Translucent Scale Correction for Optical Measuring Apparatus
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Solution Overview
Problem
Optical measuring apparatuses face challenges in accurately scanning light beams at a constant speed due to optical system and scan drive errors, leading to varying scan speeds across different measuring positions, which complicates obtaining accurate measurement results.
Innovation Solution
A correction device and method using a translucent scale with precise scale marks arranged in the scanning direction, allowing for direct measurement of pitch differences to calculate correction data for each scanning position, thereby correcting measurement errors efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction data is obtained using traditional methods with reference pins, then measurement precision can be improved, but the cycle time for obtaining correction data becomes excessively long
Solution Approach 1:
The patent replaces the mechanical reference pin system with an optical reference system. A translucent scale with scale marks is placed in the measurement area, and the light beam scanner directly measures the pitch of these scale marks using optical detection. This substitution eliminates the need for mechanical displacement operations and reference pin positioning, dramatically reducing the cycle time while maintaining measurement precision.
Solution Approach 2:
The patent creates an optical copy of the reference measurement system. Instead of using physical reference pins that must be mechanically positioned and displaced, the invention uses a translucent scale with scale marks that can be directly detected by the optical measuring apparatus. The scale marks serve as a reference pattern that can be measured without mechanical intervention, enabling rapid acquisition of correction data.
2Productivity
If the light beam scanner operates without correction, then the measurement process is simple and fast, but measurement precision deteriorates due to varying scan speeds at different positions
Solution Approach 1:
The patent performs preliminary measurement of the scale mark pitch at multiple positions across the measurement area before actual object measurement. By pre-acquiring correction data for each position, the system can compensate for scan speed variations during subsequent object measurements. This preliminary action enables the system to maintain both high measurement speed and high precision by applying position-specific corrections.
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 effectively reduces measurement errors and significantly shortens the cycle time for obtaining correction data, providing more accurate results without the need for displacing reference pins, thus improving the accuracy and efficiency of optical measuring apparatuses.
Implementation Method 1
a light beam scanner which scans with a light beam a measuring area where a measured object is placed, and a light receiver which receives a transmitted light beam from the measuring area
Data Source
AI summary
A correction device for an optical measuring apparatus obtains correction data for each scanning position of a light beam from an optical measuring apparatus that includes a light beam scanner which scans with a light beam a measuring region where a measured object is placed, and a light receiver which receives a transmitted light beam from the measuring region. The correction device includes a translucent scale having scale marks arranged at a predetermined pitch, and a support to mount the scale in the measuring region so that an arrangement direction of the scale marks is a scanning direction of the light beam.