FTIR Spectrometer Accessory Compensation

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Solution Overview

Problem

In Fourier transform infrared spectrophotometers (FTIR), the measurement accuracy decreases due to interference condition deviations caused by mounting different accessories, which lead to base distortion and changes in the positional relationship between mirrors, affecting the interference conditions and signal intensity.

Innovation Solution

The FTIR system reads accessory-specific information to adjust the interference optical system settings, including parameters for the fixed mirror alignment and light source luminance, to maintain optimal conditions for each accessory, thereby compensating for base distortion and varying optical elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different accessories are mounted in the sample chamber, then measurement versatility is improved, but interference condition deviation occurs due to base distortion

Engineering Contradiction:
Improvemeasurement versatilityVSAvoidinterference condition stability
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary measurement before sample measurement to detect the positional relationship between fixed mirror and moving mirror. Based on this preliminary detection, the system预先 adjusts the fixed mirror direction to compensate for accessory-induced base distortion, ensuring optimal interference conditions are established before actual measurement begins

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the positional relationship between fixed mirror and moving mirror using laser light and photodiode array. Based on this feedback information, the control unit dynamically adjusts the fixed mirror direction via piezoelectric elements to maintain optimal interference conditions despite accessory-mounted distortions

Inventive Principle:
Principle #23Feedback

2Reliability

If dynamic alignment is performed to prevent amplitude fluctuations, then measurement reliability is improved, but device complexity increases due to additional alignment mechanisms

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidalignment mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Laser light serves as an intermediary to detect the positional relationship between fixed mirror and moving mirror. The laser beam, with its small cross-sectional area, provides a precise reference for measuring mirror position without interfering with the main infrared measurement path

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fixed mirror serves multiple functions: it participates in the main infrared interference measurement and simultaneously acts as an adjustable element for dynamic alignment compensation. The piezoelectric elements applied to the fixed mirror enable both functions to be achieved with a single component

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

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 ensures high-accuracy measurements by maintaining optimal interference conditions and signal intensity regardless of the mounted accessory, eliminating the effects of interference condition changes and improving measurement precision.

Implementation Method 1

The adjustment of the direction of the fixed mirror is made by, for example, applying a voltage to a piezoelectric element provided on the back of the fixed mirror

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

Light is divided into two light beams by the beam splitter, one of the light beams is reflected by the fixed mirror while the other light beam is reflected by the moving mirror, and then these two reflected light beams are made to interfere with each other

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP2963400B1Fourier transform infrared spectrometer
Publication Date: 2022.09.28 SHIMADZU CORP
  • EP2963400B1 patent drawingFigure 1
  • EP2963400B1 patent drawingFigure 2~3
  • EP2963400B1 patent drawingFigure 4~5

AI summary

A Fourier transform infrared spectrophotometer that is free from an effect of interference condition change resulting from an accessory being mounted and has a high measurement accuracy is provided. A Fourier transform infrared spectrophotometer according to the present invention is a Fourier transform infrared spectrophotometer including a common base on which a sample chamber 2 and an interference optical system are mounted, where an accessory 20 can be detachably in the sample chamber, the Fourier transform infrared spectrophotometer including: accessory information reading means 22 for reading accessory information provided to the accessory 20 when the accessory 20 is mounted in the sample chamber 2; and setting condition changing means (controller 30) for changing a setting condition for the interference optical system based on the accessory information read by the accessory information reading means 22, the setting condition varying depending on, e.g., a difference in weight between respective accessories 20.