Optical Tomograph Depolarizing Means Reduces Density Stripes
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Solution Overview
Problem
Conventional optical tomographs using OCT measurements face challenges in maintaining high image quality due to variations in birefringent properties of optical fibers, leading to density stripes in tomographic images, especially during bending, twisting, and temperature changes, which can obscure diagnostic targets and increase manufacturing costs with the use of Faraday rotators and slow polarization controllers.
Innovation Solution
An optical tomograph with depolarizing means that varies the polarization state of light beams at a frequency equivalent to or higher than the scanning frequency, either within the light source unit, along the optical path, or within the optical fibers, to achieve depolarization over time, reducing density stripes without adjusting polarization directions, and allowing for a simpler and cost-effective construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Faraday rotators are used to compensate for birefringent changes, then image quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the Faraday rotator from the optical system entirely. Instead of using active polarization compensation components, the invention extracts only the necessary function of obtaining polarization-independent tomographic images through a simplified interferometer configuration that does not require polarization maintenance
Solution Approach 2:
The patent replaces expensive, complex polarization control components (Faraday rotators, polarization controllers) with simple, passive optical elements that are cheaper and require no active control mechanisms, thereby reducing manufacturing cost while maintaining image quality
2Manufacturing precision
If polarization controllers are used to adjust polarization directions, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the essential function of OCT imaging without requiring polarization control mechanisms. By using a interferometer configuration that inherently provides polarization independence, the invention removes polarization controllers and related adjustment mechanisms, thereby simplifying the device
Solution Approach 2:
The optical system is designed to automatically provide polarization-independent operation without requiring external control or adjustment mechanisms. The interferometer configuration itself ensures that polarization variations do not affect image quality, making the system self-regulating in terms of polarization
3Reliability
If Faraday rotators are installed at probe tips, then polarization compensation is achieved, but device complexity and cost increase
Solution Approach 1:
The patent removes the Faraday rotator from the probe tip location entirely. Instead of placing active compensation components at the distal end of the probe, the invention uses a interferometer configuration that provides polarization independence throughout the entire optical path, including through the optical fibers in the probe
Solution Approach 2:
The interferometer configuration serves multiple functions simultaneously: it performs OCT imaging while inherently providing polarization independence without requiring separate polarization compensation components. This multi-functionality eliminates the need for additional Faraday rotators or polarization controllers in the probe
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 depolarizing means effectively reduces density stripes in tomographic images, enabling high-quality image acquisition without adjusting polarization directions, improving image quality and reducing manufacturing costs by eliminating the need for complex polarization control mechanisms.
Implementation Method 1
depolarizing means for varying the polarization state of light beams input thereto at a frequency equivalent to or higher than the scanning frequency, such that the light beam output therefrom becomes depolarized when averaged over time
Implementation Method 2
a low coherence light beam emitted from a light source is divided into a measuring light beam and a reference light beam. Thereafter, a reflected light beam, which is the measuring light beam reflected by a measurement target, is combined with the reference light beam. Tomographic images are obtained, based on the intensity of a interference light beam obtained by combining the reflected light beam and the reference light beam
Data Source
AI summary
An optical tomograph which irradiates and scans a measuring light beam onto a measurement target at a predetermined scanning frequency, to obtain a tomographic image of the measurement target is provided. A depolarizing unit, for varying the polarization state of light beams input thereto at a frequency equivalent to or higher than the scanning frequency, such that the light beam output therefrom becomes depolarized when averaged over time, is provided in the optical path of at least one of the measuring light beam, a reference light beam, and a reflected light beam between a light source unit and a combining unit.