Penetration Hole Design for Sealing Reliability in Electronic Devices
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Solution Overview
Problem
Existing composite sensor elements face issues with sealing reliability due to sharp through holes and the use of spherical sealing members, which can lead to damage, defective sealing, and miniaturization challenges.
Innovation Solution
The design incorporates a penetration hole with a first hole portion on the outer surface and a second hole portion on the inner surface, where the second hole portion has a circular flat surface and a right-angle inner wall, allowing for improved mechanical strength and reliable sealing using a spherical sealing member that melts and spreads within the first hole portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through hole with a wide outer surface and narrow space portion is used for sealing, then the sealing structure is formed, but the tip of the through hole becomes sharp and vulnerable to impact damage
Solution Approach 1:
The penetration hole is divided into two distinct portions: a first hole portion on the outer surface side and a second hole portion on the inner surface side. This segmentation allows each portion to have optimized characteristics - the first portion provides structural strength while the second portion enables effective sealing, resolving the contradiction between strength and sealing reliability.
Solution Approach 2:
Different portions of the penetration hole are given different geometric qualities. The first hole portion has a shape optimized for mechanical strength, while the second hole portion has a shape optimized for sealing. This local differentiation of qualities allows the structure to simultaneously achieve both strength and sealing reliability without compromise.
2Reliability
If a spherical sealing member is used to seal the through hole, then sealing is attempted, but gaps form between the sealing member and the sharp corners of the through hole, resulting in defective sealing
Solution Approach 1:
The second hole portion is designed with specific local quality characteristics - a flat bottom surface and substantially vertical inner wall surface - that are optimized for receiving and sealing with a spherical sealing member. This local optimization ensures the sealing member makes proper contact without gaps, achieving both high sealing quality and manufacturing precision.
3Reliability
If the inner wall surface of the through hole is inclined with an upwardly-narrow space portion, then sealing is achieved, but the cover member becomes larger than necessary, disturbing miniaturization
Solution Approach 1:
By segmenting the penetration hole into two portions with different geometries, the design achieves effective sealing in the second hole portion without requiring the entire penetration hole to be large. This allows miniaturization of the cover member while maintaining sealing effectiveness.
Solution Approach 2:
The second hole portion is designed with specific local quality - a flat bottom and vertical walls - that enables effective sealing with minimal space requirements. This local optimization allows the cover member to be miniaturized while still achieving reliable sealing.
4Ease of manufacture
If a metal film is provided to the tip of the space portion side of the through hole, then the sealing member wets and spreads easily, but the melted sealing member scatters in the space portion and attaches to internal components, degrading their properties
Solution Approach 1:
The metal film is extracted from the second hole portion (inner surface side) and applied only to the first hole portion (outer surface side). This extraction prevents the sealing member from scattering into the internal space while maintaining the wetting and spreading characteristics needed for effective sealing in the first hole portion.
Solution Approach 2:
The metal film is applied with local quality differentiation - present on the first hole portion for sealing effectiveness, but absent from the second hole portion to prevent scattering. This localized application resolves the contradiction between ease of sealing and protection of internal 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 enhances the mechanical strength of the second hole portion, improves sealing reliability, and allows for miniaturization by preventing the sealing member from attaching to internal components, thus maintaining the integrity and functionality of the sensor.
Implementation Method 1
when introducing a spherical sealing member for sealing by melting the member
Data Source
AI summary
An electronic device includes a substrate, a lid which is bonded to the substrate, and a functional element which is provided between the substrate and the lid, in which the lid includes a penetration hole which penetrates a portion between an inner surface and an outer surface, the penetration hole includes a first hole portion and a second hole portion, a flat area of the second hole portion is set to be smaller than a flat area of the first hole portion, at least a part of an inner wall surface of the second hole portion substantially forms a right angle with respect to a bottom surface of the first hole portion, and the penetration hole is sealed with a sealing member.