OLED Array Substrate Recessed Gate-Drain Storage Capacitor
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Solution Overview
Problem
Traditional OLED display devices have high power consumption due to the large distance between the gate and drain electrodes of the storage capacitor, resulting in low storage capacitance and increased driving current requirements.
Innovation Solution
The solution involves forming a recess in the insulating layer between the gate and drain electrodes of the drive TFT, reducing the distance between them and increasing the storage capacitance, which is achieved by overlapping the gate and drain electrodes and forming a recess in the insulating layer to minimize the distance between the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a storage capacitor is formed with two insulating layers between the gate electrode and drain electrode, then the capacitor structure is complete, but the distance between electrodes is large and capacitance is small
Solution Approach 1:
The patent transitions from a planar capacitor structure to a three-dimensional structure by forming a recess in the insulating layer. This allows the drain electrode to extend downward into the recess, reducing the vertical distance between the gate and drain electrodes while maintaining the two-insulating-layer structure for electrical isolation.
Solution Approach 2:
The patent changes the geometric parameters of the capacitor structure by creating a recess with specific depth and width ratios. The recess depth is controlled to be between 0.5-2 times the insulating layer thickness, optimizing the electrode distance to increase capacitance while maintaining manufacturing feasibility.
2Reliability
If the distance between gate and drain electrodes is reduced to increase capacitance, then storage capacitance increases, but the manufacturing precision required increases
Solution Approach 1:
The recess is formed in the insulating layer before the drain electrode is deposited. This preliminary action establishes the precise geometric boundaries that will control the final electrode distance, allowing subsequent electrode formation to proceed with standard precision requirements rather than requiring ultra-precise control of the electrode deposition process itself.
Solution Approach 2:
The recess structure acts as an intermediary element that mediates between the conflicting requirements of small electrode distance and manufacturing precision. By pre-forming the recess geometry, it provides a physical template that guides electrode formation and ensures consistent spacing without requiring extremely precise control of the electrode deposition process.
3Loss of energy
If the storage capacitance is increased to reduce driving current, then power consumption decreases, but the device complexity increases
Solution Approach 1:
The recess structure serves multiple functions simultaneously: it reduces the electrode distance to increase capacitance, maintains electrical isolation through the insulating layer, and provides a manufacturable geometric template. This multi-functionality allows the same structural modification to address multiple requirements without adding separate components.
Solution Approach 2:
The drain electrode is nested within the recess structure, with the electrode material filling the recess space. This nesting approach allows the capacitor to achieve increased capacitance through the three-dimensional configuration while using the same basic electrode and insulating layer materials, avoiding the need for additional complex components.
Data Source
AI summary
An array substrate, a manufacturing method thereof and an OLED display device are provided. The array substrate comprises a plurality of pixel units disposed on a substrate, wherein each pixel unit includes a TFT structure formed on the substrate and an OLED driven by the TFT structure; the TFT structure includes a drive TFT. A drain electrode of the drive TFT is connected with the OLED; a gate electrode and the drain electrode of the drive TFT are at least partially overlapped to form a storage capacitor. A recess is formed in an insulating layer interposed between the gate electrode and the drain electrode corresponding to the overlapped area, so that the distance between the gate electrode and the drain electrode is less than the thickness of the insulating layer corresponding to the non-overlapped area.