Resonant Scanner Drive System for Microspectrometer Grating
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Solution Overview
Problem
Conventional gas analyzers, particularly mainstream spectrometers, face challenges in measuring multiple gas concentrations or partial pressures with high resolution due to bulkiness, weight, and cost issues, especially when dealing with multiple or overlapping spectral wavelengths, and require inefficient and expensive electromechanical scanner drives.
Innovation Solution
A compact and lightweight scanning spectrometer using a MEMS-fabricated oscillating mirror with a diffraction grating, which scans the spectrum across a fixed detector, allowing for efficient measurement of multiple gases with improved spectral resolution and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electromechanical scanner drives are used to rotate the diffraction grating, then spectral scanning capability is achieved, but the device becomes large, heavy, and expensive
Solution Approach 1:
The patent replaces conventional electromechanical scanner drives with a resonant piezoelectric ceramic actuator that uses piezoelectric expansion and contraction to oscillate the diffraction grating. This substitution of mechanical actuation with piezoelectric actuation dramatically reduces the size and weight of the moving components while maintaining spectral scanning capability and resolution
Solution Approach 2:
The patent utilizes resonant mechanical vibration of the piezoelectric ceramic at its natural frequency (typically 20-100 kHz) to achieve rapid oscillation of the diffraction grating. By operating at resonance, the system achieves efficient spectral scanning with minimal power consumption and without requiring large mechanical structures, thus reducing overall device weight and size
2Measurement precision
If conventional electromechanical scanner drives are used, then spectral scanning is enabled, but power consumption becomes excessive
Solution Approach 1:
The patent operates the piezoelectric ceramic actuator at its resonant frequency, where the mechanical system naturally oscillates with maximum efficiency. This resonant operation minimizes the power required to drive the diffraction grating, as the system utilizes its own mechanical energy storage rather than requiring continuous external power input, thus dramatically reducing power consumption compared to conventional electromechanical scanners
Solution Approach 2:
The patent employs periodic oscillation of the diffraction grating at the resonant frequency of the piezoelectric ceramic. This periodic action allows the system to scan the spectrum efficiently by utilizing the natural oscillation cycle, requiring power only during brief activation periods rather than continuous operation, thereby reducing overall energy consumption
3Adaptability or versatility
If the diffraction grating is rotated using motor and oscillating linkages, then spectral scanning is achieved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces complex motor-driven oscillating linkage mechanisms with a simple piezoelectric ceramic actuator that directly couples to the diffraction grating. This substitution eliminates multiple mechanical components (motors, linkages, bearings, gears) and replaces them with a single solid-state piezoelectric element, dramatically simplifying the device structure while maintaining full spectral scanning capability
Solution Approach 2:
The patent merges the functions of the motor, oscillating linkages, and grating holder into a single integrated piezoelectric actuator assembly. The piezoelectric ceramic serves simultaneously as the actuator, the oscillation mechanism, and the mounting structure for the diffraction grating, reducing component count and simplifying the overall device architecture
4Measurement precision
If conventional spectrometer designs are used, then adequate spectral resolution is achieved, but the device is too large for mainstream patient airway mounting
Solution Approach 1:
The patent replaces bulky electromechanical scanning mechanisms with compact piezoelectric actuators, enabling the entire spectrometer assembly to be miniaturized to dimensions suitable for mounting on patient airways while maintaining adequate spectral resolution for clinical gas analysis
Solution Approach 2:
The patent employs a linear array detector configuration that captures the entire spectrum simultaneously in one dimension, eliminating the need for mechanical scanning in the temporal dimension. This dimensional change allows the optical path to be folded and compacted into a small volume suitable for mainstream mounting while preserving full spectral measurement 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
The solution enables robust, cost-effective, and compact gas analysis capable of handling multiple gases with overlapping spectra, providing high sensitivity and efficient spectral data collection, suitable for use in respiratory gas monitoring.
Implementation Method 1
a resonant scanner drive system which employs a piezoelectric ceramic oscillating in response to an applied electrical signal
Implementation Method 2
directed to a diffraction grating where it is diffracted from the grating, spread out into a continuous spectrum
Implementation Method 3
a resonant scanner drive system which employs a piezoelectric ceramic oscillating in response to an applied electrical signal
Implementation Method 4
Gases that may be measured exhibit increased absorption (and reduced transmittance) at specific wavelengths in the infrared spectrum such that, the greater the gas concentration, the proportionally greater absorption and lower transmittance
Data Source
Figure 1A~2
Figure 1B~3
Figure 4A~4C
AI summary
A spectrometer is disclosed, which comprises a diffraction grating (204); and a resonant scanner drive system (200) comprising: a taut band (202) providing a rotational axis for the diffraction grating (204), wherein the diffraction grating (204) is fastened at a first side of the taut band (202); a permanent magnet (206) fastened to a second side of the taut band (202); and a first and a second spacer (208), wherein the first spacer is provided between the diffraction grating (204) and the taut band (202), wherein the second spacer is provided between the permanent magnet (206) and the taut band (202).