Touch Panel Frequency Switching to Reduce EMI Between Driving ICs
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Solution Overview
Problem
Display devices with touch panels experience electromagnetic interference (EMI) between touch electrodes due to driving signals from different touch driving ICs, which deteriorates display quality and introduces noise.
Innovation Solution
A display device with a touch panel and touch controller that uses separate touch driving ICs for different sensing areas, where each IC provides driving signals with distinct frequencies that change at predetermined time points, reducing EMI by alternating frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple touch driving ICs are used to control different sensing areas, then the touch panel can be driven effectively, but electromagnetic interference occurs between touch electrodes
Solution Approach 1:
The patent changes the frequency parameter of driving signals from different touch driving ICs to different values. Specifically, the first touch driving IC operates at a first frequency while the second touch driving IC operates at a second frequency that is different from the first frequency. This frequency differentiation reduces electromagnetic interference between touch electrodes in different sensing areas while maintaining effective touch panel driving capability.
2Ease of operation
If driving signals are supplied to touch electrodes, then touch detection is enabled, but noise is introduced in the display device
Solution Approach 1:
The patent applies frequency differentiation to driving signals from multiple touch driving ICs. By setting the first driving signal at a first frequency and the second driving signal at a second frequency (different from the first), the patent enables effective touch detection while reducing noise and electromagnetic interference in the display device.
Data Source
AI summary
A display device includes a touch panel including touch electrodes and a touch controller. The touch controller provides a driving signal to the touch electrodes and detects a touch and a touch position by sensing a change in values of capacitance formed between the touch electrodes and a common electrode. The touch controller includes a first touch driving IC corresponding to first touch electrodes in a first sensing area and a second touch driving IC corresponding to second touch electrodes included in a second sensing area. A first driving signal provided to the first touch electrodes from the first touch driving IC and a second driving signal provided to the second touch electrodes from the second touch driving IC have different frequencies.