Bent Driving Arms for Lamellar Grating Interferometer Stress Dispersion
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Solution Overview
Problem
The existing MEMS-based lamellar grating interferometers face limitations in increasing the size of the reflective surface due to stress concentration on the driving arms, which restricts the movable distance and thus the resolution of Fourier Transform InfraRed (FTIR) spectrometers.
Innovation Solution
The design incorporates driving arms formed in a repeating bent shape, similar to a spring shape, to maximize length and disperse stress, allowing for increased movable distance without exceeding the endurance limit of the driving arms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of the reflective surface is increased to improve resolution, then the movable distance increases, but stress concentration on the driving arms becomes stronger and exceeds the endurance limit
Solution Approach 1:
The driving arms are designed with a bent shape instead of a straight configuration. This curvature allows the driving arms to flex and distribute stress along their length, preventing stress concentration at specific points while enabling the reflective surface to achieve the necessary movable distance for improved resolution.
Solution Approach 2:
The geometry of the driving arms is modified by introducing bent sections with specific radii and angles. This parameter change transforms the rigid straight structure into a flexible curved structure that can accommodate larger movements without exceeding material stress limits, thereby enabling both increased reflective surface size and maintained structural integrity.
2Length of moving object
If the movable distance is increased to improve resolution, then the reflective surface size must increase, but the driving arms break due to excessive stress
Solution Approach 1:
The bent shape of the driving arms provides a geometric solution that allows for increased movable distance while maintaining reliability. The curved configuration enables the arms to flex during movement, distributing mechanical stress throughout the structure rather than concentrating it at connection points, thus preventing breakage and ensuring durability.
Solution Approach 2:
The driving arms incorporate flexible bent sections that can deform elastically during operation. This flexibility allows the structure to accommodate larger movements without permanent deformation or failure, maintaining reliability while achieving the required movable distance for improved resolution.
3Device complexity
If a straight driving arm structure is used, then the structure is simple, but stress concentrates at specific points limiting the movable distance
Solution Approach 1:
While the bent shape increases structural complexity compared to a straight arm, it dramatically improves performance by distributing stress along the curved path. The additional geometric complexity is necessary to achieve the required movable distance without stress concentration, representing an acceptable trade-off where moderate complexity increases enable significant gains in functional capability.
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
This configuration significantly reduces stress on the driving arms, enabling a longer movable distance and improved resolution for FTIR spectrometers while maintaining a miniaturized structure.
Implementation Method 1
each of the plurality of driving arms is formed in a structure of repeating a preset bent shape plural times
Data Source
AI summary
The present invention relates to a lamella grating interferometer capable of being employed in a Fourier transform infrared (FTIR) spectrometer, the interferometer including a reflective surface in a circular shape and provided with a fixed portion including fixed mirrors and a movable portion including movable mirrors that are arranged with the fixed mirrors in a crossing manner to form a lamella structure with the fixed mirrors, a plurality of driving units disposed at outside the reflective surface and configured to apply driving forces for moving the movable portion, and a plurality of driving arms connecting the driving units to the movable portion of the reflective surface, respectively, and configured to move the movable portion in response to the driving forces applied by the driving units, wherein each of the plurality of driving arms is formed in a structure of repeating a preset bent shape plural times.