Encoder Scale Dummy Pattern Layout for Faster Conductor Processing

Solution Overview

Problem

Existing methods for manufacturing scales in photoelectric and electromagnetic induction encoders involve lengthy processing times and environmental load due to excessive removal of conductor film, which can lead to increased waste and processing variations.

Innovation Solution

Incorporating dummy patterns made of the same conductor as the scale patterns, with a diameter of the largest circle in each dummy pattern being ¼ or less of the scale pattern period, reduces the amount of conductor film removal, thereby shortening processing time and reducing environmental load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conductor film is removed from the entire scale surface to form scale patterns, then scale patterns can be formed, but processing time increases and environmental load increases

Engineering Contradiction:

Improvescale pattern formationVSAvoidprocessing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-forming conductor films in dummy pattern regions before scale pattern formation. This allows the scale patterns to be created without requiring complete removal of conductor film across the entire surface, thereby reducing processing time while maintaining manufacturing precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements local quality by creating different conductor film configurations in different regions: scale patterns in measurement regions and dummy patterns in non-measurement regions. This localized differentiation allows selective processing that reduces overall processing time while maintaining the required scale pattern quality.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If conductor film is removed from the entire scale surface to form scale patterns, then scale patterns can be formed, but environmental load increases due to increased waste

Engineering Contradiction:

Improvescale pattern formationVSAvoidconductor film waste

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by pre-forming conductor films in dummy pattern regions before scale pattern formation. This allows the scale patterns to be created without requiring complete removal of conductor film across the entire surface, thereby reducing processing time while maintaining manufacturing precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements local quality by creating different conductor film configurations in different regions: scale patterns in measurement regions and dummy patterns in non-measurement regions. This localized differentiation allows selective processing that reduces overall processing time while maintaining the required scale pattern quality.

Inventive Principle:

Principle #3Local quality

3Loss of time

If dummy patterns are added to the scale surface, then processing time is reduced and environmental load is reduced, but induced currents may affect measurement accuracy

Engineering Contradiction:

Improveprocessing timeVSAvoidmeasurement accuracy

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The patent converts the potentially harmful effect of induced currents in dummy patterns into a beneficial outcome by carefully designing the dummy patterns to have dimensions (diameter ≤ 1/4 of scale pattern period) that minimize electromagnetic interference. This allows the dummy patterns to serve their purpose of reducing processing time and waste while maintaining measurement accuracy.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies parameter changes by controlling the size parameters of dummy patterns (diameter ≤ 1/4 of scale pattern period) to optimize both processing efficiency and measurement accuracy. By adjusting these dimensional parameters, the patent achieves the dual benefit of reduced processing time and maintained measurement precision.

Inventive Principle:

Principle #35Parameter changes

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 minimizes processing time and environmental impact by reducing the amount of conductor film removed, while maintaining measurement accuracy by suppressing induced currents in the dummy patterns.

Implementation Method 1

a receiving coil configured to be electromagnetically coupled to magnetic flux generated by the scale and detect a phase of the magnetic flux

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS12560460B2Scale and manufacturing method of the same

Publication Date: 2026.02.24 MITUTOYO CORP

AI summary

A scale includes a substrate, a plurality of scale patterns that are arranged along a measurement direction with a constant period on a surface of the substrate and are made of conductor, and a plurality of dummy patterns that are provided on at least a part of a region on the surface of the substrate where the plurality of scale patterns are not provided, and are made of the same conductors as the plurality of scale patterns. A diameter of a largest circle that can be formed in each of the plurality of dummy patterns centering on a point in each of the plurality of dummy patterns is ¼ or less of the period of the plurality of scale patterns.