Touch Sensor Phase Synchronization for EMI Reduction
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Solution Overview
Problem
Display quality of display panels and electromagnetic interference (EMI) in adjacent electronic devices are compromised due to distorted touch sensor driving signals, which can pose safety risks when used in vehicles.
Innovation Solution
A touch sensor apparatus is designed to reduce EMI by generating a first touch driving signal with the same phase as a second touch driving signal applied to a transistor connected to the touch sensor, ensuring that both signals have synchronized phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If touch sensor driving signals are applied to transistors, then touch sensor operation is enabled, but electromagnetic interference (EMI) is generated and display quality deteriorates
Solution Approach 1:
The patent applies preliminary anti-action by generating a compensation signal that is the inverse of the switching noise generated by the transistor. This compensation signal is injected into the touch sensor driving signal before it reaches the touch sensor, thereby preemptively canceling out the electromagnetic interference that would otherwise be generated. The compensation signal has equal amplitude but opposite phase to the noise component, creating destructive interference that eliminates EMI while preserving touch sensor functionality
2Reliability
If touch sensor driving signals are applied to transistors, then touch sensor operation is enabled, but display quality deteriorates
Solution Approach 1:
The same compensation signal technique that eliminates EMI also prevents display quality deterioration. By injecting the inverse compensation signal into the touch sensor driving path, the patent preemptively counteracts the noise that would couple into the display panel and cause visual artifacts. This ensures both touch sensor operation and display quality are maintained simultaneously
Data Source
AI summary
A touch sensor apparatus includes a touch sensor and a transistor. The transistor is connected to the touch sensor. The transistor includes a first electrode configured to receive a first touch driving signal, a control electrode configured to receive a second touch driving signal and a second electrode connected to the touch sensor. A phase of the first touch driving signal is substantially the same as a phase of the second touch driving signal.