Folded-Path Spectrometer with Concave-Mirror Focusing

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Solution Overview

Problem

Existing spectrometers face challenges in miniaturization without compromising detection accuracy due to various causes.

Innovation Solution

The spectrometer design includes an optical path formed within a space defined by the light detection element and support, with sequential reflections by reflection parts, and a dispersive part aligned along a reference line, utilizing a concave mirror to increase sensitivity and reduce optical path length, and incorporating a zero-order light capture to prevent stray light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the spectrometer is miniaturized, then the size is reduced, but detection accuracy decreases

Engineering Contradiction:
Improvespectrometer sizeVSAvoiddetection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent folds the optical path using reflection parts (mirrors) to arrange components in a three-dimensional space rather than a straight line. This allows the optical path to be compacted into a smaller volume while maintaining the necessary path length for accurate spectral measurement, effectively resolving the contradiction between miniaturization and detection accuracy.

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

Solution Approach 2:

The optical path is nested within the space formed by the light detection element and support structure. By carefully arranging the optical components (light passing part, reflection parts, dispersive part) within the available three-dimensional space, the patent achieves compact integration without compromising the optical path length required for accurate detection.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Length of stationary object

If the optical path length is shortened for miniaturization, then the spectrometer size is reduced, but light concentration accuracy decreases

Engineering Contradiction:
Improveoptical path lengthVSAvoidlight concentration accuracy
Core Design Contradiction:
Length of stationary objectVSManufacturing precision

Solution Approach 1:

The patent employs a concave mirror as one of the reflection parts to focus and concentrate light accurately onto the light detection element. The curved reflective surface enables precise light concentration even in a shortened optical path, maintaining manufacturing precision while allowing for miniaturization.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Manufacturing precision

If reflection parts are added to adjust light direction, then light concentration accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvelight concentration accuracyVSAvoidoptical component complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into the reflection parts, which serve both to redirect light along the compact optical path and to focus/concentrate light onto the detection element. This merging of functions reduces the need for separate components, thereby limiting the increase in device complexity while achieving accurate light concentration.

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

This configuration allows for miniaturization while maintaining detection accuracy by accurately concentrating dispersed light on detection channels, increasing sensitivity, and preventing stray light, thus enhancing the spectrometer's performance.

Implementation Method 1

the dispersive part has a plurality of grating grooves arranged along the reference line

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

the light passing through the light passing part is reflected by the first reflection part and the second reflection part in sequence

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

the first reflection part is a concave mirror... the light dispersed by the dispersive part may be accurately concentrated on a predetermined position of the light detection part

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP4212835B1Spectrometer, and spectrometer production method
Publication Date: 2025.10.01 HAMAMATSU PHOTONICS KK
  • EP4212835B1 patent drawingFigure 1
  • EP4212835B1 patent drawingFigure 2
  • EP4212835B1 patent drawingFigure 3

AI summary

A spectrometer 1A includes a light detection element 20 provided with a light passing part 21 and a light detection part 22, a support 30 fixed to the light detection element 20 such that a space S is formed between the light passing part 21 and the light detection part 22, a first reflection part 11 provided in the support 30 and configured to reflect light L1 passing through the light passing part 21 in the space S, a second reflection part 12 provided in the light detection element 20 and configured to reflect the light L1 reflected by the first reflection part 11 in the space S, and a dispersive part 40 provided in the support 30 and configured to disperse and reflect the light L1 reflected by the second reflection part 12 to the light detection part 22 in the space S.