Reflective Encoder Light Receiving Area Optimization

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Solution Overview

Problem

The reflection encoder's light receiving area is reduced due to the concentric light quantity distribution, limiting the effective utilization of reflected light.

Innovation Solution

A reflection encoder design with a rotating disc featuring incremental and serial absolute patterns, where the incremental light receiving element group is arranged circumferentially between the light source and the absolute light receiving element group is positioned radially outside and inside the light source, increasing the light receiving area and allowing effective utilization of reflected light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the light receiving element is arranged in a conventional manner in the reflection encoder, then the device configuration is simplified and miniaturized, but the light receiving area decreases and reflected light cannot be effectively utilized

Engineering Contradiction:
Improvedevice sizeVSAvoidlight receiving area
Core Design Contradiction:
Volume of moving objectVSArea of stationary object

Solution Approach 1:

The patent transitions from a conventional single-side arrangement to a multi-dimensional arrangement where light receiving elements are positioned both radially inside and outside the light source, and circumferentially separated. This spatial redistribution across multiple dimensions maximizes the light receiving area while maintaining the compact reflection encoder structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The light receiving elements are segmented into distinct groups: incremental light receiving elements arranged circumferentially with the light source separated between them, and absolute light receiving elements arranged radially inside and outside the light source. This segmentation allows each group to optimally receive reflected light from their respective patterns without interference.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the light receiving area is increased to effectively utilize reflected light, then the detection accuracy is improved, but the device configuration becomes more complex

Engineering Contradiction:
Improvedetection accuracyVSAvoidconfiguration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The board serves multiple functions: it supports the light source, holds all light receiving elements (incremental and absolute), provides structural framework, and enables the multi-dimensional arrangement. This universal use of the board as an integration platform increases light receiving area while avoiding additional complex components.

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

Solution Approach 2:

The patent merges the incremental and absolute light receiving elements onto a single board structure, with the light source centrally positioned and receiving elements arranged both inside and outside it. This consolidation achieves enhanced detection accuracy without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration enhances the light receiving area, improves the signal-to-noise ratio, and stabilizes absolute position detection by effectively utilizing reflected light, leading to improved detection accuracy and miniaturization of the device.

Implementation Method 1

The reflection encoder reflects light emitted from the light source on the rotating disc and makes the light receiving element receive the light

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2639558B1Reflective type encoder, servo motor and servo unit
Publication Date: 2018.04.18 YASKAWA DENKI KK
  • EP2639558B1 patent drawingFigure 1
  • EP2639558B1 patent drawingFigure 2
  • EP2639558B1 patent drawingFigure 3

AI summary

Reflected light can be effectively utilized by increasing a light receiving area. Incremental light receiving element groups 140L and 140R are separated and arranged in the circumferential direction of a rotating disc 110 while placing a light source 130 therebetween. First and second absolute light receiving element groups 150D and 150U are arranged at both sides of the outside and inside of the light source 130 in the radial direction of the rotating disc 110. As a result, first and second absolute light receiving elements 151 and 152 are continuously arranged, and also the incremental light receiving element groups 140L and 140R and the absolute light receiving element groups 150D and 150U can be arranged to surround the periphery of the light source 130 from four directions.