Optical Tomography Path Length Adjustment
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Solution Overview
Problem
Existing optical tomography systems face challenges in maintaining stable intensity and image quality due to adjustments in optical path length, leading to reduced interference light and deteriorated image quality when scanning in the direction of depth.
Innovation Solution
The optical tomography system employs a reflecting mirror, first and second lenses forming a confocal optical system, and optional additional components like a wedge-like transparent member or electro-optic element to maintain focused light paths, ensuring stable reference light and preventing image quality deterioration during optical path length adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the optical path length of the reference light is adjusted by moving only a mirror in the direction of the beam axis, then the optical path length can be changed, but the intensity of the reflected light becomes unstable when scanning in the depth direction
Solution Approach 1:
A lens is introduced as an intermediary component between the mirror and the optical fiber. The lens collects the reflected light from the mirror and directs it into the optical fiber, ensuring stable coupling efficiency. This intermediary structure allows the mirror to adjust optical path length while the lens maintains consistent light collection, resolving the contradiction between ease of adjustment and intensity stability.
2Ease of operation
If an optical path length adjusting lens is moved back and forth to adjust the optical path length, then the optical path length can be changed, but the position of focus moves and the intensity of interference light becomes unstable
Solution Approach 1:
The optical path length adjustment function is separated from the focusing function. The mirror is responsible for adjusting the optical path length by moving along the beam axis, while the lens maintains a fixed position to preserve the focus point. This segmentation of functions allows independent optimization of each component's role, eliminating the contradiction between adjustability and stability.
3Device complexity
If the optical path length is not adjusted, then the system structure remains simple, but the measurable range in the depth direction is limited
Solution Approach 1:
The mirror serves multiple functions: it acts as a beam splitter in the interferometer and simultaneously functions as an optical path length adjustment element. By moving the mirror along the beam axis, the system can adjust the measurable depth range without adding separate adjustment components. This multi-functionality approach increases adaptability while keeping the device structure relatively simple.
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 configuration stabilizes the reference light intensity and maintains image quality by keeping the focusing points unchanged, even during optical path length adjustments, allowing for high-quality tomographic imaging without reducing the amount of reference light.
Implementation Method 1
a first lens which is disposed between the reflecting mirror and the optical fiber to make parallel the measuring light or the reference light radiated from the core of the optical fiber and at the same time, to collect the measuring light or the reference light reflected by the reflecting mirror on the core of the optical fiber
Implementation Method 2
a second lens which collects the measuring light or the reference light made parallel by the first lens on the reflecting mirror and at the same time, makes parallel the measuring light or the reference light reflected by the reflecting mirror
Implementation Method 3
a reflecting mirror which reflects the measuring light or the reference light radiated from the optical fiber
Implementation Method 4
interference light is detected while the frequency of the light emitted from the light source is changed with time
Implementation Method 5
a tomographic image is generated by carrying out a Fourier analysis on the interferogram signal in the region of an optical frequency
Data Source
AI summary
Light emitted from the light source unit is divided into measuring light and reference light. An optical path length of the measuring light or the reference light which has been divided by the light dividing means is adjusted. Interference light of the reflected light and the reference light is detected and a tomographic image of the object is obtained on the basis of the detected interference light. The optical path length is adjusted by a reflecting mirror which reflects the measuring light or the reference light radiated from the optical fiber, a first lens which is disposed between the reflecting mirror and the optical fiber and a second lens which collects the measuring light or the reference light made parallel by the first lens on the reflecting mirror and makes parallel the measuring light or the reference light reflected by the reflecting mirror.