Capacitive Touch Button Shielding Against Electromagnetic Interference
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Solution Overview
Problem
Touch sensitive apparatus utilizing capacitive sensing principles is prone to electromagnetic interference from the surrounding environment, leading to incorrect input detection.
Innovation Solution
A touch sensitive structure is designed with multiple electrode layers and wires, where a conductive layer is strategically placed between external conductive objects and the wires to prevent electromagnetic interference, and is connected to a direct current voltage or floating voltage to enhance interference resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive sensing principles are used to detect touch input, then the touch sensitive apparatus can detect variations of weak currents, but it becomes prone to electromagnetic interference from the surrounding environment
Solution Approach 1:
A conductive layer is introduced as an intermediary between the external environment and the wire connecting the touch button electrode. This conductive layer acts as a shield that intercepts electromagnetic interference before it can affect the wire and cause false touch detections, while allowing the capacitive sensing function to operate normally
Solution Approach 2:
The patent utilizes the conductive layer to convert the harmful electromagnetic interference into a beneficial shielding effect. By placing the conductive layer in proximity to the wire, it attracts and redirects electromagnetic fields away from the sensitive capacitive sensing circuitry, thereby protecting the system from interference while maintaining detection sensitivity
2Reliability
If a conductive layer is added to shield wires from electromagnetic interference, then interference resistance is enhanced, but device complexity increases
Solution Approach 1:
The conductive layer is designed to serve multiple functions: it shields the wire from electromagnetic interference, maintains the capacitive sensing functionality, and can be integrated with existing touch panel structures. This multi-functionality reduces the need for additional separate shielding components, thereby limiting the increase in device complexity
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 reduces electromagnetic interference, preventing incorrect input detection and ensuring accurate touch button recognition.
Implementation Method 1
a conductive layer being arranged in between an external conductive object on top of the touch sensitive structure and at least one of following: the first wire; and the second wire
Implementation Method 2
Touch sensitive apparatus utilizing capacitive sensing principles becomes one of common input apparatus of modern electronic systems. By detecting variations of weak currents, it is used to determine whether external conductive objects such as fingers approaches or touches touch electrodes
Data Source
AI summary
A touch sensitive structure, comprising: two electrode layers for forming a touch area; and a touch button outside of the touch area. The touch button comprises two button electrodes and two corresponding wires in these two electrode layers, respectively; and a conductive layer being arranged in between a finger on top of the touch sensitive structure and one of the two wires.