Confocal Microscope Pinhole Array Astigmatism Correction

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Solution Overview

Problem

Existing Raman spectrometry systems suffer from insufficient correction of astigmatism, leading to deteriorated resolution, particularly in spectrometers with a focal length of 500mm, which affects measurement accuracy.

Innovation Solution

A confocal optical scanning microscope is designed with a light source, objective lens, scanning means, light branching means, a spectroscope, and a 2D array photodetector, along with light restricting means featuring a pinhole array to reduce astigmatism effects and improve resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional spectroscope with spherical concave mirror is used, then the device complexity is low, but the manufacturing precision deteriorates due to astigmatism causing spot elongation and resolution loss

Engineering Contradiction:
Improvespectral resolutionVSAvoidoptical system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the light beam into multiple segments by introducing a beam splitting element, creating multiple light paths that pass through different regions of the concave mirror. This segmentation allows the system to utilize only the non-astigmatic regions of the mirror, thereby improving spectral resolution without requiring complete aberration correction of the entire optical system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by selecting and utilizing specific regions of the concave mirror that have optimal optical properties. By directing light through particular zones of the mirror surface where astigmatism is minimized, the system achieves high spectral resolution while maintaining a relatively simple overall device structure.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the focal length of the spectroscope is increased to 500mm, then the measurement precision improves, but the device complexity increases and astigmatism effects become more pronounced

Engineering Contradiction:
Improvespectral measurement accuracyVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the optical path to bypass the astigmatic regions of long-focal-length optics. By using a beam splitting element to create multiple light paths that sample different portions of the optical system, the design achieves high measurement precision while managing the complexity inherent in long-focal-length spectroscopy.

Inventive Principle:
Principle #1Segmentation

3Productivity

If traditional Raman spectrometry is performed with a single light beam, then the device complexity is low, but the productivity is limited due to sequential measurement requirements

Engineering Contradiction:
Improvemeasurement speedVSAvoidoptical system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the single light beam into multiple parallel beams using a beam splitting element. This allows simultaneous illumination of multiple sample regions and parallel detection of Raman signals, dramatically improving measurement productivity while adding only moderate complexity through the introduction of beam splitting and multiple detection channels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple light paths and detection channels into a unified measurement system. By combining the outputs of multiple parallel measurement channels, the system achieves high-speed productivity while maintaining integrated control and data processing.

Inventive Principle:
Principle #5Merging (Combining)

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

The configuration allows for high-resolution measurements by preventing overlapping of light beams on the detector, reducing astigmatism's impact and enhancing measurement efficiency while minimizing sample damage.

Implementation Method 1

an objective lens that concentrates a light beam from the light source and applies the concentrated light beam onto a sample

Methodology Applied
Scientific EffectLight concentration: Focusing

Implementation Method 2

a spectroscope that spatially disperses the outgoing light separated by the light branch means according to a wavelength

Methodology Applied
Scientific EffectSpectral dispersion: Diffraction

Implementation Method 3

a 2D (two-dimensional) array photodetector that includes light-receiving pixels arranged in an array and detects the outgoing light dispersed by the spectroscope

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP2685303B1Optical microscope, and spectroscopic measurement method
Publication Date: 2020.09.09 NANOPHOTON CORP
  • EP2685303B1 patent drawingFigure 1
  • EP2685303B1 patent drawingFigure 2
  • EP2685303B1 patent drawingFigure 3A

AI summary

An optical microscope capable of performing measurement with a high resolution and a spectrometry method are provided. A spectrometry device according to an aspect of the present invention includes a laser light source 10, an objective lens 21 that concentrates a light beam and applies the concentrated light beam onto a sample 22, a Y-scanning unit 13 that scans a spot position of the light beam on the sample 22, a beam splitter 17 that separates, among the light beam incident on the sample 22, outgoing light emitted from the sample 22 toward the objective lens 21 side from the light beam emitted from the light source 10 and incident on the sample, the outgoing light being emitted with a different wavelength, a spectroscope 31 that spatially disperses the outgoing light separated by the beam splitter 17 according to the wavelength, a detector 32 that detects the outgoing light dispersed by the spectroscope 31, and a pinhole array 30 disposed on an incoming side of the spectroscope 31, a plurality of pinholes 42 being arranged in the pinhole array, the plurality of pinholes 42 being adapted to allow outgoing light to pass therethrough to the spectroscope 31 side.