Quadrant Photodiode Geometric Error Measurement
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Solution Overview
Problem
Laser interferometers, despite their high accuracy, are prohibitively expensive and complex for widespread use in regular plants, and existing methods for measuring geometric errors are cumbersome and costly, with each module requiring specific setups and adjustments.
Innovation Solution
A geometric error measuring device utilizing collimated light and at least one quadrant photodiode to measure errors in straightness, squareness, and rotational angles, with simplified configurations to reduce setup time and cost, and immunity to electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser interferometer is used to measure geometric errors, then measurement accuracy is improved, but device cost increases significantly
Solution Approach 1:
The patent replaces the expensive laser interferometer with a low-cost optical measurement device using collimated light and photodiodes. The measuring device costs only a fraction of the laser interferometer price while achieving comparable measurement accuracy for geometric errors in machine tools.
Solution Approach 2:
The patent substitutes the complex mechanical and optical system of the laser interferometer with a simpler system using collimated light sources and photodiode detectors. This replacement maintains measurement capability while dramatically reducing cost and complexity.
2Adaptability or versatility
If multiple modules are used to measure different types of errors, then measurement versatility is improved, but device complexity and setup time increase
Solution Approach 1:
The patent designs a universal measuring device that can measure multiple types of geometric errors (straightness, squareness, rotational angles) using a single integrated optical system. The device uses one collimated light source and photodiode array to perform all measurements, eliminating the need for multiple separate modules and their respective setups.
3Length of moving object
If larger reflective lens is used to measure geometric errors, then measurement range is improved, but setup difficulty and obstacle interference increase
Solution Approach 1:
The patent extracts the reflective lens component from the measurement system and replaces it with a direct collimated light source and photodiode arrangement. This eliminates the setup difficulties associated with positioning large reflective lenses perpendicular to laser rays and removes obstacles that interfere with the measurement path.
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 a cost-effective, accurate, and easy-to-use solution for measuring geometric errors, capable of simultaneous multi-axis measurements, reducing setup time and eliminating interference issues.
Implementation Method 1
The photodiode may receive the incident ray(s)
Implementation Method 2
The trajectory of the incident ray is parallel with the direction of measurement
Data Source
AI summary
A geometric error measuring device includes a measuring module and at least one (quadrant) photodiode. The measuring module has an emitting deice, which may emit at least one light ray; the photodiode may receive the incident ray. Also, the trajectory of the incident ray is parallel with the direction of measurement. If there is no geometric error, the position of the incident light ray will coincide with the position of the measured light ray. If there is a geometric error, the position of the measured light ray will not coincide with the position of the incident light ray. After the data are processed and calculated, geometric errors in straightness, squareness and rotational angles (pitch, yaw and roll) may be obtained. These geometric errors may then be corrected in the setup of a machine.