Spectrally Encoded Endoscope Grating Design for Color Imaging
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Solution Overview
Problem
Spectrally encoded endoscopes face challenges in providing color images due to wavelength-based spatial encoding, leading to loss of color information and limited field of view, with existing systems requiring multiple fibers and complicating the probe design, and experiencing crosstalk issues when increasing the field of view.
Innovation Solution
The use of multiple spectrally dispersive gratings positioned at different angles to illuminate and detect light on different planes, allowing for spatial separation of spectral bands and minimizing crosstalk, enabling the formation of color images with a wider field of view using a single mode fiber and rotating distal tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If multiple fibers with different wavelength bands are used to achieve color imaging, then color information can be obtained, but the probe diameter increases and system complexity increases
Solution Approach 1:
The probe is segmented into multiple functional components: a single broadband fiber for illumination, multiple gratings for spectral dispersion, and multiple detection waveguides for collecting different wavelength bands. This segmentation allows color imaging functionality while maintaining a compact single-fiber probe structure.
Solution Approach 2:
The patent transitions from temporal multiplexing (sequential wavelength scanning) to spatial multiplexing (simultaneous spectral dispersion). By using gratings to disperse light spatially into different wavelength bands that can be collected by multiple detection waveguides, the system achieves color imaging in a single measurement without temporal sequencing.
2Area of stationary object
If the field of view is increased by diffracting light at larger angles, then more area can be imaged, but crosstalk increases when collecting light
Solution Approach 1:
The detection system is segmented into multiple dedicated waveguides, each responsible for collecting a specific wavelength band from a specific angular range. This segmentation allows the system to handle large diffraction angles without crosstalk, as each waveguide is optimized for its specific function.
Solution Approach 2:
Each detection waveguide is optimized with specific properties (numerical aperture, core diameter, positioning) tailored to its specific function of collecting light from a particular angular range and wavelength band. This local optimization minimizes crosstalk while maximizing the overall field of view.
3Device complexity
If a single mode fiber is used to maintain narrow probe diameter, then probe size is reduced, but multiple fibers are needed for color imaging in conventional systems
Solution Approach 1:
Gratings act as intermediary elements that convert the broadband light from a single fiber into spatially separated wavelength bands. These dispersed bands are then collected by multiple detection waveguides, enabling color imaging functionality while maintaining a single-fiber illumination path.
Solution Approach 2:
The patent replaces the mechanical/physical separation of multiple illumination fibers with an optical manipulation system using gratings and waveguides. This substitution allows color imaging to be achieved through optical field manipulation rather than through multiple physical fibers.
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 allows for the creation of color images by correlating reflected lights from different gratings, reducing crosstalk and simplifying the probe design, while maintaining a narrow diameter and increasing the field of view.
Implementation Method 1
uses a broadband light source, a rotating grating and a spectroscopic detector to encode spatial information on a sample. When illuminating light to the sample, the light is spectrally dispersed along one illumination line
Implementation Method 2
one or more detection waveguides configured to receive a first reflected light and a second reflected light reflected by a sample
Data Source
AI summary
The present disclosure provides apparatuses and methods for color imaging and an increased field of view using spectrally encoded endoscopy techniques. At least one of the apparatuses includes an illumination unit having two or more spectrally dispersive gratings positioned, for example, on different planes or on the same plane but having grating vectors at an angle to each other such that bands of spectrally dispersed light propagating from the gratings propagate on different planes.