Touch Display Panel Compensation Patterns for Parasitic Capacitance
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Solution Overview
Problem
Touch display panels face performance degradation due to parasitic capacitance between display electrodes and touch electrodes, leading to inaccurate touch sensing and noise interference.
Innovation Solution
A touch display device with a substrate having active and nonactive areas, featuring touch electrodes, routing wires, and compensation patterns on the encapsulation layer, where the compensation patterns are connected to the routing wires and electrodes to reduce capacitance deviations and noise, improving touch sensing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple touch electrodes and display electrodes are arranged on the display panel, then touch recognition function is provided, but parasitic capacitance is formed between display electrode and touch electrode which degrades touch sensing performance
Solution Approach 1:
An encapsulation layer is introduced as an intermediary between the display electrode and the touch electrode. This encapsulation layer acts as a physical barrier that reduces the parasitic capacitance formed between the display electrode and touch electrode, thereby maintaining touch sensing performance while preserving the touch recognition function
Solution Approach 2:
The touch electrode structure is extracted and arranged on the encapsulation layer rather than directly on the display panel. This separation removes the problematic direct interaction between display electrodes and touch electrodes, eliminating the source of parasitic capacitance while maintaining touch functionality
2Ease of operation
If touch routing wires are used to connect touch electrodes, then touch sensing signals can be transmitted, but load on routing wires causes deviation of touch sensing signals
Solution Approach 1:
Compensation patterns with varying areas are designed to change the capacitance parameters. The compensation capacitance values are adjusted based on the length of routing wires, compensating for the signal deviation caused by routing wire load and improving measurement precision
3Adaptability or versatility
If touch sensor metal is arranged on display panel, then touch sensing function is enabled, but noise sources are generated which degrade accuracy of touch sensing signals
Solution Approach 1:
The encapsulation layer serves as an intermediary that physically separates the touch sensor metal from the display electrodes, reducing parasitic capacitance and minimizing noise sources while maintaining touch sensing functionality
Solution Approach 2:
The parasitic capacitance that initially causes noise is converted into a useful compensation mechanism. Compensation patterns are designed to utilize capacitance effects in a controlled manner, transforming the harmful parasitic capacitance into a beneficial element for signal stabilization
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 capacitance deviations and noise, enhancing the accuracy and reliability of touch sensing signals by compensating for the load on touch routing wires and mitigating noise sources, thereby improving overall touch sensing performance.
Implementation Method 1
multiple first compensation patterns arranged in the nonactive area and electrically connected to the plurality of touch routing wires; and multiple second compensation patterns arranged on the encapsulation layer corresponding to the multiple first compensation patterns
Data Source
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AI summary
Example embodiments of the present disclosure relate to a touch display device. In one example, a touch display device includes a substrate including an active area in which multiple subpixels are arranged and a nonactive area positioned outside the active area; wherein each of the multiple subpixels includes a first electrode, an organic light emitting layer and a second electrode on the organic light emitting layer; an encapsulation layer arranged on the second electrode; a plurality of touch electrodes and a plurality of touch routing wires arranged on the encapsulation layer; a touch sensing circuit configured to drive the plurality of touch electrodes through the plurality of touch routing wires; multiple connection patterns arranged on the encapsulation layer in the active area so as to electrically connect at least a portion of the plurality of touch electrodes to each other; multiple first compensation patterns arranged in the nonactive area and electrically connected to the plurality of touch routing wires; and multiple second compensation patterns arranged on the encapsulation layer corresponding to the multiple first compensation patterns.