Bent OLED Driving TFT Structure for Wider Gray-Level Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The narrow driving range of the gate voltage in the driving thin film transistor of organic light emitting diode displays makes it difficult to control the magnitude of the gate voltage Vgs, limiting the number of gray levels that can be displayed.
Innovation Solution
The organic light emitting diode display incorporates a driving semiconductor layer with bent portions and a storage capacitor that overlaps the semiconductor layer, broadening the driving range of the gate voltage and allowing for precise control of gray levels through a semiconductor layer with a zigzag form, ensuring sufficient storage capacitance even at high resolutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional planar OLED structure is used, then the manufacturing process is simple, but the display uniformity and image quality are poor due to shadow effects from source electrodes
Solution Approach 1:
The source electrode is changed from a planar two-dimensional structure to a three-dimensional raised structure that protrudes upward from the substrate surface. This dimensional change allows the electrode to be positioned above the pixel electrode, eliminating the shadow effect and improving display uniformity while maintaining manufacturing feasibility through sequential layer deposition
2Manufacturing precision
If the OLED structure is raised to improve display quality, then shadow effects are eliminated, but the manufacturing complexity increases
Solution Approach 1:
The manufacturing process is divided into distinct sequential stages: first forming the base OLED structure with pixel electrodes and ETL layers on the substrate, then separately forming the raised source electrode structure, and finally completing the connection layers. This segmentation allows each component to be optimized independently while simplifying the overall manufacturing process
3Ease of manufacture
If a planar source electrode is used, then the manufacturing process is easier, but contact holes must be formed through the source electrode to connect to pixel electrodes
Solution Approach 1:
Instead of forming contact holes through the source electrode to reach the pixel electrode (conventional approach), the structure is inverted so that the source electrode is raised above the pixel electrode level. This allows direct vertical connection without requiring etching of contact holes through the source electrode, thereby simplifying the manufacturing process
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 configuration enables more precise control of gray levels, increasing the resolution and improving display quality by allowing for a broader driving range of the gate voltage and maintaining storage capacitance, thereby enhancing the overall display performance.
Implementation Method 1
an organic light emitting diode (OLED) coupled to a driving drain electrode of the driving thin film transistor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An organic light emitting diode display includes a substrate, a scan line on the substrate for transferring a scan signal, a data line crossing the scan line and for transferring a data signal, a driving voltage line crossing the scan line and for transferring a driving voltage, a switching thin film transistor coupled to the scan line and the data line, a driving thin film transistor coupled to a switching drain electrode of the switching thin film transistor, and an organic light emitting diode (OLED) coupled to a driving drain electrode of the driving thin film transistor, wherein a driving semiconductor layer of the driving thin film transistor is bent and in a plane substantially parallel to the substrate.