Transparent Touch Display Cathode Layer Division
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Solution Overview
Problem
Conventional touch display devices with built-in touch sensors face challenges in designing and manufacturing transparent display panels that offer both self-emission and high transmittance, especially when integrated with self-emissive light emitting elements like OLEDs.
Innovation Solution
A transparent touch display device is designed with a touch sensor embedded in the display panel, utilizing a cathode electrode layer division to minimize the impact on transmittance. The touch sensor is strategically placed to overlap the display cathode electrode, and touch lines are disposed in the display panel to maintain high transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a touch sensor is embedded in the display panel, then touch sensing function is integrated and thickness is reduced, but transmittance is deteriorated
Solution Approach 1:
The cathode electrode layer is divided into a display cathode electrode and a touch cathode electrode, allowing separate optimization of display and touch functions. The touch cathode electrode is positioned in the transmissive area while the display cathode electrode is in the pixel area, enabling touch sensing without blocking light transmission paths.
Solution Approach 2:
The touch sensor components are positioned in the vertical stacking direction rather than overlapping the light transmission path in the horizontal plane. The touch cathode electrode and touch lines are disposed in different layers from the display cathode electrode, allowing touch functionality without compromising transmittance.
2Device complexity
If touch lines are disposed in the display panel, then touch sensing is enabled, but transmittance is reduced
Solution Approach 1:
The cathode electrode layer is segmented into display and touch functions, with touch lines connecting touch cathode electrodes in transmissive areas. This separation allows touch lines to be routed without blocking the light transmission path through the pixel areas.
Solution Approach 2:
Touch lines serve as intermediaries connecting touch cathode electrodes to touch driving circuits, positioned in transmissive areas where they can perform their function without interfering with light emission from the pixel areas. The encapsulation layer acts as a mediator protecting these components while maintaining transparency.
3Device complexity
If light emitting elements and touch sensor are placed in the display panel, then self-emissive performance is achieved, but touch sensing is influenced by light emitting element driving
Solution Approach 1:
The cathode electrode layer is divided into display cathode electrodes connected to light emitting elements and touch cathode electrodes connected to touch driving circuits. This electrical separation ensures that driving signals for light emission do not interfere with touch sensing signals, improving touch sensing reliability.
Solution Approach 2:
The touch sensing function is extracted from the display driving circuitry and implemented through separate touch cathode electrodes and touch lines. This extraction isolates touch sensing from the high-current display driving operations, reducing electromagnetic interference and improving touch detection accuracy.
Data Source
AI summary
A transparent touch display device according to embodiments of the disclosure may comprise a substrate including a pixel area, a first transmissive area positioned on a first side of the pixel area, and a second transmissive area positioned on a second side of the pixel area, a driving transistor disposed in the pixel area, an anode electrode disposed in the pixel area, positioned on the driving transistor, and electrically connected with a source electrode or drain electrode of the driving transistor, a light emitting layer positioned on the anode electrode, a display cathode electrode positioned on the light emitting layer, a first touch cathode electrode disposed in the first transmissive area and positioned on a first side of the display cathode electrode, a second touch cathode electrode disposed in the second transmissive area and positioned on a second side of the display cathode electrode, an encapsulation layer disposed on the display cathode electrode, the first touch cathode electrode, and the second touch cathode electrode, and a first touch line overlapping the display cathode electrode.