Touchpad Module Noise Reduction via Conductive Raised Structure
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Solution Overview
Problem
Conventional touchpad modules generate unpleasant noise due to the click collision between the deformed metal dome and the large-area circuit board, affecting user comfort during operation.
Innovation Solution
Incorporating a conductive raised structure between the circuit board and the switch to create a gap between the metal dome and the circuit board, reducing the contact area and thus the noise generated during deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the metal dome is allowed to deform and contact the circuit board to complete the electrical connection, then the switch function is achieved, but noise is generated due to the click collision between the metal dome and the large-area circuit board
Solution Approach 1:
A conductive adhesive layer is introduced as an intermediary between the metal dome and the circuit board. This adhesive layer serves as a mediator that transmits both the electrical connection and the mechanical force while reducing the direct impact collision. The adhesive layer deforms elastically during button pressing, completing the electrical circuit between the metal dome's conducting part and the circuit board's conducting part without generating the harsh click noise of direct metal-to-PCB contact.
Solution Approach 2:
The patent changes the physical parameters of the contact interface by replacing direct rigid contact with a compliant adhesive layer. The adhesive layer has specific properties (conductivity, elasticity, thickness) that are optimized to reduce impact force and noise while maintaining reliable electrical connection. The gap between the metal dome and circuit board is controlled to ensure proper deformation and contact characteristics.
2Object-generated harmful factors
If a conductive raised structure is introduced to reduce noise by creating a gap, then the contact area and noise are reduced, but the device complexity increases
Solution Approach 1:
The conductive raised structure combines multiple functions into a single component: it provides the conductive path for electrical connection, acts as a spacer to create the necessary gap, and serves as the adhesive layer for mechanical bonding. This merging of functions reduces the need for separate components and simplifies the overall assembly process despite the enhanced functionality.
Solution Approach 2:
The conductive raised structure is made of a composite material that combines conductivity (for electrical connection) with adhesive properties (for mechanical bonding) and appropriate mechanical compliance (for noise reduction). This composite material approach allows a single component to satisfy multiple requirements that would otherwise need separate parts.
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 introduction of a conductive raised structure between the circuit board and the metal dome of the switch reduces noise and enhances user comfort by minimizing the contact area, resulting in a more pleasant operating experience.
Implementation Method 1
When the switch is pushed by a triggering part, the metal dome is subjected to deformation
Implementation Method 2
the first portion of the metal dome is contacted with the first conducting part, so that the first conducting part and the second conducting part are electrically connected with each other
Data Source
AI summary
A touchpad module includes a circuit board, a switch and a conductive raised structure. The circuit board includes a first conducting part and a second conducting part. The switch is installed on the circuit board. The switch includes a metal dome. The metal dome includes a first portion corresponding to the first conducting part and a second portion corresponding to the second conducting part. When the metal dome is subjected to deformation, the first portion of the metal dome is contacted with the first conducting part. The conductive raised structure is arranged between the second conducting part and the second portion of the metal dome. Since a gap is formed between the circuit board and the second portion of the metal dome, the contact area between the metal dome and the circuit board is reduced. Consequently, the generated noise is reduced.