Optical Lens Mold with Segmented Thermal Inserts
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Solution Overview
Problem
The fabrication of lenses with microstructures via injection molding faces challenges due to the difficulty in achieving a mold insert with a microstructured surface, particularly with glass inserts, which are prone to defects like weld lines and center distortion, and the need for a high thermal conductivity mold insert to produce lenses with good optics and reduced defects.
Innovation Solution
A mold device and method utilizing a first mold insert with inverted microstructures of high thermal conductivity (5 to 1,500 W·m−1·K−1) and a second mold insert with low thermal conductivity (0.01 to 2 W·m−1·K−1), where the first insert is made of metal and the second of glass, to minimize defects by controlling the thermal conductivity and injection parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass mold insert is used to prevent weld line and center distortion defects, then defect occurrence is reduced, but the ability to fabricate microstructures on the lens surface deteriorates
Solution Approach 1:
The mold is divided into two separate inserts: a glass insert (second mold insert) for the surface that contacts the lens to prevent defects, and a metal insert (first mold insert) for the opposing surface that can be easily microstructured. This segmentation allows each material to perform its optimal function without compromise.
Solution Approach 2:
The mold system uses a composite construction with two different materials (glass and metal) each serving specific functions. The glass insert provides low thermal conductivity for defect prevention, while the metal insert provides high thermal conductivity and ease of microstructure fabrication.
2Manufacturing precision
If a metal mold insert with high thermal conductivity is used to facilitate microstructure replication, then microstructure replication quality is improved, but weld line and center distortion defects increase
Solution Approach 1:
The mold is divided into two separate inserts: a glass insert (second mold insert) for the surface that contacts the lens to prevent defects, and a metal insert (first mold insert) for the opposing surface that can be easily microstructured. This segmentation allows each material to perform its optimal function without compromise.
Solution Approach 2:
Different regions of the mold have different thermal conductivity properties tailored to their specific functions. The glass insert region provides low thermal conductivity where defect prevention is critical, while the metal insert region provides high thermal conductivity where microstructure replication is critical.
3Reliability
If a glass mold insert is used to preserve heat and heal weld line defects, then weld line healing is improved, but the ability to prevent center distortion deteriorates
Solution Approach 1:
The mold is divided into two separate inserts: a glass insert (second mold insert) for the surface that contacts the lens to prevent defects, and a metal insert (first mold insert) for the opposing surface that can be easily microstructured. This segmentation allows each material to perform its optimal function without compromise.
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
The solution effectively reduces the occurrence of weld line and center distortion defects, enabling precise replication of microstructures and producing lenses with improved optics by optimizing the thermal conductivity and injection molding parameters.
Implementation Method 1
a thermal conductivity of the first mold insert is 5 to 1,500 W·m−1·K−1 at 25° C.
Implementation Method 2
a thermal conductivity of the second mold insert is 0.01 to 2 W·m−1·K−1 at 25° C.
Data Source
AI summary
A mold device includes a mold including a first mold side and a second mold side having a lower thermal conductivity than the first mold side, the first mold side including a first mold insert disposed on a surface of the first mold side, the first mold insert including a plurality of inverted microstructures formed thereon, the plurality of inverted microstructures disposed according to a predetermined layout, wherein a thermal conductivity of the first mold side is 5 to 1,500 W·m−1·K−1 at 25° C., and a thermal conductivity of the second mold side is 0.01 to 2 W·m−1·K−1 at 25° C.