Seamless Switch Structure Using Strain Sensors

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Solution Overview

Problem

Portable electronic devices with physical buttons face challenges such as restricted internal space, complex assembly processes, increased production time, and vulnerability to dust and moisture due to gaps between buttons and casings.

Innovation Solution

A switch structure integrated into the casing using an elastic member, force transmission members, and strain sensors, which allows key functions to be performed without additional openings, simplifying production and preventing dust and moisture ingress by maintaining a seamless design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If physical buttons are installed on the casing with openings, then key functions can be provided, but the available space inside the device is restricted and the assembly process becomes complicated

Engineering Contradiction:

Improvekey functionVSAvoidassembly process

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the button structure with the casing by integrating the elastic member directly into the casing body, eliminating the need for separate button components and openings. The elastic member is formed as an integral part of the casing through injection molding, combining what were previously separate components into a unified structure.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The elastic member serves multiple functions simultaneously: it acts as the button structure for user input, provides the switching mechanism through deformation, and seals the opening to prevent dust and moisture ingress. This multi-functional design eliminates the need for separate sealing components and simplifies the overall structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If physical buttons with openings are used, then key functions are available, but dust and moisture can easily enter the device through gaps

Engineering Contradiction:

Improvekey functionVSAvoidprotection against dust and moisture

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The elastic member functions as a flexible sealing element that deforms under pressure to maintain contact with the strain sensor while simultaneously sealing the opening in the casing. This flexible component prevents dust and moisture from entering through the button opening while still allowing mechanical deformation for switching operations.

Inventive Principle:

Principle #30Flexible shells and thin films

3Shape

If seamless key design is implemented without openings, then appearance integrity is maintained and dust/moisture prevention is improved, but the switching mechanism becomes more complex

Engineering Contradiction:

Improveappearance integrityVSAvoidswitching mechanism

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical switch mechanism with a strain sensor-based detection system. Instead of using mechanical contacts that require openings, the strain sensor detects the deformation of the elastic member optically or electrically, allowing for a sealed design while maintaining switching functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The switching mechanism detects changes in the physical state of the elastic member (deformation/strain) rather than relying on mechanical position changes. By monitoring the strain parameter of the elastic member, the system can detect button presses through a sealed opening, eliminating the need for mechanical openings while maintaining functionality.

Inventive Principle:

Principle #35Parameter changes

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 simplifies production, reduces costs, and enhances the reliability and lifespan of electronic devices by eliminating gaps between the casing and keys, while maintaining the device's appearance integrity and preventing environmental hazards.

Implementation Method 1

the strain sensor is disposed on the force transmission member. The strain sensor and the force transmission member are located at two opposite sides of the elastic member respectively, and the elastic member is configured to be deformed by the force transmission member when an external force is applied to an outside of the key portion

Methodology Applied

Scientific EffectStrain: Deformation

Data Source

PatentUS9728352B2Switch structure and electronic device using the same

Publication Date: 2017.08.08 HTC CORP

AI summary

A switch structure and an electronic device using the same are provided. The electronic device has a casing, and the switch structure is disposed at an inner side of the key portion of the casing. The switch structure includes an elastic member, a force transmission member and a strain sensor. The elastic member is connected to the casing. The force transmission member is located inside the casing. The strain sensor is disposed on the elastic member, and the strain sensor and the force transmission member are disposed are two opposite sides of the elastic member respectively. The elastic member is configured to be deformed by the force transmission member when an external force is applied to an outside of the key portion.