Multi-Spot Holoscopy OCT Decoupling Numerical Apertures
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Solution Overview
Problem
Current optical coherence tomography (OCT) systems face a trade-off between achieving high lateral resolution and maintaining a large depth-detectable area, as both are linked to the numerical aperture of the optical system, making it difficult to obtain high-resolution images of the retina without reducing the accessible depth area.
Innovation Solution
The implementation of a multi-spot holoscopy OCT system that decouples the numerical apertures of illumination and detection, using a multi-hole diaphragm and a 2D detector with oversampling capabilities to achieve high lateral resolution while maintaining a large depth area, and employing a tunable light source and beam splitter to optimize image acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the numerical aperture of the optical system is increased to achieve high lateral resolution, then the lateral resolution is improved, but the depth-detectable area is reduced
Solution Approach 1:
The patent divides the detection process into multiple discrete detection points arranged in a pattern (e.g., hexagonal or square lattice). Each detection point has an independent detector that samples the backscattered light from a specific location in the sample. This segmentation allows the system to achieve high lateral resolution at each point while maintaining a large overall detection area by combining multiple points.
Solution Approach 2:
The patent transitions from conventional single-point or line scanning to a two-dimensional array of detection points. The detection points are arranged in a planar pattern that covers a large area, and the system captures depth information at each point simultaneously or in rapid succession. This dimensional expansion allows independent optimization of lateral resolution and detection area.
2Measurement precision
If the numerical aperture is increased to improve lateral resolution, then the lateral resolution is improved, but aberrations increase
Solution Approach 1:
The patent applies local quality by using a relatively small numerical aperture at each individual detection point, which minimizes aberrations locally. However, the overall system achieves high lateral resolution through the dense spatial sampling provided by the multiple detection points. Each point operates under optimal conditions with minimal aberrations, while the collective data from all points provides high-resolution imaging across a large area.
3Volume of stationary object
If the depth-detectable area is increased by using a small numerical aperture, then the detectable volume is improved, but the lateral resolution is reduced
Solution Approach 1:
The patent segments the large detection volume into multiple smaller volumetric regions, each corresponding to a detection point with a small numerical aperture. Each segment provides high lateral resolution for its local region, and the combination of all segments creates a large overall detectable volume with uniformly high resolution throughout.
Solution Approach 2:
The patent merges the data from multiple detection points with small numerical apertures to create a composite image with both high lateral resolution and large detectable volume. The individual measurements from each point are combined through computational processing to form a complete three-dimensional representation of the sample.
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 approach allows for high-resolution, three-dimensional imaging of the retina with improved signal-to-noise ratio and aberration correction, enabling better detection of retinal structures without compromising the depth area, particularly beneficial for diagnosing conditions like age-related macular degeneration.
Implementation Method 1
The backscattered radiation is combined in an interfering manner with reference radiation
Implementation Method 2
In optical coherence tomography OCT systems the lateral resolution (x and y) is defined by the numeral aperture (NA) of the optical system used
Data Source
AI summary
An optical coherence tomograph that provides wavelength tunable source radiation and an illumination and measurement beam path, a dividing element that divides source radiation into illumination radiation and reference radiation, and collects measurement radiation. The illumination and measurement beam path has scanner. A detection beam path receives measurement radiation and reference radiation and conducts them onto at least one flat panel detector in a superposed manner. A beam splitter separates the measurement radiation from the illumination radiation. The beam splitter conducts the separated measurement radiation to the detection beam path and sets the numerical aperture of the illumination of the illumination field in the eye. An optical element sets the numerical aperture with which the measurement radiation is collected in the eye and a multi-perforated aperture defines the size of an object field and a number of object spots, from which the measurement radiation reaches the flat panel detector.