Composite Nanometer Displacement Measurement System
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Solution Overview
Problem
Current nanometer displacement measurement systems using laser interference struggle with high resolution and rapid signal acquisition and demodulation, particularly due to the lack of a reference for interference signal phase subdivision in scalar light field measurements, and the increased complexity of vector vortex light field signals.
Innovation Solution
A composite measurement system combining scalar and vector light fields with multi-octave light paths, utilizing a light source, polarization beam splitting prisms, phase change modules, right-angle prisms, and interference light collection modules to collect and demodulate interference signals, enabling improved resolution and rapid signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scalar light field interference signal is used for nanometer displacement measurement, then the interference signal has obvious bright and dark boundary advantages, but it lacks a reference for interference signal phase subdivision directly
Solution Approach 1:
The patent combines scalar light field and vector vortex light field into a composite light field system. The scalar light field provides clear interference fringes while the vector vortex light field provides phase subdivision reference through its petal-shaped rotating fringes, thus merging the advantages of both fields to resolve the contradiction between signal clarity and phase reference availability.
Solution Approach 2:
The patent creates a composite light field system that integrates two different types of light fields (scalar and vector vortex) with complementary characteristics. This composite approach allows the system to simultaneously utilize the bright-dark boundary clarity of scalar fields and the phase reference capability of vector vortex fields, effectively solving the information loss problem.
2Measurement precision
If vector vortex light field interference is used to improve measurement resolution, then higher subdivision multiple is achieved, but the number of interference fringes increases making signal acquisition and demodulation more difficult
Solution Approach 1:
The patent segments the light field into two distinct components: scalar light field for providing clear interference boundaries and vector vortex light field for providing phase subdivision reference. This segmentation allows each component to perform its specialized function, reducing the overall complexity of signal processing while maintaining high measurement resolution.
Solution Approach 2:
The patent introduces a new dimension by combining scalar and vector light fields that operate in complementary ways. The scalar field operates in the intensity domain providing clear fringes, while the vector vortex field operates in the phase domain providing subdivision reference, thus adding a dimensional aspect that simplifies the overall measurement process.
3Productivity
If composite measurement system with multi-octave light paths is implemented, then rapid acquisition and demodulation is achieved, but the system structure becomes more complex
Solution Approach 1:
The patent designs the composite measurement system to perform multiple functions simultaneously: the same optical path processes both scalar and vector vortex light fields, the same detection system acquires both types of interference signals, and the same processing unit demodulates both signals. This multi-functionality reduces the need for separate dedicated components for each function, thereby improving acquisition speed without proportionally increasing system complexity.
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 system achieves rapid acquisition and demodulation of interference signals while enhancing measurement resolution by combining scalar and vector light fields, allowing for precise displacement calculations using both scalar and vector interference signals.
Implementation Method 1
The polarization beam splitting prism is arranged on an outgoing light path of the laser beam, and is configured to divide the laser beam into a first transmitted light and a first reflected light
Implementation Method 2
The first phase change module is configured to: change a phase of the first transmitted light, transmit the first transmitted light after phase change to the object, receive a first to-be-measured light reflected by the object, change a phase of the first to-be-measured light
Implementation Method 3
A composite measurement system for measuring nanometer displacement, includes: a light source, a polarization beam splitting prism, a first phase change module, a second phase change module, a first right-angle prism, a second right-angle prism, a non-polarization beam splitting prism, a scalar interference light collection module, a vector interference light collection module
Data Source
AI summary
A composite measurement system for measuring nanometer displacement is provided. The system includes: a light source, a polarization beam splitting prism, a first phase change module, a second phase change module, a first right-angle prism, a second right-angle prism, a non-polarization beam splitting prism, a scalar interference light collection module, a vector interference light collection module and a displacement calculation module. In the present disclosure, a photodetector is configured to collect an intensity of scalar interference light of the object to be measured being moved, to obtain a periodic light intensity change curve; a CCD camera is configured to collect images of interference vortex light of the object being moved; and the displacement calculation unit is configured to calculate a displacement of the object according to integer periods of the light intensity change curve and angles of image changes of the interference vortex light.