Refractive Microstructures on Spectacle Lenses via Additive Manufacturing
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Solution Overview
Problem
Current methods for creating refractive microstructures on spectacle lenses to slow down or stop myopia progression face challenges with standard additive manufacturing equipment, as they struggle to achieve the required power and stability, particularly with high powers and material limitations in molding and casting processes.
Innovation Solution
A method using additive manufacturing to form refractive microstructures on spectacle lenses by applying curable materials in layers, controlling coalescing and curing to achieve desired refractive powers, and utilizing refractive index gradients for flat topographies, allowing for the production of lenses with appropriate power using commercially available printers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If molding or casting processes are used to create refractive microstructures, then the lenses can be produced with lenslets, but the material selection is restricted (molding only works with thermoplastics) and the process becomes difficult with prefabricated lens blanks
Solution Approach 1:
The patent replaces traditional mechanical molding or casting processes with an additive manufacturing process that uses a jetting system to deposit curable material droplets. This substitution allows the use of prefabricated lens blanks and expands material selection beyond thermoplastics to include various curable materials, resolving both the ease of manufacture and material versatility issues.
2Ease of manufacture
If standard additive manufacturing equipment is used to create refractive microstructures, then commercially available printers can be utilized, but the equipment struggles to achieve the required power and stability for high power lenses
Solution Approach 1:
The patent changes key parameters of the additive manufacturing process: using jetting technology to deposit material in precise droplet patterns, controlling droplet spacing and volume, and implementing a two-pass process with different droplet densities. These parameter changes enable standard equipment to achieve the required refractive power precision by optimizing how material is deposited and cured, rather than requiring specialized high-precision equipment.
3Manufacturing precision
If lenslets are molded or cast onto prefabricated lens blanks, then the lenslets can be created on finished lenses, but the location optimization for central vision is lost
Solution Approach 1:
The patent applies preliminary action by depositing a base layer of curable material across the entire lens surface before jetting the refractive microstructure-forming droplets. This preliminary base layer creation establishes a uniform foundation that enables precise positioning of lenslets in optimal locations for central vision, while the additive nature of the process keeps manufacturing relatively simple compared to traditional molding methods.
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 the creation of spectacle lenses with refractive microstructures that effectively slow down or stop myopia progression, achieving the desired refractive power while ensuring long-term stability and adhesion of subsequent layers, using standard additive manufacturing equipment.
Implementation Method 1
The curable material is jetted as liquid or viscous material onto the surface of the spectacle lens and then cured by exposure to UV light
Implementation Method 2
The lenslets or annular structures provide a power which leads to a peripheral myopic defocus outside the field of central vision
Data Source
AI summary
A method of providing refractive microstructures on a surface of a spectacle lens body by an additive manufacturing process is provided, in which the refractive microstructures are formed by applying and curing a curable material. The process includes forming a layer of a first liquid or viscous curable material and an additional amount of the first curable material or an amount of a second liquid or viscous curable material at locations at which the refractive microstructures shall be formed before curing or pinning the at least one first curable material. Protrusions formed by the additional first curable material or the second curable material are levelled out by material transport processes within the liquid or viscous material in the layer of the at least one curable material. In addition, a spectacle lens with refractive microstructures is provided.