Anti-Reflection Layer in TFT Array Substrate for Display Panels
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Solution Overview
Problem
In liquid crystal display devices, the high light reflection at the contact interface between the base substrate and the gate electrode insulating layer of the TFT array substrate leads to low transmittance of the backlight source, particularly in high pixel density displays where the aperture ratio is low, resulting in significant backlight loss.
Innovation Solution
An anti-reflection layer is disposed between the base substrate and the gate electrode insulating layer, with refractive indexes increasing sequentially from the base substrate to the gate electrode insulating layer, reducing reflected light energy and improving transmittance by forming a half-wave loss, and also between the base substrate and the gate electrode layer in non-light-transmitting regions to increase the number of interfaces for light passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional TFT array substrate structure is used without an anti-reflection layer, then the device structure is simple, but the light transmittance is low due to high reflection at the contact interface between the base substrate and the gate electrode insulating layer
Solution Approach 1:
An anti-reflection layer with intermediate refractive index (1.7-2.0) is introduced between the base substrate (refractive index 1.5) and the gate electrode insulating layer (refractive index 2.1-2.5). This intermediary layer reduces the refractive index difference at the interface, thereby reducing light reflection and improving light transmittance from 40-50% to 60-70%.
Solution Approach 2:
The anti-reflection layer is constructed using composite material systems including silicon oxynitride (SiOxNy), aluminum oxide (AlOx), or titanium oxide (TiOx) with specific refractive indices. These composite materials provide the optimal balance between reducing reflection and maintaining device performance.
2Manufacturing precision
If the aperture ratio is reduced to increase pixel density, then the display resolution is improved, but the backlight loss increases due to higher reflection at contact interfaces
Solution Approach 1:
The anti-reflection layer serves as an intermediary that reduces reflection losses at critical interfaces. By minimizing the refractive index mismatch between the base substrate and gate electrode insulating layer, it recovers backlight that would otherwise be lost, thereby improving the effective aperture ratio and reducing backlight loss in high pixel density displays.
3Reliability
If the refractive index difference between the base substrate and gate electrode insulating layer is large, then the electrical insulation performance is improved, but the light reflection increases and transmittance decreases
Solution Approach 1:
The anti-reflection layer with intermediate refractive index (1.7-2.0) acts as a mediator that allows the gate electrode insulating layer to maintain its high electrical insulation performance with refractive index 2.1-2.5, while simultaneously reducing the optical reflection at the interface with the base substrate. The anti-reflection layer bridges the optical gap without compromising the electrical insulation function.
Solution Approach 2:
The solution applies local quality modification by introducing a layer with specific optical properties (refractive index 1.7-2.0) at the critical light-path interface, while the gate electrode insulating layer maintains its high refractive index (2.1-2.5) for electrical insulation. This localized optimization allows simultaneous achievement of good optical and electrical 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 anti-reflection layer effectively reduces reflectivity at contact interfaces, enhancing the transmittance of the backlight source in the TFT array substrate by allowing more light to pass through, particularly in light-transmitting regions, and improving overall display performance.
Implementation Method 1
the anti-reflection layer has a refractive index between a refractive index of the base substrate and a refractive index of the gate electrode insulating layer
Implementation Method 2
disposing an anti-reflection layer between a base substrate of the TFT array substrate and a gate electrode insulating layer... the anti-reflection layer effectively reduces reflectivity at contact interfaces
Data Source
AI summary
A thin film transistor (TFT) array substrate and a display panel are provided. The TFT array substrate has a base substrate, an anti-reflection layer, and a gate electrode insulating layer. The TFT array substrate has a light-transmitting region. The anti-reflection layer is disposed on the base substrate of the light-transmitting region. The gate electrode insulating layer is disposed on the anti-reflection layer. Light refractive indexes of the base substrate, the anti-reflection layer, and the gate electrode insulating layer are increasing sequentially.