Optical Tomography Focal Plane Shifting for Extended Imaging Depth
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Solution Overview
Problem
Conventional optical tomography systems face limitations in imaging depth due to scattering and absorption by biological samples, requiring expensive equipment and techniques, and partially coherent sources suffer from image quality degradation for thick samples.
Innovation Solution
An apparatus and method that utilize a sample region optical unit with cleared media and translation control to maintain optical path length constant, allowing for extended imaging depth through interference between reference and sample beams, using partially coherent light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a narrow linewidth light source is used to increase instantaneous coherence length, then imaging depth is improved, but device cost and complexity increase due to requiring expensive wavelength-swept vertical-cavity surface-emitting lasers
Solution Approach 1:
The patent changes the coherence parameter from high coherence (narrow linewidth) to partial coherence (broader linewidth), resolving the contradiction by showing that partial coherence with optical path length control can achieve extended imaging depth without requiring expensive narrow linewidth light sources
Solution Approach 2:
The patent replaces the need for expensive wavelength-swept lasers with a simpler broadband light source combined with mechanical optical path length control, substituting a complex optical system with a simpler system that uses mechanical translation to achieve the same imaging depth extension
2Length of stationary object
If optical path length is extended to increase imaging depth, then imaging depth is improved, but maintaining constant optical path length becomes difficult without complex compensation techniques
Solution Approach 1:
Instead of trying to keep the sample stationary and moving the optics to maintain optical path length, the patent inverts the approach by translating the sample itself, which naturally maintains the optical path length from the light source to the sample while extending the focal range
Solution Approach 2:
The sample translation stage serves dual purposes: it extends the imaging depth by moving the sample to different positions while simultaneously maintaining the optical path length, eliminating the need for separate compensation mechanisms
3Device complexity
If partially coherent light source is used to improve imaging stability, then device complexity is reduced, but imaging depth is limited and image quality degrades for thick biological samples
Solution Approach 1:
The patent introduces dynamic sample translation along the optical axis to extend the imaging depth of a partially coherent system, transforming a static limited-depth system into a dynamic extended-depth system without changing the light source coherence properties
Solution Approach 2:
The patent extends the imaging capability from a limited axial range to an extended axial range by utilizing sample translation in the depth dimension, effectively adding dimensional capability to overcome the imaging depth limitation of partially coherent sources
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 high-quality, label-free 3D imaging of biological samples with extended depth, maintaining coherence and image quality even as samples grow in volume, applicable to optical coherence and diffraction tomography.
Implementation Method 1
a light source generating coherent light
Implementation Method 2
obtains a three-dimensional (3D) optical tomography image of a sample based on interference between reference beam and sample beam
Implementation Method 3
the cleared media may minimize the difference in refractive index between the cleared media and the sample around the center wavelength
Data Source
AI summary
Disclosed herein is an apparatus and method for optical tomography with extended imaging depth. The apparatus obtains a three-dimensional (3D) optical tomography image of a sample based on interference between reference beam and sample beam that is scattered from or through the sample after being irradiated by a light source, and may include a sample region optical unit for adjusting the depth of a focal plane in the sample while maintaining an optical path length constant by translating the sample by a predetermined length along the optical axis of light incidence for the sample.