Polarization-Dependent Position Encoder Absorption Encoding
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Solution Overview
Problem
Existing contactless encoders face challenges in accurately measuring position in dusty and smoky industrial environments due to sensitivity to dust and dirt, and traditional polarizers are prone to noise from external reflections, compromising measurement accuracy.
Innovation Solution
A polarization-dependent encoder with a layered structure comprising a metal plate, dielectric layer, and metallic components forming resonant circuits that absorb polarized waveforms, encoding position through absorption rather than reflection, thereby reducing dependency on incidental reflections and enhancing mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional polarizers are used to encode position through reflection, then position encoding is achieved, but noise from external reflections compromises measurement accuracy
Solution Approach 1:
The patent inverts the traditional approach by using absorption instead of reflection for position encoding. The polarizer is designed to absorb polarized waveforms at specific orientations, creating dark regions in the captured image that encode position information, thereby eliminating noise from external reflections that plague reflection-based systems
Solution Approach 2:
The patent converts the harmful effect of dust and dirt scattering light into a beneficial feature by using absorption-based encoding. Since absorbed light does not scatter back, the system becomes inherently more resistant to environmental noise from dust and dirt particles that are common in industrial settings
2Measurement precision
If wire grating film polarizers are used, then position encoding is achieved, but additional reflection from substrate and objects behind corrupts the reflected signal
Solution Approach 1:
The patent extracts and eliminates the problematic substrate reflection component by using absorption-based encoding. The polarizer absorbs light at specific orientations without requiring the light to reflect back, thereby removing the harmful reflections from the substrate and objects behind that corrupt signals in reflection-based systems
3Measurement precision
If encoders are designed for high frequency position sensing, then resolution is improved, but sensitivity to dust and dirt scattering increases
Solution Approach 1:
The patent converts the harmful scattering effect into a beneficial feature by using absorption-based encoding. Since absorbed light does not scatter back, the system becomes inherently more resistant to environmental noise from dust and dirt particles, allowing high frequency position sensing with improved resolution while maintaining robustness in dusty industrial environments
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 achieves improved position sensing accuracy and mechanical stability by encoding position in the absorption of polarized waveforms, offering better resolution and resistance to environmental noise compared to traditional encoders.
Implementation Method 1
a portion of the layered structure including the metallic component forms a resonant circuit that absorbs at least a portion of the waveform of the resonant frequency
Implementation Method 2
The barcode is designed such that different parts of the barcode respond differently to the polarized incident waveform. For example, the barcode can reflect or absorb the emitted signal to encode in the reflected signal the position of the emitter
Data Source
AI summary
An encoder includes a layered structure including a metal plate, a dielectric layer arranged on the metal plate, and a plurality of metallic components arranged on the dielectric layer to form a pattern of resonant circuits. The encoder includes an emitter to emit a waveform of a resonant frequency to the layered structure and a receiver to measure amplitudes of the waveform reflected from the layered structure. The processor operatively connected to a memory storing data relating positions of the emitter with amplitudes of the reflected waveform determines a position of the emitter from the measurements of the amplitudes based on the data. The encoder includes an output interface to render the position of the emitter.