3DOF Laser Interferometer Using Polarizing Beam Splitter
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Solution Overview
Problem
Current laser interferometer systems for measuring 3DOF LGEs are complex, costly, and prone to measurement errors due to environmental fluctuations and the need for multiple detectors, which complicates the optical path and increases instability.
Innovation Solution
A system and method utilizing a laser with a polarizing beam splitter, fixed reflector, and photodetectors to simultaneously measure 3DOF LGEs by splitting and combining light beams, allowing for rapid and accurate measurement of linear geometric errors along multiple axes using a simplified optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser interferometer is used to measure 3DOF LGEs, then measurement capability is provided, but the system requires multiple detectors and complex optical paths, increasing device complexity and cost
Solution Approach 1:
The patent combines multiple measurement functions into a single detector by merging the optical paths for measuring different error components (straightness errors in Y and Z directions, and position error in X direction) through a beam combining lens, eliminating the need for multiple detectors and reducing optical path complexity
Solution Approach 2:
The single detector is designed to perform multiple measurement functions simultaneously by receiving combined light signals that contain information about all three error components, making the detector universal for measuring 3DOF LGEs without requiring specialized detectors for each error type
2Measurement precision
If multiple detectors are used to measure different error components, then comprehensive measurement is achieved, but circuit heat dissipation increases, reducing measurement stability
Solution Approach 1:
The patent merges the detection function into a single detector, eliminating multiple detector circuits and their associated heat dissipation, thereby improving measurement stability while maintaining comprehensive error measurement capability through optical path combining
Solution Approach 2:
The patent extracts the heat dissipation problem by removing multiple detectors and their circuits from the system, retaining only a single detector, thus eliminating the source of thermal instability while preserving the ability to measure all error components through optical signal combination
3Measurement precision
If different measuring accessories and interferometer adjustments are required for each measurement, then accurate measurement is possible, but measurement time increases, reducing productivity
Solution Approach 1:
The patent performs preliminary configuration by setting up the optical path to simultaneously measure all three error components (X, Y, Z) in a single installation, eliminating the need for repeated adjustments and accessory changes for different measurements, thus improving productivity without sacrificing accuracy
Solution Approach 2:
The measurement system is designed with universal capability to measure all 3DOF LGEs simultaneously using a single detector and unified optical path, eliminating the need for multiple specialized measurement configurations and accelerating the measurement process while maintaining comprehensive accuracy
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
Enables simultaneous and rapid measurement of 3DOF LGEs with improved accuracy and reduced complexity, stability, and cost compared to prior art, facilitating long-term monitoring of linear position changes between objects.
Implementation Method 1
the polarizing beam splitter is used for: 1) beam splitting: splitting the emergent light L1 into a measuring light L11 and a reference light L12
Implementation Method 2
the two beams of the measuring light L11 and the reference light L12 are superposed with each other in a spatial position, so as to form a combined light L3
Implementation Method 3
the first photodetector is used to receive the combined light L3 including the reference light L12 and the measuring light L11, so as to realize a simultaneous measurement of linear geometric errors
Implementation Method 4
the reflector in the target mirror unit is used to reflect the measuring light L11 backward, and return the measuring light L11 to the polarizing beam splitter
Data Source
AI summary
A system for simultaneously measuring 3DOF LGEs by a laser and a method therefor, including a measuring unit and a target mirror unit, the measuring unit includes a laser emitting module, a polarizing beam splitter, a fixed reflector, a first photodetector, and an interference length measuring module; the target mirror unit includes a reflector; the laser emitting module generates an emitting light L1, the polarizing beam splitter is used for 1) “beam splitting” comprising splitting the emitting light L1 into a measuring light L11 and a reference light L12, the measuring light L11 is incident on the target mirror unit and is reflected back by the target mirror unit, so as to return to the measuring unit with a 3DOF LGEs signal; and 2) “beam combining” making the measuring light L11 and the reference light L12 superposed with each other at a spatial position, so as to form a combined beam L3; by measuring a position, frequency and phase drifts of the light L3, the 3DOF LGEs of a space object moving linearly along linear axes can be rapidly measured simultaneously; or a longtime monitoring 3DOF linear position drifts of two objects in space can be realized.