Self-Capacitive Touch OLED Panel Cathode Integration
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Solution Overview
Problem
Integrating embedded self-capacitive touch technology with organic electroluminescent technology in OLED displays poses challenges in maintaining display quality and reducing panel thickness while ensuring a whole layer cathode structure.
Innovation Solution
A self-capacitive touch display panel is designed with top-emitting type organic electroluminescent structures sharing a cathode, featuring self-capacitive touch electrodes positioned above the cathode, insulated from it, and connected to a touch detection circuit, using transparent conducting materials like ITO or graphene, and a resin insulating layer to minimize interference and allow simultaneous touch and display functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If self-capacitive touch electrodes are added above the cathode, then touch function is integrated with OLED display, but panel thickness increases and display quality may deteriorate
Solution Approach 1:
The patent merges the touch electrode layer with the OLED cathode layer by using the cathode as the self-capacitive touch electrode. This integration eliminates the need for separate touch electrode layers above the cathode, thereby reducing panel thickness while maintaining both display and touch functions. The cathode serves dual purposes: as the electron injection electrode for OLED and as the self-capacitive touch sensing electrode.
Solution Approach 2:
The cathode is designed to perform multiple functions simultaneously: it acts as the cathode for organic electroluminescent light emission and as the self-capacitive touch electrode for touch detection. This multi-functionality reduces the number of additional layers needed, thereby reducing overall panel thickness while integrating touch capability into the display structure.
2Adaptability or versatility
If self-capacitive touch electrodes are positioned above the cathode, then touch detection is enabled, but electric potential interference between touch and display functions increases
Solution Approach 1:
By merging the touch electrode function with the cathode, the patent eliminates the spatial separation between touch and display functions. Since the cathode is at a fixed potential during display operation, using it as the touch electrode ensures that touch detection occurs at the same electric potential level, thereby minimizing electric potential interference between the two functions.
Solution Approach 2:
The patent utilizes the cathode's inherent electric potential during display operation for touch detection as well. By keeping the touch electrode (cathode) at the same potential as the display function requires, the system achieves equipotential operation, minimizing interference between touch sensing and light emission functions.
3Reliability
If a resin insulating layer is added between cathode and touch electrodes, then insulation is improved, but panel thickness increases
Solution Approach 1:
The patent merges the insulation function into the existing OLED encapsulation structure rather than adding a separate resin insulating layer. The encapsulation layers that are already present for protecting the OLED organic materials also serve as insulating layers for the touch electrodes, thereby providing necessary insulation without increasing panel thickness.
Solution Approach 2:
The encapsulation layers of the OLED structure perform dual functions: protecting the organic electroluminescent materials from environmental degradation and providing electrical insulation for the self-capacitive touch electrodes. This multi-functionality eliminates the need for additional dedicated insulating layers, thereby maintaining thin panel profile while ensuring adequate insulation.
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 integration reduces panel thickness, maintains display quality, and ensures a whole layer cathode structure, effectively counteracting capacitance effects to ensure consistent electric potential and minimal interference between touch and display functions.
Implementation Method 1
When the human body touches the screen, the capacitance values of the touched self-capacitance electrodes are changed. During the touch phase, a touch detection circuit may determine touch position by detecting the changes of the capacitance values of the self-capacitance electrodes.
Implementation Method 2
a resin insulating layer disposed between the cathode and the self-capacitive touch electrodes
Data Source
AI summary
The present disclosure discloses a self-capacitive touch display panel and a display device, comprising: a substrate, and a plurality of top-emitting type organic electroluminescent structures disposed on the substrate and sharing one cathode. The self-capacitive touch display panel further comprises: a plurality of self-capacitive touch electrodes disposed at the same layer, positioned above the cathode and insulated with the cathode; a plurality of touch leads electrically connected with the plurality of self-capacitive touch electrodes; and a touch detection circuit, configured to determine a touch position by detecting the change of the capacitance values of the self-capacitive touch electrodes during a touch phase. The self-capacitive touch electrodes are connected with the touch detection circuit by way of the respective touch leads. The touch display panel reduces its thickness, guarantees a whole layer cathode structure of the organic electroluminescent structures and effectively guarantees the display quality.