Optical sensor for measuring a property of an elongate textile body in a uniform optical field
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Solution Overview
Problem
Existing sensors for measuring elongate bodies, such as yarns, face difficulties in design, alignment, and assembly due to stringent coaxial arrangements of components, making them costly and inflexible.
Innovation Solution
A sensor design with a non-parallel input and output optical axis for the collimator and a divergent light source with anisotropic far-field intensity, allowing for a more flexible arrangement and compensation of irradiance asymmetry through the asymmetry of the radiant intensity, which simplifies the mechanical alignment and reduces costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stringent coaxial arrangement of components is used, then measurement precision is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The patent applies asymmetry by deliberately designing the optical system with non-coaxial arrangement where the light source optical axis and detector optical axis are not aligned. The collimator is positioned offset from the light source, creating an asymmetric geometry that simplifies assembly while maintaining measurement precision through careful optical design of the collimating element.
2Measurement precision
If a coaxial arrangement of light source, collimator, and detector is used, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent segments the optical system into distinct functional modules: light source, collimator, and detector, positioned at separate locations rather than requiring precise coaxial alignment. This modular segmentation allows independent manufacturing and assembly of each component, significantly improving ease of manufacture while maintaining measurement precision through optical design.
3Device complexity
If non-parallel input and output optical axes are used, then device complexity is reduced, but irradiance uniformity deteriorates
Solution Approach 1:
The patent applies local quality by optimizing the collimating element's geometry and positioning to create uniform irradiance distribution in the specific measuring region where the elongate body is located. The asymmetric collimator design is tailored to compensate for the non-coaxial arrangement, ensuring that the measuring region receives uniform illumination despite the simplified optical axis configuration.
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 design achieves a more uniform irradiance distribution in the measuring region, enhancing measurement accuracy and flexibility, particularly suited for measuring the diameter of elongate bodies like yarns, and allows for a more compact and cost-effective sensor configuration.
Implementation Method 1
The collimator has an input optical axis intersecting the center of the light source. It further has an output optical axis. It projects light from said light source on the input optical axis onto the output optical axis. Its function is to generate collimated light in the measuring region
Implementation Method 2
A divergent, light source having anisotropic far-field intensity with a main emission direction
Implementation Method 3
A light detector: This detector receives the light emitted by the collimator and transmitted through the measuring region
Data Source
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AI summary
A sensor for measuring a property, such as the diameter, of a yarn or another elongate body (10), has a measuring region (12) for receiving the body (10). It further has a collimator (36) for collimating the light from a divergent, anisotropic light source (22) into the measuring region (12). The collimator (36) has non-parallel input and output optical axis (38, 40), i.e. it deflects the light. The main emission direction (23) of light source (22) is aimed in a direction different from the input optical axis (38) in order to compensate for the non-uniformity of the transmission function of the collimator (36), thereby generating a uniform irradiance in the measuring region (12).