Optical Yarn Scanner Field Stop Illumination Consistency

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Solution Overview

Problem

Existing optical yarn clearers face issues with inconsistent illumination of foreign substances due to differently colored light sources being arranged at various locations, leading to potential incorrect measurement results from areas not illuminated by all light components, especially when the yarn is moving and its path is unstable.

Innovation Solution

The use of a field stop to select only the area illuminated by all light sources, ensuring the entire detector field is illuminated with all colors, eliminating the need for sample offset correction and ensuring consistent detection across the scanning area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple light sources with different spectral properties are arranged at different locations to illuminate the textile material, then the detection capability for foreign substances is improved, but the illumination consistency deteriorates because not all areas are illuminated by all light components

Engineering Contradiction:
Improvedetection capabilityVSAvoidillumination consistency
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent extracts and eliminates the problematic areas from the measurement. By using a field stop to define only the intersection area that is illuminated by all light sources, it removes from consideration the areas that are not uniformly illuminated by all light components, thus avoiding measurement errors while preserving the benefits of multiple light sources

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the spatial parameter of the measurement area by introducing a field stop that limits the detection to only those regions where all light sources converge. This parameter change ensures that the measurement is performed exclusively in areas with consistent multi-wavelength illumination

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the textile material moves through the measuring field with unstable path, then the productivity is improved, but the measurement precision deteriorates due to inconsistent illumination of foreign substances

Engineering Contradiction:
Improveprocessing speedVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent creates an equipotential measurement zone where all light sources overlap, ensuring that regardless of the yarn's lateral position or movement stability, any foreign substance passing through the intersection area is illuminated by all light components. This eliminates the need for precise position control while maintaining measurement accuracy

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The field stop acts as an intermediary element that mediates between the multiple light sources and the detector. It ensures that only light from the intersection area reaches the detector, thereby guaranteeing that foreign substances are consistently illuminated by all light sources even when the yarn path is unstable

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures robust and accurate detection of foreign substances in moving yarns by guaranteeing that all light components are applied to the same area, reducing the risk of incorrect measurements and improving the reliability of textile material scanning.

Implementation Method 1

a first sensor records light reflected from the yarn

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

a second sensor records light transmitted by the yarn

Methodology Applied
Scientific EffectLight transmission: Absorption (EM radiation)

Data Source

PatentEP2475978B1Device and method for optically scanning a moving textile material
Publication Date: 2020.02.19 USTER TECHNOLOGIES AG
  • EP2475978B1 patent drawingFigure 1~2
  • EP2475978B1 patent drawingFigure 3
  • EP2475978B1 patent drawingFigure 4~5

AI summary

The invention relates to a device (1) for optically scanning a moving textile material (9), e.g., yarn, comprising a path (91) for the textile material (9). At least two light sources (21, 22), which are arranged at various locations and emit light (71, 72) having various spectral properties, each illuminate a respective illumination area (81, 82) of the path (91). A light detector (6) detects light originating from the various illumination areas (81, 82). At least one field stop (52) allows only light (75) from a scanning area (85) that is a subset of the intersection of all illumination areas (81, 82) to hit the light detector (6). Thus, the textile material (9) is scanned by means of all involved light components (73, 74).