Optical Position Sensor for Miniaturized Endoscopic Systems
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Solution Overview
Problem
Conventional position sensors, such as incremental encoders, free beam arrangements, capacitive, and piezoresistive sensors, are not suitable for miniaturized systems like endoscopic applications due to their large size, limited accuracy, and interference from drive voltages, making it difficult to determine the deflection state of small mechanical components like microscanner mirrors.
Innovation Solution
A position sensor using optical fibers to guide and detect electromagnetic radiation, with at least two back channels arranged to receive a predefined portion of the radiation reflected by the mechanical component, allowing for accurate determination of deflection states without the need for electronic circuits near the component and decoupling from drive voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If incremental encoders are used for position sensing, then measurement precision is improved, but device size increases making it unsuitable for miniaturized systems
Solution Approach 1:
The patent replaces mechanical incremental encoders with an optical sensing system using a laser beam and photodetectors. This substitution eliminates the need for mechanical scales and complex mechanical structures, achieving miniaturization while maintaining position sensing capability through optical measurement of the mechanical component's deflection state.
Solution Approach 2:
The optical sensing components (laser source, photodetectors, optical elements) are integrated into a compact arrangement where the mechanical component itself serves as part of the sensing structure. The photodetectors are positioned to receive reflected laser beams in a confined space, nesting multiple functional elements within a minimal volume suitable for miniaturized systems.
2Measurement precision
If free beam arrangements with laser diodes and photodiodes are used, then position sensing capability is achieved, but building space requirement increases
Solution Approach 1:
The patent merges the mechanical component with the optical sensing system by using the mechanical component's surface as the reflection target and positioning photodetectors to directly receive reflected beams. This integration eliminates separate sensing assemblies and reduces the overall building space required for the position sensing function.
Solution Approach 2:
The patent transitions from discrete three-dimensional spatial arrangement of optical components to a two-dimensional planar configuration where photodetectors are positioned in a plane to receive reflected beams. This dimensional reorganization allows for more compact packaging and reduced building space while maintaining sensing functionality.
3Device complexity
If trigger diodes are used as detectors in free beam arrangements, then device complexity is reduced, but measurement capability is limited to time-discrete measurements preventing statistical deflection determination
Solution Approach 1:
The patent changes the detection parameter from simple presence/absence detection (trigger diodes) to intensity-based detection (photodetectors). This parameter change enables continuous measurement of reflected beam intensity, which provides information about the mechanical component's deflection state and allows for statistical analysis of deflections while maintaining relatively simple device architecture.
4Volume of moving object
If capacitive position sensors are used, then device size is reduced, but measurement precision deteriorates and drive voltage separation becomes difficult
Solution Approach 1:
The patent replaces capacitive sensing with optical sensing using laser beams and photodetectors. This substitution eliminates the need for capacitive structures and their associated electronic circuits, achieving miniaturization without compromising measurement precision. The optical method also naturally separates measurement signals from drive voltages since it uses electromagnetic radiation rather than electrical fields.
5Measurement precision
If piezoresistive methods are used, then position sensing is achieved in microsystem technology, but drive voltage separation becomes difficult affecting measurement resolution
Solution Approach 1:
The patent replaces piezoresistive electrical sensing with optical sensing using laser beams and photodetectors. This substitution eliminates the interference between drive voltages and measurement signals by using optical rather than electrical measurement principles. The laser beam reflects off the mechanical component without being affected by electrical fields, achieving high measurement resolution free from drive voltage interference.
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 provides a compact, accurate, and galvanically decoupled position sensor capable of determining continuous and static movements, suitable for miniaturized systems like endoscopic applications, with improved temporal resolution and reduced interference from drive signals.
Implementation Method 1
at least one channel which is implemented to guide electromagnetic radiation and direct the same to the component
Implementation Method 2
at least two back channels which are implemented to receive electromagnetic radiation reflected by the component and direct the same to the detector
Data Source
AI summary
A position sensor for detecting a position of a movably arranged component with respect to its original position including a channel which is implemented to guide electromagnetic radiation and direct the same to the component, a detector, at least two back channels which are implemented to receive the electromagnetic radiation reflected by the device and direct the same to the detector, wherein the channel and the at least two back channels are arranged with respect to each other such that the at least two back channels each receive a predefined portion of the electromagnetic radiation reflected by the component.