical conductivity (thickness 30-50nm) without suffering from excessive reflection, thereby improving light transmission rate to 99.4% while achieving low electrical resistivity.
3Illumination intensity
If a coating layer is added between the base substrate and the transparent conductive oxide film layer, then the light transmission rate is improved, but the device complexity increases
Solution Approach 1:
The coating layer is designed with specific parameter ranges (refractive index 1.6-1.8, thickness 40-160nm) that optimize light transmission while maintaining manufacturing feasibility. This parameter-based design approach achieves high light transmission rate (99.4%) without requiring complex multi-layer structures or specialized materials, thereby limiting the increase in device complexity.
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 added coating layer improves the light transmission rate of the array substrate by optimizing the refractive index and thickness, achieving maximum transmission rates of up to 99.4% in certain configurations, surpassing the performance of substrates without this layer.
Implementation Method 1
A refractive index of the coating layer is higher than that of the base substrate and lower than that of the transparent conductive oxide film layer
Implementation Method 2
suffer from a multi-layer reflection phenomenon in a process that incident light enters from the base substrate 1 and emits from the liquid crystal layer 5
Data Source
AI summary
An array substrate and a display device are disclosed. A coating layer (8) is disposed between a base substrate (1) and a first transparent conductive oxide film layer (2), a refractive index of the coating layer (8) is bigger than that of the base substrate (1) and smaller than that of the first transparent conductive oxide film layer (2). A multi-layer reflection phenomenon caused by the relatively big difference between the refractive indexes of the base substrate 1 and the first transparent conductive oxide film layer 2 can be weakened, thereby the light transmission rate of the array substrate may be improved.