Tapered PCB Contact Surfaces Prevent Solder Bridging
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Solution Overview
Problem
In miniaturized sensor systems, the challenge lies in effectively connecting printed circuit boards with small soldering contact surface distances, where traditional soldering methods often result in bridges or no connections due to the high requirement for precise positioning and increased number of signal paths, leading to conflicts between connection density and process stability.
Innovation Solution
The solution involves a printed circuit board arrangement with contact surfaces that taper or reduce in size towards the connection point, featuring a combination of circular and rectangular sections, allowing for closer packing of pads and improved solder distribution, preventing undesired connections and enabling larger tolerances and gap bridging with a concave solder profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional square or rectangular soldering pads are used, then the manufacturing process is simple, but solder bridges form between adjacent pads due to small distances
Solution Approach 1:
The patent applies asymmetry by designing the contact surface with a tapered geometry where the width decreases in the direction toward the connection point. This asymmetric shape prevents solder from spreading to neighboring pads while maintaining manufacturing feasibility, directly resolving the contradiction between connection reliability and geometric complexity.
Solution Approach 2:
The contact surface features local quality variation through its tapered geometry, where the width changes along the connection direction. This localized dimensional variation optimizes solder flow control at critical areas without requiring complete redesign of the entire pad structure, balancing reliability improvement with manufacturing simplicity.
2Productivity
If the number of soldering points is increased to accommodate more signal paths, then connection density improves, but the risk of solder bridges increases
Solution Approach 1:
The asymmetric tapered contact surface design enables higher connection density by preventing solder bridges between adjacent pads. The varying width along the connection direction creates natural solder flow barriers, allowing more signal paths to be accommodated without proportionally increasing bridge risk.
3Volume of moving object
If smaller contact surface distances are used to reduce size, then miniaturization is achieved, but positioning precision requirements increase significantly
Solution Approach 1:
The tapered asymmetric contact surface design compensates for positioning tolerances by creating a geometry that is less sensitive to lateral misalignment. The varying width provides a larger effective bonding area even when boards are slightly offset, enabling miniaturization without proportionally increasing precision requirements.
4Area of stationary object
If solder pads are placed closer together to reduce area, then space utilization improves, but solder bridging between adjacent pads occurs
Solution Approach 1:
The asymmetric tapered geometry of contact surfaces prevents solder bridging even when pads are placed close together. The width reduction toward the connection point creates natural barriers to solder flow, enabling high space utilization without sacrificing connection reliability through bridging.
5Ease of manufacture
If conventional soldering processes are used, then process simplicity is maintained, but process quality deteriorates with small distances
Solution Approach 1:
The asymmetric tapered contact surface design improves soldering process quality while maintaining conventional soldering processes. The geometry controls solder flow naturally, preventing bridges and improving wetting characteristics without requiring complex modified soldering procedures, thus preserving ease of manufacture.
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 design enhances process reliability by preventing solder bridging between adjacent pads, allowing for more pads on smaller areas, reducing solder usage, and ensuring reliable connections even with larger gaps and tolerances, resulting in a higher density of connections with improved solder distribution and reduced operational costs.
Implementation Method 1
the solder forms a meniscus, i.e. rather an inwardly curved, concave surface of the solder
Implementation Method 2
the solder forms a meniscus, i.e. rather an inwardly curved, concave surface of the solder
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
Printed circuit board arrangement with at least two printed circuit boards (2, 8) arranged perpendicular to each other, wherein a first printed circuit board (2) has first contact surfaces (6) on one side (4) at a printed circuit board edge (3), wherein a second printed circuit board (8) has second contact surfaces (10) on one side (4), wherein the second contact surfaces (10) of the second printed circuit board (8) are arranged perpendicular to the first contact surfaces (6) of the first printed circuit board (2) and the first contact surfaces (6) of the first printed circuit board (2) are electrically connected to the second contact surfaces (10) of the second printed circuit board (8) by means of solder (5), wherein the contact surfaces (6, 10) of one printed circuit board (2, 8) project along a connection point (11) to the other printed circuit board (3) towards opposite contact surfaces (10, 6) of the opposite printed circuit board (8, 2) and at least the contact surfaces (6, 10) of one printed circuit board (2, 8)8) to taper or decrease in size towards the junction (11).