Three-Dimensional Measurement Device Without Quarter-Wave Plate Errors
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Solution Overview
Problem
Existing three-dimensional measurement devices using interferometers face challenges in extending measurement range due to manufacturing errors in optical members like polarizing beam splitters and quarter-wave plates, which affect the accuracy of polarized light separation and conversion, leading to reduced measurement accuracy and efficiency.
Innovation Solution
A three-dimensional measurement device that separates and converts different wavelength lights using a configuration where the traveling directions of the lights are distinct, eliminating the need for quarter-wave plates and reducing the influence of manufacturing errors, allowing for simultaneous imaging of different wavelength lights without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If quarter-wave plates and polarizing beam splitters are used to separate and convert different wavelength lights, then the measurement range can be extended, but manufacturing errors in these optical members reduce measurement accuracy
Solution Approach 1:
The patent removes quarter-wave plates from the optical system entirely. Instead of using quarter-wave plates to convert linearly polarized light to circularly polarized light, the invention directly uses linearly polarized light of different wavelengths without requiring wavelength-specific conversion components, thereby eliminating the source of manufacturing errors while maintaining extended measurement range capability
Solution Approach 2:
The patent changes the operational parameters by using linearly polarized light directly without converting to circular polarization. By adjusting the polarization state parameters and using different wavelengths of linearly polarized light (e.g., 532nm and 635nm) with a polarizing beam splitter, the system achieves accurate wavelength separation without relying on precise quarter-wave plate manufacturing
2Adaptability or versatility
If complex optical members like quarter-wave plates are used for light conversion, then different wavelength lights can be processed, but the device complexity increases
Solution Approach 1:
The patent makes the polarizing beam splitter perform multiple functions: it simultaneously separates different wavelength lights (532nm and 635nm) and directs them along different optical paths without requiring additional wavelength-specific conversion components. This multi-functional approach reduces device complexity while maintaining versatility in processing different wavelength lights
Solution Approach 2:
The invention extracts and removes the quarter-wave plates from the optical system, eliminating the need for complex wavelength-specific light conversion components. The system achieves its goal of processing different wavelength lights using only the polarizing beam splitter and linearly polarized light sources, significantly simplifying the overall device 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
This configuration enhances measurement accuracy and extends the measurement range while improving efficiency by simplifying the optical system and reducing the need for complex components, enabling simultaneous imaging of multiple wavelength lights.
Implementation Method 1
a polarized light of a predetermined wavelength (a polarized light that is polarized in a direction inclined at an angle of 45 degrees to an X-axis direction and a Y-axis direction as a polarizing direction) is emitted downward in a Z-axis direction from the light source 101 and enters a first face 100a of the polarizing beam splitter 100. The light entering the first face 100a of the polarizing beam splitter 100 is branched into two directions at a boundary face 100e of the polarizing beam splitter 100. A P-polarized light component thereof (a linearly polarized light that is polarized in a direction parallel to the sheet surface of FIG. 16 as a polarizing direction) is transmitted downward in the Z-axis direction
Implementation Method 2
The measurement light (P-polarized light) emitted from the third face 100c of the polarizing beam splitter 100 is transmitted through a quarter-wave plate 103 to be converted into a clockwise circularly polarized light
Implementation Method 3
a three-dimensional measurement device using an interferometer have conventionally been known as the three-dimensional measurement device configured to measure the shape of a measurement object
Data Source
AI summary
A three-dimensional measurement device includes: an optical system including an optical device that splits an incident light, irradiates a measurement object with a measurement light, irradiates a reference plane with a reference light, and combines at least part of the reflected measurement light with at least part of the reflected reference light to emit a combined light; a first light emitter that emits a first light that has a first wavelength; a second light emitter that emits a second light that has a second wavelength; a first imaging device that takes an image of an output light output from the optical device in which the first light enters; a second imaging device that takes an image of an output light output from the optical device in which the second light enters; and a control device that executes three-dimensional measurement of the measurement object.