OLED Pixel Circuit Layout With Shared Capacitor Plate and Voltage Line
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Solution Overview
Problem
The manufacturing of OLED displays typically requires many masks to form TFTs and capacitors, leading to increased costs due to the complexity of the pixel structure.
Innovation Solution
The OLED display design and manufacturing method involve a reduced number of masks by using a semiconductor with separated switching and driving channels, overlapping gate electrodes, and a storage capacitor formed with the same layer as the driving voltage line, allowing for a mesh structure in the driving voltage line to prevent voltage drop and maximizing storage capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional pixel structure with separate TFTs and storage capacitors is used, then the display functionality is complete, but the manufacturing cost increases due to the complexity of the pixel structure requiring many masks
Solution Approach 1:
The patent merges the storage capacitor structure with the driving voltage line by forming the second storage capacitive plate and second driving voltage line on the same layer. This integration reduces the number of separate components and manufacturing masks required, directly addressing the contradiction between manufacturing ease and device complexity
Solution Approach 2:
The same layer serves multiple functions by simultaneously forming both the storage capacitor plates and the driving voltage lines. This multi-functional approach allows a single manufacturing step to create multiple essential components, reducing overall structure complexity while maintaining complete display functionality
2Reliability
If the driving voltage line is formed as a simple linear structure, then the manufacturing process is simple, but voltage drop occurs along the line
Solution Approach 1:
The driving voltage line is segmented into multiple sections with branching structures that connect to different pixel regions. This segmentation allows voltage to be distributed more evenly throughout the display, reducing voltage drop while maintaining manufacturing feasibility through systematic pattern repetition
Solution Approach 2:
The driving voltage line transitions from a simple linear one-dimensional structure to a two-dimensional mesh-like structure with multiple pathways. This dimensional change provides alternative current paths that reduce resistance and voltage drop, while the regular pattern maintains manufacturing simplicity
3Reliability
If the storage capacitor plates are formed on separate layers, then the capacitor structure is simple to manufacture, but the storage capacitance is reduced
Solution Approach 1:
The storage capacitor structure utilizes vertical stacking in the third dimension by forming capacitor plates on different layers (first and second gate insulating layers). This three-dimensional arrangement increases the effective capacitance area without expanding the planar footprint, maximizing storage capacitance within the available space
Solution Approach 2:
The capacitor structure is nested within the existing multi-layer gate structure of the OLED display. The first and second storage capacitive plates are integrated into the gate insulating layer stack, utilizing the vertical space between existing structural elements to house the capacitor without adding external complexity
Data Source
AI summary
An OLED display and a method of manufacturing thereof are disclosed. In one aspect, the display includes a scan line formed over a substrate and configured to transfer a scan signal, a data line and a driving voltage line crossing the scan line and respectively configured to transfer a data voltage and a driving voltage, and a switching transistor electrically connected to the scan line and the data line and including a switching drain electrode configured to output the data voltage. The display also includes a driving transistor including a driving gate electrode, a driving drain electrode, and a driving source electrode electrically connected to the switching drain electrode. The display further includes a storage capacitor including a first storage electrode electrically connected to the driving gate electrode and a second storage electrode formed on the same layer as the driving voltage line.