Capacitance Switch Segmented Electrode Two-Stage Input
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Solution Overview
Problem
Existing capacitance switches using electrostatic capacitance for two-stage input face challenges in achieving stable and high-speed responsiveness due to variations in touch area and human body capacitance, leading to inconsistent performance in devices requiring fast and continuous inputs like game mice and keyboards.
Innovation Solution
A capacitance switch design featuring a rubber member with central and peripheral projecting portions that change the distance between a movable electrode and a fixed electrode, allowing for independent movement and elastic deformation to achieve distinct capacitance changes in a single stroke, enhancing responsiveness and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a capacitance switch uses a finger as one electrode to detect capacitance changes, then the switch structure is simplified and mechanical contact is eliminated, but the capacitance value varies due to changes in touch area and human body capacitance, leading to unstable two-stage input performance
Solution Approach 1:
The movable electrode is divided into two independent moving surfaces (first moving surface and second moving surface) that can move independently. This segmentation allows each surface to be actuated by different projecting portions, enabling stable two-stage capacitance changes that are not affected by variations in human body capacitance or touch area.
Solution Approach 2:
The patent introduces a movable electrode as an intermediary element between the finger input and the fixed electrode. This movable electrode with its two independently movable surfaces acts as a mediator that translates finger pressing into distinct, stable capacitance changes at two different stages, eliminating the instability caused by direct finger-to-electrode capacitance measurement.
2Ease of operation
If a capacitance switch relies on human body capacitance for operation, then the switch can be operated without mechanical contact, but noise removal and stray capacitance countermeasures become difficult, preventing stable capacitance values
Solution Approach 1:
The movable electrode serves as an intermediary that isolates the measurement system from direct human body capacitance interference. By measuring capacitance changes between the fixed electrode and the controlled movable electrode surfaces rather than directly with the human body, the system maintains contactless operation while significantly reducing noise and stray capacitance effects.
Solution Approach 2:
The patent changes the measurement parameter from direct human body capacitance to the capacitance between the fixed electrode and the controlled movable electrode surfaces. This parameter change allows the system to operate without mechanical contact while achieving stable, noise-resistant capacitance values by measuring a controlled electrical field rather than the variable human body capacitance.
3Device complexity
If a capacitance switch uses a single moving surface, then the structure is simpler, but it cannot achieve distinct capacitance changes at two places, limiting high-speed responsiveness and continuous hit input capability
Solution Approach 1:
The movable electrode is segmented into two independently movable surfaces, each capable of being actuated by different projecting portions. This segmentation enables the switch to produce distinct capacitance changes at two different stages within a single stroke, achieving both structural simplicity and the capability for high-speed continuous hit inputs by detecting two separate capacitance transitions.
Solution Approach 2:
The patent implements periodic action by creating two distinct capacitance change events (first stage and second stage) within a single pressing stroke. The movable electrode surfaces are sequentially actuated to produce alternating capacitance states, enabling the detection of multiple input stages and supporting continuous hit input capability through rapid sequential capacitance transitions.
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 design enables stable two-stage input with high-speed responsiveness, improved durability, and reduced noise interference, allowing for precise and continuous hit inputs with enhanced S/N ratio and cost-effective manufacturing.
Implementation Method 1
a capacitance switch uses a change in electrostatic capacitance
Implementation Method 2
The pressing member has a projecting portion... configured to change a distance between the movable electrode and the fixed electrode by displacing the projecting portion
Data Source
AI summary
A capacitance switch includes an electrode portion having a first electrode and a second electrode, a moving member, and a pressing member having a projecting portion. A distance between the moving member and the electrode portion is changed by displacing the projecting portion. The moving member has a first moving surface and a second moving surface. The projecting portion includes a first projecting portion and a second projecting portion. The first projecting portion is to be displaced by first pressing of the pressing member and brings the first moving surface close to the electrode portion. The second projecting portion is to be displaced by second pressing larger than the first pressing and brings the second moving surface close to the electrode portion.