Display Signal Line Capping Layer for Reduced Light Reflection
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Solution Overview
Problem
Display devices face issues with visibility due to external light reflection from signal lines and electronic elements formed by conductive layers, which affect the image displayed.
Innovation Solution
A display device design featuring a metal layer with a capping layer made of molybdenum and tantalum, where the capping layer has a protruding tip that reduces light reflectance by covering the sidewalls of the metal layer, and a method of manufacturing this structure to minimize external light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a metal layer is used for signal lines and electronic elements, then electrical conductivity is improved, but external light reflection increases
Solution Approach 1:
The patent applies the nesting principle by placing the capping layer inside the visual field of the metal layer, specifically having the capping layer protrude from the sidewall of the metal layer to cover the exposed sidewall surface. This nested configuration allows the capping layer to be positioned within the spatial envelope of the metal layer structure, effectively shielding the metal layer from external light without adding significant external volume or complexity to the device.
Solution Approach 2:
The capping layer serves as an intermediary element between the metal layer and external light. Instead of directly addressing the reflection problem by modifying the metal layer itself or adding complex external structures, the patent introduces this intermediate capping layer that specifically targets and blocks the light reflection issue at the exposed sidewall portion, while leaving the metal layer's electrical conductivity function intact.
2Object-affected harmful factors
If the capping layer covers the sidewall of the metal layer, then light reflectance is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by establishing specific quantitative relationships for the tip protrusion dimension. The protrusion length is defined by the inequality d≥h/(tan(90°−θα))+h/(tan(θβ)), where parameters such as metal layer thickness (h), viewing angle (θα), and taper angle (θβ) are used to calculate the minimum required protrusion distance. This transforms the manufacturing precision requirement from a vague qualitative specification into a calculable quantitative parameter that can be controlled through standard manufacturing processes.
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 external light reflection, enhancing the visibility of the display device by ensuring that the metal layer is not exposed to external light, thereby improving the display's optical reflection characteristics.
Implementation Method 1
having a second light reflectance lower than the first light reflectance of the metal layer
Implementation Method 2
The capping layer includes a tip protruding from a sidewall of the metal layer... reducing external light reflection
Data Source
AI summary
A display device includes a base layer, a pixel disposed on the base layer and including a thin film transistor, and a signal line connected to the pixel. The signal line includes a metal layer and a capping layer disposed on the metal layer, including molybdenum and tantalum. The metal layer has a first light reflectance, and the capping layer has a second light reflectance that is lower than the first light reflectance of the metal layer. The capping layer includes a tip protruding from a sidewall of the metal layer, and the tip protrudes more than a contact point at which the sidewall of the metal layer contacts with the base layer when viewed in a plane. The display device has an improved external light reflection characteristic and an enhanced display quality.