Spectral Analysis Device Using Fixed Incident Angle and Polarization
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Solution Overview
Problem
Conventional spectral analysis methods, such as MAIRS and pMAIRS, face challenges with optical fringes, water vapor peak interference, and non-uniform thin film analysis due to low-angle incidence and changing incident angles, especially when using substrates with low refractive indices or single-side polished supports.
Innovation Solution
A spectral analysis device that fixes the incident angle and uses a linear polarization filter to obtain independent absorbance spectra parallel and perpendicular to the thin film, employing regression computation and intensity ratio calculations to correct for mixing ratios and eliminate noise, allowing analysis on substrates with varying refractive indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light is incident at low angles to obtain independent absorbance spectra, then spectral analysis capability is improved, but optical fringes and water vapor peak interference increase
Solution Approach 1:
The patent changes the incident angle parameter from variable (conventional MAIRS/pMAIRS) to a fixed predetermined angle. This parameter change eliminates the variation in irradiation area and stabilizes the measurement conditions, reducing optical fringes and water vapor peak interference while maintaining spectral analysis capability.
Solution Approach 2:
The patent uses a predetermined incident angle that has been optimized and established in advance, copying the successful measurement conditions to eliminate the need for angle variation. This copying approach preserves the beneficial spectral analysis capability while avoiding the harmful effects of angle changes.
2Measurement precision
If incident angle is changed during measurement to obtain independent spectra, then spectral resolution is improved, but irradiation area changes and analysis stability deteriorates
Solution Approach 1:
The patent changes the incident angle from a variable parameter to a fixed predetermined parameter. This eliminates the instability caused by changing irradiation areas while maintaining the ability to obtain independent absorbance spectra through polarization control rather than angle variation.
3Measurement precision
If conventional MAIRS or pMAIRS is used to analyze thin films, then molecular orientation analysis is improved, but support bodies with low refractive index cannot be used
Solution Approach 1:
The patent creates a universal measurement method that works with support bodies of any refractive index by using a fixed predetermined incident angle and polarization control. This eliminates the limitation of conventional methods that require high refractive index support bodies, extending adaptability to various substrate materials.
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
The solution effectively reduces noise from optical fringes and water vapor peaks, stabilizes analysis across changing incident angles, and enables accurate analysis of non-uniform thin films, even on single-side polished substrates, by generating clear and accurate absorbance spectra.
Implementation Method 1
a linear polarization filter to obtain independent absorbance spectra parallel and perpendicular to the thin film
Implementation Method 2
obtain, as two independent spectra, transition moments which are respectively parallel and perpendicular to the thin film when the spectrum of the thin film is measured by absorption spectrometry
Data Source
Figure 1
Figure 2A~4
AI summary
To provide a spectral analysis device capable of obtaining in-plane/out-of-plane absorbance spectra of a thin film even when the incident angle of light emitted from a light source to irradiate a support body is fixed. A spectral analysis device includes a light source 1, a support body 2, a linear polarization filter 3, a detection unit 4, a regression computation unit 5, and an absorbance spectrum calculation unit 6. The support body 2 is fixed such that an incident angle of the light is a predetermined incident angle θ. The linear polarization filter 3 is configured such that lights with polarization angles φn ranging from 0° to 90° are irradiated to the support body 2. The detection unit 4 detects a transmitted spectrum S from transmitted lights with the polarization angles φn. The regression computation unit 5 obtains an in-plane spectrum sip and an out-of-plane spectrum sop through regression analysis by using the transmitted spectrum S and a mixing ratio R. The absorbance spectrum calculation unit 6 calculates an in-plane absorbance spectrum Aip and an out-of-plane absorbance spectrum Aop of the thin film based on the in-plane spectrum and the out-of-plane spectrum obtained in each of a state where the thin film is supported on the support body 2 and a state where the thin film is not supported on the support body 2.