Photon Momentum Sensor with Capacitive Readout and Spiral Springs
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Solution Overview
Problem
Current photon momentum sensors lack sensitivity and accuracy in measuring laser power due to thermal distortion and environmental vibrations, which affect the precision of laser power measurement.
Innovation Solution
A photon momentum sensor design featuring a reflector plate with a central disk and annular member connected by interleaved Archimedean spiral spring legs, forming a capacitive structure with a bias plate, allowing orthogonal motion and independent operation regardless of orientation or environmental factors, along with a magnetic gradient field for enhanced sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional photon momentum sensors are used to measure laser power, then measurement capability is provided, but sensitivity is limited and orientation dependence reduces measurement precision
Solution Approach 1:
The patent replaces traditional mechanical measurement mechanisms with a capacitive sensing system. The mirror's displacement is detected through changes in capacitance between the mirror and a fixed electrode, eliminating the need for mechanical contact sensors and improving both sensitivity and orientation independence.
Solution Approach 2:
The device integrates multiple functions into a single system: the mirror serves as both the reflective element for laser power measurement and the movable component for capacitive sensing. The spring legs provide both mechanical support and the restoring force necessary for displacement measurement, reducing orientation dependence.
2Measurement precision
If traditional sensor designs are used, then basic measurement function is achieved, but thermal distortion affects measurement accuracy
Solution Approach 1:
The patent introduces a fixed electrode as an intermediary element that forms a capacitor with the movable mirror. This capacitive structure allows measurement of mirror displacement without direct mechanical contact, reducing the impact of thermal distortion on measurement accuracy.
Solution Approach 2:
The system measures changes in capacitance as a function of mirror displacement rather than directly measuring mechanical position. This parameter transformation from mechanical displacement to electrical capacitance change improves measurement accuracy by reducing sensitivity to thermal effects.
3Reliability
If simple mechanical structures are used, then device complexity is reduced, but sensitivity and measurement capability deteriorate
Solution Approach 1:
The patent employs thin, flexible spring legs made of silicon that connect the mirror to the substrate. These flexible elements provide the necessary mechanical compliance and restoring force while maintaining a simple geometric structure, achieving high sensitivity without complex mechanisms.
Solution Approach 2:
The patent uses microfabrication techniques to create precise silicon spring structures with controlled geometric parameters. The spring legs are fabricated with specific dimensions and patterns that provide the desired mechanical properties, replacing complex assembled components with monolithic microfabricated structures.
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 sensor provides high sensitivity and accuracy in measuring laser power with thermal immunity and compensation for distortions, maintaining precision across varying orientations and environmental conditions.
Implementation Method 1
a reflector plate that comprises: a central disk comprising a mirror that reflects a laser light, the central disk moving in response to reflection of the laser light
Implementation Method 2
a plurality of spring legs interposed between the central disk and the annular member and in mechanical communication with the central disk and the annular member, the plurality of spring legs comprising a first spring leg, a second spring leg, and a third spring leg, such that: the spring legs are interleaved; neighboring spring legs are spaced apart; and the spring legs individually are arranged in an Archimedean spiral that provides orthogonal motion of the central disk relative to the plane of the annular member
Implementation Method 3
a bias plate disposed opposing the reflector plate such that: the central disk of the reflector plate moves orthogonally to a plane of the bias plate in response to reflection of the laser light, and the central disk and the bias plate are arranged spaced apart as a capacitive structure
Data Source
AI summary
A photon momentum sensor includes: a reflector plate that includes: a central disk including a mirror; an annular member; a plurality of spring legs interposed between the central disk and the annular member, such that: the spring legs are interleaved; neighboring spring legs are spaced apart; and the spring legs individually are arranged in an Archimedean spiral that provides orthogonal motion of the central disk relative to the plane of the annular member; and a bias plate disposed opposing the reflector plate such that: the central disk of the reflector plate moves orthogonally to a plane of the bias plate in response to reflection of laser light, and the central disk and the bias plate are arranged spaced apart as a capacitive structure.