Optical Spatial Probe Using Grating Patterns for Extended Measurement Range
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Solution Overview
Problem
Current laser triangulation gages have limited working ranges and are prone to measurement errors due to surface texture, laser speckle, and small detector areas, which affect centroid location and resolution.
Innovation Solution
An optical device that collimates reflected light, imparts a pattern using gratings, and uses a camera or photodetectors to measure spatial relations by analyzing pattern shifts, improving measurement accuracy and range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser triangulation gage uses centroid detection method, then measurement resolution can reach micron level, but working range is limited to only a few millimeters
Solution Approach 1:
The patent segments the detector into multiple regions (first region and second region) with different functions. The first region detects the laser spot for high-resolution measurement, while the second region detects the reference beam for range determination. This segmentation allows the system to achieve both high resolution and extended working range by using different detection strategies in different detector regions.
Solution Approach 2:
The patent transitions from one-dimensional centroid detection to two-dimensional pattern detection by dividing the detector into multiple regions. The reference beam detection in the second region provides additional dimensional information about the beam's spatial distribution, enabling the system to determine both distance and displacement with high accuracy over extended ranges.
2Measurement precision
If small detector area is used for measurement, then measurement resolution is maintained, but measurement accuracy is reduced due to small number of sample points
Solution Approach 1:
The patent segments the detector into multiple functional regions, with the second region dedicated to reference beam detection. This segmentation allows the system to use a larger overall detector area without compromising the high-resolution spot detection in the first region. The increased detector area provides more sample points for accurate centroid calculation while maintaining micron-level resolution.
Solution Approach 2:
The reference beam detected in the second region acts as an intermediary that provides additional measurement information. By comparing the laser spot position in the first region with the reference beam position in the second region, the system can accurately determine both absolute distance and relative displacement, improving measurement reliability through redundant measurement pathways.
3Reliability
If full detector array is utilized for measurement, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent divides the detector into distinct regions with clear functional assignments. The first region is optimized for laser spot detection while the second region is optimized for reference beam detection. This segmentation simplifies the data processing requirements compared to using the full detector for a single measurement function, as each region can be processed independently with specialized algorithms.
Solution Approach 2:
The detector serves multiple functions simultaneously: it detects both the laser spot for displacement measurement and the reference beam for distance determination. This multi-functionality is achieved through spatial segmentation rather than requiring separate detection systems, thereby improving measurement accuracy without proportionally increasing 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
The device provides enhanced measurement accuracy and range by minimizing surface texture effects and utilizing the full detector array, allowing for precise distance and angle measurements.
Implementation Method 1
an optical collimator disposed a radial distance from the axis for collimating at least some of the light reflected off the surface and directing the collimated light along a path
Implementation Method 2
a grating disposed in the path for imparting a pattern in the collimated light
Data Source
AI summary
An optical spatial probe comprising a light source for shining a beam of light on an object and collection optics for collecting light reflected from the surface. The collected light is collimated, and the collimated light beam passed through gratings that impart patterns to the collimated beam. The collimated beam may be split into multiple beam subdivisions. A camera captures the patterns, or a plurality of photodetectors detect light intensities of the patterns to determine distance to the object.