Dual-Polarization Optical Filter for Additive Manufacturing Sensing
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Solution Overview
Problem
Additive manufacturing systems face impaired sensing and control due to spurious light emissions and mixed light signal polarizations, leading to reduced fidelity of optical signals.
Innovation Solution
A dual polarization optical filter system is employed, comprising a first and second partially transmissive polarized filter with rotationally offset polarization axes, allowing specific transmittance levels for optical signals not aligned with the polarization axes to improve signal fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single polarized filter is used to block spurious light, then light signal polarization filtering is improved, but signal transmittance is reduced
Solution Approach 1:
The optical filter is segmented into multiple polarization filters (first and second polarized filters) with different polarization axes. Each filter segment handles specific polarization components of the light signal, allowing selective blocking of spurious light while preserving useful optical signals through the segmented filtering path.
Solution Approach 2:
The polarization filters are configured to be partially transmissive rather than completely blocking. The transmittance is optimized to allow sufficient useful light to pass through while blocking harmful spurious light, avoiding excessive attenuation of the useful signal.
2Measurement precision
If polarization filtering is increased to improve signal fidelity, then measurement precision is improved, but signal intensity is reduced
Solution Approach 1:
The optical filter employs a composite structure of multiple polarization filters with different orientations. This composite filtering approach achieves superior polarization selectivity and signal fidelity while maintaining adequate light intensity through the coordinated action of multiple filter elements.
Solution Approach 2:
The polarization axes of the filters are specifically oriented at different angles (e.g., 0 degrees and 45 degrees) to optimize the balance between filtering effectiveness and signal transmission. This parameter optimization ensures high measurement precision without excessive signal attenuation.
3Reliability
If multiple polarized filters are used to enhance filtering, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
Multiple polarization filters are merged into a single integrated optical filter assembly. The filters are arranged in sequence within a compact structure, combining the filtering functions of multiple elements into one unified component that achieves high signal-to-noise ratio without proportionally increasing system complexity.
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 dual polarization optical filter significantly enhances the signal-to-noise ratio (SNR) of optical sensors, enabling more accurate sensing and control of the additive manufacturing process, and allowing for the detection of micron-size defects.
Implementation Method 1
a first partially transmissive polarized filter having a first polarization axis and a second partially transmissive polarized filter having a second polarization axis
Implementation Method 2
a first partially transmissive polarized filter having a first polarization axis and a second partially transmissive polarized filter having a second polarization axis
Data Source
AI summary
An additive manufacturing system comprises a build plane and an energy source configured to direct energy onto a work region of the build plane. An optical detector is configured to receive one or more optical signals from the work region. An optical filter is positioned between the work region and the optical detector, wherein the optical filter includes a first partially transmissive polarized filter having a first polarization axis and a second partially transmissive polarized filter having a second polarization axis. The first polarization axis is rotationally offset from the second polarization axis approximately 90 degrees. The optical filter improves the signal to noise ratio of the optical sensors.