Flexible PCB Pad Overlap for Uniform Heating
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Solution Overview
Problem
In electronic devices, particularly in large connection regions between flexible printed wiring boards and connection members, temperature unevenness occurs due to differential heat dissipation, making uniform connection challenging and expensive to achieve.
Innovation Solution
The electronic device incorporates a flexible printed wiring board with conductive pads that overlap and protrude beyond connection pads at the outer edge, allowing for uniform heating and connection through the use of low and high melting-point solders, ensuring reliable electrical connections despite temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the connection region is made relatively large to accommodate increased device capacity and complexity, then the device can handle more connections, but temperature unevenness occurs during heating making uniform connection difficult
Solution Approach 1:
The patent applies local quality by making the pad larger than the connection pad, specifically extending the pad beyond the outer edge of the connection pad group. This creates a localized heat reservoir at the periphery of the connection region,针对性地 addressing the temperature unevenness at outer edge portions while maintaining a large overall connection region for increased capacity.
2Ease of manufacture
If conventional heating methods are used on a large connection region, then the heating process is simple, but outer edge portions dissipate heat more than central portions causing temperature unevenness
Solution Approach 1:
The pad is designed with non-uniform dimensions, being larger than the connection pad and extending beyond the outer edge of the connection pad group. This creates a localized heat reservoir at the periphery that compensates for higher heat dissipation at outer edges, achieving temperature uniformity while maintaining manufacturing simplicity.
Solution Approach 2:
The enlarged pad structure serves as a pre-designed heat reservoir that anticipates and compensates for the inevitable heat dissipation at outer edges during the heating process. This beforehand cushioning of heat ensures that even portions receive adequate temperature without requiring complex heating control.
3Temperature
If the pad size is increased to compensate for heat dissipation at outer edges, then temperature uniformity improves, but the device structure becomes more complex
Solution Approach 1:
The patent merges the heat reservoir function with the existing pad structure. The pad is simply made larger than the connection pad, extending beyond the outer edge of the connection pad group, thereby combining the heating compensation function with the electrical connection function in a single integrated structure without adding separate components.
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 configuration ensures uniform heating and reliable electrical connections across the bonding region, effectively addressing temperature unevenness and enhancing connection reliability, even in devices with increased capacity and complexity.
Implementation Method 1
a pad provided on another surface side of the insulating layer and having heat conductivity
Implementation Method 2
a connection member comprising a plurality of connection terminals connected to the connection pads via a solder
Data Source
AI summary
According to one embodiment, an electronic device includes a flexible printed wiring board includes an insulating layer, a plurality of connection pads provided on one side of the insulating layer and constituting a group, and a pad provided on another surface side of the insulating layer and having heat conductivity, wherein the pad overlaps one or more connection pads positioned at an outer edge of the group of connection pads via the insulating layer and comprises a portion extending on the outside of the connection pad on the outer edge, and a connection member includes a plurality of connection terminals connected to the connection pads via a solder.