Laser Welded Metal Pad with Coating for Electronic Device Corrosion

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Solution Overview

Problem

Metallic electronic devices with low surface hardness, such as those made from aluminum, magnesium, titanium, and zinc, are prone to corrosion and contact failures due to friction with C-clips, leading to malfunctions, and conventional attachment methods like ultrasonic welding are hindered by internal structures in the device.

Innovation Solution

A metal pad with a conductive first coating layer of lower light reflectivity than the pad itself is laser-welded to a metal terminal part, and optionally a second coating layer with greater hardness is applied, along with the use of double-sided tape for attachment, to prevent corrosion and ensure secure bonding regardless of the internal structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal case with low surface hardness is used to achieve high structural rigidity, less weight, and small thickness, then the structural performance is improved, but the metal terminal part is easily corroded and damaged due to friction with the C-clip

Engineering Contradiction:

Improvestructural rigidityVSAvoidcorrosion resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies composite materials by bonding a metal pad (with high hardness and corrosion resistance) to the metal terminal part of the metal case. This creates a composite structure where the metal case provides structural rigidity while the metal pad provides corrosion resistance and hardness, resolving the contradiction between structural performance and reliability.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If ultrasonic welding method is used to attach the metal pad to the metal terminal part, then the manufacturing process is easier and quicker, but the head of the ultrasonic horn is interfered with by the injection-molded structure in the narrow part, making welding impossible

Engineering Contradiction:

Improveattachment processVSAvoidapplicability to narrow parts

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical ultrasonic welding system with a laser welding system. Laser welding uses a focused laser beam that can access narrow and confined spaces without requiring physical contact or large equipment, thereby resolving the contradiction between ease of manufacture and adaptability to narrow parts with injection-molded structures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a metal pad with high light reflectivity is used for laser welding, then the conductivity and corrosion resistance are improved, but the laser welding is difficult due to high light reflectivity

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidlaser welding process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies a first coating layer on the metal pad before laser welding. This preliminary coating layer has lower light reflectivity than the metal pad itself, enabling the laser beam to be effectively absorbed and concentrated for welding. After welding, the metal pad's original corrosion resistance and conductivity are preserved, resolving the contradiction between reliability and ease of manufacture.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The first coating layer acts as an intermediary between the laser beam and the metal pad. It facilitates laser energy absorption and transfer to the metal pad, enabling successful welding of high-reflectivity materials while preserving their inherent corrosion resistance and conductivity properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution effectively prevents corrosion and ensures reliable bonding of the metal pad to the terminal part, enhancing the durability and functionality of the electronic device by using laser welding and strategic coating layers, while allowing for easier manufacturing and avoiding the limitations of ultrasonic welding.

Implementation Method 1

a metal pad bonded to the metal terminal part by laser welding

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 2

at least one melting part formed surrounding the metal pad by the laser welding

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

light reflectivity of the conductive first coating layer is lower than light reflectivity of the metal pad

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 4

The double-sided tape may be attached only to a center portion of the metal pad

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentUS11374306B2Electronic device comprising metal case having metal pad attached thereto

Publication Date: 2022.06.28 SAMSUNG ELECTRONICS CO LTD

AI summary

An electronic device comprising a metal case having a metal pad attached thereto is disclosed. According to the present invention, the electronic device comprises: a metal case having a metal terminal part formed therein; a metal pad joined to the metal terminal part by laser welding; and a conductive first coating layer coated on one surface of the metal pad, wherein the light reflectivity of the first coating layer is lower than the light reflectivity of the metal pad.