Mold Set with Dual Spacers for Optical Element Press Molding
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Solution Overview
Problem
In press molding of optical elements like glass, friction-generated shearing forces hinder smooth shrinkage and mold release due to uneven thermal expansion coefficients between the mold and the glass, leading to incomplete release and manufacturing inefficiencies.
Innovation Solution
A mold set with a high expansion ring and a low expansion ring, where the high expansion ring secures the interval during pressurization and the low expansion ring secures it during cooling, allowing for controlled shrinkage and smooth mold release by managing thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional mold set with a single spacer is used during press molding, then the mold structure is simple, but the optical element cannot release smoothly from the mold due to friction and thermal expansion differences
Solution Approach 1:
The single spacer is divided into two separate spacers: a first spacer that maintains the mold interval during pressurization at high temperature, and a second spacer that maintains the interval during cooling at low temperature. This segmentation allows each spacer to be optimized for its specific temperature condition, enabling smooth mold release while managing thermal expansion differences.
Solution Approach 2:
The patent uses spacers made of materials with different thermal expansion coefficients to match the thermal characteristics of the optical material at different temperatures. The first spacer has thermal expansion properties suitable for high-temperature pressurization, while the second spacer has properties suitable for low-temperature cooling, allowing the mold interval to be properly maintained throughout the temperature transition.
2Manufacturing precision
If the mold interval is fixed for both pressurization and cooling stages, then the mold structure is simple, but the optical element thickness precision deteriorates due to uneven shrinkage
Solution Approach 1:
The mold interval control is segmented into two distinct stages using two separate spacers. The first spacer controls the interval during pressurization when the optical material is hot and pliable, while the second spacer controls the interval during cooling when the material shrinks. This allows precise control of the optical element thickness at each stage, preventing deformation and ensuring dimensional accuracy.
Solution Approach 2:
The mold set dynamically adapts the interval-maintaining component based on temperature conditions. During pressurization, the first spacer is active; during cooling, the second spacer becomes active. This dynamic switching allows the mold to properly accommodate the thermal shrinkage of the optical material while maintaining precise thickness control.
3Stability of the object's composition
If cooling is performed without proper interval management, then the process is simple, but the optical element deforms due to uneven shrinkage and friction
Solution Approach 1:
The cooling process is supported by segmented interval management using two spacers. The first spacer maintains the mold interval during the transition from pressurization to cooling, while the second spacer maintains the interval throughout the cooling process. This prevents uneven shrinkage and deformation of the optical element by ensuring consistent mold spacing during the critical cooling phase.
Solution Approach 2:
The first spacer performs a preliminary action by maintaining the mold interval during the transition from pressurization to cooling, preparing the mold set for the subsequent cooling phase. This preliminary interval management prevents deformation before cooling begins, and the second spacer continues this function throughout cooling, ensuring the optical element maintains its shape.
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
Enables smooth release of optical elements from the mold by adjusting the pressurization and cooling stages, reducing manufacturing complexity and improving the precision of optical element thickness and release timing.
Implementation Method 1
the first spacer has a higher linear expansion coefficient than the second spacer
Data Source
AI summary
A mold set includes: a first mold and a second mold placed so that they sandwich an optical material and face each other; and a first spacer and a second spacer provided between the first and second molds, wherein: the first spacer secures an interval between the first and second molds at a first temperature achieved in a process of pressurizing the optical material; the first spacer shrinks in a mold opening-closing direction more greatly than the second spacer while the first temperature is changing to a second temperature achieved in a process of cooling the optical material; and the second spacer secures the interval between the first and second molds at the second temperature.