OLED Cathode Holes for Touch Field Transmission
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Solution Overview
Problem
Existing display devices with integrated touch panels, such as liquid crystal display devices and OLEDs, face challenges in reducing device size and component count while maintaining effective touch functionality, particularly in top-emission pixel structures where the conventional cathode electrode blocks electric fields from touch panel electrodes.
Innovation Solution
The display device incorporates a top-emission pixel structure with a cathode electrode featuring holes formed by perforating walls, allowing electric fields from touch panel electrodes to pass through and reach the contact surface, and integrates touch panel control functions into the driver IC, reducing the number of components and manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional cathode electrode is used in a top-emission pixel structure, then light transmission is maintained, but electric fields from touch panel electrodes are blocked and cannot reach the contact surface
Solution Approach 1:
The cathode electrode is segmented by forming holes (first through-holes and second through-holes) through it, creating multiple discrete conductive regions separated by insulating walls. This segmentation allows electric fields to pass through the holes while maintaining the electrode's light transmission function, resolving the contradiction between blocking electric fields and maintaining touch functionality.
Solution Approach 2:
Insulating walls are introduced as intermediary structures between the segmented cathode electrode regions. These walls filled with insulating material serve as mediators that electrically isolate adjacent electrode regions while allowing electric fields to pass through the holes, enabling touch functionality without compromising the electrode's structural integrity.
2Device complexity
If the number of components is reduced to simplify device structure, then manufacturing complexity decreases, but maintaining effective touch functionality becomes more difficult
Solution Approach 1:
The cathode electrode structure is merged with the touch panel electrode structure by forming holes through the cathode electrode and using the same insulating walls for both electrical isolation and structural support. This merging allows the display device to maintain touch functionality with a simplified structure, reducing the number of separate components needed.
Solution Approach 2:
The cathode electrode is designed to serve multiple functions: it acts as both the light-emitting electrode for the OLED and as part of the touch panel electrode structure. The holes and insulating walls in the cathode electrode simultaneously provide electrical isolation for touch sensing and maintain structural integrity, giving the component universal functionality.
3Reliability
If holes are formed in the cathode electrode to allow electric field passage, then touch functionality is enabled, but the structural integrity and light transmission may be compromised
Solution Approach 1:
The cathode electrode is designed with a porous structure containing first through-holes and second through-holes. This porous design allows electric fields to pass through while the remaining electrode material maintains structural integrity. The insulating walls filling these holes further reinforce the structure while enabling electrical isolation.
Solution Approach 2:
The cathode electrode structure is created as a composite by forming holes and filling them with insulating material. This composite structure combines the conductive properties of the electrode material with the insulating and structural properties of the filled material, maintaining both structural integrity and electric field transmission capability.
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 enables a simpler structure, reduced device size, and improved touch functionality by allowing the detection of contact points without increasing the number of components or thickness, while maintaining effective light transmission and display performance.
Implementation Method 1
The upper electrode is an electrode configured to transmit light from the organic light-emitting layers toward the encapsulation structural unit
Implementation Method 2
Electric fields generated by the touch panel electrodes pass through the holes in the upper electrodes
Data Source
AI summary
A display device includes an insulating substrate, an encapsulation structural unit opposed to the insulating substrate, lower electrodes and one upper electrode disposed between the insulating substrate and the encapsulation structural unit, and organic light-emitting layers each disposed between the one upper electrode and one of the lower electrodes, perforating walls standing toward the encapsulation structural unit, circuits formed between the insulating substrate and the lower electrodes to control supply of electric current to the lower electrodes, and touch panel electrodes formed between the insulating substrate and the lower electrodes. The upper electrode is an electrode configured to transmit light from the organic light-emitting layers toward the encapsulation structural unit and has holes each formed in such a manner that one of the perforating walls stands through the hole. Electric fields generated by the touch panel electrodes pass through the holes in the upper electrodes.