Touch Display Common-Electrode Circuit for Parasitic Noise
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Solution Overview
Problem
Parasitic capacitance between the display panel and the touch panel in touch display devices increases with distance, causing noise during touch sensing and deteriorating both touch sensitivity and image quality.
Innovation Solution
A touch display device design that includes a common electrode coupled to source lines and touch electrodes through capacitors, with a touch driving circuit generating touch information based on the difference between touch signals and driving signals, and correcting touch signals using gray information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the distance between the display panel and the touch panel increases, then the parasitic capacitance increases, but the touch sensing sensitivity deteriorates and image quality deteriorates
Solution Approach 1:
The patent introduces a common electrode as an intermediary component between the display panel and the touch panel. This common electrode is coupled to both the display panel and the touch panel through capacitors, serving as a mediator that reduces parasitic capacitance while maintaining electrical isolation. The intermediary structure allows the system to benefit from reduced noise interference without sacrificing touch sensing sensitivity or image quality
Solution Approach 2:
The patent extracts the common electrode as a separate, independent component from both the display panel and the touch panel. By taking out the common electrode as a distinct element coupled through capacitors, the design separates the functions of the display panel and touch panel while reducing their electromagnetic interference. This extraction allows the common electrode to serve as a dedicated noise reduction element without being part of either panel's internal structure
2Object-affected harmful factors
If the distance between the display panel and the touch panel increases, then the parasitic capacitance increases, but the image quality deteriorates
Solution Approach 1:
The common electrode acts as an intermediary that protects the image quality by reducing noise interference from the touch panel. The capacitor-coupled common electrode structure filters out parasitic capacitance effects, ensuring that image data signals remain clean and undistorted even when the distance between panels increases
Solution Approach 2:
By extracting the common electrode as a separate component, the patent isolates the image quality-critical display panel from the noise-generating touch panel. The common electrode is taken out as a dedicated noise reduction element that does not interfere with the display panel's image rendering function
3Reliability
If a separate touch driving circuit is added to generate touch driving signals, then the touch sensing function is improved, but the device complexity increases
Solution Approach 1:
The patent merges the touch driving circuit with the existing display driving circuit, allowing the display driving circuit to generate both display data signals and touch driving signals. This consolidation eliminates the need for a completely separate touch driving circuit, reducing device complexity while maintaining reliable touch sensing functionality
Solution Approach 2:
The display driving circuit is designed to perform multiple functions: driving the display panel and generating touch driving signals for the touch panel. This multi-functionality approach allows a single circuit to serve dual purposes, reducing overall device complexity while ensuring reliable operation of both display and touch sensing functions
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
Reduces noise interference, enhancing touch sensitivity and image quality while operating with low power consumption.
Implementation Method 1
a plurality of first capacitors between the plurality of source lines and the common electrode; and a plurality of touch electrodes coupled to the common electrode through a plurality of second capacitors
Data Source
AI summary
A touch display device, including a display panel including: a plurality of source lines configured to provide a plurality of source signals to a plurality of pixels, and a common electrode coupled to the plurality of source lines; a plurality of touch electrodes coupled to the common electrode, and configured to provide a plurality of touch signals according to a plurality of touch driving signals received from the common electrode; and a touch driving circuit configured to generate a plurality of pieces of touch information based on a difference between the plurality of touch signals and each of the plurality of touch driving signals.