Continuous 3D Printing of Intraocular Lenses with Variable Aperture
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Solution Overview
Problem
Current SLA 3D printing systems are limited by pixel resolution and stepper motor incremental layer steps, resulting in 'stair-stepped' surface finishes that are unsuitable for producing intraocular lenses (IOLs) with smooth, curved surfaces.
Innovation Solution
A continuous additive fabrication system using a light source assembly with a motorized variable aperture and a drive mechanism for continuous movement of the curing plane through a photopolymer resin bath, allowing for smooth, continuously curved surfaces by adjusting the aperture size and shape in synchronization with the movement of the curing plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current SLA 3D printing systems use pixel-based image projection and stepper motor incremental layer steps, then the manufacturing process can be implemented with standard components, but the surface finish becomes stair-stepped rather than smooth
Solution Approach 1:
The patent replaces the mechanical stepper motor system with a continuous motion system. Instead of using discrete incremental steps to move the build plate, the system employs continuous motion control to move the build plate through the photopolymer resin, eliminating the stair-stepped surface finish caused by discrete layer deposition.
Solution Approach 2:
The patent introduces dynamic control of the aperture size during the printing process. The aperture is continuously adjusted in size and shape during curing to maintain a consistent focal spot size on the build plate, enabling smooth surface finishes while using continuous motion rather than discrete steps.
2Measurement precision
If pixel-based image projection is used to create complex shapes, then adaptability is improved, but resolution is limited by pixel size
Solution Approach 1:
The patent replaces the pixel-based image projection system with a direct digital light processing approach. Instead of projecting images through discrete pixels, the system uses a digital micromirror device or similar technology to directly control light delivery, achieving higher lateral resolution independent of pixel size limitations.
Solution Approach 2:
The patent transitions from two-dimensional pixel-based projection to three-dimensional continuous light control. By using a focusable light source with variable aperture, the system can precisely control the focal spot in three dimensions, achieving high resolution while maintaining the ability to create complex three-dimensional shapes.
3Manufacturing precision
If fixed incremental layer steps are used for curing, then the manufacturing process is simplified, but smooth curved surfaces cannot be achieved
Solution Approach 1:
The patent implements continuous curing action by moving the build plate continuously through the photopolymer resin rather than in discrete steps. The aperture size is continuously adjusted during this motion to maintain consistent focal spot dimensions, enabling the creation of smooth curved surfaces through uninterrupted material deposition.
Solution Approach 2:
The patent dynamically changes the aperture parameters (size and shape) during the printing process. By continuously adjusting the aperture while the build plate moves, the system maintains a consistent focal spot size on the build plate, enabling smooth curved surfaces without requiring fixed incremental layer steps.
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 system enables the generation of smooth, high-resolution, optical-quality surfaces suitable for IOLs, overcoming the limitations of conventional SLA 3D printing systems by producing parts with continuous curvature rather than stair-stepped surfaces.
Implementation Method 1
Stereolithography (SLA) is a type of 3D printing process that produces layers of a solid part by curing liquid materials using photopolymerization. This is a process by which a vat of liquid polymer is exposed to light, causing chains of molecules to link together and form polymers that comprise one layer of a three-dimensional solid object.
Data Source
AI summary
A continuous additive fabrication system comprises a bath of photopolymer resin and a light source assembly having a light source and a motorized variable aperture. The light source assembly is operable to generate a focus point in the bath of photopolymer resin, the shape of the focus point at a curing plane within the bath of photopolymer resin corresponding to the shape of the motorized variable aperture. The continuous additive fabrication system further comprises a platform configured to support a build object and a drive mechanism (coupled to at least one of the platform and the light source assembly) configured to continuously move the curing plane through the bath of photopolymer resin. A size and/or shape of the motorized variable aperture is changed while the curing plane in continuously moved through the bath of photopolymer resin.