Optical Surfacing Tool with Taut Membrane for Concave Lenses
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Solution Overview
Problem
Existing optical surfacing tools often suffer from appearance defects such as the 'orange skin' and 'sheeplike' effects, particularly when working with concave surfaces, which are difficult to avoid despite improvements in tool design.
Innovation Solution
An optical grade surfacing tool featuring a rigid support with an elastically compressible interface and a flexible pad attached to an elastically stretchy membrane with radial straps that maintain tension and surround the interface, ensuring consistent contact with surfaces of varying altitudes, including concave surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a flexible pad with larger diameter than the interface is used, then surface appearance quality is improved, but the tool complexity increases and not all appearance defects are eliminated
Solution Approach 1:
The patent employs a flexible membrane structure that covers the interface and extends beyond its periphery. This membrane is tensioned by radial straps to maintain uniform tension across its surface, enabling the pad to conform to concave optical surfaces while eliminating appearance defects such as orange skin and sheeplike effects without increasing overall tool complexity
Solution Approach 2:
The membrane is divided into multiple radial straps that radiate from the periphery of the interface toward its center. These straps are independently tensioned and attached to the rigid support, allowing the membrane to adapt to surface curvature variations while maintaining uniform tension distribution across the entire working surface
2Adaptability or versatility
If the pad diameter is increased beyond the interface periphery, then contact with concave surfaces is improved, but the device complexity increases
Solution Approach 1:
The flexible membrane extends beyond the interface periphery and is tensioned by radial straps to maintain uniform tension. This enables the pad to conform to concave optical surfaces, improving adaptability while the membrane-strap system itself represents a controlled increase in device complexity that is justified by the performance improvement
Solution Approach 2:
The membrane and strap system is designed to be dynamically adaptable to different surface curvatures. The radial straps can be adjusted or selected in different configurations to optimize the membrane's ability to conform to various concave surface geometries, enhancing versatility without requiring a completely different tool design for each application
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
The tool achieves high-quality surfacing with reduced appearance defects by maintaining contact and distributing pressure uniformly, even on surfaces with significant curvature variations, such as those for corrective eyeglass lenses.
Implementation Method 1
an elastically compressible interface attached to the rigid support, including a central part that is in line with to said end surface of the rigid support and a peripheral part that is transversely beyond said end surface of the rigid support
Implementation Method 2
said pad is carried by an elastically stretchy membrane, said membrane including: a central plateau having a first transverse end surface to which said pad is stuck and a second transverse end surface pressed against and covering said second transverse end surface of said interface; and a plurality of straps each projecting radially from the periphery of said plateau and each having a distal part interengaged with an attachment means situated in line with the first end surface of the interface, each of said straps passing around said lateral surface of the interface and then extending as far as said attachment means, each strap being taut
Implementation Method 3
The optical surface is generally driven in rotation, friction between it and the tool being sufficient to entrain the tool so that it rotates with it
Data Source
AI summary
An optical-grade surfacing tool includes: a rigid holder (60); an elastically compressible interface (12) secured to the rigid holder (60); and a flexible pad (13) that can be applied against a surface to be machined (71) and secured to the interface (12) opposite the rigid holder (60). The pad (13) is carried by an elastically extensible membrane (14) including: a central plate (15); and a plurality of straps (18) each radially protruding from the periphery of the plate (15) and each having a distal portion engaged with a fastening element (38), each strap (18) rotating about the side surface (28) of the interface (12) and extending up to the fastening element, each strap (18) being taut.