Gradient Dielectric Inkjet Printing via Spectral Polymerization Control
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Solution Overview
Problem
Current inkjet printing methods for manufacturing dielectric elements, such as optics, face limitations in creating complex dielectric properties and freeform surface curvatures without precise control over the curing process, particularly in achieving volumetric nanoparticle concentration gradients.
Innovation Solution
The method involves using inkjet printable complex-dielectric-inks with different photoinitiators having distinct wavelength selective photo-polymerization absorption bands, allowing for spectrally discrete exposure to control the polymerization of layers, resulting in a volumetric nanoparticle concentration gradient, and incorporating a radical reaction inhibitor to manage the curing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single photoinitiator system is used for curing all layers, then the curing process is simple, but precise control over polymerization of different layers is lost
Solution Approach 1:
The patent divides the curing process into segments by using multiple photoinitiators (first photoinitiator for UV curing, second photoinitiator for visible light curing) that can be selectively activated by different wavelength ranges. This allows independent control over polymerization of different layers or regions, enabling precise manufacturing control without requiring a single complex curing system.
Solution Approach 2:
The patent changes the parameter of photoinitiator absorption characteristics by selecting photoinitiators with different absorption spectra (one absorbing UV, another absorbing visible light). This parameter change enables selective curing of specific layers containing specific photoinitiators, achieving precise control over the polymerization process while maintaining relative simplicity in the curing mechanism.
2Manufacturing precision
If nanoparticle concentration is uniform throughout the dielectric element, then the ink formulation is simple, but the ability to create gradient refractive index optics is limited
Solution Approach 1:
The patent applies local quality by varying the nanoparticle concentration in different spatial regions of the dielectric element. By controlling the deposition process to create volumetric nanoparticle concentration gradients, the patent enables creation of gradient refractive index optics where different regions have different optical properties, directly achieving the desired local variation in refractive index.
Solution Approach 2:
The patent uses composite materials by combining dielectric material with dispersed nanoparticles to create nanocomposite inks. The varying nanoparticle concentrations in different regions create composite structures with spatially varying effective refractive indices, enabling gradient optics while using relatively simple inkjet deposition processes.
3Manufacturing precision
If layer perimeter border and infill are cured simultaneously, then the curing process is fast, but control over structural formation is reduced
Solution Approach 1:
The patent applies preliminary action by curing the layer perimeter border first to establish the structural framework and boundaries, then subsequently curing the infill area. This sequential approach ensures proper structural formation and boundary definition while maintaining acceptable curing speeds through efficient use of the photoinitiator system.
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
This approach enables precise control over the manufacturing of gradient refractive index optics with spatially varying properties, allowing for the creation of complex dielectric structures with controlled curing, enhancing the precision and uniformity of the dielectric elements.
Implementation Method 1
A curing mechanism, typically ultraviolet or infrared optical sources, cures the deposited droplets
Implementation Method 2
different wavelength selective photo-polymerization absorption bands such that spectrally discrete exposure results in different degrees of polymerization
Data Source
AI summary
A method of inkjet printing a gradient dielectric element in a deposition and photo-polymerization process. The method comprises: providing a plurality of complex-dielectric-inks that are inkjet printable including a nanocomposite-ink with an organic-matrix and a nanoparticle filler dispersed within. The plurality of complex-dielectric-inks have a first complex-dielectric-ink having a first photoinitiator and a second complex-dielectric-ink with a second photoinitiator. The first and second complex-dielectric-ink have different wavelength selective photo-polymerization absorption bands such that spectrally discrete exposure results in different degrees of polymerization of the first and second complex-dielectric-ink. The method further comprises providing an optical source to polymerize the complex-dielectric-inks, depositing droplets of the plurality of complex-dielectric-ink and curing the plurality of complex-dielectric-inks, wherein deposition of the plurality of layers result in a volumetric nanoparticle concentration gradient.