AMOLED Storage Capacitor Vertical Dielectric Design
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Solution Overview
Problem
Conventional AMOLED array substrates have a low pixel aperture opening ratio due to the large area occupied by storage capacitors, leading to poor display quality and signal distortion, as the storage capacitor's plates are not optimally designed, causing parasitic capacitance and affecting data transmission.
Innovation Solution
The AMOLED array substrate design features a storage capacitor with its top and bottom plates spaced apart by a pixel definition layer, where the pixel definition layer acts as a dielectric, reducing the area occupied by opaque electrodes and minimizing parasitic capacitance, and the plates are not electrically connected to the source electrode, improving data transmission stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the storage capacitor is designed with large area plates to increase capacitance, then the storage capacity is improved, but the pixel aperture opening ratio deteriorates due to occupation of light emitting area
Solution Approach 1:
The patent transitions from planar capacitor plates to a three-dimensional structure where the pixel definition layer serves as the dielectric between the gate electrode and the anode. This vertical arrangement increases capacitance without occupying additional horizontal light-emitting area, directly resolving the contradiction between storage capacity and aperture ratio.
Solution Approach 2:
The pixel definition layer is assigned multiple functions: it defines pixel boundaries, acts as the dielectric layer for the storage capacitor, and serves as the anode of the OLED. This multi-functionality eliminates the need for separate capacitor plates, increasing capacitance while preserving light-emitting area.
2Device complexity
If the storage capacitor plates are placed in the same layer as gate lines and data lines, then the device complexity is reduced, but parasitic capacitance increases causing signal transmission degradation
Solution Approach 1:
The storage capacitor is constructed vertically using the pixel definition layer as dielectric, separating the capacitor structure from the planar arrangement of gate and data lines. This three-dimensional configuration minimizes parasitic capacitance between capacitor plates and signal lines while maintaining manufacturing simplicity.
3Device complexity
If the source electrode is electrically connected to the storage capacitor plate, then the device complexity is reduced, but the source electrode potential becomes unstable causing data signal distortion
Solution Approach 1:
The patent extracts the storage capacitor's bottom plate from the source electrode, making them electrically independent. The gate electrode serves as the capacitor plate instead, which is electrically isolated from the source electrode by the gate insulation layer. This separation stabilizes the source electrode potential while maintaining a simple overall structure.
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 design significantly enhances the pixel aperture opening ratio and display quality by reducing the area of opaque electrodes and stabilizing data transmission, ensuring accurate brightness for grey scaling signals.
Implementation Method 1
the part of the pixel definition layer located between the top plate and the bottom plate of the storage capacitor is used as a dielectric layer of the storage capacitor
Implementation Method 2
an organic light-emitting diode (abbreviated as OLED) may be classified into two categories, that is, a passive matrix (abbreviated as PM) PMOLED and an active matrix (abbreviated as AM) AMOLED
Data Source
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AI summary
The present disclosure provides an active matrix organic light-emitting diode array substrate comprising: a substrate; a plurality of pixel units located on the substrate and arranged in an array, each of the plurality of pixel units comprising a thin film transistor, an organic light-emitting diode and a bottom plate of a storage capacitor. ; a pixel definition layer spacing apart two adjacent pixel units from each other; and a top plate of the storage capacitor provided on the pixel definition layer, the top plate of the storage capacitor being spaced apart from the bottom plate of the storage capacitor by the pixel definition layer. The bottom plate is arranged above a gate electrode of the thin film transistor and electrically connected to the gate electrode of the thin film transistor.