Microstructured Spectacle Lenses via CNC Turning
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Solution Overview
Problem
The high production costs and sensitivity of diffractive microstructures in spectacle lenses make their integration into the manufacturing process challenging, particularly when combined with mechanical processing that can damage or contaminate these structures, necessitating protective measures during machining and polishing steps.
Innovation Solution
A method where a diffractive microstructure is directly formed on the lens blank's surface during material removal processes like milling or turning, eliminating the need for separate polishing steps and allowing for the integration of refractive and diffractive effects in a single surface, thereby simplifying the production of individually manufactured spectacle lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If diffractive microstructures are produced on a lens surface before mechanical processing, then the optical effect is achieved, but the microstructure is damaged or contaminated by subsequent machining operations
Solution Approach 1:
The diffractive microstructure is produced as a final step after all mechanical processing operations are completed. This preliminary action sequencing ensures the microstructure is not exposed to damaging machining operations, while still achieving the desired optical effect in the finished lens.
Solution Approach 2:
The production process is segmented into distinct phases: mechanical processing phases (milling, turning, grinding) followed by a separate microstructure production phase. This segmentation isolates the fragile microstructure creation from the harsh mechanical processing environment.
2Manufacturing precision
If traditional mechanical processing steps (milling, turning, grinding, polishing) are used to produce prescription lens surfaces, then the desired surface geometry is achieved, but the production time and complexity increase
Solution Approach 1:
The production of prescription lens surfaces and diffractive microstructures is merged into a single integrated process step. The microstructure is produced directly on the prescription lens surface during the final processing operation, eliminating the need for separate polishing steps and reducing overall production time.
Solution Approach 2:
The time-consuming polishing step is extracted and eliminated from the traditional multi-step process. By producing the microstructure directly during material removal operations, the separate polishing operation becomes unnecessary, significantly reducing production time.
3Manufacturing precision
If diffractive microstructures are produced on lens surfaces, then chromatic errors are reduced, but production costs increase due to complex machining requirements
Solution Approach 1:
The existing material removal tools and processes used for prescription surface production are made to serve the dual purpose of creating both the prescription geometry and the diffractive microstructure. This self-service approach eliminates the need for specialized expensive machining equipment, thereby reducing production costs.
Solution Approach 2:
The machining process is given multi-functionality: it simultaneously produces the prescription lens surface geometry and the diffractive microstructure pattern. This universal approach allows a single process to achieve multiple objectives, avoiding the need for separate specialized processing 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
This approach reduces production complexity and costs by eliminating the need for time-consuming polishing and potentially grinding steps, ensuring sufficient surface quality for optical performance while integrating diffractive microstructures effectively, thus enhancing the manufacturing efficiency of spectacle lenses with diffractive effects.
Implementation Method 1
a diffractive microstructure is directly formed on the lens blank's surface during material removal processes like milling or turning
Data Source
Figure 1
Figure 2A~2B
AI summary
The invention relates to a method for providing spectacle lenses (10) that have a microstructure (18) on at least one side. A procedure is described, in which the structure is introduced into a face of the lens after the processing of said face of the lens. Said method offers the advantage, in comparison to other methods, that processing steps used to achieve the necessary optical quality of the corresponding surface can be omitted. The microstructuring of the back face of a spectacle lens by CNC-controlled turning after a first shaping processing is mentioned as a concrete embodiment, wherein the polishing step is omitted.