OLED Display Panel Storage Capacitor Layout for Aperture Ratio
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Solution Overview
Problem
In OLED display panels, particularly bottom-emitting and dual-sides emitting types, the arrangement of storage capacitors leads to a small effective light emitting region and a low aperture ratio, complicating the manufacturing process and increasing costs when touch sensing elements are integrated.
Innovation Solution
The design incorporates a capacitor dielectric layer within the sub-pixel, positioning the storage capacitor between substrates to increase the storage capacitor area, and integrates self-capacitance or mutual-capacitance sensing electrodes with the patterned conductive layer to enable both touch and display functions, while minimizing the impact on the light emitting region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the storage capacitor is arranged in the sub-pixel area, then the storage capacitor can be integrated into the display panel, but the effective light emitting region becomes very small and the aperture ratio becomes relatively small
Solution Approach 1:
The storage capacitor is positioned between the first substrate and second substrate in the vertical dimension, utilizing the thickness direction of the display panel. This three-dimensional arrangement allows the capacitor to occupy space in the Z-direction rather than competing for area in the X-Y plane, thereby preserving the light emitting region while achieving capacitor integration.
Solution Approach 2:
The storage capacitor is nested within the sub-pixel structure by positioning it between the substrates and using the conductive bump that protrudes from the second substrate. The capacitor dielectric layer covers the conductive bump, and the capacitor electrodes are integrated with the existing pixel electrode and connecting wire structure, embedding the capacitor function within the existing display architecture.
2Adaptability or versatility
If an additional touch sensing element is designed in an OLED, then touch sensing function is added, but the manufacturing process becomes more complex and the aperture ratio becomes even smaller
Solution Approach 1:
The touch sensing electrode is merged with the patterned conductive layer that already exists in the sub-pixel structure. The sensing electrode and the pixel electrode share the same conductive material layer and formation process, eliminating the need for separate touch electrode layers and simplifying the manufacturing process while achieving both display and touch sensing functions.
Solution Approach 2:
The patterned conductive layer serves dual functions: as the pixel electrode for light emission and as the sensing electrode for touch detection. This multi-functional design allows the same structural element to perform both display and touch sensing roles, reducing device complexity and maintaining aperture ratio.
3Adaptability or versatility
If the sensing electrode is placed in the sub-pixel area, then touch sensing is enabled, but it affects the light emitting region
Solution Approach 1:
The sensing electrode is positioned in the vertical dimension between the substrates rather than occupying horizontal space in the light emitting region. The conductive bump protruding from the second substrate and the capacitor dielectric layer covering it create vertical stacking that enables sensing functionality without blocking light emission from the electroluminescent layer.
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 approach enhances the aperture ratio, simplifies the manufacturing process, reduces costs, and maintains a stable display effect by optimizing the layout of the capacitor elements within the OLED panel.
Implementation Method 1
An aspect of the present disclosure provides a display panel, having a first substrate and a second substrate disposed on the first substrate, and the display panel is defined to include a plurality of sub-pixels. Each of the sub-pixels includes a data line, a scan line, a power line, a switching element, a driving element, a protective layer, a patterned electrode layer, an electroluminescent layer, a counter electrode
Data Source
AI summary
A display panel includes a substrate, a conductive bump, a capacitor dielectric layer, a sensing electrode, a counter substrate opposite to the substrate, an electroluminescent layer, and a counter electrode. The conductive bump protrudes from an inner surface of the substrate and includes an upper capacitor electrode and a bump covered by the upper capacitor electrode. The bump is disposed between the inner surface of the substrate and the upper capacitor electrode. The capacitor dielectric layer covers the conductive bump and a portion of the inner surface of the substrate. The sensing electrode is disposed on the inner surface of the substrate or an inner surface of the counter substrate. The counter substrate has at least one pixel electrode and a first capacitor electrode separated from the pixel electrode. The electroluminescent layer is disposed between the pixel electrode and the counter electrode.