Resin Optical Prism Molding With Welds Outside Optical Surfaces
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Solution Overview
Problem
Existing methods for manufacturing optical resin prisms face challenges in achieving rapid heat dissipation and uniform temperature distribution, leading to strain and refractive-index distribution, which deteriorate the optical properties of the prism, while also increasing manufacturing costs and cycle times due to complex mold configurations.
Innovation Solution
The method involves two-stage injection molding, where a first molded portion is cooled and then used as a core for the second molded portion, with the molten resin injected through a gate to form a weld outside the optical surface areas, minimizing temperature distribution and strain by controlling resin flow and weld formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resin is cooled and solidified in a conventional mold, then the manufacturing process is simple and fast, but a temperature distribution is produced in the resin leading to internal strain and refractive-index distribution
Solution Approach 1:
The mold cavity is divided into a core portion and a cladding portion, with each having different thermal conductivity properties. The core portion has lower thermal conductivity to maintain temperature and reduce strain, while the cladding portion has higher thermal conductivity for efficient heat dissipation. This segmentation allows simultaneous achievement of optical quality and manufacturing efficiency.
2Manufacturing precision
If the core portion is designed to generate heat and delay cooling, then the temperature distribution is reduced and internal strain is minimized, but the molding cycle time increases significantly
Solution Approach 1:
Different portions of the mold cavity are assigned different thermal conductivity properties according to their specific functions. The core portion uses material with lower thermal conductivity to minimize strain in critical areas, while the cladding portion uses material with higher thermal conductivity to enable rapid heat dissipation and reduce overall cycle time. This local differentiation resolves the contradiction between strain reduction and productivity.
3Manufacturing precision
If the core portion is made with lower thermal conductivity than the cladding portion, then temperature distribution and internal strain are reduced, but the mold structure becomes more complex
Solution Approach 1:
The mold cavity is constructed as a composite structure with the core portion made of a material having lower thermal conductivity and the cladding portion made of a material having higher thermal conductivity. This composite material approach allows the mold to exhibit different thermal properties in different regions, achieving uniform temperature distribution and reduced internal strain without requiring complex mechanical structures or active heating/cooling 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 approach reduces internal strain and maintains excellent optical properties by ensuring welds are formed outside the optical surface areas, thereby improving manufacturing efficiency and reducing costs without compromising optical performance.
Implementation Method 1
The space (cavity) is filled with molten resin, and then the molten resin is cooled and solidified for obtaining the resin prism
Data Source
AI summary
An optical element made of resin includes a first surface configured to serve as an optical surface, a second surface configured to serve as an optical surface, a third surface configured to serve as an optical surface, and a fourth surface configured to connect to the third surface. The third surface includes a peripheral area and an inner area, and a distance from an outer edge of the third surface to a position in the peripheral area is equal to or smaller than 5 mm and a distance from the outer edge of the third surface to a position in the inner area is larger than 5 mm. A weld is formed in at least any one of the peripheral area of the third surface and the fourth surface.