Stacked Fabry-Perot Interferometer for Optical Resolution
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Solution Overview
Problem
Existing MEMS devices, particularly Fabry-Perot interferometers, face challenges in achieving high optical resolution due to mechanical defects and non-perfect parallelism and mirror curvature, limiting their suitability for applications like health monitoring and gas analysis.
Innovation Solution
The development of a multi-sensing system in a stacked configuration using a Fabry-Perot Interferometer with electrostatically tunable mirrors and multiple mirror stacks, which enhances optical sensitivity and resolution by allowing precise control of mirror spacing and reflectivity, enabling sub-nanometer deflection detection and broader spectral range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional Fabry-Perot interferometer structures are used, then the device can detect acoustic signals and pressure, but the optical resolution is limited due to mechanical defects and non-perfect parallelism
Solution Approach 1:
The patent divides the traditional single-cavity Fabry-Perot structure into multiple stacked optical cavities (first, second, and third cavities with different orientations). This segmentation allows each cavity to contribute to different aspects of light modulation, improving overall optical resolution while distributing mechanical stress across multiple independent structures, thereby reducing the impact of individual mechanical defects
Solution Approach 2:
The patent introduces multi-dimensional cavity orientations (first cavity in first orientation, second cavity in second orientation, third cavity in third orientation) to detect acoustic signals from different directions. This dimensional approach enhances measurement precision by capturing acoustic energy from multiple spatial perspectives, compensating for limitations in any single orientation and improving robustness against mechanical defects
2Manufacturing precision
If bulk micromachining processes are used for FPI fabrication, then stable substrate is available for optical deposition, but high optical resolution cannot be achieved due to mechanical defects and lack of high quality optical surface
Solution Approach 1:
The patent combines multiple optical cavities with different orientations into a single integrated device, merging their individual optical paths and detection capabilities. This consolidation allows the device to achieve high optical resolution by combining the strengths of multiple cavity configurations while maintaining a stable substrate foundation through the bulk micromachining process
Solution Approach 2:
The patent employs composite structural design with multiple cavity types (different orientations and configurations) within a single device, creating a composite optical system that leverages the advantages of each cavity type to achieve superior overall optical resolution and measurement precision
3Adaptability or versatility
If multiple Fabry-Perot sensors are serially concatenated, then gas analysis capability is enhanced, but the device complexity increases
Solution Approach 1:
The patent designs a multi-cavity device where each cavity serves multiple functions: acoustic signal detection, pressure sensing, and gas analysis. The first, second, and third cavities with different orientations collectively provide versatile detection capabilities, enabling the single device to perform gas analysis, acoustic monitoring, and pressure measurement without requiring separate dedicated sensors for each function
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 approach results in a high-finesse Fabry-Perot sensor with improved sensitivity and resolution, enabling effective detection of acoustic signals, pressure, and gas analysis with reduced power consumption and noise, suitable for harsh environments.
Implementation Method 1
The mechanical movement, such as deflection, is then converted into an electric signal through the use of piezo-resistive/electric material, or through changing capacitance between the moving part and a reference plate
Implementation Method 2
Optical detection systems based on Fabry-Perot interferometry (FPI) allows for highly sensitive sensors that can potentially detect displacement on sub-nanometer scale. This type of sensor consists of two partially transparent parallel plates with reflective inner surfaces, forming a cavity with an optical resonance that depends on the distance between the plates
Implementation Method 3
The development of a multi-sensing system in a stacked configuration using a Fabry-Perot Interferometer with electrostatically tunable mirrors and multiple mirror stacks, which enhances optical sensitivity and resolution by allowing precise control of mirror spacing and reflectivity
Data Source
AI summary
This invention describes the structure and function of an integrated multi-sensing systems in stacked configuration. Integrated systems described herein may be configured to form a microphone, pressure sensor, gas sensor or accelerometer. The method uses Fabry-Perot Interferometer in conjunction with light source and a photodetector integrated in stacked configuration. It also describes a configurable method for tuning the integrated system to specific resonance frequency using electrostatic actuators.