Raman Spectroscopy Optical Filter for Simultaneous Visualization

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Solution Overview

Problem

Current Raman spectrometry systems face challenges in simultaneously performing measurements and visualization of samples due to handling difficulties with retractable optical components, which can lead to mechanical movement issues, reproducibility problems, and interference from stray light, making it impossible to visualize the sample during measurements.

Innovation Solution

The use of optical filters that separate the excitation laser beam from the display beam, allowing for simultaneous visualization and Raman measurement by utilizing distinct spectral ranges for each, eliminating the need for mechanical movements and reducing optical intensity losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a retractable optical component is used to remove the illumination and viewing system from the optical path, then the Raman measurement can be performed, but the device complexity increases and reliability decreases due to mechanical movement issues

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the harmful illumination light from the optical path by using a specific optical filter that blocks the illumination wavelength while transmitting the Raman signal wavelength. This eliminates the need for mechanical retraction mechanisms while maintaining measurement capability, thereby reducing device complexity and improving reliability simultaneously

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an optical filter as an intermediary component that selectively transmits different wavelengths. This filter acts as a mediator between the illumination system and the detection system, allowing both to coexist in the same optical path without interference, thus avoiding mechanical movement components

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a semi-transparent slide is placed in the optical path for simultaneous visualization and measurement, then the sample can be viewed during measurement, but the Raman signal intensity decreases due to optical losses

Engineering Contradiction:
Improveoperational convenienceVSAvoidRaman signal intensity
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies local quality by using a wavelength-selective optical filter that has different transmission properties for different wavelengths. The filter is designed to completely block the illumination wavelength while fully transmitting the Raman signal wavelength, thus allowing visualization during measurement without any loss of Raman signal intensity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the spectral parameter of the optical path by introducing a filter with specific wavelength selectivity. This parameter change allows the system to separate the illumination light from the Raman signal in the spectral domain, enabling simultaneous visualization and measurement without optical losses

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If the illumination source is present during Raman measurement, then the sample can be visualized, but stray light interferes with the detection of weak Raman signals

Engineering Contradiction:
Improvevisualization capabilityVSAvoidstray light interference
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful illumination light into a beneficial element by using its specific wavelength characteristics. The optical filter is designed to block the illumination wavelength while transmitting the Raman signal wavelength, thus the presence of strong illumination light actually helps to demonstrate the effectiveness of the wavelength-selective filtering approach

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 solution enables simultaneous visualization and Raman measurement without mechanical parts, significantly reducing optical losses and allowing for real-time autofocus adjustments and object tracking, while maintaining high efficiency in Raman signal measurement.

Implementation Method 1

an optical filter capable of reflecting said excitation laser beam of spectral band B0 and transmitting said visualization beam of spectral band BV; an optical filter capable of transmitting said excitation laser beam of spectral band B0 and reflecting said visualization beam of spectral band BV

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

Raman spectroscopy is based on measuring transitions between vibrational states of a polyatomic, molecular, or ionic structure... A sample illuminated by a monochromatic light source (a laser) scatters light that is no longer monochromatic but exhibits scattering bands at different frequencies

Methodology Applied
Scientific EffectRaman scattering: Scattering

Implementation Method 3

The excitation laser beam is typically focused by an objective lens... enabling the analysis of samples with micrometer spatial resolution

Methodology Applied
Scientific EffectOptical focusing: Lens

Data Source

PatentEP2656027B1Device and method for observing and for measuring raman scattering
Publication Date: 2021.11.03 HORIBA FRANCE SAS
  • EP2656027B1 patent drawingFigure 1~2
  • EP2656027B1 patent drawingFigure 3~4
  • EP2656027B1 patent drawingFigure 5~7

AI summary

The present invention relates to a method and optical device for Raman spectroscopy and for observing a sample (7), said device including an optical means for stacking an excitation laser beam (1) having a spectral band B 0 and an observation beam (2) having a spectral band B V so as to form a combined excitation and observation incident beam, and an optical separation means arranged in the path of a collected beam for scattering on the sample (7) and including a first filtering means (12), a second filtering means (13) capable of spatially separating said collected beam into a first secondary beam and two tertiary beams, each of which includes a spectral band selected from the spectral band B 0 of the laser, the spectral band B V of the observation beam, and the spectral band B R of the Raman scattering beam, respectively.