Touchpad Module with Elastic-Member Spacing for High Sensitivity
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Solution Overview
Problem
Existing touchpad modules face challenges in improving sensitivity when pressed, particularly due to limitations in manufacturing thin elastic members and inadequate vibration effects.
Innovation Solution
The design incorporates a support member with a protruding portion and a capacitive sensing element, along with an elastic member and a printed circuit board assembly, where the spacing between the capacitive sensing element and the protruding portion is controlled to enhance sensitivity, and includes a shielding layer to reduce stray capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the spacing between the capacitive sensing element and the protruding portion is reduced to increase sensitivity, then measurement precision is improved, but manufacturing precision becomes more difficult to achieve
Solution Approach 1:
The patent introduces an elastic member as an intermediary component between the support member and the printed circuit board assembly. This elastic member acts as a mediator that defines and controls the spacing between the capacitive sensing element and the protruding portion, making the spacing controllable through the elastic member's thickness rather than direct assembly tolerances.
Solution Approach 2:
The patent changes the parameter of spacing control from direct mechanical assembly to elastic member thickness. By using the elastic member's thickness as the determining factor for spacing, the design allows for easier manufacturing control since the elastic member can be manufactured with controlled thickness within a broader range (0.3mm to 1.0mm) while still achieving the required small spacing (less than elastic member thickness).
2Measurement precision
If a thin elastic member is used to reduce spacing and improve sensitivity, then measurement precision is improved, but ease of manufacture deteriorates due to manufacturing limitations
Solution Approach 1:
The patent expands the acceptable parameter range for elastic member thickness from the conventional thin range to a broader range of 0.3mm to 1.0mm. This parameter change allows manufacturers to use thicker, easier-to-manufacture elastic members while still achieving the required small spacing between the capacitive sensing element and the protruding portion, thereby improving ease of manufacture without sacrificing sensitivity.
3Measurement precision
If the spacing is made smaller than the elastic member thickness to achieve high sensitivity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The elastic member serves as an intermediary that simplifies the overall structure by integrating the spacing control function into a single component. Rather than requiring complex assembly mechanisms or precision-machined features on multiple parts, the elastic member's thickness alone determines the spacing, reducing structural complexity while achieving high sensitivity.
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 achieves high sensitivity and effective vibration in touchpad modules, overcoming manufacturing limitations and enhancing performance when pressed.
Implementation Method 1
the printed circuit board assembly is located over the support member and includes a capacitive sensing element corresponding to the protruding portion of the support member
Implementation Method 2
The elastic member is disposed between the support member and the printed circuit board assembly. When the touchpad module is not pressed, a spacing between the capacitive sensing element and the protruding portion is smaller than a thickness of the elastic member.
Data Source
AI summary
A touchpad module includes a support member, a printed circuit board assembly (PCBA) and an elastic member. The support member has a protruding portion. The printed circuit board assembly is located over the support member and includes a capacitive sensing element corresponding to the protruding portion of the support member. The elastic member is disposed between the support member and the printed circuit board assembly. When the touchpad module is not pressed, a spacing between the capacitive sensing element and the protruding portion is smaller than a thickness of the elastic member.