ATR Prism Reference Measurement for Noise-Free Substrate Spectra
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Solution Overview
Problem
Existing substrate measurement techniques using the Attenuated Total Reflection (ATR) method face challenges in accurately detecting the state of samples due to noise from the prism or other sources, which affects the precision of the measurements.
Innovation Solution
A measurement method involving a first and second measurement step, where infrared light is irradiated and reflected light is measured both on a prism alone and on a prism arranged on a substrate, with a calculation step to determine an absorbance spectrum by subtracting the intensity spectra, effectively canceling out noise and allowing for precise detection of the sample state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ATR method is used to measure the substrate surface, then the surface layer or surface state can be evaluated, but noise from the prism or other sources reduces measurement precision
Solution Approach 1:
The patent extracts and removes the noise component from the measurement system by introducing a reference measurement (prism alone) that captures only the noise and instrumental artifacts. This reference spectrum is then subtracted from the sample measurement spectrum, effectively taking out the harmful noise factors and leaving only the genuine sample signal.
Solution Approach 2:
The reference measurement serves as an intermediary that mediates between the noisy instrumental signal and the true sample signal. By measuring the prism alone first and using this as a reference, the system creates an intermediate step that allows for noise cancellation when comparing against the sample measurement.
2Difficulty of detecting and measuring
If a prism is brought into contact with the substrate surface for measurement, then surface evaluation is enabled, but the prism noise interferes with the detection of sample state
Solution Approach 1:
The measurement process is segmented into two distinct parts: a reference measurement (prism alone) and a sample measurement (prism with substrate). This segmentation allows the noise characteristics to be isolated in the reference measurement and subsequently removed from the sample measurement, improving detection precision while maintaining surface evaluation capability.
Solution Approach 2:
The harmful noise component is extracted through the reference measurement approach. By measuring the prism separately and subtracting its spectrum from the sample measurement, the noise generated by the prism-contact configuration is removed, enabling precise detection of the sample state.
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 enables accurate detection of the sample state by isolating the signal from the substrate, improving measurement precision and reducing noise interference.
Implementation Method 1
the reflected light totally reflected by a surface of the prism in contact with the substrate and penetrating from the prism toward the substrate side
Implementation Method 2
an absorbance spectrum is calculated from an intensity spectrum indicating the absorbance of infrared light for each wave number
Data Source
AI summary
A measurement method includes: a first measurement step of irradiating a prism with infrared light and measuring reflected light totally reflected by the prism; a second measurement step of irradiating the prism with infrared light while the prism is arranged on a substrate and measuring reflected light totally reflected by a surface of the prism on the substrate; and a calculation step of calculating an absorbance spectrum from an intensity spectrum of infrared light for each wave number of the reflected light measured in the first measurement step and an intensity spectrum of infrared light for each wave number of the reflected light measured in the second measurement step.