In-Cell Touch Electrode Switching for Faster Coordinate Output
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Solution Overview
Problem
Existing display systems with touch detection functions require improvements in reducing the time from touch to outputting touch coordinates, particularly in in-cell touch displays.
Innovation Solution
A display system with a control device that includes a touch detection circuit with multiple common electrodes and switches, allowing for time division between image display and touch detection, using A/D conversion circuits to enhance touch detection speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If touch detection is performed continuously on all common electrodes, then touch detection accuracy is improved, but the time to output touch coordinates increases
Solution Approach 1:
The patent divides the touch detection process into segments by grouping common electrodes into different sets (first set, second set, third set) and performing detection on different sets during different time periods. This segmentation allows the system to detect touches on multiple electrode groups simultaneously or in rapid succession, improving both detection accuracy and response time.
Solution Approach 2:
The patent implements periodic touch detection by alternately switching between different electrode sets in a predetermined sequence. The touch detection circuit periodically selects different common electrodes or electrode groups for detection based on time division multiplexing, enabling efficient utilization of detection resources while maintaining accurate touch detection across the entire display surface.
2Speed
If multiple A/D conversion circuits are used for parallel touch detection, then touch detection speed is improved, but device complexity increases
Solution Approach 1:
The patent employs dynamic switching mechanisms where the touch detection circuit can dynamically select and switch between different common electrodes and A/D conversion circuits based on the current detection phase. This dynamic allocation allows the system to achieve parallel detection capabilities while maintaining flexibility and reducing the need for dedicated A/D converters for every electrode.
Solution Approach 2:
The patent makes the A/D conversion circuits multi-functional by having them serve multiple common electrodes at different time periods. The same A/D conversion circuit can be reused across different electrode groups through time division multiplexing, reducing the total number of A/D converters needed while maintaining high detection speed through parallel processing of multiple electrode sets.
3Measurement precision
If common electrodes are arranged in a dense matrix for high-resolution touch detection, then touch detection precision is improved, but signal line complexity increases
Solution Approach 1:
The patent resolves the signal line complexity issue by transitioning from a purely spatial arrangement to a temporal dimension. Instead of providing dedicated signal lines for every electrode simultaneously, the system uses time division multiplexing where electrodes are activated and detected in sequential time slots, effectively adding a time dimension to the electrode-addressing scheme and reducing the number of simultaneous signal connections required.
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 system significantly reduces the time to output touch coordinates by alternating between image display and touch detection periods, improving operational efficiency and accuracy.
Implementation Method 1
a first A/D conversion circuit that performs A/D conversion on a signal supplied to a first input node; and a second A/D conversion circuit that performs A/D conversion on a signal supplied to a second input node
Data Source
AI summary
A touch detection circuit performs detection of a touch by an object to a display device, based on a touch detection signal received from each of multiple common electrodes of the display device. One of a set of first and second common electrodes and a set of first and third common electrodes is arranged in the same column, and the other is arranged in the same row. At least one of the sets are adjacent to each other. First and second A/D conversion circuits perform A/D conversion on a signal supplied to a first input node and a signal supplied to a second input node, respectively. First, second, and third switches switch between conduction and non-conduction between the first common electrode and the first input node, between the second common electrode and the second input node, and between the third common electrode and the first input node, respectively.