Abscissa Calibration Jig for Laser Interference Measuring Apparatus
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Solution Overview
Problem
Laser interference measuring apparatuses with convergent optics face challenges in accurately calibrating abscissas due to image distortion and nonlinearity, especially when measuring spherical surfaces, as existing methods are limited in evaluating higher-order abscissa errors and require difficult-to-manufacture reflective optical elements.
Innovation Solution
An abscissa calibration jig with an image projection unit, supported by rotatable mechanisms, projects a marker image onto the light receiving unit, allowing for precise calibration by aligning the focal position of the convergent optics with the rotation center and rotating the image projection unit to adjust the marker's position, enabling detection of distortion and calculation of correction values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a convergent optics is used to measure spherical surfaces, then the measurement capability is improved, but image distortion and nonlinearity occur causing abscissa calibration errors
Solution Approach 1:
The patent applies preliminary action by performing abscissa calibration before actual measurements using a calibration jig with known reference positions. The calibration jig projects marker images at predetermined locations, allowing the system to pre-calculate correction values for distortion and nonlinearity errors that will occur during subsequent spherical surface measurements.
Solution Approach 2:
The patent uses a calibration jig that creates marker images serving as copies of known reference positions. These marker images are projected onto the light receiving unit at specific locations corresponding to predetermined abscissas, allowing the system to compare expected positions with actual detected positions and generate correction data without requiring complex reflective optical elements.
2Measurement precision
If existing calibration methods using reflective optical elements are used, then abscissa errors can be evaluated, but the manufacturing difficulty increases significantly
Solution Approach 1:
The patent replaces complex reflective optical elements with a calibration jig that projects marker images. Instead of using physically complex diffraction gratings or reflective elements with precise angular characteristics, the system uses a simpler projection mechanism that creates virtual reference markers, achieving the same calibration purpose with much easier manufacturing.
Solution Approach 2:
The patent substitutes mechanical/optical reflective elements with an image projection system. Rather than relying on physical reflective surfaces with specific geometric properties, the system uses projected marker images whose positions can be precisely controlled and calculated, replacing complex mechanical optical components with a more manufacturable projection-based approach.
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 method allows for easy and precise calibration of abscissas in laser interference measuring apparatuses, effectively addressing the limitations of existing technologies by simplifying the calibration process and improving accuracy across the visual field.
Implementation Method 1
an image projection unit for projecting an image having a marker at one point on the image
Implementation Method 2
a first support mechanism configured to rotatably support the image projection unit around a first rotation axis passing a predetermined rotation center; and a second support mechanism configured to rotatably support the first support mechanism around a second rotation axis crossing the first rotation axis at the rotation center
Implementation Method 3
the focal position of a convergent optics of the laser interference measuring apparatus is aligned with the rotation center of the abscissa calibration jig
Implementation Method 4
a light receiving unit configured to receive the light from the abscissa calibration jig
Data Source
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AI summary
An abscissa calibration jig of a laser interference measuring apparatus, includes: an image projection unit configured to project an image with a marker; a first support mechanism configured to rotatably support the image projection unit around a first rotation axis passing a predetermined rotation center; and a second support mechanism configured to rotatably support the first support mechanism around a second rotation axis crossing the first rotation axis at the rotation center.