Compact Interference Spectrometer Without Moving Mirrors

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Solution Overview

Problem

Existing spectral measurement devices for biological components require large sizes due to the need for high-accuracy drive mechanisms or increased detector sizes to achieve accurate and high wavelength resolution, which is not feasible for non-invasive measurements.

Innovation Solution

A spectral measurement device that combines light into a single parallel beam, divides it into two beams with an optical path length difference using a phase shifter, and detects overlapping regions on a detector to form an interferogram, allowing for accurate spectral characteristics without increasing device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high-accuracy drive mechanism is used to move the movable mirror, then measurement precision is improved, but device complexity and size increase

Engineering Contradiction:
Improvespectral measurement accuracyVSAvoiddrive mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical mirror movement system with an optical path difference introduction unit that can introduce optical path differences without requiring high-precision mechanical movement. This substitution eliminates the need for complex drive mechanisms while maintaining spectral measurement accuracy, directly resolving the contradiction between measurement precision and device complexity.

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

2Measurement precision

If the detector size is increased to achieve high wavelength resolution, then measurement precision is improved, but device size increases

Engineering Contradiction:
Improvewavelength resolutionVSAvoiddetector size
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent introduces optical path differences in a temporal dimension rather than requiring spatial expansion of the detector. By using the optical path difference introduction unit to create interference patterns over time, the system achieves high wavelength resolution without increasing detector area, resolving the contradiction between measurement precision and device size.

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

3Measurement precision

If the movable mirror is moved with high motion straightness, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvespectral characteristics accuracyVSAvoidmirror movement mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent eliminates the movable mirror mechanism entirely by replacing it with an optical path difference introduction unit. This substitution removes the requirement for high motion straightness and complex mirror movement mechanisms, while still enabling accurate spectral measurements through optical path difference control.

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

4Measurement precision

If the optical path length difference is varied by moving the movable mirror, then spectral characteristics are obtained, but device size increases

Engineering Contradiction:
Improvespectral characteristics acquisitionVSAvoiddevice volume
Core Design Contradiction:
Measurement precisionVSVolume of stationary object

Solution Approach 1:

The patent replaces the mechanical mirror movement system with a compact optical path difference introduction unit. This substitution enables spectral characteristics acquisition through optical path difference variation without requiring the large device volume associated with movable mirror mechanisms, directly resolving the contradiction between measurement precision and device volume.

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

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 accurate and high wavelength-resolution spectral measurements without enlarging the device, utilizing a compact design that includes a phase shifter with integrated optical elements to enhance spectral characteristics acquisition.

Implementation Method 1

an objective lens, and a processing unit. The combining optical system may be composed of one objective lens

Methodology Applied
Scientific EffectLight propagation: Light

Implementation Method 2

a phase shifter configured to divide a parallel light beam combined in the combining optical system into a first light beam and a second light beam, configured to emit the first light beam and the second light beam toward the light-receiving face while providing an optical path length difference between the first light beam and the second light beam

Methodology Applied
Scientific EffectOptical interference: Interference

Data Source

PatentEP4657036A1Spectrometer and spectroscopic method
Publication Date: 2025.12.03 KAGAWA UNIVERSITY
  • EP4657036A1 patent drawingFigure 1A~2A
  • EP4657036A1 patent drawingFigure 2B~3B
  • EP4657036A1 patent drawingFigure 3C~4

AI summary

The present invention includes: combining light emitted from a measurement point of an object to be measured into one parallel light beam by means of a combining optical system; dividing, by a phase shifter, a parallel light beam emitted from the combining optical system into a first light beam and a second light beam, emitting the first light beam and the second light beam toward the light-receiving face while providing an optical path length difference between the first light beam and the second light beam, and causing the first light beam and the second light beam to planarly enter the light-receiving face so that at least a part of an incident region of the first light beam on the light-receiving face and at least a part of an incident region of the second light beam overlap with each other; and obtaining an interferogram at the measurement point based on an intensity distribution of light in a region where an incident region of the first light beam and an incident region of the second light beam on the light-receiving face overlap, and acquiring a spectrum by Fourier-transforming the interferogram.