Conformal Shielding via Embedded Stencil Walls
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Solution Overview
Problem
Conventional conformal shielding methods for surface mounted circuit devices on printed circuit boards are time-consuming and require multiple processes, including repeated cleanings and baking, due to the need for large surface areas and precise placement of metal frames or etching of shielding walls.
Innovation Solution
A print mold stencil with embedded electrically conductive shielding walls is used, allowing for quick positioning and encapsulation of circuit components with molding material, reducing the need for extensive surface area and simplifying the shielding process by embedding shielding walls within the stencil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conformal shielding methods using metal frames or etched trenches are used, then electromagnetic interference shielding is achieved, but the process becomes time-consuming and requires multiple repeated cleanings and baking steps
Solution Approach 1:
The patent combines the shielding wall formation and molding material application into a single integrated stencil structure. The stencil simultaneously provides the shielding walls through its side walls and the molding cavity through its bottom surface, eliminating the need for separate etching and molding steps. This merging of functions directly reduces production time while maintaining shielding efficacy.
Solution Approach 2:
The shielding walls are pre-formed as integral parts of the stencil structure before the molding process begins. By preparing the shielding structure in advance as part of the mold, the patent eliminates the need for time-consuming post-processing steps such as laser etching and multiple cleaning cycles, thereby reducing overall production time while ensuring proper shielding.
2Reliability
If metal frames are used for conformal shielding with large tolerances in placement accuracy, then a relatively large surface area on the PCB is required, but this increases the device footprint
Solution Approach 1:
The patent uses a thin stencil structure that can be precisely positioned and removed after molding. The stencil's thin film nature allows for accurate placement without requiring large tolerance margins, enabling compact shielding structures that minimize PCB surface area while maintaining effective electromagnetic shielding through the conformal molding process.
3Reliability
If laser etching and conductive gel application are used to form shielding walls, then the process involves many repeated cleanings and baking steps, but this increases manufacturing complexity
Solution Approach 1:
The patent extracts the shielding wall formation process from the traditional multi-step sequence of laser etching, gel application, cleaning, and baking. Instead, the shielding walls are directly formed as integral structures of the stencil itself, eliminating the need for separate wall formation steps and the associated repeated cleanings and baking operations, thereby simplifying the overall manufacturing process.
Data Source
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AI summary
Methods and apparatus for providing conformal shielding are disclosed to provide electromagnetic interference shielding of circuit components mounted on a circuit board. A print mold stencil is provided with one or more conductive shielding walls disposed within the stencil before its application to the circuit board and detachable therefrom, and also configured to encompass the circuit components. In this manner a shielded compartment volume is defined by walls of the print mold stencil and one or more of the conductive shielding walls, and may be easily and quickly applied to the circuit board to encompass the components for shielding. A conformal shielding layer is then formed from a molding material disposed in the shielded compartment volume that encompasses the components, as well as a conductive layer disposed on the outer surface of the material, and coupling of the shielding walls with a ground plane in the circuit board.