Touch Display EMI Reduction via Reverse Phase Signal
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Solution Overview
Problem
Existing touch display apparatuses experience increased electromagnetic interference (EMI) due to touch driving signals, which affects system stability and touch sensing performance, and can also impact peripheral electronic devices.
Innovation Solution
The use of a reverse phase signal corresponding to the touch driving signal for touch driving in the touch display apparatus, which reduces EMI levels without requiring additional lines or pins on the display panel or printed circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a touch driving signal is applied to touch electrodes for touch sensing, then touch sensing function is enabled, but electromagnetic interference (EMI) level increases
Solution Approach 1:
The patent applies preliminary anti-action by generating a compensation signal that is the inverse phase of the touch driving signal before the EMI problem occurs. This compensation signal is injected into the sensing electrode to preemptively counteract the electromagnetic interference that would otherwise be generated by the touch driving signal, thereby preventing the harmful EMI effect while maintaining touch sensing functionality.
Solution Approach 2:
The patent converts the harmful EMI effect into a beneficial outcome by using the inverse phase signal to cancel out the electromagnetic interference. The compensation signal, which is generated based on the touch driving signal characteristics, transforms the potential harmful EMI into a useful cancellation mechanism that improves overall system performance and reduces interference with peripheral devices.
2Measurement precision
If a high voltage pulse type signal is used for touch driving, then touch sensing sensitivity is improved, but EMI level increases and system stability deteriorates
Solution Approach 1:
The patent applies preliminary anti-action by generating a compensation signal that is the inverse phase of the high voltage pulse type touch driving signal. This compensation signal is injected into the sensing electrode to preemptively counteract the electromagnetic interference and stability issues that would otherwise be caused by the high voltage pulse signal, thereby enabling the use of high voltage pulses for improved sensitivity while preventing the associated harmful effects.
3Object-generated harmful factors
If additional lines or pins are added to reduce EMI, then EMI level decreases, but device complexity increases
Solution Approach 1:
The patent applies merging by combining the compensation signal function with the existing touch driving signal transmission path. The inverse phase signal is generated and injected through existing circuitry and lines, merging the EMI reduction function into the existing structure without requiring additional lines or pins, thereby reducing EMI levels while avoiding increased device complexity.
Solution Approach 2:
The patent applies universality by making the existing touch driving lines serve dual functions: transmitting the touch driving signal and carrying the compensation signal for EMI reduction. This multi-functionality approach allows the same lines to perform both driving and interference cancellation tasks, eliminating the need for additional dedicated lines or pins for EMI reduction.
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 approach effectively minimizes EMI levels, enhancing the stability of the touch display system and improving touch sensing performance while avoiding the need for additional components or infrastructure.
Implementation Method 1
The use of a reverse phase signal corresponding to the touch driving signal for touch driving in the touch display apparatus
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~5
AI summary
A touch display apparatus is disclosed, which includes a display panel (110) on which pixels and touch electrodes (TE) are disposed, a main power integrated circuit (200) generating a common voltage (Vcom) signal applied to the touch electrodes (TE) and at least one gate voltage signal applied to the pixels, a touch power integrated circuit (300) outputting a touch driving signal (Vcom_TDS) of a pulse type in accordance with a touch synchronization signal (Tsync) that defines a display driving period (DS) and a touch driving period (TS), outputting a load free driving signal (VGL_LFD) of the pulse type by using a gate low voltage (VGL) signal of the at least one gate voltage signal, and outputting at least one pseudo touch driving signal corresponding to a pulse patterns of the touch driving signal (Vcom_TDS) and the load free driving signal (VGL_LFD) and having reverse phase which is inverted, by using at least one gate high voltage signal of the at least one gate voltage signal, and a gate driving circuit (140) supplying a gate pulse based on the at least one gate voltage signal to gate lines (GL) connected to the pixels for the display driving period (DS), and supplying the load free driving signal (VGL_LFD) to the gate lines (GL) for the touch driving period (TS).