Touch Display Driving Apparatus for Noise Reduction
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Solution Overview
Problem
In in-cell touch display panels, the difference in charge on gate lines during touch sensing operations affects the accuracy of touch detection due to the time-sharing display and touch driving periods, leading to noise signals that impact judgment.
Innovation Solution
A touch display driving apparatus with a display driver circuit and a touch driver circuit that divides the display frame period into display and touch driving periods, ensuring the touch driving period for a common electrode row is not temporally adjacent to the display driving period of its corresponding gate lines, thereby minimizing charge differences and improving touch sensing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the common electrode layer is electrically connected to the touch sensing circuit for touch sensing during the touch driving period, then the touch sensing function is enabled, but the display operation is interrupted and must be performed in a time-sharing manner
Solution Approach 1:
The patent dynamically switches the electrical connection state of the common electrode layer between two modes: connected to the common voltage source during display driving periods, and connected to the touch sensing circuit during touch driving periods. This dynamic reconfiguration enables the system to adapt between display and touch sensing functions without permanent structural changes.
Solution Approach 2:
The common electrode layer serves multiple functions by being electrically connected to different circuits at different times. It functions as a common electrode for display operation when connected to the common voltage source, and as a touch sensing electrode when connected to the touch sensing circuit, thereby achieving multi-functionality with a single structural element.
2Speed
If the touch driving periods are inserted between display driving periods with higher update frequency, then touch sensing responsiveness is improved, but charge differences on gate lines create noise signals that reduce touch sensing accuracy
Solution Approach 1:
The patent performs preliminary discharge of gate lines during display driving periods before the touch driving period begins. By discharging the gate lines to a reference voltage level during the display operation, the system prepares the gate lines in a known state before touch sensing, reducing the charge difference that would otherwise create noise during touch detection.
Solution Approach 2:
The patent changes the electrical parameter (voltage level) of the gate lines from their driven state during display operation to a discharged reference voltage state before touch sensing. This parameter change eliminates the charge difference between consecutive touch driving periods, thereby reducing noise signals and improving touch sensing accuracy while maintaining high update frequency.
3Reliability
If the common electrode layer is electrically connected to the common voltage source during display driving periods, then the display operation is ensured, but the touch sensing operation must be deferred to non-adjacent touch driving periods
Solution Approach 1:
The patent implements periodic alternation between display driving periods and touch driving periods. During display driving periods, the common electrode is connected to the common voltage source for reliable display operation. During non-adjacent touch driving periods, it is connected to the touch sensing circuit. This periodic switching ensures both display reliability and touch sensing functionality without temporal conflict.
Data Source
AI summary
A touch display driving apparatus and an operation method thereof are provided. A display frame period is divided into a plurality of display driving periods and a plurality of touch driving periods. During the display driving periods, the display driver circuit drives a touch display panel. During the touch driving periods, the touch driver circuit detects common electrode rows of the touch display panel. The common electrode rows are parallel to a plurality of gate lines of the touch display panel. Each of the common electrode rows serves as a current common electrode row, wherein the current common electrode row covers a plurality of corresponding gate lines of the gate lines. The touch driving period during which the current common electrode row being detected is not temporally adjacent to the display driving period during which the corresponding gate lines being driven.