Progressive Lens Polishing with Tilted Orientation for Even Removal
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Solution Overview
Problem
Existing polishing methods for progressive surfaces of lenses result in inhomogeneous material removal and longer processing times, leading to reduced optical quality and increased shape errors due to varying curvature and pressure distribution issues.
Innovation Solution
A method and system that tilts the lens about a tilt axis perpendicular to its central symmetry axis, ensuring the near and distance portion edge zones are at the same height, allowing for improved pressure distribution and reduced polishing time by up to 50%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing methods are used with the lens in standard orientation, then the polishing process can be performed with simple setup, but the pressure distribution on the lens surface becomes inhomogeneous leading to inhomogeneous material removal
Solution Approach 1:
The patent applies asymmetry by tilting the lens at a specific angle (alpha) relative to the polishing tool rotation axis. This asymmetric positioning compensates for the inherent asymmetry in progressive lens curvature, where the distance portion has different curvature than the near portion. By introducing this controlled asymmetric tilt, the patent achieves more uniform pressure distribution across the entire lens surface during polishing, directly resolving the homogeneity problem while accepting increased positioning complexity as a necessary trade-off.
Solution Approach 2:
The patent introduces a new dimensional parameter - the tilt angle (alpha) - to the traditional polishing setup. Instead of only adjusting radial and axial positions, the lens is tilted around an axis perpendicular to both the rotation axis and the optical axis. This additional degree of freedom allows independent control of pressure distribution across different zones of the progressive lens, enabling homogeneous material removal that was not achievable with conventional two-dimensional positioning.
2Manufacturing precision
If the lens is tilted to achieve homogeneous pressure distribution, then material removal becomes more uniform, but the polishing setup and操作流程 become more complex
Solution Approach 1:
The patent implements preliminary action by pre-calculating and pre-setting the optimal tilt angle (alpha) based on the specific progressive lens parameters (addition power, base curve, diameter). This calculation is performed before the polishing operation, and the lens is positioned at this predetermined angle. By doing the computational work in advance and setting a fixed optimal position, the patent achieves uniform surface finishing while minimizing the complexity during actual operation, as the operator only needs to position the lens at the pre-determined angle rather than continuously adjust it.
3Productivity
If conventional polishing orientation is used, then the processing setup is simpler, but the polishing time increases due to need for longer processing to compensate for low pressure areas
Solution Approach 1:
The patent applies asymmetry by tilting the lens at a specific angle (alpha) relative to the polishing tool rotation axis. This asymmetric positioning compensates for the inherent asymmetry in progressive lens curvature, where the distance portion has different curvature than the near portion. By introducing this controlled asymmetric tilt, the patent achieves more uniform pressure distribution across the entire lens surface during polishing, directly resolving the homogeneity problem while accepting increased positioning complexity as a necessary trade-off.
Solution Approach 2:
The patent implements preliminary action by pre-calculating and pre-setting the optimal tilt angle (alpha) based on the specific progressive lens parameters (addition power, base curve, diameter). This calculation is performed before the polishing operation, and the lens is positioned at this predetermined angle. By doing the computational work in advance and setting a fixed optimal position, the patent achieves uniform surface finishing while minimizing the complexity during actual operation, as the operator only needs to position the lens at the pre-determined angle rather than continuously adjust it.
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
Enhances even material removal and reduces polishing time, improving optical quality and efficiency, enabling the production of progressive surfaces of lenses, especially those with higher addition power, by ensuring the near and distance zones are arranged at the same height, allowing for improved pressure distribution and reduced polishing time by up to 50%.
Implementation Method 1
mechanical polishing of optical lenses... the optical surface of the lens is brought together with a polishing tool and subjected to a defined pressure
Implementation Method 2
An intermediate layer is arranged on the active surface of the base. A polishing agent carrier is arranged on the elastic intermediate layer... the tool surface adapts to every part of the lens surface during the polishing process
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3
AI summary
The present invention relates to a method (100, 120) for polishing a progressive surface (12) of a lens (10), wherein the method (100, 120) comprises the following steps: holding (102), by a workpiece holder (42), the lens (10) in a first orientation (80); and polishing (104), by a polishing tool (52), the progressive surface (12) of the lens (10) while the lens (10) is held by the workpiece holder (42) in the first orientation (80), wherein, in the first orientation (80), the lens (10) is tilted about a tilt axis (82) by a tilt angle (α), wherein the tilt axis (82) is perpendicular to a central symmetry axis (70), in particular wherein the progressive surface (12) comprises a near portion edge zone (28) and a distance portion edge zone (26), wherein, in the first orientation (80), the lens (10) is tilted in such a way that the near portion edge zone (28) and the distance portion edge zone (26) are substantially at the same height in a direction parallel to the central symmetry axis (70). Further, the present invention relates to a system (40) for polishing a progressive surface (12) of a lens (10).