Temporal Spectroscopy for High-Speed Product Inspection
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Solution Overview
Problem
Conventional spectroscopic methods for product inspection, such as HPLC and diffraction grating-based techniques, are time-consuming and lack the capability for high-speed, high-accuracy quality determination, especially for products requiring total inspection, due to limitations in measurement speed and sensitivity, particularly for products with low transmittance.
Innovation Solution
A product inspection method using broadband pulsed light with pulse stretching, where the wavelength and elapsed time have a one-to-one relationship, allowing for high-speed quality determination without the need for diffraction grating sweeping, and enabling high signal-to-noise ratio measurement through temporal spectroscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional diffraction grating spectroscopic measurement is used, then measurement accuracy can be maintained, but measurement speed is too slow for high-speed total inspection
Solution Approach 1:
The patent employs pulsed broadband light with pulse width stretching to create a time-resolved spectrum where each time point corresponds to a specific wavelength. This periodic pulsed action eliminates the need for continuous wavelength sweeping, achieving high-speed measurement while maintaining spectral resolution.
Solution Approach 2:
The patent replaces the mechanical wavelength sweeping system (diffraction grating rotation) with a temporal dispersion system using pulse-stretched pulsed light. This substitution eliminates mechanical movement, enabling high-speed measurement without the time loss associated with mechanical sweeping.
2Speed
If diffraction grating sweeping is performed quickly to increase measurement speed, then inspection speed improves, but signal-to-noise ratio deteriorates
Solution Approach 1:
The use of pulsed light with stretching allows the system to accumulate light energy over the extended pulse duration while maintaining high temporal resolution. This periodic pulsed action with stretching enables high signal-to-noise ratio measurements without requiring slow mechanical sweeping.
Solution Approach 2:
The patent changes the temporal parameter of the light pulse by stretching the pulse width, which extends the measurement time window and allows sufficient light accumulation for high signal-to-noise ratio while maintaining high inspection speed through the pulsed regime.
3Measurement precision
If conventional HPLC extraction and dissolution method is used, then quality determination accuracy is high, but inspection time becomes too long for total inspection
Solution Approach 1:
The patent extracts and measures the intrinsic optical properties of the product directly without physical extraction and dissolution. By measuring the product in its original state using pulsed broadband light with temporal dispersion, the method achieves both high accuracy and high speed.
Solution Approach 2:
The patent replaces the complex mechanical and chemical extraction-dissolution-measurement system with a direct optical measurement system using pulsed broadband light. This substitution eliminates time-consuming preparation steps while maintaining measurement accuracy.
4Speed
If area sensor with multiple photoelectric conversion elements is used, then sweeping is unnecessary, but sufficient light amount for high SN ratio cannot be achieved
Solution Approach 1:
The patent uses pulsed broadband light with pulse stretching to concentrate light energy into extended temporal pulses. This periodic pulsed action with stretching provides sufficient light amount for high signal-to-noise ratio measurements while maintaining high speed through the pulsed regime and eliminating the need for mechanical sweeping.
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 rapid and reliable quality determination of products by eliminating the need for time-consuming diffraction grating operations and ensuring high signal-to-noise ratio measurements, facilitating total inspection and improving inspection speed and accuracy.
Implementation Method 1
a stretching step of stretching a pulse width of the emitted pulsed light by a stretching element such that a wavelength and an elapsed time in one pulse have a one-to-one relationship in one pulse
Implementation Method 2
a light receiving step of receiving, by a light receiver, light from the product irradiated with the stretched pulsed light
Data Source
AI summary
Super continuum light having a continuous spectrum over at least 1100 to 1300 nm is emitted from a pulsed light source, is pulse-stretched by a stretching element such that a relationship between a wavelength and an elapsed time in one pulse is one to one, and is radiated to a product. The light transmitted through the product is received by a light receiver, and output data is input to the determination unit. A quality determination program of the determination unit calculates an absorption spectrum from the output data, quantifies the absorption spectrum by chemometrics, and compares the absorption spectrum with a reference value to determine quality. The product determined to be a defective product is excluded by an exclusion mechanism.