Touch Display Voltage Adjustment Noise
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Solution Overview
Problem
Dynamic changes in the common voltage of touch display panels, such as OLED display panels, cause parasitic capacitance-induced common mode noise, leading to misjudgments during touch sensing operations.
Innovation Solution
A touch display device and method that includes a power management circuit, a display driving circuit, and a touch circuit, where the touch circuit selectively ignores or suspends touch sensing operations during voltage adjustment periods to prevent interference from common mode noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the power management circuit adjusts the common voltage dynamically, then the display quality is improved, but the touch sensing accuracy deteriorates due to parasitic capacitance-induced common mode noise
Solution Approach 1:
The touch circuit suspends touch sensing operations before the common voltage adjustment occurs. The display driving circuit notifies the power management circuit of upcoming voltage adjustments, allowing the touch circuit to proactively pause sensing operations in advance, preventing noise interference before it occurs.
Solution Approach 2:
The patent separates the touch sensing operation timing from the common voltage adjustment timing. By extracting the touch sensing function from continuous operation and suspending it during voltage adjustment periods, the system eliminates the interference between voltage changes and touch sensing measurements.
2Speed
If the touch circuit continuously performs touch sensing operations, then the touch responsiveness is improved, but misjudgments occur during voltage adjustment periods
Solution Approach 1:
The touch circuit operates in periodic intervals rather than continuously. It suspends operations during common voltage adjustment periods and resumes them when voltage is stable, creating a periodic on-off pattern that avoids noise interference while maintaining overall responsiveness.
Solution Approach 2:
The system uses notification signals from the display driving circuit to proactively suspend touch sensing before voltage adjustments occur. This preliminary action prevents misjudgments by pausing sensing operations in advance of known interference events.
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
Prevents misjudgments during voltage adjustment periods by suspending or ignoring touch sensing data, ensuring accurate touch sensing operations on touch display panels.
Implementation Method 1
A parasitic capacitance Cc exists between a common voltage layer and the touch sensing layer 110 of the display panel 120. A voltage adjustment of the display panel 120 becomes a common mode noise CMN of the touch sensing layer 110 through the parasitic capacitance Cc.
Data Source
AI summary
A touch display device and an operation method thereof are provided. The touch display device includes a touch display panel, a power management circuit, a display driving circuit, and a touch circuit. The display driving circuit drives the touch display panel to display an image, and notifies the power management circuit to perform a voltage adjustment of a common voltage supplied to the touch display panel in a voltage adjustment period. The touch circuit individually performs a touch sensing operation on multiple sensing lines of a touch sensing layer of the touch display panel, so as to generate multiple touch sensing data corresponding to the sensing lines. The touch circuit ignores the touch sensing data corresponding to the voltage adjustment period, or the touch circuit suspends performing the touch sensing operation on the sensing lines of the touch sensing layer during the voltage adjustment period.