Scanning Mirror Displacement Measurement with Angle Feedback
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Solution Overview
Problem
Conventional three-dimensional measuring methods using the light section method require prolonged measurement times, as they scan the entire measurement object even when only specific parts need to be measured, leading to inefficiencies and reduced accuracy due to wider irradiation angles and lower measurement light density.
Innovation Solution
A displacement measuring apparatus with a light projector, scanning part, light receiver, setting unit, angle measuring unit, and measurement controller that allows for precise control of the scanning mirror's angle and scanning range, enabling focused measurement at specific positions with adjustable pitch and density, reducing measurement time while maintaining high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the measurement light scans the whole measurement object, then the three-dimensional shape can be measured, but the measurement time is prolonged
Solution Approach 1:
The patent divides the measurement object into multiple measurement regions and performs measurement on each region separately. The measurement light scans only the necessary regions rather than the entire object, thereby reducing measurement time while still obtaining complete three-dimensional shape information through segmented measurement.
Solution Approach 2:
The patent implements partial scanning by measuring only specific regions of the measurement object that are necessary for obtaining the three-dimensional shape, rather than scanning the entire object. This partial action approach reduces measurement time while maintaining measurement completeness.
2Loss of time
If the scanning range is limited to the measurement position and vicinity, then the measurement time is reduced, but the irradiation angle becomes unclear and the scanning range becomes wider than necessary
Solution Approach 1:
The patent uses an angle measuring unit to measure the irradiation angle of the scanning mirror and provides feedback to the measurement controller. The controller adjusts the scanning mirror angle based on this feedback to achieve precise control of the measurement light irradiation angle, ensuring accurate measurement while maintaining reduced scanning range.
Solution Approach 2:
The patent dynamically adjusts the scanning mirror angle as a parameter to optimize the irradiation angle of the measurement light. By changing the angle parameter based on measured feedback, the system achieves precise control over the scanning range, ensuring it is neither too wide nor too narrow.
3Measurement precision
If the measurement light is emitted at a fine pitch to improve measurement accuracy, then the measurement precision increases, but the measurement time is further prolonged
Solution Approach 1:
The patent applies different measurement light pitches to different regions: a fine pitch is used in the region of interest around the measurement position to ensure high measurement accuracy, while a coarser pitch is used in surrounding areas. This local quality differentiation maintains measurement precision where needed while reducing overall measurement time.
Solution Approach 2:
The patent applies fine-pitch measurement light only to the specific region where high measurement accuracy is required, rather than uniformly across the entire measurement object. This partial application of fine pitch reduces the total number of scan lines while maintaining accuracy in critical areas.
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
Enables rapid and accurate displacement measurement at predetermined positions by optimizing the scanning range and angle, allowing for efficient measurement of specific parts of the measurement object without unnecessary scanning, thus reducing overall measurement time and improving accuracy.
Implementation Method 1
light that is reflected back from the surface of the measurement object is received by a light receiving element
Implementation Method 2
The measurement light is made to scan by the scanning part and is reflected back from different positions in the second direction of the measurement object
Data Source
AI summary
To enable measuring a displacement at a predetermined position of a measurement object for a short time at a high accuracy. While a scanning mirror is moved in a first scanning range to cause measurement light to irradiate a measurement position, a first irradiation angle of the scanning mirror at the time the measurement light is emitted to the measurement position is obtained. While a scanning mirror is moved in a second scanning range that covers the first irradiation angle and that is narrower than the first scanning range, and a second irradiation angle at the time the measurement light is emitted to the measurement position is obtained. A light receiver outputs a received-light quantity distribution, and a displacement at the measurement position is measured on the basis of the second irradiation angle and the position in a second direction of the measurement position.