Rigid Fluid-Permeable Blocking Piece for Lens Blank Vacuum Fixation
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Solution Overview
Problem
Conventional methods for blocking lens blanks, such as using metallic alloys or polymeric materials, face environmental disadvantages, mechanical deformations, and high energy consumption, while alternative vacuum-based methods often result in undesired deformations due to inhomogeneous pressure distribution.
Innovation Solution
A blocking piece featuring a rigid fluid-permeable material with a blank contacting element and a support element that applies a vacuum across the entire upper surface to securely hold the lens blank, eliminating the need for metallic alloys and reducing energy consumption by avoiding heating and cooling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic alloy is used for blocking lens blanks, then the lens blank can be securely fixed to the blocking piece, but environmental disadvantages and high energy consumption for heating and cooling processes occur
Solution Approach 1:
The patent replaces the thermal-mechanical blocking system (heating/cooling metallic alloy) with a pure mechanical vacuum system. The vacuum blocking piece uses atmospheric pressure differential to hold the lens blank, eliminating the need for thermal energy input and output cycles while maintaining secure fixation.
Solution Approach 2:
The invention employs vacuum (pneumatic principle) to create the blocking force. By creating a pressure differential between the atmospheric pressure on the lens blank's outer surface and the reduced pressure inside the vacuum chamber, the lens blank is firmly held without requiring metallic alloys and associated thermal processing.
2Reliability
If conventional vacuum blocking with recesses is used, then the lens blank can be held by vacuum, but undesired deformations occur due to inhomogeneous pressure distribution
Solution Approach 1:
The patent creates a homogeneous pressure distribution across the entire lens blank surface by using a flat blocking surface without recesses. The vacuum is applied uniformly across the whole lens area, ensuring even pressure distribution that prevents local deformations while maintaining secure holding.
Solution Approach 2:
The invention eliminates the segmented recess structure and instead uses a continuous, uniform vacuum field acting across the entire lens blank surface. This uniform approach distributes the holding force evenly, preventing the deformations that occur with localized recess-based vacuum systems.
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 provides a stable, deformation-free blocking method that improves environmental compatibility, reduces costs, and enhances the precision of lens blanks by ensuring homogeneous pressure distribution, thus maintaining the integrity of the lens shape during processing.
Implementation Method 1
applying a vacuum within the blocking piece to provide a suction through essentially the entire upper surface of the blank contacting element to suck the lens blank to the upper surface
Data Source
AI summary
A blocking piece for vacuum blocking a lens blank is disclosed. The blocking piece includes a blank contacting element formed of a rigid fluid-permeable material having an upper surface for contacting the lens blank. The blocking piece further includes a support element having an upper part tightly enclosing the blank contacting element on a peripheral surface of the blank contacting element and a lower part adapted to engage with a clamping device for clamping the blocking piece. The lens blank is fixed to the upper surface of the blank contacting element by applying a vacuum within the blocking piece to provide suction through essentially the entire upper surface of the blank contacting element. The disclosure further relates to a method for blocking a lens blank and a use of an element formed of a rigid fluid-permeable material as a part of a blocking piece.