Al-Cu Alloy Micro-Mirror Reflectivity
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Solution Overview
Problem
Conventional spatial light modulator micro-mirrors, typically made of Al:Si:Ti alloys, have limited reflectivity, which is not sufficient for certain applications, and are prone to material constraints like film stress and hillocking, limiting their performance in optical communication and video display systems.
Innovation Solution
The use of an Al—Cu alloy with small amounts of copper (up to 2.0%) for the micro-mirrors, which enhances reflectivity while reducing hillocking and maintaining compatibility with semiconductor processing, thereby improving mechanical stability and reflectivity without increasing surface-induced stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional Al:Si:Ti alloy is used for micro-mirrors, then manufacturing compatibility is maintained, but reflectivity is limited and hillocking occurs
Solution Approach 1:
The patent changes the material composition parameters by replacing Si and Ti elements with Cu element in the aluminum alloy, specifically using Al-Cu alloys with 0.5-2.0% copper content. This parameter change resolves the contradiction by achieving higher reflectivity (90% or higher in visible spectrum) while reducing hillocking compared to conventional Al:Si:Ti alloys
Solution Approach 2:
The patent uses composite material approach by creating an Al-Cu alloy system that combines the advantages of aluminum (low density, good ductility, ease of fabrication) with copper (high reflectivity, resistance to hillocking). The specific composition range of 98-99.5% Al and 0.5-2.0% Cu creates a composite material that simultaneously improves reflectivity and reduces hillocking while maintaining manufacturing compatibility
2Ease of manufacture
If pure aluminum is used for micro-mirrors, then ease of fabrication is improved, but mechanical hardness is insufficient
Solution Approach 1:
The patent modifies the material composition by adding copper (0.5-2.0%) to pure aluminum, creating an Al-Cu alloy. This parameter change simultaneously maintains ease of fabrication (inheriting from aluminum) while improving micro-hardness (enhanced by copper addition), resolving the contradiction between fabrication ease and mechanical strength
3Illumination intensity
If conventional alloys are used, then material constraints are satisfied, but reflectivity enhancement is limited
Solution Approach 1:
The patent optimizes the alloy composition parameters by selecting specific copper content ranges (0.5-2.0%) that simultaneously achieve high reflectivity (90% or higher) and maintain compatibility with conventional DMD processing techniques. This parameter optimization resolves the contradiction by enhancing reflectivity while preserving adaptability to existing 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 Al—Cu alloy micro-mirrors achieve a reflectance coefficient of 90% or higher in the visible spectrum, offering a 4% increase over conventional materials, while reducing hillocking and maintaining compatibility with existing DMD processing techniques, thus enhancing the performance of spatial light modulators.
Implementation Method 1
each pixel element comprising a deformable micro-mirror operable to reflect the light beam in at least one direction
Data Source
AI summary
In accordance with the teachings of the present invention, a spatial light modulator mirror metal having enhanced reflectivity is provided. In a particular embodiment of the present invention, a light processing system includes a light source operable to provide a light beam along a light path and a spatial light modulator positioned in the light path, the spatial light modulator comprising an array of pixel elements, each pixel element comprising a deformable micro-mirror operable to reflect the light beam in at least one direction. At least a portion of each deformable micro-mirror comprises an Al—Cu alloy. A controller electrically connected to the spatial light modulator is operable to provide electrical signals to the spatial light modulator to cause the spatial light modulator to selectively deform the pixel elements, thereby selectively reflecting incident light beams along a projection light path.