Optical Tomograph Automatic Path Length Adjustment
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Solution Overview
Problem
Existing optical tomographs face challenges in maintaining accurate optical path length adjustments due to temperature fluctuations and fiber bending, leading to shifts in the obtainment position of optical tomographic images.
Innovation Solution
An optical tomograph that automatically adjusts optical path length differences by detecting interference light beams and administering frequency analysis, using a configuration with a light source unit, light dividing section, irradiating section, combining section, interference light detecting sections, and an optical path length adjusting section to ensure accurate alignment of measuring and reference light beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical path length is adjusted manually, then device complexity is reduced, but measurement precision deteriorates due to temperature fluctuations and fiber bending
Solution Approach 1:
The patent employs a feedback mechanism where the optical path length is automatically adjusted based on detected interference patterns. The system continuously monitors the optical path difference between reference and measurement beams, and automatically compensates for changes caused by temperature fluctuations and fiber bending, thereby maintaining measurement precision without requiring manual intervention.
Solution Approach 2:
The optical tomograph performs self-adjustment of the optical path length through automated detection and correction mechanisms. The system uses its own interference signal to detect optical path differences and automatically adjusts the optical path to maintain accuracy, eliminating the need for external manual adjustment and reducing device complexity.
2Measurement precision
If optical path length is adjusted automatically, then measurement precision is improved, but device complexity increases due to additional detecting and adjusting sections
Solution Approach 1:
The patent integrates multiple functions into existing components. The interference light detecting section serves both to capture the interference pattern for tomographic imaging and to detect optical path length differences for automatic adjustment. Similarly, the optical path length adjusting section works in conjunction with existing optical components, thereby improving measurement precision without proportionally increasing overall system complexity.
3Productivity
If frequency domain OCT measurement is used, then productivity is improved by obtaining images at high speeds, but measurement precision deteriorates when optical path length difference is great
Solution Approach 1:
The patent performs preliminary adjustment of the optical path length to ensure that the optical path difference between the reference and measurement beams remains within an optimal range before acquiring frequency domain OCT data. This preliminary action prevents degradation of spatial frequency accuracy while maintaining the high-speed imaging capability of frequency domain OCT.
Solution Approach 2:
The system continuously monitors the optical path length difference and provides real-time feedback to the adjusting mechanism. This feedback ensures that even during high-speed frequency domain OCT measurement, the optical path difference remains within the range that maintains measurement precision, thereby resolving the contradiction between speed and accuracy.
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 solution enables the automatic adjustment of optical path lengths at desired timings, improving the reliability and accuracy of optical tomographic image acquisition by minimizing the impact of temperature changes and fiber bending.
Implementation Method 1
Optical tomographs that employ light interference of low interference light have also been proposed
Implementation Method 2
an SD-OCT optical tomograph divides a wide band low coherence light beam emitted by a light source into a measuring light beam and a reference light beam by a Michelson interferometer
Data Source
AI summary
An optical tomograph obtains tomographic images by administering frequency analysis on an interference light beam formed by interference between a reflected light beam, which is a measuring light beam reflected by a measurement target, and a reference light beam. A tomographic data obtaining section obtains tomographic data to be used for optical path length adjustment each time that the position, onto which the measuring light beam is irradiated, is changed. An optical path length adjusting section adjusts the optical path length of one of the measuring light beam, the reflected light beam, and the reference light beam, based on the obtained tomographic data.