Shielding Electrode Touch Display Noise Reduction
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Solution Overview
Problem
Touch sensing accuracy and sensitivity in display devices are compromised due to parasitic capacitances formed between electrodes for display driving and touch sensing, especially in rear emission structures where noise from display driving interferes with touch sensing signals.
Innovation Solution
Incorporating a shielding electrode between touch electrodes and thin film transistors or light emitting elements, and synchronizing the driving of touch and shielding electrodes to reduce noise and improve signal accuracy, allowing for effective touch sensing independent of display driving periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If touch electrodes and display electrodes are arranged on the display panel, then touch sensing function is enabled, but parasitic capacitances are formed between electrodes causing noise and deteriorating touch sensing accuracy
Solution Approach 1:
A shielding electrode is introduced as an intermediary component between the touch electrode and display electrodes. This shielding electrode acts as a mediator that blocks parasitic capacitance coupling, preventing noise from display driving signals from affecting touch sensing signals, thereby resolving the contradiction between enabling touch sensing and maintaining sensing accuracy
Solution Approach 2:
The patent utilizes the concept of controlled parasitic capacitance by introducing a shielding electrode that creates a defined capacitive coupling path. Instead of allowing uncontrolled parasitic capacitance to cause noise, the shielding electrode establishes a predictable capacitive relationship that can be compensated for through driving schemes, converting the harmful effect into a manageable parameter
2Measurement precision
If shielding electrode is added to reduce noise, then touch sensing accuracy is improved, but device structure and complexity increase
Solution Approach 1:
The shielding electrode is designed to serve multiple functions: it acts as a shield against parasitic capacitance, provides a reference potential for signal compensation, and can be integrated with existing display electrode structures. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving noise reduction
Solution Approach 2:
The shielding electrode structure is merged with the existing display electrode layout and driving circuitry. By integrating the shielding function into the existing structural framework rather than adding completely separate components, the patent minimizes the increase in device complexity while still achieving the noise reduction goal
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 noise-related interference from display driving, enhancing the accuracy and sensitivity of touch sensing in display devices with rear emission structures by isolating touch electrodes from parasitic capacitances and optimizing driving schemes.
Implementation Method 1
there is a problem that the accuracy and sensitivity of touch sensing may be deteriorated due to parasitic capacitances formed between electrodes for display driving and electrodes for touch sensing
Data Source
AI summary
The present disclosure relates to a touch display device, and more specifically, relates to a touch display device having a bottom emission structure. According to the touch display device, by disposing a touch electrode and a touch planarization layer between a substrate and a thin film transistor, a touch sensing function can be implemented without affecting the disposing of components for display driving. Further, by disposing a shielding electrode to which a constant voltage or a signal equal to a touch driving signal is applied between the touch electrode and a light emitting element, a noise of a touch sensing signal caused by display driving can be reduced and the performance of touch sensing performed together with the display driving can be improved.