OCT Device Spatial Light Modulator Diffraction Grating Scattering
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Solution Overview
Problem
Conventional optical coherence tomography (OCT) devices face challenges in maintaining high resolution imaging deep within scattering media due to noise and multi-scattering effects, which limit their ability to construct clear images of targets embedded in thick scattering media.
Innovation Solution
The proposed OCT device incorporates a spatial light modulator for controlling the incident angle of the sample beam and a diffraction grating to filter multi-scattering signals, allowing for high-resolution imaging by selectively transmitting only the first diffraction component of the reference beam, thereby enhancing image quality and depth penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional OCT devices use point scanning or off-axis holography to capture images, then two-dimensional or wide-field imaging can be achieved, but imaging distortion occurs due to multi-scattering within scattering media
Solution Approach 1:
The patent segments the scattered light into single-scattered light and multi-scattered light components using a diffraction grating. The diffraction grating spatially separates different scattering orders, allowing the system to selectively capture only single-scattered light while rejecting multi-scattered light, thereby eliminating imaging distortion while maintaining wide-field coverage
Solution Approach 2:
The patent extracts the useful single-scattered light component from the total scattered light by using a diffraction grating to separate different scattering orders. By selecting only the first diffraction component (single scattering) and blocking higher-order diffractions (multi-scattering), the system removes the harmful multi-scattering effects while preserving the desired imaging signal
2Measurement precision
If OCT devices capture images through interference signals between reflected light from matter and reference beam, then tomographic images can be obtained, but noise increases and verification of sample data becomes difficult when scattering is strong
Solution Approach 1:
The diffraction grating segments the light path into distinct diffraction orders, where the first order contains single-scattered light and higher orders contain multi-scattered light. This spatial segmentation allows selective detection of single-scattered light, significantly reducing noise while maintaining tomographic image quality
Solution Approach 2:
The system extracts only the first diffraction component from the diffraction grating output, which corresponds to single-scattered light. By blocking higher-order diffraction components that contain multi-scattered light and noise, the system achieves high-contrast tomographic images with minimal noise interference
3Object-affected harmful factors
If angular compounding OCT devices measure images at different incident angles and cumulatively add intensity, then noise is reduced and contrast is enhanced, but image construction is limited when noise intensity is stronger than signal due to severe multi-scattering
Solution Approach 1:
Instead of accumulating all scattered light intensities as in conventional angular compounding, the patent inverts the approach by selectively blocking multi-scattered light and accumulating only single-scattered light from different angles. This reversal of the selection criterion enables effective image construction even in severely scattering media where conventional methods fail
Solution Approach 2:
The patent extracts only the single-scattered light component at each incident angle using the diffraction grating, then accumulates these extracted components. This selective extraction prevents noise accumulation while maintaining signal strength, enabling image construction in regimes where conventional angular compounding fails due to overwhelming noise
4Area of stationary object
If optical microscopy is used to image targets in thick scattering media, then imaging can be performed, but resolving power is lost due to dominance of strong multiple-scattered waves over single-scattered waves
Solution Approach 1:
The diffraction grating extracts only the single-scattered light component from the total light returning from deep within scattering media. By blocking multi-scattered light that would otherwise dominate and reduce resolution, the system maintains full optical resolving power even at imaging depths ten times greater than conventional methods
Solution Approach 2:
The system segments the returning light by scattering order using the diffraction grating, allowing separate detection and accumulation of single-scattered light from different depths. This segmentation enables deep imaging while preserving resolving power by excluding the degrading effect of multi-scattered light
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 construction of high-resolution, three-dimensional images with reduced noise and increased imaging depth, achieving a tenfold increase in depth over conventional methods and distinguishing single from multiple-scattered waves, thereby improving imaging capabilities in biomedical and life science applications.
Implementation Method 1
a diffraction grating for transmitting only a first diffraction component of the reference beam
Implementation Method 2
a spatial light modulator enabling a plurality of ramp patterns for controlling an incident angle of the sample beam
Implementation Method 3
an image of the matter within a medium is captured by generating an interference image formed by the interference between the sample beam and the reference beam
Data Source
AI summary
A device for optical coherence tomography (OCT) is provided. The device includes a light source for generating a sample beam incident on a matter and a reference beam for creating interference with the sample beam; a spatial light modulator enabling a plurality of ramp patterns for controlling an incident angle of the sample beam; and a diffraction grating for transmitting only a first diffraction component of the reference beam; whereby an image of the matter within a medium is captured by generating an interference image formed by the interference between the sample beam and the reference beam.