Optical Position Detector for Rotating Objects
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Solution Overview
Problem
Existing position detectors for rotatably supported objects, such as those used in galvanometer scanners, face challenges with precision, temperature dependency, and high moment of inertia, which affect the accuracy and speed of rotation angle positioning.
Innovation Solution
A position detector system utilizing a light source, diffraction grating, and optical interference to determine the rotation angle position of a rotatably supported object, where the light beam is diffracted and the interference pattern is analyzed to detect changes in brightness, allowing for precise angle determination without increasing the moment of inertia of the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scale disk is added to increase angle resolution, then measurement precision is improved, but the moment of inertia increases
Solution Approach 1:
The patent replaces the traditional mechanical scale disk approach with an optical measurement system. Instead of increasing the physical size of a scale disk to improve angle resolution, the invention uses optical scanning of a compact scale pattern combined with evaluation circuitry to achieve high angle resolution without adding significant moment of inertia. The scale pattern is scanned optically and the angle position is determined by evaluating the scanned signal, allowing high precision measurement without the mechanical inertia penalty of a large diameter scale disk.
2Measurement precision
If a large diameter scale disk is used to achieve higher angle resolution, then measurement precision is improved, but the moment of inertia increases significantly
Solution Approach 1:
The patent replaces the mechanical scale disk approach with an optical measurement system. Instead of increasing the physical size of a scale disk to improve angle resolution, the invention uses optical scanning of a compact scale pattern combined with evaluation circuitry to achieve high angle resolution without adding significant moment of inertia. The scale pattern is scanned optically and the angle position is determined by evaluating the scanned signal, allowing high precision measurement without the mechanical inertia penalty of a large diameter scale disk.
3Measurement precision
If capacitive position detectors are used for angle measurement, then measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex capacitive position detectors with a simpler optical detection system. Instead of using variable capacitors with rotatable electrodes or dielectric elements, the invention employs an optical scanner that scans a scale pattern and uses evaluation circuitry to determine angle position. This optical approach simplifies the detector structure while maintaining high measurement precision, avoiding the complexity of capacitive sensing elements and their associated readout circuits.
4Device complexity
If optical position detectors with light blockers are used, then device complexity is reduced, but measurement precision deteriorates due to temperature dependency and non-linear output
Solution Approach 1:
The patent replaces simple but inaccurate optical position detectors with an enhanced optical scanning system. Instead of using basic light blockers that shadow light depending on angular position, the invention employs an optical scanner that scans a scale pattern and uses evaluation circuitry to determine angle position. This approach maintains the simplicity of optical detection while dramatically improving measurement precision by eliminating temperature dependency and non-linear output characteristics through the scanning and evaluation process.
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 system provides precise and stable rotation angle positioning with reduced inertia, enabling faster repositioning and improved dynamics by decoupling the moment of inertia from the rotation angle measurement process.
Implementation Method 1
the light of the reflected light beam is diffracted by the diffraction grating, thereby producing diffraction light
Implementation Method 2
an optical interference device which is disposed in the optical path of the diffraction light and is configured such as to be able to bring different diffraction orders of the diffraction light to interference, thereby producing an interference pattern
Implementation Method 3
a mirror which is connected to the object in such a way that it co-rotates with the object during a rotation of the object and which is disposed in such way that the light beam is reflected therefrom onto the diffraction grating
Data Source
AI summary
Position detector for determining the rotation angle position of a rotatably supported object, comprising a light source for producing a light beam, a diffraction grating, a mirror which is connected with the object in a co-rotating manner in such a way that the light beam is reflected therefrom onto the diffraction grating and passes over the diffraction grating during a rotation of the mirror, thereby producing diffraction light, an interference device which is configured such as to be able to bring different diffraction orders of the diffraction light to interference, thereby producing an interference pattern, a light detector by means of which a brightness course, caused by the passing over of the diffraction grating with the reflected light beam, of the interference pattern can be detected, and an evaluation unit by which the rotation angle position of the object can be determined based on the brightness course.