Optical Element Manufacturing Pressure Release Control
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Solution Overview
Problem
Conventional methods for manufacturing optical elements face challenges in demolding, leading to reduced surface accuracy and increased risk of cracking or breaking due to inadequate pressure control during the cooling process.
Innovation Solution
A method involving heating an optical material to a transition point, pressurizing it using opposing molds, and controlling the release of pressure at specific speeds to facilitate elastic deformation over viscous deformation, allowing for precise demolding and maintaining surface accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure is continuously applied and reduced during cooling, then cracking and breaking are prevented, but surface accuracy is reduced upon demolding
Solution Approach 1:
The cooling process is divided into two distinct stages: first cooling to a second temperature (higher than strain point) while maintaining pressure, then second cooling to a third temperature (lower than second temperature) after pressure release. This segmentation allows different pressure conditions for different cooling phases, preventing both cracking and surface accuracy loss.
Solution Approach 2:
The optical material is pre-cooled to a second temperature (above strain point) before pressure release, ensuring it reaches a state where elastic deformation can occur preferentially. This preliminary cooling action prepares the material to withstand pressure release without cracking while maintaining surface accuracy during final cooling.
2Reliability
If pressure is released quickly, then elastic deformation occurs preferentially preventing cracking, but demolding control becomes difficult
Solution Approach 1:
The patent uses pre-calculated set speeds for pressure release based on the optical material's properties and molding conditions. The control system monitors the pressure release speed and adjusts it to maintain the preferred elastic deformation regime, providing feedback control that prevents cracking while ensuring predictable demolding behavior.
3Ease of operation
If pressure is released slowly, then viscous deformation occurs preferentially allowing better demolding control, but cracking risk increases
Solution Approach 1:
The patent changes the temperature parameter during the cooling process to control the deformation mode. By cooling to a second temperature above the strain point before pressure release, the material's viscoelastic properties are adjusted so that elastic deformation occurs preferentially during pressure release, preventing cracking while maintaining demolding control.
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 approach enhances demolding success rates and maintains surface accuracy by controlling the release of pressure to manage elastic strain, preventing unintentional demolding and reducing the risk of cracking.
Implementation Method 1
releasing the predetermined load at a set speed that is higher than or equal to a speed obtained in advance, at which an elastic deformation occurs preferentially over a viscous deformation in the optical material upon releasing a load
Implementation Method 2
releasing the predetermined load at a set speed that is lower than or equal to a speed obtained in advance, at which a viscous deformation occurs preferentially over an elastic deformation in the optical material upon releasing a load
Implementation Method 3
heating an optical material up to a first temperature that is higher than a transition point
Implementation Method 4
first cooling the optical material down to a second temperature that is higher than a strain point and lower than the first temperature while pressurizing the optical material with a predetermined load
Implementation Method 5
second cooling the optical material down to a third temperature that is lower than the second temperature
Data Source
AI summary
A method for manufacturing an optical element includes heating an optical material up to a first temperature that is higher than a transition point, pressurizing the optical material using a first mold and a second mold that are situated opposite to each other across the optical material, first cooling the optical material down to a second temperature that is higher than a strain point and lower than the first temperature while pressurizing the optical material with a predetermined load using the first mold and the second mold, releasing the predetermined load at a set speed that is higher than or equal to a speed obtained in advance, at which an elastic deformation occurs preferentially over a viscous deformation in the optical material upon releasing a load, and second cooling the optical material down to a third temperature that is lower than the second temperature.