OLED Storage Capacitor Stacked Electrodes Aperture Ratio
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Solution Overview
Problem
In organic light emitting diode (OLED) display devices, achieving a high aperture ratio while maintaining sufficient storage capacitance is challenging due to the need for larger storage capacitors, which reduces the pixel region's aperture ratio.
Innovation Solution
The implementation of a dual gate structure for thin film transistors and a storage capacitor design with stacked sub-storage capacitors within the same occupation area, enhancing capacitance without enlarging the storage capacitor domain, thereby maintaining a high aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode area of the storage capacitor is enlarged to provide high capacitance, then the storage capacitance is improved, but the aperture ratio of the pixel region is reduced
Solution Approach 1:
The patent transitions from a conventional planar capacitor structure to a three-dimensional stacked capacitor structure. Multiple capacitor electrodes are stacked vertically within the same pixel region, utilizing the vertical dimension to increase capacitance without expanding the horizontal footprint. This dimensional change allows the storage capacitor to achieve high capacitance while maintaining a large aperture ratio.
Solution Approach 2:
The patent implements a nested structure where multiple capacitor electrodes are stacked one above another within the same occupation area. The first, second, third, and fourth capacitor electrodes are arranged in a nested vertical configuration, with insulating films separating them. This nesting approach maximizes the use of vertical space to increase storage capacitance without consuming additional pixel region area.
2Speed
If thin film transistors are used to achieve high speed response, then the response speed is improved, but the device complexity increases
Solution Approach 1:
The patent divides the transistor gate into two separate gates (first gate electrode and second gate electrode) positioned on opposite sides of the channel layer. This segmentation allows independent control of the channel from both sides, enabling high-speed switching operations. The dual-gate structure can be integrated into the existing pixel circuit without significantly increasing overall device complexity.
Data Source
AI summary
An organic light emitting diode display device is disclosed which includes: scan, data and power lines crossing one another and arranged to define a pixel region; a switching thin film transistor disposed at an intersection of the scan and data lines; an organic light emitting diode disposed in the pixel region; a driving thin film transistor disposed between the power line and the organic light emitting diode; and a storage capacitor disposed adjacently to the organic light emitting diode and configured to charge a data signal which is applied from the data line. The storage capacitor includes a plurality of sub storage capacitors in which a plurality of storage electrodes are stacked alternately with one another.