PCB Connector Coverlay for Scratch Resistance
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Solution Overview
Problem
Conventional PCB connectors with solder mask have weak scratch resistance, leading to potential short circuits and reduced cosmetic quality due to exposure of copper layers, and issues like escutcheon lifting, wear, adhesive oozing, and water leakage in polycarbonate escutcheon-based connectors.
Innovation Solution
A printed circuit board (PCB) connector interface module with a heat and scratch-resistant coverlay adjacent to contact pads, and a solder mask on a second layer, along with inner layers of PCBs and contact vias to enhance durability and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solder mask is used on a PCB connector, then electrical insulation is provided, but scratch resistance is weak leading to copper layer exposure and short circuits
Solution Approach 1:
The patent applies composite materials by combining a solder mask layer with an additional protective coverlay layer. The coverlay is specifically positioned over the copper contact pads and interconnects, creating a composite protective structure that enhances scratch resistance while maintaining electrical insulation properties. This composite approach allows the connector to resist scratching during accessory insertion/removal cycles.
Solution Approach 2:
The protective structure is segmented into distinct functional layers: the solder mask providing base insulation and the additional coverlay providing enhanced mechanical protection over critical copper areas. This segmentation allows each layer to be optimized for its specific function while working together to solve the scratch resistance problem.
2Strength
If a polycarbonate escutcheon is used, then structural support is provided, but issues like lifting, wear, adhesive oozing, and water leakage occur
Solution Approach 1:
The patent extracts the escutcheon component from the connector assembly, eliminating the polycarbonate escutcheon that caused lifting, wear, adhesive oozing, and water leakage problems. By removing this problematic element, the design avoids all associated reliability issues while maintaining structural support through the PCB itself.
Solution Approach 2:
The PCB substrate acts as an intermediary, replacing the escutcheon's structural support function while providing inherent water leakage resistance through its laminated construction. The PCB's multi-layer structure with adhesive bonds between layers prevents water infiltration that plagued the escutcheon design.
3Reliability
If the coverlay surface is higher than contact pads, then scratch protection is improved, but manufacturing precision and surface levelness deteriorate
Solution Approach 1:
The protective coverlay is applied with local quality by positioning it specifically over the copper contact pads and interconnect areas that require protection, rather than uniformly across the entire connector surface. This localized application provides scratch protection where needed while maintaining a flush surface profile with the contact pads.
Data Source
AI summary
A printed circuit board (PCB) connector interface module and an accessory system. The module including a first layer, a second layer, and a plurality of inner layers. The first layer includes a first set of contact pads configured to electrically connect to an accessory device, and a heat and scratch resistant coverlay that is adjacent to and has a first surface that is level with a first surface of the first set of contact pads. The second layer including a second set of contact pads configured to electrically connect to an internal printed circuit board (PCB) of an electronic apparatus. The plurality of inner layers including one or more printed circuit boards (PCB) and a plurality of contact vias, wherein the plurality of contact vias electrically connect the first set of contact pads to the second set of contact pads.