Optical Element Manufacturing File for Differential Voxel Curing
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Solution Overview
Problem
Additive manufacturing technologies for ophthalmic lenses often result in optical defects due to layer interfaces and pixelation patterns, leading to diffraction issues, as the material hardens unevenly and at different times across layers, affecting the optical properties and usability of the lenses.
Innovation Solution
A method that involves creating a manufacturing file with kinetic parameters to control the curing pace of the material, allowing for differential curing steps and energy distribution across voxels, ensuring the skin of the lens hardens faster than the core and reducing optical defects by allowing layers to mix and homogenize their properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If additive manufacturing is used to produce optical elements layer-by-layer, then the manufacturing flexibility and prototype capability are improved, but optical defects and diffraction issues occur due to layer interfaces and uneven material hardening
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-distributing curing energy across multiple future layers before the manufacturing process begins. The system computes the complete energy distribution map in advance, accounting for how light will propagate through and cure material in subsequent layers, thereby preventing optical defects before they occur during manufacturing.
Solution Approach 2:
The patent implements feedback by using the computed curing state of previously cured layers to adjust and optimize the energy distribution for current and future layers. The system continuously monitors the cumulative energy received by each voxel and uses this information to prevent over-curing or under-curing, ensuring optimal optical quality throughout the manufacturing process.
2Productivity
If the curable material is cured quickly to improve productivity, then the manufacturing speed increases, but optical defects increase due to uneven hardening and layer separation
Solution Approach 1:
The patent applies periodic action by dividing the curing process into controlled intervals across multiple layers. Instead of continuous curing, the system applies energy in periodic pulses corresponding to each layer deposition, with each pulse carefully calibrated to achieve partial curing that allows subsequent layers to interpenetrate and homogenize while maintaining overall manufacturing speed.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the curing energy parameters (intensity, duration, distribution) based on the depth and position of each voxel. The system varies these parameters to optimize the balance between manufacturing speed and optical quality, applying higher energy to surface layers for rapid solidification while using lower energy for deeper layers to maintain homogeneity.
3Strength
If the skin of the lens is cured faster than the core, then the structural integrity and shape stability are improved, but internal stress and potential cracking may occur
Solution Approach 1:
The patent applies local quality by differentiating the curing energy distribution between different regions of the optical element. Surface voxels (skin) receive higher curing energy to achieve rapid solidification and shape stability, while core voxels receive lower, more gradual energy to prevent excessive internal stress. This spatially varying energy distribution ensures both structural integrity and reliability.
Solution Approach 2:
The patent implements beforehand cushioning by pre-computing the stress distribution and energy accumulation throughout the manufacturing process. The system anticipates potential stress concentration points and adjusts the energy distribution in advance to cushion against excessive stress buildup, preventing cracking and maintaining reliability while still achieving rapid surface curing.
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 minimizes optical defects by ensuring the skin of the lens is rigid quickly while allowing the core to fully interpenetrate with subsequent layers, enhancing the optical quality and usability of the lenses by reducing diffraction issues and mechanical stress vulnerabilities.
Implementation Method 1
An example of additive manufacturing technology consists in using a container (or vat) full of liquid curable material and in curing the material layer by layer
Data Source
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AI summary
The invention relates to a method for outputting a manufacturing file for producing an optical element (100) from a curable material (50) by using an additive manufacturing technology, comprising the steps of: - acquiring the desired geometry of the optical element, - obtaining a discretization of the desired geometry in volume units described by data relative to position parameters of the volume units and to the dimension of the volume units, - associating at least a volume unit with a kinetic parameter that relates to the curing pace imposed to the curable material of the volume unit, - producing, using at least one processor, a manufacturing file comprising said data and said kinetic parameter for manufacturing at least the optical element, and - outputting said manufacturing file.