In-Mold Decoration for Reflective Polymer Optical Elements
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Solution Overview
Problem
Injection molded polymer optics require expensive processes to be made reflective or coated, doubling their cost, making them less viable as a cost-effective alternative to glass optics in optical applications like barcode scanning.
Innovation Solution
The method involves using in-mold decoration techniques to transfer a reflective coating from a preform sheet to a molded optical element during the injection molding process, utilizing a carrier material like polycarbonate resin with a silver or reflective coating, which adheres to the plastic injection material, reducing the need for additional coating applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If injection molded polymer optics are made reflective using conventional coating processes, then the optical element achieves reflective properties, but the production cost doubles
Solution Approach 1:
The patent combines the molding process and coating application into a single integrated operation. The preform sheet with coating is positioned in the mold cavity before injection, allowing the coating to transfer to the optical element during molding. This eliminates the need for separate coating equipment and processes, thereby reducing production cost while achieving reflective properties.
Solution Approach 2:
The coating is applied to the preform sheet in advance before the molding process. This preliminary coating application allows the coating material to be ready for transfer during injection molding, eliminating the need for post-molding coating operations and reducing overall production cost.
2Reliability
If conventional coating processes are used on molded optics, then the optical element achieves the desired coating, but the process complexity and expense increase significantly
Solution Approach 1:
The patent merges the coating application step with the injection molding process by using a preform sheet that transfers its coating during molding. This integration eliminates multiple separate processes (molding, then separate coating), reducing process complexity while maintaining coating quality through controlled transfer conditions.
3Reliability
If separate coating processes are applied after molding, then the optical element can be coated, but production time and cost double
Solution Approach 1:
The coating is pre-applied to the preform sheet before molding. During the injection molding process, the coating transfers to the optical element, combining two operations (coating and molding) into one. This eliminates the need for post-molding coating steps, thereby improving production efficiency and reducing overall production time.
Solution Approach 2:
The coating transfer occurs continuously during the injection molding process rather than as a separate discrete step. The coating material transfers as the molten polymer contacts the preform sheet, maintaining continuous production flow and improving productivity by eliminating idle time between molding and coating operations.
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 allows for the cost-effective production of coated optical elements with optical quality reflective surfaces, reducing production costs and maintaining the lower cost advantage of polymer optics while meeting optical quality standards.
Implementation Method 1
During the molding process, coating material 14 adheres to the injection material
Data Source
AI summary
A method of producing a coated optical element which uses in-mold decoration (IMG) techniques. The method includes injection molding an element adjacent a coating of a preform sheet, whereby the coating transfers to the element to create the optical element.