Optical Tomography System Wavelength Selection and Path Adjustment
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Solution Overview
Problem
In optical tomography systems, particularly SS-OCT, adjusting the measurement initiating position is time-consuming due to the need for frequency-analysis and limited depth range, requiring manual adjustment of optical path lengths to accommodate individual probe differences and ensure interference occurs within the coherence length.
Innovation Solution
An optical tomography system with a light source emitting a predetermined wavelength band and a wavelength selecting means, controlled by a control means to switch between measurement initiating position adjusting and image obtaining modes, using ASE light for rapid position adjustment and high-resolution imaging, with automatic optical path length adjustment to ensure interference signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency-analysis is performed to obtain tomographic image signals in SS-OCT, then high-resolution imaging is achieved, but the time required for signal processing increases
Solution Approach 1:
The patent applies preliminary action by performing position adjustment using time-domain OCT measurement before switching to spectral-domain measurement for high-resolution imaging. This preliminary position alignment ensures that the subsequent high-resolution imaging requires minimal signal processing time, as the measurement initiating position is already optimized.
Solution Approach 2:
The system dynamically switches between two measurement modes: time-domain OCT for rapid position adjustment and spectral-domain OCT for high-resolution imaging. This dynamic adaptation allows the system to optimize processing time during position adjustment while maintaining high imaging resolution during actual measurement.
2Reliability
If manual adjustment of optical path lengths is performed to accommodate individual probe differences, then interference signal generation is ensured, but the operation time increases
Solution Approach 1:
The patent implements feedback by using the detected interference light intensity to automatically determine the measurement initiating position. The system continuously monitors the interference signal and automatically adjusts the optical path length based on the detected signal strength, eliminating the need for manual adjustment while ensuring reliable interference signal generation.
Solution Approach 2:
The system performs self-adjustment of the measurement initiating position by automatically analyzing the interference light intensity and determining the optimal position without external intervention. This self-service mechanism accommodates individual probe differences automatically, ensuring reliable interference signal generation while minimizing adjustment time.
3Measurement precision
If the measurement initiating position is manually adjusted to ensure interference occurs within the coherence length, then measurement accuracy is improved, but the ease of operation decreases
Solution Approach 1:
The system uses feedback from the detected interference light intensity to automatically determine the measurement initiating position. By monitoring the interference signal and using it to control the optical path length adjustment, the system achieves accurate positioning without requiring manual intervention, thereby maintaining both precision and ease of operation.
Solution Approach 2:
The patent replaces manual mechanical adjustment with automated optical control. Instead of manually adjusting optical components, the system uses the detected interference signal to automatically control the optical path length, substituting mechanical operation with optical feedback control to achieve both accuracy and ease of use.
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 significantly reduces the time required for signal processing and position adjustment, enabling efficient and accurate measurement initiating position adjustment and high-resolution tomographic imaging by controlling wavelength selection and optical path lengths.
Implementation Method 1
an optical tomographic image is obtained on the basis of an interference of light by low coherence light
Implementation Method 2
interference light due to the superposition is detected by, for instance, heterodyne detection
Implementation Method 3
a light source which emits light having a predetermined wavelength band and with a wavelength selecting means which selects the wavelength emitted from the light source
Implementation Method 4
an optical path length adjusting means which adjusts the optical path length of the measuring light or the reference light divided by the light dividing means
Implementation Method 5
interference light due to the superposition is detected by, for instance, heterodyne detection
Implementation Method 6
a tomographic image is generated by carrying out a Fourier analysis on the interferogram signal in the region of an optical frequency
Data Source
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AI summary
In a coherence tomography measurement, interference light (L4) of the reflected light (L3) of the measuring light (L1) from the object (S) and the reference light (L2) is detected. A controller (70) switches between a position adjusting mode and a tomographic image obtaining mode. A light source (11) which emits light having a predetermined wavelength band is provided and the wavelength emitted from the light source is selected. The controller controls so that a laser beam is emitted while the wavelength is swept at a predetermined period and the tomographic image signal is obtained on the basis of the interference light by the laser beam in the image obtaining mode, while controls so that light of a predetermined wavelength is emitted and the tomographic image signal is obtained on the basis of the interference light by the light of a predetermined wavelength in the position adjusting mode.