Mobile Spectral Probe with Spatially Variable Filter

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Solution Overview

Problem

Conventional sensors attached to processing vessels are limited by their fixed position, which restricts inspection capabilities to the immediate vicinity and can degrade spectral selectivity due to angle-dependent wavelength properties of thin film filters, necessitating the development of a more versatile and accurate monitoring system.

Innovation Solution

A spatially variable filter (SVF) based spectral probe with a movable and hermetically sealed spherical housing, equipped with multiple windows, light sources, optical filters, and photodetectors, capable of transmitting data wirelessly, and featuring a propulsion and buoyancy system for immersion in materials, allowing for spectral evaluation at various times and locations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If stationary sensors with fixed position are used, then device complexity is reduced, but measurement precision and inspection capability are limited to immediate vicinity only

Engineering Contradiction:
Improvesensor structureVSAvoidspectral evaluation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The sensor system transitions from stationary to mobile, allowing the probe to move freely within the processing vessel to access different locations for spectral evaluation. This dynamic positioning capability enables comprehensive monitoring of the entire process volume while maintaining relatively simple device structure through the use of autonomous mobile sensors.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If thin film optical filters are used without collimating elements, then device complexity is reduced, but spectral selectivity deteriorates due to angle-dependent wavelength properties

Engineering Contradiction:
Improveoptical system structureVSAvoidspectral selectivity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system changes the angular parameter by allowing light to incident on the thin film filter at varied angles depending on the direction of incoming light from different spatial locations. This parameter change approach enables the filter to maintain spectral selectivity across different viewing angles without requiring collimating optics, thus reducing device complexity while preserving measurement precision.

Inventive Principle:
Principle #35Parameter changes

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

Enables comprehensive and accurate monitoring of flowing materials by reducing the dependence on bulky collimating lenses, providing robust and flexible process monitoring capabilities across a wide spectral range, and enabling real-time data transmission and adjustment of process parameters.

Implementation Method 1

a spatially variable filter (SVF) for separating incoming light into a spectrum of constituent wavelength signals

Methodology Applied
Scientific EffectSpatially variable filter: Filter (optical)

Implementation Method 2

a photodetector array for detecting optical power levels of individual wavelength signals

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3128303B1In-situ spectral process monitoring
Publication Date: 2023.10.04 VIAVI SOLUTIONS INC(US)
  • EP3128303B1 patent drawingFigure 1
  • EP3128303B1 patent drawingFigure 2
  • EP3128303B1 patent drawingFigure 4

AI summary

Increasing the precision of process monitoring may be improved if the sensors take the form of travelling probes riding along with the flowing materials in the manufacturing process rather than sample only when the process moves passed the sensors fixed location. The probe includes an outer housing hermetically sealed from the flowing materials, and a light source for transmitting light through a window in the housing onto the flowing materials. A spatially variable optical filter (SVF) captures light returning from the flowing materials, and separates the captured light into a spectrum of constituent wavelength signals for transmission to a detector array, which provides a power reading for each constituent wavelength signal.