Guide Rail Encoder Markings for High-Contrast Bright-Field Sensing
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Solution Overview
Problem
Existing linear encoder scales exhibit low contrast in sensor signals, leading to inadequate detection of position changes and insufficient accuracy in displacement measurement, particularly when using bright-field measurement principles.
Innovation Solution
A method involving a pulsed laser to introduce microstructures into the guide rail surface, creating absorption areas with high contrast for bright-field measurement by altering the surface with ultrashort laser pulses, resulting in a microstructured surface that absorbs light perpendicularly incident light, enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional scattering or absorption regions are used in linear encoder scales, then the sensor device can detect position changes, but the sensor signal exhibits low contrast leading to inadequate detection accuracy
Solution Approach 1:
The patent applies local quality by creating marking areas with microstructures that have fundamentally different optical properties from mirror areas. The microstructured marking areas exhibit strong light absorption perpendicular to the surface, while mirror areas maintain smooth reflective surfaces. This local differentiation creates high contrast in sensor signals, enabling reliable detection of position changes with improved measurement precision.
Solution Approach 2:
The patent utilizes optical property changes (analogous to color changes) by transforming the surface of marking areas through microstructuring. The microstructured surfaces absorb light perpendicular to the surface, creating a distinct optical signature that contrasts sharply with the reflective mirror areas. This optical transformation enables the sensor device to reliably distinguish between marking and mirror areas, significantly improving sensor signal contrast and detection accuracy.
2Measurement precision
If pulsed laser is used to create microstructures on guide rail surface, then high contrast absorption areas are achieved for bright-field measurement, but the manufacturing process becomes more complex
Solution Approach 1:
The patent replaces conventional mechanical or chemical surface treatment methods with a pulsed laser-based microstructuring process. The pulsed laser directly transforms the guide rail surface material through controlled ablation and melting, creating microstructures without mechanical contact or chemical reactions. This substitution enables precise control over microstructure geometry and optical properties, achieving high measurement precision while maintaining manufacturing efficiency.
Solution Approach 2:
The patent applies parameter changes by carefully controlling pulsed laser parameters (pulse duration, energy density, scanning speed, pulse overlap) to transform the guide rail surface. By adjusting these parameters, the process creates optimal microstructures for light absorption perpendicular to the surface. The parameter optimization enables high contrast marking areas while managing manufacturing complexity through systematic control of laser processing conditions.
3Manufacturing precision
If the laser beam irradiates overlapping sub-areas to create microstructure, then uniform absorption characteristics are achieved, but the processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-planning the laser beam scanning path and pulse overlap pattern before processing. The scanning strategy is designed in advance to ensure optimal overlap between adjacent sub-areas, guaranteeing uniform microstructure formation across the entire marking area. This preliminary planning enables efficient processing by minimizing redundant pulses while maintaining uniformity, thus reducing overall processing time without sacrificing manufacturing precision.
Solution Approach 2:
The patent utilizes periodic action through the repetitive pulsed laser irradiation pattern. The laser beam delivers pulses at regular intervals along the scanning path with consistent overlap between adjacent pulses. This periodic delivery of energy ensures uniform microstructure formation across the marking area while maintaining high processing speed. The regular pulse pattern optimizes the balance between uniformity and processing time by creating consistent thermal accumulation and material transformation.
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
The method achieves high-contrast detection of position changes using bright-field measurement, improving the accuracy and reliability of displacement measurement in linear encoders.
Implementation Method 1
A method involves a pulsed laser to introduce microstructures into a surface of a guide rail
Implementation Method 2
creating absorption areas with high contrast for bright-field measurement by altering the surface with ultrashort laser pulses, resulting in a microstructured surface that absorbs light perpendicularly incident light
Data Source
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Figure 3A~3B
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AI summary
The invention relates to a method for applying a dimensioned representation (15) to a surface of a guide rail of a linear profile rail guide, wherein the guide rail has a first side surface and wherein the dimensioned representation (15) comprises at least one track (SP1, SP2) extending linearly in the longitudinal direction (X) of the guide rail with several mirror areas (S; S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15) and marking areas (M; M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12, M13, M14).The method comprises providing a pulsed laser for generating a laser beam and providing at least one of the marking areas (M; M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12, M13, M14) by introducing a microstructure into a first area of the first side surface of the guide rail corresponding to the at least one marking area, by generating the laser beam with a sequence of several light pulses and directing the laser beam onto the first area of the first side surface in such a way that the laser beam is moved two-dimensionally relative to the first area and is successively irradiated by the light pulses, wherein each of the different irradiated sub-areas overlaps with at least two other irradiated sub-areas in the longitudinal direction (X) ortransverse to the longitudinal direction (X) which has at least one track (SP1, SP2).