Touch Sensing Circuit for Distinguishing Normal and False Inputs
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Solution Overview
Problem
Conventional touch sensing devices struggle to distinguish between normal touch inputs and unintentional force applications, leading to malfunctions, and they often require significant internal space and are difficult to make dustproof and waterproof.
Innovation Solution
A touch sensing device comprising a substrate with multiple sensors and a sensing circuit that compares oscillation signals generated by first and second sensors to determine the nature of a touch input, distinguishing between normal and malfunctioning inputs based on force values and predetermined reference values, and is designed to be integrated within a housing to replace mechanical buttons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical switches are used to implement switch function, then switch functionality is achieved, but device size and internal space increase
Solution Approach 1:
The patent replaces mechanical switches with a touch sensing device that uses capacitive sensing technology. The touch sensing device includes a touch sensor configured to detect touch input through changes in capacitance, eliminating the need for mechanical moving parts. This substitution reduces internal space requirements while maintaining switch functionality, and enables integration into sleek, modern device designs with smooth surfaces.
Solution Approach 2:
The patent changes the operating principle from mechanical movement to electrical parameter detection. The touch sensor detects touch input by measuring changes in capacitance (electrical parameter) rather than detecting mechanical displacement. This parameter change allows the switch function to be implemented without mechanical components, reducing internal space and enabling dustproof and waterproof designs.
2Reliability
If mechanical switches are used, then switch function is provided, but design quality deteriorates due to protruding shape and non-integral structure
Solution Approach 1:
The patent replaces mechanical switches with a touch sensing device that has no protruding mechanical parts. The touch sensor is integrated into the device housing or display surface, creating a flush, smooth design. The sensor detects touch through electrical field changes rather than mechanical contact, allowing the surface to remain continuous and aesthetically pleasing while providing switch functionality.
Solution Approach 2:
The patent merges the switch function with the device housing or display surface. The touch sensor is integrated into the existing structure rather than being added as a separate mechanical component. This merging creates an integral design where the switch interface is seamlessly combined with the device body, improving design quality and unity of construction.
3Ease of operation
If mechanical switches are used, then switch operation is enabled, but dustproof and waterproof performance deteriorates
Solution Approach 1:
The patent replaces mechanical switches with a touch sensing device that has no moving parts or gaps. The touch sensor detects input through capacitive changes in the sealed surface, eliminating openings that would allow dust and water ingress. The entire surface can be sealed while maintaining touch sensitivity, achieving both ease of operation and environmental protection.
Solution Approach 2:
The patent uses a touch sensor that can be integrated into flexible or sealed surfaces. The sensor structure allows the housing to maintain its protective sealing while providing touch input capability. The thin film or flexible substrate of the touch sensor conforms to the sealed surface, allowing dustproof and waterproof construction without compromising switch operation.
4Volume of moving object
If touch sensor is positioned close to housing surface, then compact design is achieved, but sensor may detect unintended force applications
Solution Approach 1:
The patent uses a sensing circuit that analyzes the characteristics of the signal detected by the touch sensor. The circuit distinguishes between intentional touch input and unintended force application by evaluating signal parameters such as capacitance change magnitude, duration, and pattern. This feedback mechanism allows the system to filter out false triggers while maintaining high sensor proximity to the housing surface for compact design.
Solution Approach 2:
The patent changes the detection parameter from simple force detection to capacitive change detection with signal analysis. The touch sensor measures capacitance changes rather than direct force, and the sensing circuit processes these electrical parameters to distinguish valid touch input from unintended contact. This parameter change enables high reliability even with the sensor positioned close to the housing surface.
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 effectively differentiates between normal touch inputs and unintentional force applications, reducing malfunctions and enabling a more compact, dustproof, and waterproof design for wearable devices.
Implementation Method 1
The first and second oscillation signals may have resonance frequencies that vary in accordance with the applied touch input
Data Source
AI summary
A touch sensing device includes: a substrate; a first sensor disposed on the substrate; a second sensor disposed on the substrate; and a sensing circuit electrically connected to the first sensor and the second sensor. The sensing circuit is configured to compare signals sensed by the first sensor and the second sensor in accordance with an applied touch input and determine whether the applied touch input is normal.