Magnetic Scale with Segmented Tracks for Positioning in Strong Fields
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Solution Overview
Problem
Existing position determination methods, such as magnetic linear scales, fail to accurately read positions in strong magnetic fields due to remagnetization of bits, leading to indistinguishable polarity and inability to determine position.
Innovation Solution
A substrate with a scale applied using a pressure medium containing magnetizable and/or magnetic particles, featuring areas with and without the medium, generating a stronger magnetic field when an external field is applied, allowing for accurate position determination through varying graduation marks and magnetic field gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic linear scale with repeating bit pattern is used for position determination, then relative position measurement is achieved, but in strong magnetic fields every second bit gets remagnetized causing indistinguishable polarity and position determination failure
Solution Approach 1:
The scale pattern is segmented into multiple tracks with different functions: a first track with coarse pitch for absolute position determination and a second track with fine pitch for relative position determination. This segmentation allows the system to differentiate between absolute and relative measurements, preventing the remagnetization issue from causing complete measurement failure.
Solution Approach 2:
The invention uses asymmetric bit patterns where the first track has a different pitch than the second track. The first track uses a coarser pitch with distinguishable absolute positions, while the second track uses a finer repeating pitch. This asymmetry in pitch between tracks allows the system to identify absolute positions even when remagnetization occurs in strong magnetic fields.
2Measurement precision
If a distinguishable bit pattern with different width increments is used for absolute position determination, then absolute position can be identified, but the structure becomes more complex and manufacturing more difficult
Solution Approach 1:
The scale is divided into multiple tracks, each serving a specific function. The first track provides absolute position information with coarser pitch, while the second track provides relative position information with finer pitch. This segmentation simplifies the overall design compared to using a single complex distinguishable pattern, as each track can be optimized independently for its specific purpose.
3Adaptability or versatility
If magnetic particles are used in the scale pattern, then magnetic field reading is enabled, but in strong external magnetic fields the particles get remagnetized causing loss of position information
Solution Approach 1:
By dividing the scale into multiple tracks with different pitch values, the system can use the first track for absolute position determination which remains valid even when remagnetization occurs. The second track provides additional relative position information when conditions permit. This segmentation ensures continued operation and position determination capability in strong magnetic fields.
Solution Approach 2:
The evaluation unit acts as an intermediary that processes signals from both tracks and determines the final position. It can detect remagnetization conditions and rely primarily on the first track's absolute position information when remagnetization is detected, thereby mediating between the magnetic particles and the position determination process to maintain reliability.
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 error-free position reading even in strong magnetic fields, with higher accuracy and cost-effectiveness, allowing for both absolute and relative position determination using tick marks and characters, and enabling precise measurement with smaller structures.
Implementation Method 1
the magnetic properties of the substrate are such that when an external magnetic field is applied to the device or when the magnetic field of the magnetic particles is read, a stronger magnetic field is generated by the pressure medium than by the substrate
Implementation Method 2
a scale with a printing medium comprising magnetizable and/or magnetic particles
Data Source
Figure 1~3
Figure 4
AI summary
The invention relates to an object comprising a substrate (2) and a scale (3) which is applied onto the substrate (2) using a printing medium which has magnetizable and/or magnetic particles and which has regions that have the printing medium and regions (5) that are free of the printing medium. The scale is designed to indicate positions by means of the regions which have the printing medium and the regions (5) which are free of the printing medium. The magnetic properties of the substrate (2) are such that when an external magnetic field is applied to the object (1) or when the magnetic field of the magnetic particles from the printing medium is read, a stronger magnetic field is generated than that of the substrate (2).