Flexible Touch Panel Cathode Interference Shielding
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Solution Overview
Problem
The interference from the electron emitting layer (cathode) of flexible OLED touch panels poses a significant challenge for in-cell touch technology, as the thin film packaging material is close to the cathode, affecting the touch sensor signals and reducing their sensitivity.
Innovation Solution
A flexible touch panel design is implemented with a conductive layer, insulation layers, and a protection layer on an OLED substrate, where the conductive layer is used to input a voltage signal that shields signal interference from the cathode, enhancing the sensitivity of the touch sensor by expelling electric field lines and forming a capacitor structure for effective touch signal sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thin film packaging material is used to package the OLED substrate, then the flexibility and thinness of the display module is improved, but the packaging material is close to the cathode which causes electric field interference to the touch sensor signals
Solution Approach 1:
A conductive layer is introduced as an intermediary between the packaging layer and the first electrode layer. This conductive layer serves as a shield that blocks the electric field lines from the cathode from directly reaching the touch sensor, thereby eliminating the harmful interference while maintaining the thin and flexible structure.
Solution Approach 2:
The harmful electric field interference is extracted and redirected away from the touch sensor by the conductive layer. The conductive layer captures the electric field lines from the first electrode layer and guides them towards the second electrode layer, preventing them from interacting with the cathode's electric field.
2Device complexity
If the touch sensor is incorporated directly on the flexible OLED touch panel (in-cell touch), then the integration and flexibility are improved, but the cathode's electric field directly influences the touch sensor driving signals causing reduced signal sensitivity
Solution Approach 1:
The conductive layer acts as a protective intermediary that separates the cathode's electric field from the touch sensor's operating electric field. By introducing this intermediate layer, the touch sensor can maintain high sensitivity while being integrated directly on the flexible OLED panel.
Solution Approach 2:
The conductive layer pre-establishes a shielding effect against the cathode's electric field before the touch sensor signals are affected. This preliminary protective action prevents the harmful interference from occurring in the first place, ensuring signal sensitivity is maintained.
3Measurement precision
If the conductive layer is added to shield the electric field interference, then the touch signal sensitivity is improved, but the device structure becomes more complex
Solution Approach 1:
The conductive layer serves multiple functions simultaneously: it acts as an electric field shield to block interference from the cathode, serves as an electrode in the capacitor structure for touch sensing, and maintains the flexibility of the overall structure. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The conductive layer merges the shielding function with the electrode function in a single integrated component. Rather than adding a separate shield layer, the conductive layer performs both the shielding role and the capacitive sensing role, thereby reducing overall structural complexity.
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 design effectively shields signal interference from the cathode, improving the sensitivity of the touch sensor and enabling better detection of touch signals, while maintaining the flexibility of the OLED substrate.
Implementation Method 1
the first voltage signal is utilized to have the conductive layer expelling electric field lines generated by the first electrode layer so as to shield signal interference between the first electrode layer and a cathode layer
Implementation Method 2
the first electrode layer, the second insulation layer, and the second electrode layer form a capacitor structure for sensing a touch signal
Data Source
AI summary
A flexible touch panel located on an OLED substrate is provided. The flexible touch panel includes a conductive layer, a first insulation layer, a first electrode layer, a second insulation layer, a second electrode layer, and a protection layer disposed in a serial. The conductive layer is disposed on a packaging layer of the OLED substrate. The first insulation layer and the first electrode layer are stacked on the conductive layer. The first electrode layer, the second insulation layer, and the second electrode layer form a capacitor structure for sensing a touch signal. The conductive layer is utilized for inputting a first voltage signal. The first voltage signal has the conductive layer expelling electric field lines generated by the first electrode layer to shield signal interference between the first electrode layer and a cathode layer of the OLED substrate. A manufacturing method thereof and a touch device are also provided.