Rigid-Flex PCB Shielding via Direct Printing
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Solution Overview
Problem
Rigid-flex printed circuit boards face challenges with the risk of shielding film damage and high manufacturing costs due to complex processes like punching, pasting, and baking, and fail to meet requirements for power supply and signal processing.
Innovation Solution
The method involves forming shielding structures with copper layers and metal seed layers on adhesive sheet layers, which are directly pressed onto the inner circuit substrate, reducing the risk of breakage and simplifying the manufacturing process by eliminating unnecessary steps, and using selective electroplating to form outer circuit layers that meet design requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shielding film of silver paste conductive cloth is formed on the flexible area and rigid area using conventional processes (punching, pasting, pressing, tearing protective film, baking), then the shielding film can be applied to the rigid-flex printed circuit board, but the shielding film is at risk of being damaged and manufacturing costs increase
Solution Approach 1:
The patent replaces mechanical processes (punching, pasting, pressing, tearing, baking) with a printing process. The shielding film is formed by printing conductive material directly onto the flexible and rigid areas, eliminating the need for mechanical manipulation steps that cause damage and increase complexity.
Solution Approach 2:
The patent changes the formation method parameter from mechanical assembly to direct printing. This parameter change transforms the shielding film application from a multi-step mechanical process to a single-step printing process, improving durability by eliminating mechanical stress and reducing process complexity.
2Adaptability or versatility
If outer layer circuits are formed by tenting process, then the circuits can be created on the rigid-flex printed circuit board, but the design requirements for power supply (thick copper and high current) and signal processing (thin wire) cannot be met
Solution Approach 1:
The patent applies different copper thicknesses to different areas of the circuit board. Thick copper is used in power supply areas to handle high current, while thin wire is used in signal processing areas. This local differentiation allows the single printing process to meet diverse design requirements that the conventional tenting process cannot satisfy.
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 enhances the durability of the shielding film, reduces manufacturing costs, and ensures the rigid-flex printed circuit boards can handle both high current and thin wire requirements effectively.
Implementation Method 1
forming shielding structures with copper layers and metal seed layers
Data Source
AI summary
A rigid-flex printed circuit board includes an inner circuit substrate, two adhesive sheet layers formed on the inner circuit substrate, two shielding structures, and two outer circuit layers. The inner circuit substrate is divided into a flexible area, a first and second rigid area. Each shielding structure includes a copper layer, a metal seed layer formed on the copper layer, a flexible dielectric layer formed on the metal seed layer, and a backing adhesive sheet layer formed on the flexible medium layer. The backing adhesive sheet layer is pressed on the adhesive sheet layer and the inner circuit substrate located in the flexible area. Each outer circuit layer is formed on the copper layer, located in the first rigid area and the second rigid area and electrically connected to the inner circuit substrate.