Optical Angle Sensor with Refractive Structure
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Solution Overview
Problem
Existing angle sensors face challenges in precision, magnetic interference, energy supply fluctuations, and miniaturization, particularly in applications like aerospace where static measurements and immunity to magnetic influences are required.
Innovation Solution
An optical angle sensor with a rotary element and refractive structure, where the beam path through the refractive structure changes based on the angle of rotation, allowing for static measurements without a reference point and immunity to magnetic influences, using a refractive structure with a different index than the rotary element material, and incorporating redundancy and compensation for light intensity fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic sensors are used for angle measurement, then measurement capability is provided, but the system becomes sensitive to external magnetic influences and requires reference point movement
Solution Approach 1:
The patent replaces magnetic field-based sensing with an optical measurement system. A light source emits light through a rotating element with refractive structures (such as radial slots or patterns) to a photodetector. The optical path changes with rotation angle, enabling angle measurement without magnetic fields, thus eliminating sensitivity to external magnetic influences while maintaining measurement precision.
2Reliability
If multiple sensors are employed to compensate for power supply fluctuations, then measurement reliability improves, but device complexity and space requirements increase
Solution Approach 1:
The optical system inherently provides stability against power supply fluctuations through its measurement principle. The photodetector measures the intensity of light transmitted through the rotating element, and since the light source and detector remain stationary relative to each other, fluctuations in power supply affect both the emitted and detected light equally, canceling out in the measurement ratio. This self-compensating mechanism achieves reliability without requiring multiple sensors or complex compensation circuits.
3Measurement precision
If encoder discs or magnetic sensors are used, then angle detection is enabled, but the system design becomes complex and miniaturization is hindered
Solution Approach 1:
The patent integrates the light source, rotating element with refractive structures, and photodetector into a compact assembly. The rotating element serves multiple functions: it is the mechanical component whose angle is measured, the optical element that modulates light based on rotation, and the reference structure for measurement. This merging of functions into a single integrated optical unit enables precise angle detection while significantly reducing the overall system volume and facilitating miniaturization.
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
Enables precise, magnetic-field-independent, and miniaturized angle measurements, suitable for applications like satellite engine control, with continuous measurement ranges and reduced complexity.
Implementation Method 1
at least one refractive structure is provided in the rotating element having a second refractive index n2, wherein n2 ≠ n1... in order to refract and thus influence the light depending on the specific rotation angle
Data Source
Figure 1~2b
Figure 3a~3b
Figure 4~5a
AI summary
The invention relates to a sensor for determining an angle of rotation (Θ) about an axis of rotation (2), the sensor (1) comprising a rotary element (4) which is mounted in a base element (3) so as to be rotatable about the axis of rotation (2) and is produced from a first material having a first index of refraction n1, wherein a light generation means (5a, 5b, 5c) is provided which is fixedly arranged relative to the base element (3) and a light detection means (6a, 6b, 6c) is provided which is fixedly arranged relative to the base element (3), in order to detect a light signal emitted by the light generation means (5a, 5b, 5c) and passing through the rotary element (4) along a beam path (8a, 8b, 8c). According to the invention, in the rotary element (4) a refraction structure (9a, 9b, 9c) is provided which has a second index of refraction n2, wherein n2 ≠ n1 and wherein the beam path (8a, 8b, 8c) extends at least in a first angle of rotation range through the refraction structure (9a, 9b, 9c), in order to be able to assign a specific angle of rotation (Θ) to the light signal detected by the light detection means (6a, 6b, 6c) at least in the first angle of rotation range.