Composite Substrate Positioning for Bonding Reliability
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Solution Overview
Problem
Existing composite substrates face issues with adverse electrical characteristics and bonding reliability due to the proximity of projection-shaped conductors on printed wiring boards and cables, leading to potential short-circuits and unreliable connections.
Innovation Solution
A composite substrate design featuring a flexible board with positioning members and a mounting board, where the flexible board includes end portions, bonding portions, and positioning members, and the mounting board has corresponding bonding and positioning members, allowing for precise positioning and surface mounting to enhance electrical characteristics and bonding reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the projection-shaped conductor of the fixing portion and the conductor pattern of the cable are located in proximity to each other to achieve electrical connection, then the electrical connection between the cable and the printed wiring board is established, but the risk of short-circuit increases and the electrical characteristics may be adversely affected
Solution Approach 1:
The patent introduces a positioning member as an intermediary element between the projection-shaped conductor and the conductor pattern. This positioning member physically separates the two conductive elements while still allowing them to establish electrical connection through the bonding process, thereby preventing direct contact that could cause short-circuits while maintaining reliable electrical connection
Solution Approach 2:
The positioning member is pre-installed on the printed wiring board before the bonding process. This preliminary positioning ensures that when the cable is bonded to the board, the projection-shaped conductor and conductor pattern are correctly aligned and separated by the appropriate distance, preventing short-circuits before they can occur
2Strength
If the projection-shaped conductor and conductor pattern are placed close together to ensure bonding reliability, then the connection strength is improved, but the electrical characteristics may be adversely affected due to potential short-circuits
Solution Approach 1:
The positioning member serves as a mediator that allows the bonding process to proceed with strong adhesion while maintaining the necessary separation between conductive elements. The positioning member is bonded along with the cable and board, providing both mechanical strength and electrical isolation
3Device complexity
If the flexible board is positioned without precise positioning members to simplify the structure, then the device complexity is reduced, but deformation and displacement during bonding occur leading to unreliable connections
Solution Approach 1:
The positioning members are pre-installed on the printed wiring board before the bonding process. These members provide reference points that guide the positioning of the flexible board during bonding, ensuring accurate alignment and preventing displacement while adding minimal structural complexity
Data Source
AI summary
A composite substrate includes a flat cable and a mounting board. The flat cable includes a first end portion and a second end portion, and a first bonding portion, a circuit portion, and a second bonding portion in this order in the length direction from the first end portion toward the second end portion. A positioning hole is disposed between the first end portion and the first bonding portion in the length direction. Another positioning hole is disposed between the second end portion and the second bonding portion in the length direction. The mounting board includes a mounting land conductor and a convex portion. The convex portion is fitted in the positioning hole. The mounting land conductor is bonded by surface mounting to an external connection conductor of the first bonding portion and an external connection conductor of the second bonding portion.