Aluminum Conductive Layer for Reflecting Electrode and Wire
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Solution Overview
Problem
In semitransparent liquid crystal displays, forming separate wires and reflecting electrodes increases manufacturing costs, and forming them simultaneously results in reduced visible light reflectance.
Innovation Solution
A display device structure where a metal conductive layer made of aluminum or aluminum alloy, with an intermediate impurity-containing layer, serves both as a low-resistance wire and a high-reflectance reflecting electrode, reducing contact resistance and manufacturing costs by using the same layer for both functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire width is increased to reduce wire resistance, then wire resistance decreases, but light transmission region decreases causing luminance decrease
Solution Approach 1:
The invention changes the material parameter of the drain electrode from conventional materials to a multi-layer aluminum-refractory metal structure. This parameter change enables achieving low wire resistance with narrower wire width, thereby maintaining light transmission region and luminance while reducing wire resistance.
2Reliability
If separate conductive layer is formed on drain electrode surface to reduce contact resistance, then contact resistance decreases, but manufacturing cost increases due to additional film formation and patterning
Solution Approach 1:
The invention merges the drain electrode formation process with the reflective layer formation process. The upper refractory metal layer of the drain electrode serves dual purposes: reducing contact resistance and providing reflectivity. This merging eliminates the need for separate conductive layer formation and patterning, reducing manufacturing cost while maintaining low contact resistance.
Solution Approach 2:
The upper refractory metal layer of the drain electrode performs multiple functions: it provides low contact resistance with transparent conductive material and simultaneously serves as a reflective layer. This multi-functionality eliminates the need for separate processes, resolving the contradiction between contact resistance reduction and manufacturing cost.
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 achieves high reflectance for visible light while maintaining low electric resistance, thereby reducing manufacturing costs and enhancing display performance without additional processing steps.
Implementation Method 1
an intermediate impurity-containing layer made of aluminum or an aluminum alloy containing impurities
Implementation Method 2
achieving high reflectance for visible light
Data Source
AI summary
A display device includes a metal conductive layer formed on a substrate, a transparent electrode film formed on the substrate and joined to the metal conductive layer and an interlayer insulating film isolating the metal conductive layer and the transparent conductive film. The metal conductive layer has a lower aluminum layer made of aluminum or aluminum alloy, an intermediate impurity containing layer made of aluminum or aluminum alloy containing impurities and formed on a substantially entire upper surface of the lower aluminum layer and an upper aluminum layer made of aluminum or aluminum alloy and formed on the intermediate impurity containing layer. In the interlayer insulating film and the upper aluminum layer, a contact hole penetrates therethrough and locally exposes the intermediate impurity containing layer, and the transparent electrode film is joined to the metal conductive layer in the intermediate impurity containing layer exposed from the contact hole.