Wiring Board Capacitor Mounting Angles for Crack Resistance
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Solution Overview
Problem
The existing arrangement of capacitors on wiring boards is prone to cracking due to stress applied during the insertion and removal of connectors, leading to potential short circuits, particularly when the mounting angle of monolithic ceramic capacitors is not optimally aligned relative to the stress direction.
Innovation Solution
The capacitors are mounted on the wiring board at specific angles ranging from 0 to 5 degrees or 85 to 90 degrees relative to the connector's insertion-removal position, minimizing the likelihood of cracking by aligning the stress direction perpendicular or parallel to the capacitor's mounting direction, thereby preventing strain-induced cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If capacitors are mounted at arbitrary angles on the wiring board, then the arrangement flexibility is improved, but the reliability deteriorates due to stress-induced cracking during connector insertion and removal
Solution Approach 1:
The patent applies local quality by specifying different mounting angle requirements for capacitors located within 10 mm of the connector periphery versus those farther away. Capacitors in the high-stress zone (within 10 mm) must be mounted at 0-5 degrees or 85-90 degrees relative to the insertion-removal direction, while capacitors outside this zone can have arbitrary mounting angles. This localized constraint allows arrangement flexibility for distant capacitors while ensuring crack resistance for nearby capacitors.
2Area of stationary object
If capacitors are mounted close to the connector periphery, then the space utilization is improved, but the reliability deteriorates due to higher stress concentration during connector insertion and removal
Solution Approach 1:
The patent differentiates between two spatial zones: a high-stress zone within 10 mm of the connector periphery where capacitors must follow strict angular constraints (0-5 degrees or 85-90 degrees), and a low-stress zone beyond 10 mm where capacitors can be mounted at arbitrary angles. This allows maximum space utilization in the low-stress zone while protecting the high-stress zone from cracking through controlled orientation.
3Ease of manufacture
If the substrate rigidity is low (e.g., resin substrate), then the ease of manufacture is improved, but the reliability deteriorates due to increased stress transmission to mounted components
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning capacitors at optimal mounting angles (0-5 degrees or 85-90 degrees relative to insertion-removal direction) before stress occurs during connector insertion or removal. This preventive orientation ensures that when stress is applied to low-rigidity resin substrates, the capacitors are already oriented to minimize crack risk, counteracting the inherent vulnerability of flexible substrates before damage can occur.
Data Source
AI summary
A wiring board includes a substrate, a connector on the substrate, and at least one monolithic ceramic capacitor including a pair of electrodes and mounted at a mounting angle on the substrate. The connector has an insertion-removal position at which a stress starts in insertion and removal of a counterpart connector into and from the connector. When a first line segment connects centers of the electrodes in a plan view, and a second line segment connects a center of the insertion-removal position and a center of the first line segment in the plan view, the mounting angle is an angle between the first line segment and the second line segment and is from 0 to 90 degrees. The mounting angle is from 0 to 5 degrees or from 85 to 90 degrees in an area within 10 mm from a periphery of the connector on the substrate.