Absolute Position Scale Structure With Separated Feature Patterning

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Solution Overview

Problem

Existing methods for manufacturing absolute position measurement scale structures are inefficient and prone to errors, especially at small scale periods, due to uneven substrate alteration processes that disrupt the regular lattice structure, leading to inaccurate extraction of fine-pitch phase information.

Innovation Solution

A method involving separate processes to form primary and secondary features at regularly and irregularly spaced locations along the measurement dimension, ensuring the primary features are uninterrupted and optimally phased with secondary features, enhancing spatial periodicity and manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single process is used to form all scale features at irregularly spaced locations, then the manufacturing process is simpler, but the spatial periodicity of scale features deteriorates, leading to inaccurate fine-pitch phase information extraction

Engineering Contradiction:

Improvemanufacturing process complexityVSAvoidspatial periodicity of scale features

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The manufacturing process is segmented into two separate processes: a first process that forms primary features at regularly spaced locations to establish spatial periodicity, and a second process that forms secondary features at irregularly spaced locations to encode absolute position information. This segmentation resolves the contradiction by allowing each process to optimize for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first process that forms primary features with regular spacing is performed before the second process that forms secondary features with irregular spacing. This preliminary action establishes the spatial periodicity foundation first, ensuring that fine-pitch phase information can be accurately extracted, and then the absolute position encoding is added without disrupting the periodic structure.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If substrate alteration is performed at irregularly spaced locations in a single pass, then manufacturing speed is faster, but manufacturing precision deteriorates due to uneven substrate alteration

Engineering Contradiction:

Improvemanufacturing speedVSAvoiduniformity of substrate alteration

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The single-pass substrate alteration process is segmented into two separate passes: a first pass that alters the substrate at regularly spaced locations to form primary features with uniform characteristics, and a second pass that alters the substrate at irregularly spaced locations to form secondary features. This segmentation resolves the contradiction by allowing each pass to maintain optimal processing conditions for its specific feature type.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first process uses periodic action by altering the substrate at regularly spaced locations according to a predetermined spatial period, ensuring uniform substrate alteration and consistent primary feature formation. This periodic approach maintains manufacturing precision while the separate second process handles the irregular features.

Inventive Principle:

Principle #19Periodic action

3Device complexity

If primary and secondary features are formed in the same process, then device complexity is reduced, but measurement precision deteriorates due to disrupted lattice structure

Engineering Contradiction:

Improvenumber of manufacturing processesVSAvoidfine-pitch phase information accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The formation of primary features and secondary features is segmented into separate processes. The first process forms primary features that maintain the regular lattice structure necessary for fine-pitch phase information extraction, while the second process forms secondary features that encode absolute position information. This segmentation ensures that the lattice structure is not disrupted, preserving measurement precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The primary features are formed in advance before the secondary features are added. This preliminary action establishes the regular lattice structure first, ensuring that the foundation for accurate fine-pitch phase measurement is in place before the absolute position encoding features are introduced, thereby preventing disruption of the measurement-critical structure.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4667878A1Method of making absolute position measurement scale structure

Publication Date: 2025.12.24 RENISHAW PLC

Figure 1~4(b)
Figure 2
Figure 3(a)~3(b)

AI summary

A method for making an absolute position measurement scale structure which comprises a substrate having a scale track extending along a measurement dimension, the scale track comprising a series of scale features, the method comprising making the scale features via the following two processes: a process configured to alter the substrate within the scale track at regularly spaced locations along the measurement dimension, according to a predetermined spatial period p, so as to form a plurality of primary features; and a process configured to alter the substrate within the scale track at plurality of irregularly spaced locations along the measurement dimension so as to form secondary features.