Inclined Receiving Surface for Spectacle Lens Blocking
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Solution Overview
Problem
Current methods for blocking spectacle lens blanks often result in deformation due to heat-induced shrinkage of blocking materials, incomplete support during processing, and the use of toxic heavy metals, leading to optical and cosmetic defects, especially in non-round lenses.
Innovation Solution
A device with a receiving component having a convex or concave receiving surface and an inclined mating surface, allowing full surface contact and reduced mass of blocking material, which is easily removable and supports the lens blank over its entire surface, minimizing shrinkage distortions and using low-rigidity materials to avoid heavy metal fumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lens blank is blocked using conventional methods with liquid-to-solid phase transition materials, then the blocking material provides sufficient support during processing, but the heat-induced shrinkage and phase transition cause deformation and optical defects
Solution Approach 1:
The patent changes the physical state parameter of the blocking material from liquid-to-solid phase transition to elastomeric solid state. The elastomeric material remains in a consistent solid state during processing, eliminating heat-induced shrinkage and phase transition deformations while maintaining support stability through its viscoelastic properties
Solution Approach 2:
The patent explicitly avoids phase transitions by using elastomeric materials that remain in a stable solid state throughout the blocking and processing operations, thereby eliminating the harmful effects of phase transition-induced deformation on optical accuracy
2Stability of the object's composition
If the lens blank is blocked with high-rigidity materials to prevent deformation, then structural stability is improved, but toxic heavy metal fumes are generated during machining
Solution Approach 1:
The patent changes the material composition parameter from high-rigidity materials containing heavy metals to elastomeric materials with lower rigidity but sufficient structural stability. The elastomeric materials provide adequate support during machining without generating toxic heavy metal fumes
Solution Approach 2:
The patent employs disposable elastomeric blocking materials that are inexpensive and environmentally friendly, replacing expensive and hazardous high-rigidity materials. These elastomeric materials can be discarded after use without causing environmental contamination from heavy metals
3Manufacturing precision
If the lens blank is blocked with reduced mass of blocking material to minimize shrinkage, then shrinkage distortion is reduced, but support coverage during processing is insufficient
Solution Approach 1:
The patent changes the mechanical property parameter of the blocking material from rigid to elastomeric, enabling the material to provide adequate support coverage with reduced mass. The elastomeric material's ability to conform and distribute pressure allows sufficient support with less material, thereby minimizing shrinkage distortion while maintaining reliability
4Manufacturing precision
If the lens blank is prismatically blocked to avoid high dynamic demands on the machine, then machining accuracy is improved, but the blocking process becomes more complex
Solution Approach 1:
The patent changes the material property parameter to elastomeric, which allows the blocking process to accommodate prismatic lenses without requiring complex prismatic blocking procedures. The elastomeric material's flexibility enables it to adapt to various lens geometries, simplifying the blocking process while maintaining machining accuracy
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 solution enables precise prismatic blocking with reduced distortions and cosmetic defects, supporting the lens blank fully during processing and reducing the need for high-rigidity materials, while minimizing the use of toxic heavy metals.
Implementation Method 1
the receiving surface is designed such that the spectacle lens blank can be placed substantially over its entire surface on the receiving surface when blocking
Implementation Method 2
the essentially wedge-shaped gap is filled with liquid wax, plastic, UV-curing plastic, or a low-melting-point metal alloy (e.g., Alloy) as the block material and cooled until solidified or cured by UV light
Implementation Method 3
liquid wax, plastic, UV-curing plastic, or a low-melting-point metal alloy (e.g., Alloy) as the block material and cooled until solidified or cured by UV light
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A device for blocking a spectacle lens blank (15) which has a finished surface (16) and, opposite said finished surface (16), a machining surface for machining in a machining device, comprises a receiving component (9) having a convex, plane or concave receiving surface (13) for blocking the finished surface (16) of the spectacle lens blank (15). The receiving component (9) has a substantially flat counter-surface (10) on the side opposite the receiving surface (13). The normal (11) of said counter-surface (10) is inclined by 1° to 10° with respect to the normal (14) in the center of the receiving surface (13).