Touch Display Parasitic Capacitance Reduction via Insulation Mediator
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Solution Overview
Problem
In display devices with touch functions, the close proximity of touch electrodes to cathode electrodes leads to parasitic capacitance, causing incomplete charging and discharging of touch capacitance, resulting in detection errors and reduced touch performance.
Innovation Solution
A display device with a touch driving chip and a signal conversion unit that provides specific driving signals to the touch driving electrode and cathode electrode, respectively, to ensure complete charging and discharging cycles, reducing the impact of parasitic capacitance and enhancing touch detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the touch layer is deposited directly on the encapsulation layer to reduce cost and thickness, then the device structure is simplified and cost is reduced, but the spacing between touch electrode and cathode electrode becomes small resulting in large parasitic capacitance
Solution Approach 1:
An insulation layer is introduced as an intermediary between the cathode electrode and touch electrode. This insulation layer acts as a mediator that reduces the harmful parasitic capacitance coupling between the two electrodes while maintaining the overall compact structure and reducing costs compared to traditional multi-layer encapsulation approaches.
2Length of stationary object
If the spacing between touch electrode and cathode electrode is reduced to decrease device thickness, then the device becomes thinner, but the parasitic capacitance increases causing detection errors
Solution Approach 1:
The insulation layer serves as a mediator that enables reduced electrode spacing (thinner device) while preventing excessive parasitic capacitance. By introducing this intermediate layer, the patent achieves both goals: decreased device thickness and maintained touch detection accuracy through reduced parasitic coupling.
Solution Approach 2:
The patent changes the electrical parameters of the system by introducing an insulation layer with specific dielectric properties. This parameter change (adding insulation) allows the spacing parameter to be reduced while keeping the parasitic capacitance parameter within acceptable limits, thus maintaining detection precision.
3Ease of manufacture
If the touch electrode is positioned close to the cathode electrode to simplify structure, then manufacturing is simplified, but the parasitic capacitance affects touch capacitance charging and discharging causing detection errors
Solution Approach 1:
The insulation layer is introduced as a manufacturing-friendly intermediary that maintains the simplified direct-deposition structure while improving signal reliability. This layer can be integrated into existing manufacturing processes and effectively reduces parasitic capacitance interference, ensuring reliable touch signal detection.
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 accelerates charging and discharging of touch driving electrodes, allowing the touch capacitance to reach standard values, thereby improving touch detection accuracy and minimizing detection errors.
Implementation Method 1
there would be a small spacing between a touch electrode in the touch layer and a cathode electrode in the array layer, thereby resulting in a large parasitic capacitance between the touch electrode and the cathode electrode
Data Source
AI summary
Provided is a display device including: a display panel including a cathode layer including a cathode electrode, and touch electrodes including a touch driving electrode; a touch driving chip electrically connected to and providing a touch driving signal to the touch driving electrode; and a signal conversion unit electrically connected to a first electrode and providing a first driving signal to the first electrode. During the charging period, the touch driving signal is charged from a first level to a second level, and the first driving signal is charged from a third level to a fourth level. During the discharging period, the touch driving signal is discharged from the second level to the first level, and the first driving signal is discharged from the fourth level to the third level. The first electrode is the cathode electrode, or located between the touch driving electrode and the cathode electrode.