Flexible Substrate With Constricted Projecting Portion

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Solution Overview

Problem

Flexible substrates experience degradation in electrical connection reliability due to bending stress when connected to other members, leading to potential rupture of electrical connections.

Innovation Solution

A flexible substrate design featuring a base portion and a projecting portion with a constricted and wide section, where components are placed in the wide section, limiting bending stress transmission through a constricted path, thereby reducing high bending stress on components and electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the flexible substrate is bent to connect to another member, then the substrate can be mounted flexibly, but bending stress causes rupture of electrical connections and degradation of reliability

Engineering Contradiction:

Improveflexibility of substrate mountingVSAvoidelectrical connection reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The substrate is divided into a base portion and a projecting portion with a constricted portion between them. This segmentation allows the base portion to bend for flexible mounting while the constricted portion limits bending stress transmission to the component mounting area, protecting electrical connections from rupture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the substrate are given different structural properties: the base portion is designed to be flexible for mounting, while the projecting portion containing components is protected from bending stress through the constricted portion design. This local differentiation allows simultaneous achievement of flexibility and connection reliability.

Inventive Principle:

Principle #3Local quality

2Reliability

If thicker or harder resin layers are used to protect components from bending stress, then connection integrity is maintained, but heat dissipation capability is reduced

Engineering Contradiction:

Improveconnection integrityVSAvoidheat dissipation capability

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The substrate structure segments the bending stress path through the constricted portion, protecting components without requiring thicker resin layers. This maintains the original thin-profile design with good heat dissipation while ensuring connection integrity through geometric design rather than material thickness.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10271423B2Flexible substrate

Publication Date: 2019.04.23 MURATA MFG CO LTD

AI summary

A flexible substrate includes a substrate including interconnection wiring on a surface of or in the substrate, a component disposed on the surface of or in the substrate and electrically connected to the interconnection wiring, and an external connection conductor provided on the surface of the substrate. The substrate includes, when viewed two-dimensionally, a base portion where the external connection conductor is disposed, and a projecting portion projecting from the base portion. The projecting portion includes a first constricted portion provided at a connection to the base portion, and a first wide portion provided on an extension of the first constricted portion and having a width greater than that of the first constricted portion, with the component being disposed in the first wide portion.