Organic Light Emitting Device Storage Capacitor Aperture Ratio
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Solution Overview
Problem
The challenge in organic light emitting devices is to increase storage capacitance without reducing the aperture ratio, as the storage electrodes and lines, when widened to enhance capacitance, overlap with signal lines, reducing the device's luminance and efficiency.
Innovation Solution
The solution involves forming a storage capacitor with a second conductive layer made of transparent materials like ITO or IZO, which overlaps the pixel electrode via the organic light emitting member, allowing for increased storage capacitance without reducing the aperture ratio by using the same layer as the common electrode and applying a voltage difference less than the light emitting threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the storage electrode and storage electrode line are widened to increase storage capacitance, then the storage capacitance is improved, but the aperture ratio is reduced
Solution Approach 1:
The patent merges the storage capacitor structure with the common electrode structure by forming the second conductive layer of the storage capacitor simultaneously with the common electrode in the same manufacturing step. This integration allows the storage capacitor to share the common electrode area, eliminating the need for separate storage electrode structures that would reduce the aperture ratio.
Solution Approach 2:
The common electrode serves dual functions: it acts as the common electrode for the organic light emitting device and simultaneously serves as the second conductive layer for the storage capacitor. This multi-functionality enables the storage capacitance to be achieved without requiring additional dedicated storage electrode structures that would occupy pixel area and reduce aperture ratio.
2Quantity of substance
If the storage electrode and storage electrode line are formed with wide area to form high storage capacitance, then the storage capacitance is improved, but the luminance is reduced due to overlap with signal lines
Solution Approach 1:
The patent combines the storage capacitor formation process with the common electrode formation process, so that the second conductive layer is created in the same step as the common electrode. This merging eliminates the need for separate wide-area storage electrodes that would overlap with signal lines and block light, thereby maintaining high luminance while achieving sufficient storage capacitance.
Solution Approach 2:
The common electrode performs multiple functions including serving as the cathode for light emission and as the second conductive layer for charge storage. This multi-functionality eliminates the need for additional opaque storage electrode structures that would interfere with light output, thus maintaining high luminance while providing adequate storage capacitance.
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 enables a high storage capacitance without compromising the aperture ratio, ensuring stable current supply and improved luminance in organic light emitting devices.
Implementation Method 1
the excitons emit light as discharge energy
Implementation Method 2
The capacitor includes two conductive layers overlapping each other via an insulating layer therebetween, and the storage capacitance is proportional to the area of the two conductive layers
Data Source
AI summary
An organic light emitting device, according to an exemplary embodiment of the present invention, includes a thin film transistor array panel including a pixel electrode, an organic light emitting member formed on the pixel electrode, a common electrode formed on the organic light emitting member, and a storage capacitor including a first conductive layer and a second conductive layer overlapping each other via the organic light emitting member. The first conductive layer may be formed with the same layer as the pixel electrode, and the second conductive layer may be formed with the same layer as the common electrode.