Aluminum Alloy Wire Grid Polarizer Hillock Prevention
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Solution Overview
Problem
The manufacturing process of wire grid polarizers often results in non-uniform metal wire patterns due to the formation of hillocks when aluminum is exposed to high temperatures, leading to reliability issues.
Innovation Solution
A polarizer is manufactured using an aluminum alloy with nickel and lanthanum impurity elements, where the content of lanthanum is between 0.01 at% and 0.08 at% to enhance heat resistance and prevent hillock formation, and the wire grid layer is designed with specific dimensions and materials to improve polarization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aluminum is used as the metal layer material, then ease of manufacture and reflectance are improved, but hillocks occur during high temperature exposure causing non-uniform wire patterns
Solution Approach 1:
The patent changes the material parameters by introducing specific impurity elements (nickel: 0.01-0.1 at%, lanthanum: 0.01-0.08 at%) into the aluminum alloy to modify its thermal stability properties, preventing hillock formation during high temperature mask formation processes while maintaining the ease of aluminum deposition
Solution Approach 2:
The patent creates a composite material system by forming an aluminum alloy layer with controlled impurity elements rather than using pure aluminum. This composite structure combines the beneficial properties of aluminum (ease of deposition, reflectance) with the thermal stability provided by nickel and lanthanum additions
2Ease of manufacture
If aluminum is exposed to high temperature environment during mask formation, then mask formation process is completed, but hillocks form causing reliability deterioration
Solution Approach 1:
The patent applies beforehand cushioning by pre-introducing nickel and lanthanum impurity elements into the aluminum alloy layer before the high temperature mask formation process. These elements act as a protective mechanism that prevents hillock formation during subsequent thermal exposure, thereby maintaining reliability while allowing the mask formation process to proceed
3Temperature
If lanthanum content is increased to prevent hillocks, then heat resistance is improved, but manufacturing cost and material complexity increase
Solution Approach 1:
The patent optimizes the lanthanum content parameter within a specific range (0.01-0.08 at%) to achieve the minimum effective concentration for preventing hillocks. This parameter optimization balances heat resistance improvement with material simplicity, avoiding excessive lanthanum addition that would increase cost and complexity unnecessarily
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 results in a polarizer with improved reliability and optical properties, including increased transmittance and reflectance, while preventing the occurrence of hillocks and maintaining uniformity even at high temperatures.
Implementation Method 1
an aluminum alloy layer containing nickel and lanthanum as impurity elements... the content of lanthanum is 0.01 at% to 0.08 at%... to enhance heat resistance and prevent hillock formation
Implementation Method 2
a wire grid layer disposed on the base layer... a plurality of wire metal patterns spaced apart from each other at predetermined intervals... serves to convert light of a natural state into polarized light of a single straight state
Data Source
Figure 1
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AI summary
Provided is a polarizer. The polarizer includes a base layer and a wire grid layer which is disposed on the base layer and which include a plurality of wire metal patterns extending along a first direction and spaced apart from each other along a second direction crossing the first direction, wherein the wire grid layer is made of an aluminum (Al) alloy containing nickel (Ni) and lanthanum (La).