Confocal Displacement Sensor with Multi-Pinhole Waveform Processing
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Solution Overview
Problem
Confocal displacement sensors face challenges in accurately measuring displacement of rough surface objects due to irregular reflections, leading to fluctuating measurement values and low accuracy, especially when the displacement gauge is not properly positioned.
Innovation Solution
A confocal displacement sensor system that uses multiple pinholes to form irradiation spots on the object, statistically processes light reception waveforms to generate a representative waveform, and includes a measurement control section to calculate displacements, thereby reducing the impact of surface irregularities and gauge positioning errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single pinhole is used for measurement, then the device structure is simple, but measurement accuracy deteriorates due to irregular reflection from rough surfaces
Solution Approach 1:
The patent divides the single pinhole into multiple pinholes (first pinhole and second pinhole). Each pinhole independently emits detection light and receives reflected light. The measurement control section combines the light reception waveforms from both pinholes to obtain a representative waveform, thereby reducing the impact of irregular reflections from rough surfaces and improving measurement accuracy.
2Measurement precision
If multiple pinholes are used to improve measurement accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent combines the light reception waveforms from multiple pinholes through statistical processing in the measurement control section. By merging the signals and generating a representative waveform, the system reduces the impact of irregular reflections and achieves more stable measurements without requiring complex additional components for each pinhole.
3Reliability
If the displacement gauge is precisely positioned, then measurement stability improves, but positioning difficulty increases due to sensitivity to positional deviation
Solution Approach 1:
The patent uses multiple pinholes distributed across different positions. This segmentation allows the system to capture reflected light from multiple locations on the measurement object. Even if the gauge position deviates slightly, the combined waveforms from multiple pinholes maintain measurement stability, reducing sensitivity to positional deviations.
4Measurement precision
If multiple light reception waveforms are processed, then measurement accuracy improves through statistical processing, but processing complexity increases
Solution Approach 1:
The measurement control section automatically performs statistical processing on the light reception waveforms from multiple pinholes to generate a representative waveform. This self-service approach eliminates the need for manual intervention in waveform selection and processing, reducing operational complexity while maintaining improved measurement accuracy through automated signal combination and analysis.
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 approach stabilizes measurement values and improves accuracy by averaging irregular reflections and correcting for positional deviations, preventing measurement fluctuations beyond the degree of surface roughness and ensuring precise displacement measurements.
Implementation Method 1
an optical member that causes an axial chromatic aberration in detection light emitted via the pinhole and converges the detection light toward the measurement object
Implementation Method 2
a spectroscope that spectrally disperses reflected light from the measurement object
Implementation Method 3
The pinhole allows, in the detection light irradiated on the measurement object via the optical member, detection light having a wavelength reflected while focusing on the measurement object to pass
Data Source
AI summary
The confocal displacement sensor includes a light source for light projection configured to generate light having a plurality of wavelengths, a plurality of pinholes, an optical member configured to cause an axial chromatic aberration in the plurality of detection lights respectively emitted via the plurality of pinholes and converge the plurality of detection lights toward the measurement object, a spectroscope configured to respectively spectrally disperse, in the detection lights irradiated on the measurement object via the optical member, a plurality of detection lights respectively passed through the plurality of pinholes by being reflected while focusing on the measurement object and generate a plurality of light reception waveforms representing light reception intensities for each wavelength, and a measurement control section configured to statistically process the plurality of light reception waveforms and generate a representative light reception waveform from the plurality of light reception waveforms.