Capacitive Touch Switch Threshold Control for Faster Release Detection
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Solution Overview
Problem
Capacitive touch switch apparatuses with touch electrodes of shapes extending in the longitudinal direction or irregular shapes, such as those used in air conditioner controllers, experience slow response times when transitioning from a touch state to a non-touch state, leading to an unpleasant user experience due to delayed detection of finger removal.
Innovation Solution
A capacitive touch switch apparatus that includes a touch electrode, a touch detection circuit, and a threshold determination circuit. The threshold determination circuit adjusts the threshold values based on the touch detection signal, increasing the threshold from a first level indicative of no touch to a second level indicative of touch, thereby enhancing the response speed from a touch state to a non-touch state without altering the response speed from a non-touch state to a touch state, using a voltage divider circuit and a switching circuit to change the threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a touch electrode with an extended longitudinal shape or irregular shape is used, then the touch detection area is improved, but the response speed in transition from touch state to non-touch state deteriorates
Solution Approach 1:
The patent applies dynamics by making the threshold value changeable based on the touch detection signal level. The threshold determination circuit dynamically adjusts the threshold between a first level (when touch detection signal indicates no touch) and a second level (when touch detection signal indicates touch presence). This dynamic threshold adjustment enables faster response when transitioning from touch to non-touch state while maintaining adequate detection area coverage.
Solution Approach 2:
The patent changes the parameter of threshold voltage based on the state of the touch detection signal. By switching between a first threshold level and a second threshold level according to whether a touch is detected, the system optimizes the balance between detection sensitivity and response speed. This parameter change allows the extended or irregularly shaped electrode to maintain its detection area advantage while achieving improved response characteristics.
2Device complexity
If a fixed threshold is used for touch detection, then the circuit complexity is reduced, but the response speed in transition from touch state to non-touch state deteriorates
Solution Approach 1:
The patent introduces a dynamic threshold adjustment mechanism through the threshold determination circuit, which receives the touch detection signal and outputs an appropriate threshold level. This dynamic approach improves response speed without excessive complexity increase, as the threshold switching is directly coupled to the touch detection signal state, creating an efficient responsive system.
Solution Approach 2:
The threshold determination circuit implements feedback by monitoring the touch detection signal level and adjusting the threshold accordingly. When the touch detection signal indicates touch presence, the circuit switches to a second threshold level; when it indicates no touch, it switches to a first threshold level. This feedback mechanism enables automatic optimization of response characteristics based on real-time touch state.
3Speed
If the threshold is increased to improve response speed from touch to non-touch state, then the response speed is improved, but the detection sensitivity may deteriorate
Solution Approach 1:
The patent dynamically adjusts the threshold based on the touch detection signal level rather than using a fixed high threshold. The threshold determination circuit switches between a first level and a second level, allowing the system to maintain detection sensitivity when no touch is present while achieving faster response when transition to non-touch state is needed. This dynamic adjustment prevents detection sensitivity deterioration.
Solution Approach 2:
The patent changes the threshold parameter adaptively based on operational state. By switching between different threshold levels rather than continuously adjusting or permanently setting a high threshold, the system maintains measurement precision for touch detection while achieving improved response speed for state transitions. The parameter change is state-dependent, preserving detection accuracy.
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 increases the response speed of the touch electrode when transitioning from a touch state to a non-touch state, reducing the likelihood of user-perceived slowness and minimizing chattering, while maintaining the response speed from a non-touch state to a touch state, thus improving user experience.
Implementation Method 1
a capacitive touch switch apparatus includes: a touch electrode; a touch detection circuit that generates a capacitance signal indicative of a capacitance of the touch electrode
Data Source
AI summary
A capacitive touch switch apparatus includes a touch electrode; a touch detection circuit that generates a capacitance signal indicative of a capacitance of the touch electrode in accordance with a touch to the touch electrode, and generates and outputs a touch detection signal indicative of presence or absence of the touch by comparing the capacitance signal with a predetermined threshold; and a threshold determination circuit that supplies a threshold determination signal for determining the threshold to the touch detection circuit. The threshold determination circuit supplies the threshold determination signal to the touch detection circuit so as to increase the threshold in accordance with a change of the touch detection signal from a first level indicative of absence of the touch to a second level indicative of presence of the touch.