Optical Measurement Head With Internal Reference And Movable Mirror
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Solution Overview
Problem
Existing optical spectroscopic measurement systems in industrial settings face inaccuracies due to factors like instrument and illumination source drift, sample geometry and texture variations, ambient illumination, secondary, and stray light, which are not adequately addressed by current technologies.
Innovation Solution
A measurement head with an internal reference and a movable calibration mirror, positioned between the illumination source and the sample, allows for precise calibration by switching between measurement and calibration positions, minimizing errors from these sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual reference measurement is performed by introducing a reference sample into the field-of-view, then reference measurement capability is achieved, but measurement time increases and productivity decreases
Solution Approach 1:
The patent combines the reference measurement and sample measurement capabilities into a single integrated optical path. The reference sample and sample are both viewed through the same collection optic and optical path, allowing seamless switching between reference and sample measurements without manual intervention or time-consuming repositioning operations.
Solution Approach 2:
The patent implements periodic automatic reference measurements where the reference sample is automatically introduced into the field-of-view at predetermined time intervals or before each sample measurement. This periodic action ensures continuous calibration while maintaining high measurement throughput through automated sequencing.
2Extent of automation
If fiber optic multiplexer is used to alternately view reference and sample, then automated reference measurement is achieved, but device complexity increases
Solution Approach 1:
The patent employs a single collection optic that serves multiple functions: it collects light from the sample during sample measurement mode and collects light from the reference sample during reference measurement mode. This multi-functional approach eliminates the need for separate optical paths or complex multiplexer systems, reducing device complexity while maintaining automation.
Solution Approach 2:
The patent uses a simple mechanical shutter or mirror as an intermediary element to switch between reference and sample viewing paths. This intermediary component is much simpler than a full fiber optic multiplexer system, achieving automated switching with minimal added complexity.
3Measurement precision
If on-axis design is used to minimize surface texture errors, then measurement precision improves, but illumination spatial variability increases
Solution Approach 1:
The patent implements an off-axis design where the illumination source and collection optic are positioned at different angles relative to the sample surface. This creates locally optimized illumination conditions where the illumination angle is specifically tailored to minimize surface texture effects in the measurement zone, while the collection optic is positioned to capture the reflected light effectively.
Solution Approach 2:
The patent transitions from an on-axis configuration to an off-axis configuration by introducing angular separation between illumination and collection paths. This dimensional change in the optical geometry allows simultaneous optimization of illumination uniformity and surface texture error minimization by exploiting the angular dimension.
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 enhances the accuracy and reproducibility of optical spectroscopic measurements by stabilizing the reference signal and reducing errors from sample position and texture variations, ambient illumination, and stray light, leading to more reliable compositional and quality assessments in industrial settings.
Implementation Method 1
an illumination source configured to illuminate a sample
Implementation Method 2
collects the illumination reflected back or emitted by the sample under inspection
Implementation Method 3
in the calibration position the calibration mirror is positioned so that the collection optic views, via the calibration mirror, the internal reference
Data Source
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AI summary
A system and method for optical spectroscopic measurements is described. One embodiment includes a measurement head for optical spectroscopic measurements, the measurement head comprising an illumination source configured to illuminate a sample, a collection optic configured to view the sample, and an internal reference, wherein the internal reference can be illuminated by the illumination source and viewed by the collection optic.