Position Detection Signal Separation Using Dual-Period Scales
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Solution Overview
Problem
Existing position detecting apparatuses face reduced precision due to imperfect separation of modulation signals using spatial filters, leading to distorted signal waveforms and compromised position detection accuracy.
Innovation Solution
A position detecting apparatus employing a scale with two patterns of different periods and a detection element array to generate signals with distinct phases, where a deriving unit separates and corrects these signals to derive precise position information by performing multiple processing steps, effectively removing residual signal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spatial filter is used to separate modulation signals, then signal separation is achieved, but perfect separation cannot be carried out and other modulation signal components remain to distort signal waveform
Solution Approach 1:
The patent segments the modulation signals by using multiple detection element arrays, each tuned to detect specific spatial modulation periods. This segmentation allows separate processing of different frequency components, enabling perfect separation of modulation signals without the waveform distortion that occurs with conventional spatial filters.
Solution Approach 2:
The patent introduces phase information as an intermediary parameter to represent position. By using phase differences between detected signals rather than directly processing the raw modulation signals, the system achieves accurate position detection while avoiding the signal waveform distortion caused by imperfect spatial filter separation.
2Adaptability or versatility
If multiple modulation signals are detected simultaneously, then position information can be obtained, but signal separation becomes imperfect and detection precision is reduced
Solution Approach 1:
The detection system is segmented into multiple independent detection element arrays, each optimized for specific spatial modulation periods. This allows simultaneous detection of multiple modulation signals while maintaining signal integrity through dedicated processing paths for each signal type.
Solution Approach 2:
Each detection element array is designed with local quality optimized for its specific detection function - different arrays have different spatial resolution characteristics matched to their assigned modulation periods. This localized optimization enables precise simultaneous detection of multiple signals without cross-contamination.
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
This approach enhances position detection precision by accurately separating and correcting signal components, resulting in improved accuracy and reduced errors in position detection.
Implementation Method 1
a detection element array having a plurality of detecting elements, each of detecting elements being arranged in the predetermined direction and detecting energy intensities based on the first pattern and the second pattern
Data Source
AI summary
A position detector, includes: a scale having first and second patterns having respective first and second period; a detector array including elements each detecting energy intensities based on the patterns; a generator configured to generate first and second signals having phases different from each other obtained based on the patterns respectively; and a deriver deriving a position of the array relative to the scale based on the signals, wherein the scale is movable relative to the array; the deriver derives a reference position as a detection element array position relative to the scale based on the signals, performs a first process to derive a array position relative to the scale by a array displacement relative to the reference position is derived based on the first signals, and performs a second process in which a relative array position is derived based on the position derived by the first process.