Push Switch Laser Welding for Stable Sheet Attachment

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Solution Overview

Problem

Conventional push switches face challenges in maintaining stability as the size of electronic apparatuses decreases, leading to reduced contact areas between the protective sheet and the case, which affects the secure holding of the protective sheet and results in unstable operation.

Innovation Solution

The push switch incorporates a protective sheet welded to the case using laser irradiation, forming a linear first welding place along the edge of the sheet and the case's upper surface, ensuring a strong and stable attachment even with reduced contact areas, and includes a pressing member to enhance the click feeling and operation reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the size of electronic apparatuses is decreased, then the compactness is improved, but the contact area between the protective sheet and the case is reduced, leading to unstable holding

Engineering Contradiction:

Improvesize of electronic apparatusVSAvoidstability of protective sheet holding

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent replaces the conventional adhesive bonding method with laser welding technology. The laser beam melts the resin material of the case and the protective sheet, creating a strong weld joint that maintains reliability even with reduced contact areas. This substitution of mechanical/chemical bonding (adhesive) with thermal bonding (laser welding) resolves the contradiction between miniaturization and stable holding.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the bonding method from adhesive-based to laser-based, fundamentally altering the physical and chemical parameters of the joining process. By using laser irradiation, the bonding strength, contact area requirements, and thermal properties are optimized to maintain stable holding in compact devices.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If adhesive bonding is used to attach the protective sheet, then the manufacturing process is simple, but the holding strength is insufficient for small-sized devices

Engineering Contradiction:

Improvesimplicity of mounting processVSAvoidholding strength of protective sheet

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent replaces adhesive bonding with laser welding, substituting a chemical bonding process with a thermal processing method. This maintains manufacturing simplicity while dramatically improving holding strength, as laser welding creates strong metallurgical or resin-based bonds without requiring adhesives.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The laser beam acts as an intermediary energy carrier, transferring thermal energy to the bonding interface between the protective sheet and case. This intermediary mechanism enables strong bonding without direct mechanical or chemical contact, resolving the contradiction between ease of manufacture and bonding strength.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If the contact area is reduced to enable miniaturization, then the device size is decreased, but the operational stability deteriorates

Engineering Contradiction:

Improvedevice sizeVSAvoidoperational stability

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent replaces adhesive bonding with laser welding to maintain operational stability with reduced contact areas. The laser-induced thermal bonding creates stronger, more concentrated joints that are effective even with minimal contact area, enabling miniaturization without sacrificing operational stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution allows for a more stable and reliable operation of the push switch with improved click feeling, maintaining performance even with smaller sizes, and reduces the number of mounting steps while ensuring high-quality and cost-effective production.

Implementation Method 1

The protective sheet and at least a part of an upper surface of the wall part of the case are welded together as a first welding place

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentUS9536687B2Push switch

Publication Date: 2017.01.03 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A push switch includes a switch contact part for carrying out electrical connection by pressing, a case having a wall part on a periphery thereof and accommodating the switch contact part in a concave portion surrounded by the wall part, and a protective sheet covering the concave portion. The protective sheet and at least a part of an upper surface of the wall part of the case are welded together as a first welding place.