Press-Fit Flex-to-Rigid PCB Connection Pin Without Solder Sleeves
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Solution Overview
Problem
The existing methods for electrically connecting flexible printed circuits to rigid printed circuits are costly, time-consuming, and prone to mechanical stress due to the need for additional components like sleeves and soldering, which are not compatible with all insulation types and create fragile zones.
Innovation Solution
A method involving a conductive connection pin with a press-fit end that engages a metallized hole in the rigid circuit, sandwiching the flexible circuit for direct electrical contact without additional components, using a support portion with protuberances to maintain contact under stress, and optionally creating a through-hole for alignment or piercing during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional components like sleeves are used to connect flexible printed circuit to rigid printed circuit, then electrical connection can be achieved, but manufacturing cost increases and device complexity increases
Solution Approach 1:
The patent merges the electrical connection function and mechanical support function into a single integrated connection pin. The pin simultaneously provides electrical conductivity, structural support, and mechanical anchoring through its press-fit design, eliminating the need for separate sleeves or additional components that were previously required to achieve reliable electrical connection between flexible and rigid printed circuits.
Solution Approach 2:
The connection pin serves multiple functions: it provides electrical conduction, mechanical support, anchoring through press-fit engagement, and structural reinforcement. This multi-functional design replaces multiple specialized components, reducing overall device complexity while maintaining connection reliability across different application scenarios.
2Reliability
If additional components and soldering steps are used to connect flexible printed circuit to rigid printed circuit, then electrical connection can be established, but manufacturing time increases and productivity decreases
Solution Approach 1:
The patent extracts the soldering step from the connection process by using a pure mechanical press-fit system. The connection pin is simply inserted and mechanically locked into place through interference fit, eliminating the time-consuming soldering operation while maintaining reliable electrical and mechanical connection. This extraction of the soldering step significantly improves manufacturing throughput.
Solution Approach 2:
The connection pin is pre-designed with integrated features including the press-fit geometry and electrical contact surfaces before assembly. This preliminary preparation allows for direct insertion and immediate functional connection without requiring additional manufacturing steps or post-assembly adjustments, thereby accelerating the manufacturing process.
3Reliability
If soldering is used to connect additional components to flexible printed circuit, then electrical connection can be achieved, but the connection becomes fragile and reliability decreases under mechanical stress
Solution Approach 1:
The patent replaces the solder-based mechanical joint with a pure mechanical press-fit system. The connection pin is retained through interference fit and friction forces generated by the press-fit engagement, eliminating the fragile solder joint that is susceptible to mechanical stress. This mechanical substitution provides superior strength and reliability under vibration, shock, and thermal cycling conditions.
Solution Approach 2:
The press-fit connection utilizes radial compressive forces distributed around the cylindrical interface between the connection pin and the hole. This radial stress distribution creates a uniform frictional lock that resists pull-out forces and mechanical stress from multiple directions, providing superior mechanical strength compared to the localized stress concentration in solder joints.
4Reliability
If conventional press-fit pins are used to connect flexible printed circuit to rigid printed circuit, then electrical connection can be achieved, but additional components and assembly steps are required
Solution Approach 1:
The patent combines the electrical connection function and mechanical support function into a single integrated connection pin. The pin simultaneously provides electrical conductivity, structural support, and mechanical anchoring through its press-fit design, eliminating the need for separate sleeves or additional components that were previously required to achieve reliable electrical connection between flexible and rigid printed circuits.
Data Source
Figure 1~2
Figure 3
Figure 4~4a
AI summary
An electrical connection according to the invention comprises superimposing a flexible printed circuit board (200) onto a rigid printed circuit board (100) by aligning a hole (231) in a contact area (230) of the flexible circuit with a plated-through hole (131) of the rigid circuit. A connecting pin (300) made of conductive material is then inserted through the hole in the flexible circuit such that a first press-fit end (310) of the connecting pin is inserted into the plated-through hole, and an opposite end (320) of the connecting pin holds the flexible circuit against the rigid circuit by pressing against the contact area. By being in contact with the contact area and with the plated-through hole, the connecting pin establishes an electrical connection between the two printed circuit boards without requiring an additional connecting component on the flexible circuit.