3D-Printed Optical Elements With Skin-Core Curing Control
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Solution Overview
Problem
Additive manufacturing technologies in ophthalmic lens production often result in optical defects due to layer interfaces and non-uniform hardening, leading to diffraction issues.
Innovation Solution
A method involving multiple curing steps with varying surface energies is applied, where the outer layer (skin) is cured faster than the inner layer (core) to ensure stability and geometry preservation, using a curing surface energy distribution that creates a thin, hardened skin to anchor the core layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the material is fully cured before depositing the overlapping layer, then the mechanical strength is sufficient, but optical defects and diffraction occur at layer interfaces
Solution Approach 1:
The patent applies preliminary partial curing to the first layer before depositing the second layer. The curing unit irradiates the first layer with energy below the threshold required for complete curing, creating a semi-cured state that maintains both mechanical strength and material fluidity. This preliminary action allows subsequent layers to mix with the previous layer, eliminating interface defects while maintaining structural integrity.
2Object-generated harmful factors
If the material is not fully cured to allow layer mixing, then optical defects are reduced, but the geometry and shape of layers become unstable
Solution Approach 1:
The patent applies different curing energies to different regions of the material. The curing unit irradiates with energy below the complete curing threshold, creating a semi-cured state that maintains both material fluidity for mixing and sufficient structural support for geometry stability. This local quality control allows the material to exhibit both fluid and solid properties simultaneously.
3Ease of manufacture
If uniform curing energy is applied, then the manufacturing process is simple, but diffraction defects occur due to non-uniform hardening points
Solution Approach 1:
The patent changes the curing energy parameter by applying energy below the complete curing threshold. This parameter modification ensures uniform curing across all layers, preventing the formation of diffraction defects caused by non-uniform hardening. The consistent sub-threshold energy application creates homogeneous material properties throughout the optical element.
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 allowing the layers to reorganize and mix, maintaining the desired geometry even under mechanical stress, resulting in high-quality optical elements.
Implementation Method 1
a curing unit (2) suitable for irradiating the surface (55) of the curable material (50) with a curing surface energy E
Data Source
Figure 1~2
Figure 3A~5C
Figure 6A~9
AI summary
A method and a device for the production of an optical element (100) from a curable material by using an additive manufacturing technology. This method comprises a multiplicity of curing steps for curing said curable material inside outlines (C1) whose geometry are determined according to the geometry of said optical element, by applying a curing surface energy onto the curable material that is higher in a first area (A1) that extends sensibly along said sliced outline than in a second area (A2) situated within the first area, the curing surface energy applied to the second area being strictly lower than a first predetermined energy threshold.