Scanning Apparatus Electronic Distance Control Without Sensor
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Solution Overview
Problem
Current scanning devices face challenges in achieving high-precision, non-contact measurements of small measuring fields due to limitations in distance sensitivity, positioning accuracy, and planarity fluctuations, particularly when dealing with varying paper thicknesses and large edge distances between illumination and measurement spots.
Innovation Solution
The scanning device employs an active height and distance control system, utilizing a color measuring head with independent z-axis movement and a tracking system, along with a dual white reference calibration method, to maintain a consistent measuring distance and compensate for planarity errors, enabling precise measurements across different paper thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed working distance is used to simplify the measuring system design, then the device complexity is reduced, but the measurement precision deteriorates due to distance sensitivity and positioning accuracy requirements
Solution Approach 1:
The patent implements an active height control system that dynamically adjusts the measuring head's position in the z-direction to maintain a constant measuring distance despite variations in substrate thickness and planarity. This dynamic adaptation resolves the contradiction by allowing a relatively simple mechanical design while achieving high measurement precision through real-time position correction.
Solution Approach 2:
The system uses a distance sensor to continuously monitor the actual measuring distance and feeds this information back to the height control mechanism. This feedback loop enables automatic compensation for distance variations, maintaining measurement precision without requiring an overly complex mechanical design with inherent distance compensation.
2Reliability
If a large edge distance is maintained between illumination and measurement spots to accommodate planarity errors, then the reliability of measurement is improved, but the measurement precision deteriorates due to increased crosstalk and reduced spot size
Solution Approach 1:
By dynamically adjusting the measuring head height to maintain a constant measuring distance, the system minimizes the edge distance between illumination and measurement spots while compensating for planarity errors through active height control rather than through a fixed large safety margin.
Solution Approach 2:
The system performs preliminary height adjustment and positioning before measurement to ensure the optimal edge distance is achieved, allowing measurements to be taken with minimal edge distance while maintaining reliability through pre-established proper positioning.
3Manufacturing precision
If mechanical contact is used to maintain measuring distance then the positioning accuracy is improved, but the adaptability deteriorates due to inability to handle varying paper thicknesses
Solution Approach 1:
The patent replaces mechanical contact-based distance maintenance with an active height control system that uses distance sensing and motorized adjustment. This substitution allows the system to adapt to varying paper thicknesses while maintaining positioning accuracy through electronic control rather than mechanical constraint.
Solution Approach 2:
The system changes the measuring distance parameter dynamically based on the detected substrate thickness and surface position, allowing adaptation to different paper thicknesses while maintaining optimal measurement conditions through active adjustment of the z-position.
4Productivity
If small measuring fields are used to save waste and increase measurement capacity, then the productivity is improved, but the measurement precision deteriorates due to increased difficulty in clean measurement
Solution Approach 1:
The active height control system enables precise measurement of small fields by dynamically maintaining the optimal measuring distance, ensuring that even with reduced field sizes, the measurement precision is preserved through real-time position correction and stable optical coupling.
Data Source
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AI summary
A scanning device for the point-by-point measurement of the color properties of a test object comprises a support surface for the test object, a color measuring head, a drive unit for moving the color measuring head across the support surface in at least one dimension thereof and for adjusting the height of the color measuring head in a direction perpendicular to the support surface, and a measuring and drive control unit that controls the drive unit and cooperates with the color measuring head. It is equipped with an electronic distance control system which, by means of the drive unit, sets the distance of the color measuring head above the measurement point in a direction perpendicular to the support surface to a target measuring distance for each measurement point. The electronic distance control system operates using measured values generated by the color measuring head and distance values calculated from these values.Due to its specific design, the scanning device is suitable for non-contact, high-precision measurement of even the smallest measuring fields and does not require separate sensors for distance control.