Lensless Multispectral Infrared Imaging Using Reflected Light

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Solution Overview

Problem

Existing IR imaging technologies require invasive sample preparation and are bulky, complex, and time-consuming, limiting their application to in-vivo or in-situ measurements.

Innovation Solution

A lensless infrared imaging device using quantum cascade lasers and an IR imager without intermediate lenses, configured to detect reflected light opposite to the emission direction, allowing non-invasive, compact, and rapid multispectral imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a microscope coupled with a polychromatic IR source and FTIR spectrometer is used for imaging, then spectral analysis capability is improved, but device complexity and acquisition time increase significantly

Engineering Contradiction:
Improvespectral analysis capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes the FTIR spectrometer from the imaging system, replacing it with a simpler detector array that directly captures spectral information. This extraction of the complex spectral analysis component while retaining the essential spectral measurement capability directly reduces device complexity and acquisition time.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical scanning system required by FTIR spectrometry with a parallel detector array that simultaneously captures spectral data across multiple wavelengths. This substitution of sequential mechanical scanning with parallel optical detection eliminates the complex mechanical movements and significantly reduces acquisition time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a microscope coupled with a polychromatic IR source and FTIR spectrometer is used for imaging, then spectral analysis capability is improved, but acquisition time increases significantly

Engineering Contradiction:
Improvespectral analysis capabilityVSAvoidacquisition time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements continuous spectral acquisition by simultaneously detecting multiple wavelengths across the entire field of view in a single operation, rather than sequentially scanning through wavelengths or regions. This continuous parallel measurement approach maintains spectral analysis capability while eliminating the time-consuming sequential process.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent performs preliminary spectral dispersion and detection across the entire field of view before any analysis is required, capturing all spectral information simultaneously. This preliminary parallel acquisition of spectral data across all spatial positions eliminates the need for time-consuming sequential scanning during the measurement process.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If QCL lasers and an IR imager are used for multispectral imaging, then imaging speed is improved, but device size and complexity increase

Engineering Contradiction:
Improveimaging speedVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the QCL laser sources and IR imager detector array into a single integrated imaging device with a compact form factor. By combining these components in a unified structure with shared optical paths and support mechanisms, the device achieves high imaging speed while reducing overall complexity and size compared to separate systems.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If sample preparation in the form of a thin section is required, then imaging quality is improved, but invasiveness increases

Engineering Contradiction:
Improveimaging qualityVSAvoidinvasiveness
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary optical coupling mechanism that enables direct imaging of the sample surface without requiring physical sectioning or preparation. The optical system acts as an intermediary that captures spectral information from the intact sample, eliminating the need for invasive thin section preparation while maintaining imaging quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 non-invasive, wide-field imaging with reduced acquisition time and device compactness, suitable for in-vivo and in-situ applications.

Implementation Method 1

The emergence of quantum cascade lasers (QCLs) makes it possible to create a multitude of monochromatic IR sources, covering the spectral range of polychromatic IR sources

Methodology Applied
Scientific EffectQuantum cascade laser emission: Laser

Implementation Method 2

A detector sensitive in the infrared is sufficient to quantify the intensity of the light transmitted or scattered by the sample for each of the QCL wavelengths

Methodology Applied
Scientific EffectInfrared absorption and transmission: Absorption (EM radiation)

Implementation Method 3

The sensor is configured to detect a reflected portion of the emitted light, particularly along detection directions that are opposite to the emission directions of the light emitted by the light source

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4078146B1Lensless multi-spectral infrared imaging device and fabrication method thereof
Publication Date: 2026.03.25 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4078146B1 patent drawingFigure 1A~1B
  • EP4078146B1 patent drawingFigure 2~3
  • EP4078146B1 patent drawingFigure 4~5

AI summary

The invention relates to a lensless infrared imaging device (1) intended for imaging a sample (2), comprising at least one light source (3, 3a, 3b, 31) configured to emit light at several wavelengths in the infrared range, and at least one sensor (4) configured to detect some of the emitted light that has interacted with the sample (2), the sensor (4) comprising a plurality of pixels (41), the device being characterised in that the sensor (4) is configured to detect a reflected part of the emitted light. The invention also relates to a method for manufacturing this device.