Ophthalmic Lens Point Map Curvature Smoothing for Digital Surfacing
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Solution Overview
Problem
Digital surfacing machines face limitations in producing customized ophthalmic lenses due to physical constraints such as cutting tool diameter, rotational speed, and movement speed, which can result in abrupt curvature changes that are difficult to machine, leading to errors in lens production.
Innovation Solution
A laboratory lens processing system adjusts point map files to smooth out surface curvatures based on the physical characteristics of the digital surfacing machine, ensuring that the specified lens design can be accurately manufactured by modifying the curvature to match the machine's capabilities, using data from databases and feedback to optimize the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If digital surfacing machines use standard cutting tools with fixed diameter and speed parameters, then the manufacturing process is simple and fast, but the machine cannot accurately produce lenses with complex or abrupt curvature changes
Solution Approach 1:
The system performs preliminary smoothing of the point map file before manufacturing. The curvature smoothing module pre-processes the lens design data to reduce abrupt curvature changes, ensuring the surfacing machine can accurately reproduce the intended surface without encountering machining difficulties during the actual manufacturing process.
Solution Approach 2:
The system modifies the parameters of the point map file by adjusting curvature values to match the physical capabilities of the surfacing machine. The curvature smoothing module transforms the original design parameters into modified parameters that are within the machine's manufacturable range, balancing precision requirements with machine limitations.
2Reliability
If the lens design includes abrupt curvature changes to meet patient prescription requirements, then the lens functionality is optimized, but the surfacing machine cannot accurately machine these regions due to physical constraints
Solution Approach 1:
The system changes the curvature parameters in the point map file to reduce abrupt transitions. The curvature smoothing module adjusts the numerical values representing surface curvature, transforming difficult-to-machine abrupt changes into gradual transitions that the surfacing machine can reliably reproduce within its physical constraints.
Solution Approach 2:
The system applies preliminary anti-action by pre-smoothing the curvature profile to prevent machining errors before they occur. By reducing abrupt curvature changes in advance, the system counteracts the potential negative effects of the surfacing machine's physical limitations, ensuring reliable manufacturing without requiring post-processing corrections.
3Manufacturing precision
If the point map file is modified to smooth out curvatures, then the lens can be manufactured with fewer errors, but the original lens design precision may be compromised
Solution Approach 1:
The system carefully modifies curvature parameters within acceptable tolerances. The curvature smoothing module adjusts the point map file parameters to be slightly different from the original design but still within the range that maintains optical functionality, achieving a balance between manufacturability and design precision.
Solution Approach 2:
The system uses feedback from the surfacing machine's actual capabilities to guide the smoothing process. By considering the machine's physical constraints and performance characteristics, the curvature smoothing module makes adjustments that maintain the essential design requirements while ensuring the modified curvatures can be accurately reproduced by the specific manufacturing equipment.
Data Source
AI summary
A system that can analyze and modify a point map file corresponding to a lens design is described. The lens design is optimized to meet a patient's ophthalmic prescription. However, a digital surfacing machine may not be physically capable of producing on a lens blank a lens curvature required by the prescription and defined by the point map file. The system takes into account limitations of physical characteristics of the digital surfacing machine, such as the diameter and speed of movement of the cutting tool, and modifies the point map file so that the digital surfacing machine can produce the lens curvature on the lens blank.