Micro-Raman Focus Alignment Using Fluorescence Reference Layers
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Solution Overview
Problem
Existing micro-Raman spectroscopy systems struggle to align the laser focus with the sample surface to maximize Raman and Rayleigh scattering intensities across materials with different compositions and optical characteristics, especially when the sample surface is not flat, leading to inconsistent optical microscopic imaging and difficulty in optimizing the distance between the sample and the objective lens.
Innovation Solution
A micro-Raman spectrometer system that includes a stage holding a sample with a fluorescent material, a laser optical system, a Raman scattered light detector, a fluorescence detector, and a controller that adjusts the Z position based on fluorescence detection to stabilize high spatial resolution mapping measurements across materials with varying compositions and physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between the sample and objective lens is adjusted to maximize Raman scattering intensity, then measurement precision is improved, but device complexity increases due to the need for complex alignment procedures
Solution Approach 1:
The patent introduces a fluorescent material as an intermediary substance applied to the sample surface. This fluorescent material serves as a mediator that enables automatic focus alignment by providing a detectable signal (fluorescence intensity) that correlates with laser focus position, thereby eliminating the need for complex manual alignment procedures while maintaining high measurement precision
Solution Approach 2:
The patent replaces the mechanical/manual focus adjustment system with an optical-based automatic focusing system. Instead of relying on operators to manually adjust the distance between the objective lens and sample, the system uses fluorescence detection to automatically determine the optimal focus position, substituting mechanical alignment with optical signal-based control
2Adaptability or versatility
If mapping measurement is performed across materials with different compositions and optical characteristics, then measurement versatility is improved, but measurement precision deteriorates due to inconsistent focus alignment
Solution Approach 1:
The fluorescent material acts as a universal intermediary that works across different material types. By applying this standardized fluorescent substance to the sample surface regardless of the underlying material composition, the system achieves consistent focus alignment across diverse materials, maintaining both versatility and precision
Solution Approach 2:
The patent applies a homogeneous fluorescent material layer across the entire sample surface, creating a uniform reference signal that enables consistent focus alignment regardless of the heterogeneous underlying materials. This homogenization of the surface signal allows the system to treat different materials uniformly during the focusing process
3Measurement precision
If the laser spot diameter is narrowed to achieve high spatial resolution, then measurement precision is improved, but measurement time increases due to the need for precise focus alignment at each position
Solution Approach 1:
The patent replaces time-consuming manual focus adjustment with automatic fluorescence-based focusing. This substitution eliminates the need for operators to spend time carefully adjusting focus at each measurement position, significantly reducing measurement time while maintaining high spatial resolution through automated precision control
Solution Approach 2:
The system performs self-alignment by automatically detecting fluorescence intensity and adjusting the focus position accordingly. This self-service capability eliminates the need for external operator intervention during the focusing process, enabling rapid automated measurements across multiple positions while maintaining high spatial resolution
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 stable high spatial resolution measurements regardless of surface shape or material type, allowing for accurate optical characterization without pre-processing and reducing measurement time by using fluorescence intensity for focus alignment.
Implementation Method 1
a fluorescent material applied to a surface of the sample is excitable by a wavelength of the Raman measurement laser light
Implementation Method 2
a Raman scattered light detection unit (15R) that detects Raman scattered light (RL) from the sample (16)
Data Source
AI summary
According to some embodiments, a micro-Raman spectrometer includes a stage configured to hold a sample on a surface of which a fluorescent material is applied. The micro-Raman spectrometer includes a laser optical system configured to irradiate the sample with laser light. The micro-Raman spectrometer includes a Raman scattered light detector configured to detect Raman scattered light emitted from the sample. The micro-Raman spectrometer includes a fluorescence detector configured to detect fluorescence emitted from the fluorescent material. The micro-Raman spectrometer includes an analyzer configured to analyze a Raman signal of the Raman scattered light detector and a fluorescence signal of the fluorescence detector. The micro-Raman spectrometer includes a controller connected to the analyzer and configured to control the stage and the laser optical system.