Interferometer with Triple-Path Beam Routing
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Solution Overview
Problem
Existing interferometers require complex and costly production of polarization beam splitter cubes and triple prisms, with precise alignment and complex mounting, and are not suitable for large tilting tolerances of measurement objects.
Innovation Solution
An interferometer design using two transparent flat plates with optical elements that split and recombine beams, eliminating the need for beam splitter cubes and triple prisms, allowing for simpler and cost-effective production and enabling parallel guidance of measuring and reference beams to compensate for tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If polarization beam splitter cubes and triple prisms are used, then beam splitting and recombination can be achieved, but the production becomes complex and costly with precise alignment requirements
Solution Approach 1:
The patent divides the beam path into multiple segments using separate beam splitters and reflectors instead of integrated cubes. The measuring beam and reference beam are separated into distinct paths with individual optical components, allowing independent alignment and simplifying manufacturing while maintaining measurement precision.
Solution Approach 2:
The patent extracts the beam splitting function from the complex polarization beam splitter cube and implements it using simpler, separate optical components. The beam splitting functionality is achieved through individual beam splitters positioned at strategic locations, eliminating the need for precision-aligned cubic assemblies.
2Reliability
If beam splitter cubes and triple prisms are used, then interferometer functionality is achieved, but the mounting becomes complex with low-drift requirements
Solution Approach 1:
The optical path is segmented into modular sections with discrete components that can be mounted independently. This segmentation allows each component to be positioned and secured separately using standard mounting techniques, reducing the need for complex low-drift assemblies while maintaining overall system stability.
Solution Approach 2:
The patent changes the geometric parameters of the optical path by using extended beam paths with multiple reflections. This allows the use of simpler mounting configurations with larger tolerances, as the multiple bounce paths compensate for minor misalignments and reduce sensitivity to mounting drift.
3Adaptability or versatility
If triple prism is designed to be large, then large tilting tolerances of measurement object are accommodated, but the device size increases
Solution Approach 1:
The patent uses multiple reflections in the vertical and lateral dimensions to create extended optical paths. By utilizing three-dimensional space for beam routing with multiple bounces between reflectors and beam splitters, the system accommodates tilting objects without requiring a larger horizontal footprint, as the compensation occurs through spatially distributed optical paths.
Solution Approach 2:
The optical components are arranged in a nested configuration where beam paths are folded back through the same physical space multiple times. This nesting allows the optical path length to be extended within a compact footprint, enabling tilting tolerance accommodation without increasing the overall device size.
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 design simplifies production, reduces alignment complexity, and maintains signal modulation even with tilting, enabling precise distance measurements across different heights.
Implementation Method 1
a first beam splitter (30.1), which splits a beam of rays (S) emitted by the light source (10) into at least one measuring beam (M) and at least one reference beam (R)
Implementation Method 2
the measuring beam and the reference beam propagate parallel to one another in the direction of the measuring and reference reflector
Implementation Method 3
at least one distance signal from the interfering measurement and reference beam bundles superimposed at the point of merger with regard to the position of the measurement object
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
An interferometer is described, comprising a light source, a beam splitter, a reference reflector, a measuring reflector, a detection unit, and at least two transparent flat plates. The beam splitter splits a beam into at least one measuring beam and one reference beam. Until they rejoin, the measuring beam propagates in one measuring arm, and the reference beam propagates in another. The reference beam is incident on the reference reflector located in the reference arm at least three times. The measuring reflector is located in the measuring arm and connected to a test object, which is movable along a measurement direction relative to the reference reflector; the measuring beam is incident on the measuring reflector at least three times. The detection unit can detect at least one distance signal from the interfering measuring and reference beams with respect to the position of the test object.The planar plates are arranged parallel to each other in the beam path between the light source and the detection unit. At least the measuring reflector is movable relative to the planar plates along the measurement direction. Each planar plate comprises several optical elements that exert such an optical effect on the measuring beam and the reference beam that they propagate parallel to each other in the direction of the measuring and reference reflectors.