Ophthalmic Lens Thickness Optimization for 3D-Printed Optical Elements
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Solution Overview
Problem
Existing methods for manufacturing ophthalmic lenses with complementary optical elements using additive manufacturing are time-consuming, prone to weaknesses due to multiple interfaces, and can result in haze, yellow transmission, and visible discontinuities, making it difficult to achieve thin lenses with accurate thickness optimization, especially for myopia or hyperopia.
Innovation Solution
A method involving determining and optimizing the thickness of the complementary optical element by varying the distance between characterizing surfaces to reach a threshold, minimizing layers and material volume while ensuring the optical function, using additive manufacturing techniques like polymer jetting and stereolithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additive manufacturing is used to create the complementary optical element, then the optical function can be customized and added onto the starting optical system, but the manufacturing time increases due to the deposition of multiple predetermined volumes of material
Solution Approach 1:
The optical element is divided into a starting optical system and a complementary optical element that can be manufactured separately using additive manufacturing, then assembled together. This allows the complementary element to be optimized for additive manufacturing while the starting system provides the base structure.
Solution Approach 2:
The patent optimizes the geometric parameters of the complementary optical element, specifically the thickness and volume of material deposited, to minimize the number of layers required while maintaining the necessary optical function. This reduces manufacturing time by decreasing the number of deposition iterations.
2Reliability
If multiple layers of material are deposited to form the complementary optical element, then the optical function can be achieved, but the number of interfaces increases leading to weaknesses and delamination risks
Solution Approach 1:
The patent employs a thin film approach by optimizing the complementary optical element to achieve the required optical function with minimal material thickness. This reduces the number of layers and interfaces, thereby minimizing delamination risks while maintaining optical performance.
Solution Approach 2:
The complementary optical element is designed to integrate seamlessly with the starting optical system, merging the two components into a unified structure. This reduces the number of interfaces and potential delamination points while maintaining the customized optical function.
3Length of stationary object
If the ophthalmic lens is made thinner, then the aesthetic and optical performance improves, but the starting optical system becomes difficult to manufacture with accurate surfaces and stable shape
Solution Approach 1:
The lens system is segmented into a starting optical system and a complementary optical element. The starting system can be manufactured with standard thickness and conventional manufacturing methods, ensuring surface accuracy and shape stability, while the complementary element adds the necessary optical function with minimal additional thickness.
Solution Approach 2:
The patent optimizes the parameters of the complementary optical element, particularly its thickness and curvature, to achieve the desired overall lens thickness reduction while maintaining manufacturing precision of the starting system. The complementary element compensates for thickness variations without compromising surface accuracy.
4Ease of manufacture
If material for additive manufacturing is used, then the complementary optical element can be formed, but haze and yellow transmission occur due to ultraviolet absorbers
Solution Approach 1:
The patent extracts the problematic material properties from the additive manufacturing process by selecting materials with reduced UV absorption and lower haze characteristics. This allows additive manufacturing to be used while minimizing the harmful optical effects of the deposited material.
Solution Approach 2:
The patent employs composite material strategies by combining the additive-manufactured complementary optical element with the starting optical system made of optically clear material. This composite structure compensates for the optical imperfections of the additive-manufactured portion while maintaining overall optical quality.
5Device complexity
If the complementary optical element does not cover the entire surface of the starting optical system, then the manufacturing complexity is reduced, but visible discontinuities occur due to differences in transmission and reflection properties
Solution Approach 1:
The patent applies local quality by designing the complementary optical element to cover only the specific regions where optical correction is needed, rather than the entire surface. The optical properties are optimized locally to match the starting system in the covered regions, minimizing visible discontinuities while reducing manufacturing complexity.
Solution Approach 2:
The patent optimizes the geometric and optical parameters of the complementary optical element, including its thickness, curvature, and material properties, to match the transmission and reflection characteristics of the starting optical system. This parameter optimization reduces visible discontinuities at the boundaries while maintaining manufacturing simplicity.
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 reduces manufacturing time, minimizes interfaces and discontinuities, maintains optical quality, and ensures accurate thickness optimization, thereby enhancing the durability and clarity of the ophthalmic lenses.
Implementation Method 1
the complementary optical element is formed by the deposition of a plurality of predetermined volumes of material. Particularly, the complementary optical element is generated by adding thin layers of material one on top of the other
Data Source
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AI summary
The invention concerns a method of determining at least one parameter of an ophthalmic lens (40) comprising a complementary optical element (12) obtained by additive manufacturing and configured to provide at least a part of the optical function of the ophthalmic lens, the determining method comprising: - a step of providing two characterizing surfaces simulating two opposite surfaces of a complementary optical element (12), the distance between the two characterizing surfaces along a thickness axis (Z) defining the thickness of the complementary optical element, - a step of optimizing the distance between the two characterizing surfaces (20) along the thickness axis (Z) so that the thickness of the complementary optical element reaches a thickness threshold while complying with the optical function of the ophthalmic lens (40), and - a step of determining at least one parameter of the ophthalmic lens (40) on the basis of said optimized distance.