Optical Imaging Spectroscopy with Fiber Bundle and Microlens Arrays

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Solution Overview

Problem

Current imaging spectroscopy techniques, particularly Raman spectroscopy, are time-consuming when scanning large-area samples due to the need for stepwise scanning, which is inefficient for quickly changing samples or large areas like potentially cancerous skin tissues.

Innovation Solution

A device for simultaneous spectrally and spatially resolved acquisition of all pixels using a light source, signal detection unit, and an optical system with a fiber bundle, two microlens arrays, and a square core fiber, allowing for the collection and focusing of scattered light onto a large-scale detector chip, enabling the capture of entire images without scanning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If point-by-point scanning is used for imaging spectroscopy, then measurement precision is improved, but measurement time increases significantly

Engineering Contradiction:
Improvespectroscopic measurement precisionVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the sample area into multiple discrete regions that can be measured simultaneously. By using an array of detectors arranged in a matrix configuration, each detector measures a specific region of the sample at the same time, eliminating the need for sequential scanning while maintaining spectroscopic precision for each region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from one-dimensional sequential scanning to two-dimensional parallel measurement by arranging detectors in a matrix array. This dimensional change allows simultaneous acquisition of spectral data from multiple spatial locations, dramatically reducing measurement time while preserving measurement precision through the use of multiple independent detection channels.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If parallel data collection techniques are used, then measurement time is reduced, but device complexity increases

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

Solution Approach 1:

The patent employs a microlens array that serves multiple functions: it focuses light from different sample regions onto corresponding detectors, acts as a spatial encoding element, and enables parallel measurement of multiple regions simultaneously. This single multi-functional component achieves parallel data collection without requiring complex optical switching or tuning mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses multiple identical detector elements arranged in an array, where each detector is a copy of the others. This replication allows simultaneous measurement of multiple sample regions without requiring complex unique detection paths for each region, simplifying the overall system architecture while enabling parallel data collection.

Inventive Principle:
Principle #26Copying

3Loss of energy

If full-throughput snapshot techniques are used, then light loss is minimized, but spatial resolution may be compromised

Engineering Contradiction:
Improvelight lossVSAvoidspatial resolution
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent assigns different spatial sampling characteristics to different regions of the detector array. Each detector element in the matrix is optimized to capture light from its corresponding sample region with appropriate spatial resolution, allowing the system to maintain high spatial resolution where needed while efficiently collecting light across the entire field of view without sequential scanning losses.

Inventive Principle:
Principle #3Local quality

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 approach significantly reduces measurement time, allowing for rapid acquisition of high-contrast Raman images of large areas, such as cancerous tissues, with measurement times per pixel reduced to as low as 5 ms, enabling faster identification and analysis.

Implementation Method 1

a first microlens array arranged in the first light path, whereby the first microlens array is arranged to focus the light onto the sample as well as to collect the light that is scattered, emitted or reflected by the sample

Methodology Applied
Scientific EffectLight focusing: Lens

Implementation Method 2

a fiber bundle provided for guiding the scattered, emitted or reflected light to the detection unit

Methodology Applied
Scientific EffectOptical fiber guidance: Optical Fibre

Implementation Method 3

If the excitation light is monochromatic and shows sufficient intensity, the scattered light shows Raman lines, i.e. color shifts that are related to the vibration states of the impinged molecules and the crystal structures

Methodology Applied
Scientific EffectRaman scattering: Scattering

Implementation Method 4

a large-scale detector chip, which is arranged to image the row of fibers

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP3203215B1Optical imaging spectroscopy of large-area samples
Publication Date: 2019.08.14 LEIBNIZ INST FUER ASTROPHYSIK POTSDAM AIP
  • EP3203215B1 patent drawingFigure 1
  • EP3203215B1 patent drawingFigure 2
  • EP3203215B1 patent drawingFigure 3

AI summary

Described herein is a device (100) for simultaneous spectrally resolved acquisition of all pixels of large-area (up to 1 cm2) samples (103), the device (100) comprising at least: a light source (101), a signal detection unit (102) for measuring the spectroscopic signal, an optical system for directing light in form of a first light path (104) onto the sample (103) and for collecting light that is scattered, emitted or reflected by the sample (103) and guiding the collected light away from the sample towards the signal detection unit (102) in form of a second light path (105), wherein the optical system is characterized in that a fiber bundle (107) is provided for guiding the scattered, emitted or reflected light to the signal detection unit (102), the fibers of the fiber bundle are arranged as fiber matrix (106) at the sample side, and arranged as one row (114) at the side of the signal detection unit (102), a first microlens array (111) is arranged in the first light path (103), whereby the first microlens array (111) focusses the light onto the sample (103) as well as collects the light that is scattered, emitted or reflected by the sample (103), and a second microlens array (110) is arranged in the second light path (105), whereby the second microlens array (110) focusses the collected light individually into single fibers (107, 108) of the fiber matrix (106). Preferably, a square core fiber (126) is provided for guiding the light to the first light path (104). The fiber bundle (107) preferably comprises at least 100 and more preferably at least 400 multimode fibers (108). Described is also the use of the device according to the invention for imaging of large-area (up to 1 cm2) samples using Raman, fluorescence, fluorescence lifetime, and reflectance spectroscopy. The great advantage of the present invention is that simultaneous imaging spectroscopy can be performed on a great number of pixels of the sample under investigation.