Touch Sensor Integrated Display Device Electrode Segmentation
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Solution Overview
Problem
Existing touch sensor technologies for display devices face issues with increased thickness and reduced brightness due to add-on type sensors, and increased parasitic capacitance and reduced touch sensitivity with on-cell type sensors.
Innovation Solution
A touch sensor integrated type display device that divides the common electrode into touch driving and sensing electrodes, connects some common electrodes to ground through an electrostatic discharge circuit, and uses resistance reducing wires to minimize mutual capacitance between touch driving and sensing electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If add-on type touch sensor is mounted on display device, then touch functionality is added, but thickness of display device increases
Solution Approach 1:
The patent merges the touch sensor electrodes with the common electrode of the display device by forming the touch sensor electrodes on the same substrate as the common electrode. This integration eliminates the need for separate add-on touch sensor layers, thereby maintaining touch functionality while reducing overall device thickness.
Solution Approach 2:
The common electrode serves dual functions: as the common electrode for liquid crystal driving and as the touch sensing electrode for touch detection. This multi-functionality reduces the number of separate components needed, thereby reducing thickness while maintaining both display and touch capabilities.
2Length of stationary object
If on-cell type touch sensor is formed on glass substrate, then thickness is reduced compared to add-on type, but parasitic capacitance increases and touch sensitivity decreases
Solution Approach 1:
The patent segments the common electrode into multiple regions: a first region that serves as the touch sensing electrode and a second region that serves as the common electrode for liquid crystal driving. This segmentation reduces parasitic capacitance between touch electrodes and the common electrode, thereby improving touch sensitivity while maintaining the thin on-cell structure.
Solution Approach 2:
Different regions of the electrode structure are assigned different functions: the first region is optimized for touch sensing with specific capacitance characteristics, while the second region is optimized for common electrode functionality. This local differentiation reduces unwanted parasitic effects and improves overall touch sensitivity.
3Device complexity
If common electrode is used for both touch driving and sensing, then device complexity is reduced, but static electricity damage risk increases
Solution Approach 1:
The patent introduces an electrostatic discharge circuit as an intermediary protection mechanism. This circuit includes electrostatic discharge electrodes connected to the common electrode and grounded through discharge paths, providing protection against static electricity damage while maintaining the simplified integrated electrode structure.
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
This configuration reduces parasitic capacitance, enhances touch sensitivity, and decreases the thickness of the display device by allowing the common electrode to serve as both touch driving and sensing electrodes, thereby improving touch performance and preventing damage from static electricity.
Implementation Method 1
connecting some of the divided common electrodes to ground through an electrostatic discharge circuit
Data Source
AI summary
A touch sensor integrated type display device includes gate lines and data lines; a plurality of pixel electrodes respectively formed in pixel areas defined by crossings of the gate and data lines; a first electrode formed between first pixel electrodes and in parallel with a first gate line of the gate lines, the first pixel electrodes being adjacent to each other with the first gate line interposed therebetween; second electrodes formed between second pixel electrodes and arranged in a line in parallel with a second gate line adjacent to the first gate line, the second pixel electrodes being adjacent to each other with the second gate line interposed therebetween; and third electrodes, each of which is formed in parallel with the data lines and contacts the second electrodes, at least a portion of each of the third electrodes overlapping the first and second pixel electrodes.