Fixed-Point Detector Using Diffraction Gratings for Displacement Measurement

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Solution Overview

Problem

Existing displacement-measuring apparatuses with multiple fixed-point detecting patterns face difficulties in distinguishing between patterns and selecting a desired fixed point without shading, leading to complex user operations.

Innovation Solution

A fixed-point detector with multiple patterns, each having a pair of diffraction gratings that diffract light in different directions, uses a movable light source and photoelectric conversion elements to receive and convert diffracted light beams, allowing for the selection of a fixed point by equalizing electric signal levels between different combinations of photoelectric conversion elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple fixed-point detecting patterns are provided in a displacement-measuring apparatus, then the versatility and adaptability of the apparatus is improved, but the device complexity increases and the ease of operation deteriorates due to the need for shading sheets and complex selection procedures

Engineering Contradiction:
Improveability to detect different fixed pointsVSAvoiddifficulty in selecting fixed point
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The detector is divided into multiple independent fixed-point detecting patterns, each capable of detecting a specific fixed point. Each pattern consists of separate photoelectric conversion elements that can be independently controlled, allowing the system to select which pattern is active without affecting others, thus maintaining ease of operation while providing versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control of photoelectric conversion elements through selective activation. The control unit can dynamically enable or disable specific photoelectric conversion elements based on which fixed point needs to be detected, allowing the system to adapt to different measurement requirements without manual shading or complex reconfiguration.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If multiple fixed-point detecting patterns are provided without shading, then the ease of operation is improved, but the reliability of fixed point detection deteriorates due to interference from multiple patterns

Engineering Contradiction:
Improveelimination of shading procedureVSAvoidaccuracy of fixed point detection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Each fixed-point detecting pattern is segmented into dedicated photoelectric conversion elements that are spatially separated and functionally independent. This segmentation ensures that when one pattern is active, other patterns do not interfere with the detection, maintaining reliability without requiring shading sheets or manual intervention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control unit receives signals from multiple photoelectric conversion elements and uses feedback mechanisms to determine which fixed point detection pattern should be active. Based on the received signals, the control unit selectively processes outputs from specific patterns, ensuring accurate fixed point detection even when multiple patterns are physically present in the system.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If different combinations of photoelectric conversion elements are used for different patterns, then the manufacturing precision requirement is reduced, but the device complexity increases

Engineering Contradiction:
Improvetolerance in pattern arrangementVSAvoidcomplexity of control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control unit is designed as a universal controller that can manage multiple fixed-point detecting patterns using the same basic control logic. By implementing a multi-functional control system, the patent reduces the need for high manufacturing precision in pattern arrangements while avoiding excessive complexity through standardized control procedures that work across all patterns.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 easy distinction and selection of fixed points from multiple patterns without shading, simplifying the user process and reducing operational complexity.

Implementation Method 1

Each of the fixed-point detecting patterns has a pair of diffraction gratings for diffracting incident light in different directions

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

a photoelectric converter converting the light beams diffracted from the respective diffraction gratings into electric signals

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP2023095B1Fixed-point detector and displacement-measuring apparatus
Publication Date: 2016.09.14 DMG MORI CO LTD
  • EP2023095B1 patent drawingFigure 1
  • EP2023095B1 patent drawingFigure 2A~2C
  • EP2023095B1 patent drawingFigure 3

AI summary

A fixed-point detector is provided. The fixed-point detector includes a plurality of fixed-point detecting patterns, a fixed-point detecting light source, and a plurality of photoelectric conversion elements. The plurality of fixed-point detecting patterns each have a pair of diffraction gratings for diffracting incident light in different directions. The fixed-point detecting light source irradiates the pair of diffraction gratings with light while moving in the measurement-axis direction with respect to the plurality of fixed-point detecting patterns. The plurality of photoelectric conversion elements move together with the fixed-point detecting light source, while receiving light beams diffracted by the respective diffraction gratings of the plurality of fixed-point detecting patterns and converting the diffracted light beams into electric signals.