Angled Fiber Facets for Scanned Beam Imaging Sensitivity
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Solution Overview
Problem
Scanned beam imagers experience reduced detection sensitivity at wide angles and edges of the field of view due to cosn falloff of illumination and lack of detection sensitivity, particularly in systems using resonant mirrors with sinusoidal angular deflecting movement.
Innovation Solution
A scanning beam assembly featuring a beam generator, beam director, and multi-mode optical fibers with angled end surfaces and diffusive coatings to broaden sensitivity and increase numerical aperture, allowing fibers to face different directions and areas within the field of view, enhancing light collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical fibers with flat end surfaces are used, then the system structure is simple, but detection sensitivity is reduced at wide angles and edges of the field of view
Solution Approach 1:
The patent applies local quality by creating different regions on the fiber bundle end surface with different orientations. The end surface is divided into multiple facets, each facing a different direction, allowing light from different angular regions of the field of view to be collected efficiently. This resolves the contradiction by making the fiber structure non-uniform at the local level (faceted surface) to improve detection sensitivity at wide angles while maintaining overall system simplicity.
2Measurement precision
If the numerical aperture of optical fibers is increased, then light collection efficiency improves, but the acceptance angle becomes too narrow to cover wide field of view angles
Solution Approach 1:
The patent applies dimensionality change by transitioning from a single-orientation fiber end surface to a multi-faceted three-dimensional surface structure. Each facet is oriented at different angles to capture light from different directions in the field of view. This resolves the contradiction by adding angular dimensionality to the light collection capability, allowing the system to maintain high numerical aperture while covering a wide angular range through the faceted geometry.
3Productivity
If resonant mirrors with sinusoidal angular deflecting movement are used, then the scanning mechanism is simple, but cosn falloff of illumination reduces detection sensitivity at field of view edges
Solution Approach 1:
The patent converts the harmful cosn falloff effect into a benefit by orienting fiber facets to specifically capture light at wide angles where the falloff occurs. The faceted end surface structure is designed so that facets at different orientations compensate for the angular-dependent illumination falloff, transforming the scanning mirror's sinusoidal motion characteristic from a source of sensitivity loss into an opportunity for enhanced wide-angle light collection.
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
The solution significantly improves light collection and detection sensitivity across the entire field of view, particularly at wide angles and edges, by increasing the acceptance cone and numerical aperture of the optical fibers, leading to enhanced imaging performance.
Implementation Method 1
diffusive coatings to broaden sensitivity and increase numerical aperture
Implementation Method 2
multi-mode optical fibers for receiving radiation scattered from the field of view
Data Source
AI summary
A scanning beam assembly includes a beam generator to generate a beam of radiation; at least one reflector configured to deflect the beam across a field of view; and a plurality of multi-mode optical fibers for receiving radiation reflected from the field of view, wherein the optical fibers have end surfaces that face in at least two different directions, or wherein the optical fibers are configured to receive scattered radiation from an angular field of view larger than that determined by their individual numerical apertures.