In-Cell Touch Display Driver Timing Optimization
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Solution Overview
Problem
In display devices with integrated in-cell type touch screens, the display driving time is insufficient due to the time division between display and touch sensing periods, leading to inefficiencies in high-resolution displays.
Innovation Solution
The display device includes a panel with electrodes divided into groups, where a display driver IC applies a common voltage during display driving modes and a touch scan signal during touch driving modes, optimizing the timing to increase display driving time and reduce touch driving time by sequentially applying signals to adjacent electrode units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the display device uses time-division driving for both display and touch sensing periods, then both functions can be integrated in a single device, but the display driving time becomes insufficient for high-resolution displays
Solution Approach 1:
The electrodes are divided into multiple groups (first group, second group, third group, etc.) that can be sequentially activated. During touch sensing period, only specific electrode groups are activated at different time slots rather than all electrodes simultaneously, allowing extended display driving time while maintaining integrated functionality.
2Reliability
If all electrodes are activated simultaneously for touch sensing, then touch detection coverage is maximized, but display driving time is reduced
Solution Approach 1:
Touch sensing is performed periodically by sequentially activating different electrode groups in different time slots. The first electrode group is activated during first time slot, second electrode group during second time slot, and so on. This periodic activation maintains comprehensive touch detection coverage while extending the overall display driving time.
3Speed
If touch sensing is performed in every frame period, then touch responsiveness is improved, but display driving time is further reduced
Solution Approach 1:
Instead of activating all electrodes for touch sensing in every frame, only specific electrode groups are activated in specific time slots. This partial action approach maintains adequate touch responsiveness by sampling different electrode groups sequentially, while significantly extending the display driving time compared to full-electrode simultaneous activation.
Data Source
AI summary
Disclosed is a display device with integrated touch screen. The display device includes a panel configured to include a plurality of electrodes divided into n groups; and a display driver IC configured to, apply a common voltage to the electrodes during a display driving mode of a first frame, apply a touch scan signal to a first group and a first adjacent electrode unit included in a second group during a touch driving mode of the first frame, apply the common voltage to the electrodes during the display driving mode of a second frame, and apply the touch scan signal to the second group and a second adjacent electrode unit included in the first group adjacent to the second group during the touch driving mode of the second frame.