Chromatic Confocal Sensor Position Deviation Compensation
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Solution Overview
Problem
Chromatic confocal sensors face challenges in accurately measuring the position of objects based on the wavelength of measurement light reflected, particularly due to deviations in the position of diffraction gratings or the sensor, which affect measurement accuracy.
Innovation Solution
A chromatic confocal sensor system that emits multiple light beams of different wavelengths, converges them at distinct focal positions, and uses a spectroscope with diffraction gratings to split the reflected light into diffracted beams, allowing for accurate position calculation based on the difference between the light reception positions of these beams, even when the grating or sensor position deviates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the position of diffraction gratings or sensor is fixed, then the device structure is simple, but measurement accuracy deteriorates when positional deviation occurs
Solution Approach 1:
The system automatically compensates for positional deviations between diffraction gratings and sensor without requiring external adjustment mechanisms. The measurement method inherently absorbs positioning errors by using the relative positional relationship between multiple diffracted light beams, making the system self-correcting and eliminating the need for complex positioning correction devices.
Solution Approach 2:
The invention changes the measurement parameter from absolute position detection to relative position difference detection. By measuring the difference in reception positions between multiple diffracted light beams (e.g., +1st order and -1st order), the system transforms positional deviation into a measurable parameter that can be compensated for in the calculation, thereby maintaining measurement accuracy despite device positioning variations.
2Measurement precision
If multiple diffracted light beams are used, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The spectroscope is segmented into multiple functional elements including diffraction gratings and multiple sensors that detect different diffracted light beams. This segmentation allows each component to focus on detecting specific beams (e.g., +1st order, -1st order, 0th order), and the measurement system integrates these segmented detections to calculate position, achieving high accuracy without requiring a single complex sensor system.
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 enables highly accurate position measurement of objects by absorbing positional deviations and improving measurement accuracy, making the system robust to environmental changes and compact in design.
Implementation Method 1
an objective lens that converges the plurality of light beams at different focal positions and selects, as measurement light, light reflected by an object to be measured at the focal position
Implementation Method 2
diffraction gratings that split the selected measurement light into a plurality of diffracted light beams
Implementation Method 3
a sensor that receives two or more of the plurality of diffracted light beams
Data Source
AI summary
Provided is a chromatic confocal sensor including: a light source section that emits a plurality of light beams having different wavelengths; an optical head that includes an objective lens that converges the plurality of light beams at different focal positions and selects, as measurement light, light reflected by an object to be measured at the focal position out of the plurality of light beams; a spectroscope including diffraction gratings that split the selected measurement light into a plurality of diffracted light beams and a sensor that receives two or more of the plurality of diffracted light beams; and a signal processing/control section that calculates a position of the object to be measured based on a difference between light reception positions of the two or more diffracted light beams received by the sensor.