In-Cell Touch Electrode Layout for Self-Capacitance OLED Displays
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Solution Overview
Problem
Existing display devices face challenges in integrating effective touch sensing capabilities while maintaining a simplified structure and efficient operation of sub pixels, particularly in LED-based displays.
Innovation Solution
The display device incorporates sub pixels with a driving transistor and a light emitting diode, and touch units with a touch sensing transistor and electrode on the same layer, allowing for self-capacitance touch sensing and in-cell touch detection using assembly lines as touch sensing lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate touch sensing structure is added to the display device, then touch sensing capability is improved, but device complexity increases
Solution Approach 1:
The patent combines the touch sensing function with the existing pixel structure by integrating touch electrodes into the same layer as pixel electrodes. This merging approach allows the display device to gain touch sensing capability without adding completely separate touch sensing structures, thereby improving versatility while controlling complexity.
Solution Approach 2:
The patent implements multi-functionality by enabling the display pixels to serve dual purposes: both light emission for display and touch sensing. The pixel electrodes are designed to function as both display elements and touch sensing elements, allowing one structure to perform multiple functions and reducing overall device complexity.
2Device complexity
If touch units are integrated on the same layer as sub pixels, then structure simplification is achieved, but signal interference between display and touch functions may occur
Solution Approach 1:
The patent employs time-divisional driving where display and touch operations are performed in alternating time periods. During display periods, pixel electrodes emit light; during touch sensing periods, the same electrodes sense touch input. This periodic alternation prevents simultaneous operation conflicts and signal interference while maintaining structural integration.
Solution Approach 2:
The patent implements dynamic control by selectively activating different electrode groups at different times. The driving transistor controls the dynamic switching between display mode and touch sensing mode, allowing the system to adapt its function based on operational requirements and preventing signal interference through temporal separation.
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 simplifies the touch unit structure, enables simultaneous and time-divisional driving of sub pixels and touch units, enhancing touch sensitivity and display performance.
Implementation Method 1
each includes a driving transistor, a light emitting diode, and a pixel electrode connecting the driving transistor and the light emitting diode
Implementation Method 2
the pixel electrode and the touch electrode are disposed on the same layer to sense the touch by a self-capacitance manner
Data Source
AI summary
A display device according to an example includes a plurality of sub pixels disposed on a substrate, and a plurality of touch units disposed on the substrate. Each sub pixel can include a driving transistor, a light emitting diode, and a pixel electrode connecting the driving transistor and the light emitting diode. Each touch unit can include a touch sensing transistor and a touch electrode connected to the touch sensing transistor, where the pixel electrode and the touch electrode are disposed on the same layer. Accordingly, the pixel electrode and the touch electrode are disposed on the substrate to sense the touch by a self-capacitance manner.