Chip Component Case Sealing to Prevent Resin-Induced Contact Failure
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Solution Overview
Problem
Contact failure between a metal terminal and a terminal electrode in electronic devices can occur due to misalignment caused by the expansion of potting resin during reflow-soldering, leading to insufficient contact and potential defects in moisture resistance and impact resistance.
Innovation Solution
An electronic device design that includes a case with an accommodation recess, a conductive terminal connected to the terminal electrode, and a case cover that covers the opening-edge surface, with a space between the opening-edge recess and the case cover filled with resin, ensuring airtight sealing and preventing misalignment of the contact points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the accommodation recess is filled with potting resin to ensure moisture resistance or impact resistance, then the reliability of the chip component is improved, but the contact point between the metal terminal and the terminal electrode may become misaligned due to expansion of the resin, resulting in contact failure
Solution Approach 1:
The patent divides the sealing function into two separate regions: the accommodation recess remains empty to maintain contact precision, while the opening-edge recess is filled with resin to provide moisture sealing. This segmentation allows each region to fulfill its specific function without interference.
Solution Approach 2:
The patent applies resin filling selectively only to the opening-edge recess rather than the entire accommodation recess. This local application provides moisture resistance at the critical sealing location while avoiding expansion-induced misalignment in the contact area.
2Reliability
If the accommodation recess is filled with resin to improve moisture resistance, then the hermeticity is improved, but the device complexity increases due to the need for complete sealing
Solution Approach 1:
The patent segments the sealing structure into an opening-edge recess that receives resin for hermetic sealing, while the accommodation recess remains open. This reduces the complexity of the overall sealing system by limiting resin application to only the necessary perimeter region.
Solution Approach 2:
The case cover acts as an intermediary element that bridges the opening-edge recess and the accommodation recess. It provides the sealing interface where resin is applied, eliminating the need for the accommodation recess itself to be sealed with resin.
3Volume of moving object
If the case cover is disposed on the inner opening-edge surface, then the electronic device can be reduced in size, but the protrusion of the case cover from the level of the opening of the case may occur
Solution Approach 1:
The patent creates an inner opening-edge surface that is positioned lower than the outer opening-edge surface, allowing the case cover to sit flush with the opening level. This localized depth variation enables compact device sizing without case cover protrusion.
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
The design enhances moisture resistance and prevents contact failure between the metal terminal and terminal electrode, maintaining the integrity of the electronic device without the need for resin filling the accommodation recess, thus improving reliability and performance.
Implementation Method 1
when an electronic device is reflow-soldered, a contact point between a metal terminal and a terminal electrode may be misaligned due to, for example, expansion of the potting resin
Data Source
AI summary
An electronic device includes a chip component including a terminal electrode, a case having an accommodation recess accommodating the chip component, a conductive terminal attached to the case and connected to the terminal electrode, and a case cover disposed on an opening-edge surface of the case so as to cover the accommodation recess. The opening-edge surface has an opening-edge recess at least partly covered by the case cover. The opening-edge recess and the case cover have a space therebetween. The space is filled with a resin.