Integrated Optical Magnetic Sensor for Absolute Position
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Solution Overview
Problem
Existing sensor devices fail to provide unambiguous, absolute, and highly precise position information over extended linear or angular ranges while maintaining a compact design and small installation space, as they often suffer from limited resolution, inaccuracy, and the need for reference marks or complex production processes.
Innovation Solution
A sensor device combining an optical sensor system with a reflection-based zeroth-order measurement and a magnetic sensor system, where the optical and magnetic scales are integrated in a common scale body, allowing for unambiguous absolute position calculation using a computing unit that synchronizes the signals from both systems, ensuring high resolution and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensor systems are used to achieve high resolution below 10 nm, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines magnetic and optical sensor systems into a single integrated device. The magnetic sensor provides absolute position information with lower resolution requirements, while the optical sensor enhances precision. By merging these systems and using a common scale structure, the patent achieves high measurement precision without proportionally increasing device complexity, as the systems share common components and infrastructure.
2Reliability
If magnetic sensor systems are used to achieve insensitivity to contamination and simple design, then reliability is improved, but measurement precision is limited to a few hundred nanometers
Solution Approach 1:
The patent merges magnetic and optical sensor systems where the magnetic sensor provides contamination-resistant operation and absolute position information, while the optical sensor delivers high-resolution measurements. The combination allows the system to achieve both reliability through magnetic sensing and high precision through optical sensing, with the scale structures designed to work together in an integrated manner.
3Measurement precision
If separate magnetic and optical sensor systems are combined as in DE 19520299A1, then absolute position information can be obtained, but the device requires relatively large installation space and height
Solution Approach 1:
The patent implements a nested configuration where the magnetic scale and optical scale are superimposed on each other in the same spatial region. The magnetic scale is positioned on a first surface of the scale carrier while the optical scale is positioned on a second surface, allowing both sensing systems to access their respective scales without requiring additional installation height. This nesting approach enables compact integration of multiple sensor systems.
4Measurement precision
If optical scales with smaller periods are used to achieve resolution below 10 nm, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines magnetic and optical scale structures that can be manufactured using compatible processes. The magnetic scale with its larger period structure and the optical scale with smaller period structure are integrated on a common carrier, allowing both to be produced together. This merging approach enables the optical scale to achieve high resolution through smaller periods while the magnetic scale provides a manufacturing-friendly baseline structure.
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
The solution enables unambiguous absolute position information over any linear measurement path or full rotation, with improved resolution and compactness, eliminating the need for reference marks and reducing installation space, while maintaining accuracy and reliability across temperature changes.
Implementation Method 1
The optical sensor system (102) is designed to operate in reflection mode and to utilize only zeroth-order reflections
Implementation Method 2
a magnetic sensor system (101) with a measuring unit (101) and a scale (203) interacting with the measuring unit (101)
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~5(b)
AI summary
The invention relates to a sensor device and method for detecting measurement data relating to the absolute position of a linearly or rotationally moveable body, comprising an optical sensor system, wherein the optical sensor system uses exclusively zero-order rejections for the position measuring, and a magnetic sensor system which emits a second sensor output signal depending on the position to be determined of the moveable body, wherein the gauge of the optical sensor system and the gauge of the magnetic sensor system are integrated in a common gauge body, and a computer unit which is provided to obtain the first sensor output signal and the second sensor output signal and to generate a common sensor output signal from the first sensor output signal and the second sensor output signal, wherein the current period of the second sensor system can be deduced from the first sensor output signal at every time, in order to calculate clear absolute position information based on the first and second sensor output signal.