Monolithic Optical Element for Forward-Viewing Spectrally Encoded Endoscopy
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Solution Overview
Problem
Current spectrally encoded endoscopy (SEE) probes face challenges in miniaturization for forward-view imaging, experiencing limitations such as restricted field angle, aberrations due to cylindrical side walls, and challenges in navigating inside organs without a clear view of what is in front of the probe, along with issues like cross-talk between excitation and detected light and loss of field of view.
Innovation Solution
The design incorporates a probe with an illumination element and a detection element, featuring a light guiding component, a light focusing component, and a first dispersive component, with multiple multimode optical fibers surrounding the illumination element to form a ring at the distal end, which are connected to a second dispersive component and a detector, allowing for improved light collection and reduced speckle, enabling a forward-view configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional SEE probe design with double-prism grating is used for forward-view imaging, then forward-view imaging capability is achieved, but the probe size becomes too large for practical use in small optics
Solution Approach 1:
The patent integrates the dispersive element directly into the fiber tip structure, nesting multiple functional components (illumination fiber, collection fibers, grating) within a compact cylindrical arrangement. The collection fibers are positioned around the illumination fiber in a nested configuration, allowing forward-view imaging in a miniaturized probe form factor.
Solution Approach 2:
The patent transitions from a side-view configuration to a forward-view configuration by changing the spatial arrangement of optical components. The dispersive grating is oriented to diffract light in the forward direction along the probe axis, utilizing the longitudinal dimension of the probe for imaging rather than lateral viewing.
2Volume of moving object
If the probe is miniaturized to fit small optics, then probe size is reduced, but the field angle becomes restricted and aberrations increase
Solution Approach 1:
The patent uses high-numerical-aperture collection fibers (NA=0.66) with specific core diameters (125 μm) to maximize light collection efficiency in the limited space. The fibers are positioned at optimized distances from the grating to capture diffracted light across the desired field angle, compensating for the miniaturized form factor.
Solution Approach 2:
The patent employs a specific grating period (1379 lines/mm) and incident angle (30 degrees) to optimize the dispersion characteristics and field of view. The combination of grating parameters, fiber NA, and geometric arrangement is tuned to achieve adequate field angle and image quality despite the small probe size.
3Device complexity
If a core/clad configuration is used for illumination and detection, then the probe structure is simplified, but cross-talk between excitation and detected light occurs
Solution Approach 1:
The patent physically separates the illumination function (central fiber) from the detection function (surrounding collection fibers). This spatial segmentation prevents cross-talk by ensuring that excitation light and collected signal light travel through distinct optical paths, with the collection fibers positioned to capture only reflected light from the sample.
4Manufacturing precision
If a separate fiber is used for detection, then the field of view is maintained, but the probe size increases and light collection efficiency decreases
Solution Approach 1:
The patent combines multiple collection fibers into a single bundled array that surrounds the illumination fiber. This merging of detection channels maintains the field of view by capturing light from multiple angles simultaneously, while reducing probe size by integrating all detection functions into a compact fiber bundle rather than using separate extended optical paths.
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 enhances the signal level and effective field of view, allowing for high-definition, forward-view imaging in small optics, facilitating use in applications like orthopedics, ear, eye, and sinuses, and pediatric surgery, while minimizing probe size and trauma.
Implementation Method 1
The illumination element comprises a light guiding component
Implementation Method 2
a light focusing component; and a first dispersive component. Broadband light is diffracted by a grating at the tip of the fiber, producing a dispersed spectrum on the sample
Implementation Method 3
broadband light is diffracted by a grating at the tip of the fiber, producing a dispersed spectrum on the sample
Implementation Method 4
Light returned from the sample is detected using a spectrometer
Data Source
AI summary
Exemplary spectrally encoded probes are provided having forward view capabilities. These probes are configured such that the detection element comprises a plurality of light collecting components, where the distal ends at least partially surround the illumination element and the proximal ends form a linear array that is optically connected to a dispersive component.