Push Button Switch Member Using Laminated Elastic Sheet
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Solution Overview
Problem
Conventional push button switch members face challenges in achieving a small thickness, high durability, and excellent click feeling while maintaining low manufacturing costs, with issues such as fragile silicone rubber components and poor dimensional stability of thermoplastic elastomers leading to deformation and reduced click feeling over time.
Innovation Solution
A member for a push button switch comprising a metal sheet with holes for key tops and an elastic sheet made of laminated urethane film and silicone rubber, which improves durability and flexibility, allowing for reduced thickness and enhanced click feeling, along with decorative features and integrated light-emitting capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the floating portion is reduced to achieve a thinner member, then the overall thickness is reduced, but the floating portion becomes fragile and breaks easily
Solution Approach 1:
The patent applies composite materials by combining a thermoplastic elastomer base layer with a thermosetting elastomer coating layer. The thermoplastic elastomer provides dimensional stability and structural support, while the thermosetting elastomer enhances surface properties and durability. This composite structure allows the floating portion to maintain high strength even at reduced thickness, resolving the contradiction between thinness and fragility.
2Length of moving object
If thermoplastic elastomer is used to reduce thickness, then the member can be made thinner, but dimensional stability is poor and yield is low
Solution Approach 1:
The patent uses a composite material system where the thermoplastic elastomer base layer provides flexibility and thinness, while the thermosetting elastomer coating layer provides dimensional stability and structural integrity. The combination allows the member to be made thinner while maintaining excellent dimensional stability, as the thermosetting layer compensates for the inherent dimensional instability of thin thermoplastic elastomer layers.
3Length of moving object
If thermoplastic elastomer with high strength is used, then the member can be made thinner, but the key pad deforms due to pressing force over time
Solution Approach 1:
The patent employs a composite material structure where the thermoplastic elastomer base layer provides initial strength and thinness, while the thermosetting elastomer coating layer provides superior elasticity and resistance to permanent deformation. Under repeated pressing forces, the thermosetting layer's excellent elastic recovery properties prevent the key pad from deforming, thereby improving durability while maintaining thin dimensions.
4Strength
If metal frame is used instead of resin frame to increase rigidity, then rigidity is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses composite materials to achieve high rigidity in the frame structure. By combining thermoplastic elastomer and thermosetting elastomer in a composite construction, the frame attains metal-like rigidity and structural strength while maintaining the manufacturing advantages of molded materials. This allows complex frame geometries to be produced through molding processes rather than metal fabrication, reducing manufacturing complexity and cost while achieving the required rigidity.
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 enables a push button switch with a smaller thickness, improved durability, and enhanced click feeling, while also allowing for various design options and improved visibility, particularly in dark environments, while maintaining low manufacturing costs.
Implementation Method 1
an elastic sheet that is disposed on the metal sheet so as to be positioned on the same side as or opposite side to the key tops. The elastic sheet is fitted into the holes and comes in contact with the key tops at positions of the holes. The elastic sheet includes a urethane film and a silicone rubber, which are laminated in a thickness direction of the metal sheet.
Data Source
AI summary
A member for a push button switch that has a small thickness, high durability, and excellent click feeling and can be manufactured at low cost. The member for the push button switch includes one or more key tops, a metal sheet including at least holes that correspond to positions of the key tops, and an elastic sheet that is provided on the metal sheet so as to be positioned on the same side as or opposite side to the key tops. The elastic sheet is fitted into the holes and comes in contact with the key tops at positions of the holes. The elastic sheet includes a urethane film or polycarbonate, and a silicone rubber, which are laminated in a thickness direction of the metal sheet.