OLED Pixel Transistor Segmentation for Leakage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In organic light emitting diode (OLED) display devices, low frequency driving techniques to reduce power consumption can lead to image quality degradation due to leakage currents from transistors, causing stored data voltages to be distorted.
Innovation Solution
The implementation of a pixel structure with specific transistor configurations, including sub-transistors and reference voltage application, to reduce leakage currents between nodes, thereby maintaining image quality during low frequency driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low frequency driving is used to reduce power consumption, then energy efficiency is improved, but leakage currents distort stored data voltages and degrade image quality
Solution Approach 1:
The third transistor is divided into first and second sub-transistors coupled in series, and the fourth transistor is divided into third and fourth sub-transistors coupled in series. This segmentation reduces leakage currents between the gate node and other nodes, preventing distortion of stored data voltages during low frequency driving while maintaining power consumption benefits
Solution Approach 2:
Eighth and ninth transistors are introduced as intermediary elements to apply reference voltages to nodes between the sub-transistors. These intermediary transistors actively compensate for leakage effects by maintaining stable voltage levels at critical nodes, thereby preserving image quality during low frequency operation
2Reliability
If sub-transistors are added to reduce leakage current, then image quality is improved, but device complexity increases
Solution Approach 1:
The third transistor is segmented into first and second sub-transistors, and the fourth transistor is segmented into third and fourth sub-transistors. This segmentation strategically reduces leakage paths at critical nodes while maintaining overall circuit functionality, achieving image quality improvement with controlled complexity increase
Solution Approach 2:
The eighth and ninth transistors serve multiple functions: they apply reference voltages to stabilize nodes, compensate for leakage effects, and maintain voltage levels during emission periods. This multi-functionality justifies the added complexity by delivering multiple benefits from additional components
Data Source
AI summary
A pixel of an organic light emitting diode display device includes a capacitor, a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, a ninth transistor and an organic light emitting diode. The third transistor includes first and second sub-transistors which are coupled to each other in series between a drain of the first transistor and a gate node, and a fourth transistor includes third and fourth sub-transistors which are coupled to each other in series between a line of an initialization voltage and the gate node. The eighth transistor applies a reference voltage to a first node between the first and second sub-transistors in response to an emission signal, and a ninth transistor applies the reference voltage to a second node between the third and fourth sub-transistors in response to the emission signal.