Interference Imaging of Multiple Scattering Objects With Stable Phase Control

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Solution Overview

Problem

Conventional two-beam interference methods for imaging multiple scattering objects, such as three-dimensional cell tissues, require a laser light source with a long coherence length and are sensitive to environmental variations, leading to instability in interference signals.

Innovation Solution

An observation apparatus and method that uses spatially coherent light to irradiate an object with first and second light beams along fixed and varying directions, capturing interference intensity images at different phase differences to generate complex amplitude images, reducing the influence of multiple scattered light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional two-beam interference method is used to image multiple scattering objects, then interference pattern can be obtained, but the system requires laser light source with long coherence length and is sensitive to environmental variations causing instability

Engineering Contradiction:
Improvestability of interference signalVSAvoidcomplexity of optical system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a spatial light modulator as an intermediary device that actively compensates for optical path difference variations caused by environmental factors. This mediator dynamically adjusts the reference light phase to maintain stable interference patterns without requiring complex mechanical stabilization systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the coherence length parameter of the light source by using a super luminescent diode instead of a conventional laser, and dynamically adjusts the optical path difference through electronic control of the spatial light modulator, thereby maintaining interference stability without long coherence length requirements

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional two-beam interference method is used, then interference pattern can be captured, but adjustment of optical system is difficult and optical path difference changes due to environmental variation

Engineering Contradiction:
Improveease of optical system adjustmentVSAvoidstability against environmental variation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical optical path adjustment mechanisms with electronic phase modulation using a spatial light modulator. This substitution eliminates complex mechanical adjustments and provides stable, electronically controllable phase compensation that is insensitive to environmental vibrations and temperature changes

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

Solution Approach 2:

The system transitions from static optical path configuration to dynamic phase compensation by using a spatial light modulator that can real-time adjust the reference light phase in response to environmental variations, making the system adaptive rather than rigid

Inventive Principle:
Principle #15Dynamics

3Loss of information

If QPI is used to image three-dimensional cell tissue, then non-staining and non-invasive imaging is achieved, but the acquired image is merely a two-dimensional projection unable to grasp true three-dimensional structure

Engineering Contradiction:
Improveinformation loss in imagingVSAvoidthree-dimensional structural accuracy
Core Design Contradiction:
Loss of informationVSManufacturing precision

Solution Approach 1:

The patent transforms the imaging from two-dimensional projection to three-dimensional reconstruction by measuring optical path differences at multiple wavelengths and applying spectral interferometry to recover depth information, thereby adding the third dimension to the image data

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

4Measurement precision

If OCT is used for non-staining imaging of three-dimensional cell tissue, then non-invasive imaging is achieved, but the resolution is low and signal interpretation is difficult

Engineering Contradiction:
Improveimaging resolutionVSAvoidsignal interpretability
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The system improves resolution by changing the wavelength parameter and using spectral interferometry to achieve optical sectioning capability, while the use of multiple wavelengths provides dispersion information that enhances signal interpretation and material characterization

Inventive Principle:
Principle #35Parameter changes

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 and effective observation of multiple scattering objects by minimizing the impact of environmental variations and improving image clarity.

Implementation Method 1

an imaging unit for receiving both the first light and the second light which irradiate the observation object and pass through the observation object, and capturing an interference intensity image generated by interference between the first light and the second light

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP4653933A1Observation device and observation method
Publication Date: 2025.11.26 HAMAMATSU PHOTONICS KK
  • EP4653933A1 patent drawingFigure 1
  • EP4653933A1 patent drawingFigure 2
  • EP4653933A1 patent drawingFigure 3

AI summary

An observation apparatus 1A includes a light source 10, an irradiation unit 31, an imaging unit 50, and a processing unit 60. The irradiation unit 31 inputs spatially coherent light output from the light source 10, generates first light and second light from the input light, and irradiates an observation object S with the first light and the second light in an overlapping manner. The irradiation unit 31 irradiates the observation object S with the first light along a fixed light irradiation direction, and irradiates the observation object S with the second light along each of a plurality of light irradiation directions. The imaging unit 50 receives both the first light and the second light, and captures an interference intensity image generated by interference between the first light and the second light. The processing unit 60 performs required processing based on the interference intensity image to generate a complex amplitude image and the like. Thus, an observation apparatus capable of reducing influence of multiple scattered light and easily observing an observation object even in the case in which the observation object is a multiple scattering object is realized.