Laser Milled Mirror Plate Truss Structure for Flatness
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Solution Overview
Problem
Existing methods for manufacturing torsional hinged mirrors with high-speed rotational capabilities face challenges in achieving superior flatness due to flexing issues at the mirror edges, which are not adequately addressed by traditional etching processes that result in undercutting and reduced mass distribution, leading to increased weight and cost.
Innovation Solution
A method involving laser milling to create a contoured multilevel structure with an integral truss layer and center spines, allowing for selective removal of silicon material to form a 3D truss structure that avoids undercutting and increases the contact area between levels, resulting in a flatter and lighter mirror with reduced flexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional etching processes are used to manufacture torsional hinged mirrors, then manufacturing cost and time are reduced, but the mirror surface flatness deteriorates due to flexing at the edges
Solution Approach 1:
The patent applies preliminary action by pre-forming reinforcement structures (ridges and trusses) into the mirror substrate before the etching process. These structures are created by selectively removing material in specific patterns, establishing a rigid framework that prevents edge flexing during subsequent high-speed operation. This preliminary structuring allows the mirror to maintain flatness at higher speeds without requiring slower manufacturing processes.
Solution Approach 2:
The patent transitions from a traditional planar mirror structure to a three-dimensional contoured structure with varying thickness. By creating raised ridges and truss formations that extend upward from the mirror surface, the invention adds vertical dimensionality to provide structural reinforcement. This dimensional change creates inherent stiffness against flexing while maintaining the overall mirror shape and optical surface integrity.
2Stability of the object's composition
If the mirror is made thicker to reduce flexing, then structural stability improves, but weight increases to an unsatisfactory level
Solution Approach 1:
The patent applies local quality by concentrating additional material only in specific locations where structural reinforcement is needed, rather than uniformly thickening the entire mirror. Ridges and truss structures are positioned strategically at the edges and support points where flexing occurs, providing localized stiffness enhancement. This allows the mirror to achieve required structural stability while keeping the overall weight low by maintaining thin sections in non-critical areas.
Solution Approach 2:
The patent creates a composite structural system combining regions of varying thickness within the same mirror substrate. The structure integrates thin, lightweight sections for general areas with thicker, reinforced sections at critical locations, forming a composite architecture that optimizes the strength-to-weight ratio. This composite approach allows the mirror to exhibit high structural stability in critical zones while maintaining low overall weight.
3Manufacturing precision
If complex truss structures are etched in the hinge plate and oscillating member, then flatness is improved, but manufacturing speed decreases and cost increases
Solution Approach 1:
The patent merges the reinforcement structures directly into the oscillating member itself, eliminating the need for separate truss components in the hinge plate. By integrating the ridges and trusses as integral parts of the oscillating member's contoured surface, the design simplifies the overall assembly while maintaining the flatness-enhancing functionality. This integration reduces the number of discrete parts and assembly steps, thereby reducing manufacturing complexity and 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 laser milling process enhances the flatness and reduces flexing at the mirror edges, providing a faster and less expensive manufacturing method for torsional hinged devices with improved structural integrity and weight reduction.
Implementation Method 1
the back side of a silicon layer such as for example a silicon wafer is laser milled in at least one area
Data Source
AI summary
A multilevel mirror plate suitable for use with a torsional hinged mirror assembly is laser milled to provide a more effective truss structure in less time and at a reduced cost.