Shielded PCB Connecting Member for Low Resistance Grounding
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Solution Overview
Problem
Conventional shielded printed wiring boards face issues with uneven pressure application during the production of reinforcing members, leading to insufficient penetration of conductive particles into the insulating layer of the shielding film, resulting in increased electrical resistance due to the presence of depressions and projections on the circuit pattern or ground circuit.
Innovation Solution
The use of a connecting member with a metal foil and conductive filler or protrusions that penetrate the insulating layer of the electromagnetic wave shielding film, ensuring even pressure distribution and contact with the shielding layer, thereby establishing a low electrical resistance connection between the substrate film's ground circuit and the reinforcing member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reinforcing member is pressed against the shielding film to make conductive particles penetrate the insulating layer, then electrical connection is achieved, but pressure is unevenly applied causing insufficient penetration and increased electrical resistance
Solution Approach 1:
The patent introduces a connecting member as an intermediary between the reinforcing member and the shielding film. This connecting member includes a conductive adhesive layer with spherical conductive particles that uniformly penetrate the insulating layer of the shielding film, ensuring even pressure distribution and reliable electrical connection without the defects of direct pressing
Solution Approach 2:
The patent changes the physical state and arrangement of conductive particles by using spherical conductive particles in a conductive adhesive layer. This parameter change allows the particles to uniformly penetrate the insulating layer when pressed, solving the problem of uneven pressure application and ensuring consistent electrical connection quality
2Shape
If the insulating layer includes depressions and projections from circuit patterns, then the shielding film follows the circuit structure, but the reinforcing member and conductive adhesive cannot follow the depressions and projections making penetration difficult
Solution Approach 1:
The patent applies local quality by using spherical conductive particles in the conductive adhesive layer that can individually adapt to local variations in the insulating layer surface. These spherical particles can penetrate into depressions and projections uniformly, ensuring consistent electrical connection quality across the entire shielding film surface regardless of surface irregularities
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 ensures a reliable electrical connection between the substrate film's ground circuit and the reinforcing member, reducing electrical resistance and enhancing the shielding effectiveness of the printed wiring board.
Implementation Method 1
after the shielding film is arranged on the printed wiring board, the reinforcing member is arranged by pressing the reinforcing member against the shielding film in such a manner that the spherical conductive particles of the reinforcing member penetrate the insulating layer of the shielding film
Implementation Method 2
The reinforcement member is adhered to the insulating layer with a conductive adhesive containing spherical conductive particles
Data Source
AI summary
A shielded printed wiring board includes a substrate film including a base film and printed circuits including a ground circuit formed on the base film; an electromagnetic wave shielding film including a shielding layer and an insulating layer; and a reinforcing member including a conductive adhesive layer and a metal reinforcing plate, wherein the ground circuit of the substrate film is sufficiently electrically connected to the metal reinforcing plate of the reinforcing member. The shielded printed wiring board of the present invention includes a substrate film including a base film and printed circuits including a ground circuit formed on the base film; an electromagnetic wave shielding film including a shielding layer and an insulating layer; a connecting member including a metal foil and a conductive filler fixed to the metal foil with an adhesive resin; and a reinforcing member including a conductive adhesive layer and a metal reinforcing plate, wherein the electromagnetic wave shielding film is arranged on the substrate film in such a manner that the insulating layer of the electromagnetic wave shielding film is located on the shielding layer of the electromagnetic wave shielding film, the connecting member is arranged on the electromagnetic wave shielding film in such a manner that the conductive filler of the connecting member penetrates the insulating layer of the electromagnetic wave shielding film and that the conductive filler of the connecting member is in contact with the shielding layer of the electromagnetic wave shielding film, the reinforcing member is arranged on the electromagnetic wave shielding film and the connecting member in such a manner that the conductive adhesive layer of the reinforcing member is in contact with the insulating layer of the electromagnetic wave shielding film and the metal foil of the connecting member, and the ground circuit of the substrate film is electrically connected to the metal reinforcing plate of the reinforcing member.