Electronic Device Lid Structure Restricting Thermal Cycle Connection Failures

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Solution Overview

Problem

Connection failures occur in connecting members of electronic devices due to deformation of component boards caused by thermal cycles, particularly at the solder balls of ball grid array packages.

Innovation Solution

An electronic device design that includes a circuit component mounted on a component board, connected via deformable connectors, with a lid member joined to the component board to cover the circuit component, suppressing deformation away from the substrate at specific locations to restrict connection failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the component board is mounted on the substrate via connecting members, then the electronic device can be assembled and function, but the connecting members (solder balls) are subject to distortion due to thermal cycles causing connection failures

Engineering Contradiction:

Improveconnection reliabilityVSAvoidthermal cycle distortion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The lid member is positioned in advance to oppose and counteract the distortion forces that thermal cycles will exert on the deformable connector. By pre-establishing this counteracting structure, the connector is protected from connection failures before the thermal cycling occurs.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The lid member is selectively positioned to cover only the specific region where the deformable connector is located, providing localized protection and counteracting distortion precisely where needed rather than requiring universal reinforcement of the entire component board.

Inventive Principle:

Principle #3Local quality

2Reliability

If the lid member covers the circuit component, then the circuit component is protected, but the lid member must be precisely positioned to avoid interfering with electrodes and connecting members

Engineering Contradiction:

Improvecomponent protectionVSAvoidlid member positioning precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The lid member is designed to cover only the specific region needed for protection (the circuit component area) while leaving other regions (electrode areas) exposed. This selective covering reduces the precision requirements compared to a full-coverage lid, as the lid only needs to be positioned correctly over its designated protection zone.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If the deformable connector is used to connect the component board, then flexibility and stress absorption are improved, but the connector is more susceptible to distortion and connection failures under thermal cycling

Engineering Contradiction:

Improvethermal stress absorptionVSAvoidconnector connection reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The lid member is pre-positioned to counteract the distortion forces that will act on the deformable connector during thermal cycling. This preliminary counteraction allows the connector to maintain its flexibility and stress-absorption capabilities while being protected from connection failures.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The lid member acts as a counterweight or counteracting force against the distortion forces experienced by the deformable connector. By opposing these forces, the lid member enables the connector to maintain its adaptive properties without suffering connection failures.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 effectively restricts deformation of the component board, preventing connection failures at solder balls susceptible to thermal cycles, thereby enhancing the reliability and longevity of the electronic device.

Implementation Method 1

a deformable connector subject to distortion due to thermal cycle

Methodology Applied

Scientific EffectDeformation: Deformation

Implementation Method 2

subject to distortion due to thermal cycle

Methodology Applied

Scientific EffectThermal cycle: Thermal Expansion

Data Source

PatentUS20250254794A1Electronic device

Publication Date: 2025.08.07 DENSO CORP

AI summary

An electronic device includes: a component board having a first surface on which a circuit component is mounted; a substrate on which the component board is mounted via a plurality of connecting members; and a lid member joined to the first surface of the component board to cover the circuit component. The component board has a second surface opposite to the first surface. Electrodes are arranged on the second surface and connected with the connecting members. The connecting members have a deformable connector where a distortion occurs due to thermal cycle. The first surface has an opposing region opposite to the electrode to which the deformable connector is connected, and the lid member is joined to the first surface of the component board within the opposing region.