Pixel Circuit P-Type N-Type Transistors Leakage Control
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Solution Overview
Problem
As display devices evolve to smaller pixel sizes with more complex circuits, they face challenges in minimizing defects and ensuring reliability, particularly in the control and efficiency of current flow through transistors and light emitting elements.
Innovation Solution
The proposed solution involves a pixel design with a specific configuration of transistors, including P-type and N-type thin film transistors, and connection lines with insulation layers, which are strategically positioned to control current flow and minimize leakage, using a combination of scan signals to activate and deactivate transistors for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is reduced to achieve high resolution, then the display device can provide higher resolution, but the circuit structure becomes more complicated and reliability decreases
Solution Approach 1:
The patent combines the third transistor (T3) and fourth transistor (T4) into a single pixel circuit structure, where T3 is a P-type thin film transistor and T4 is an N-type thin film transistor. This integrated design allows for efficient current control and leakage reduction without requiring additional transistors, thereby managing circuit complexity while maintaining high resolution performance
Solution Approach 2:
The patent applies different transistor types (P-type and N-type) in specific locations within the pixel circuit to optimize local current control characteristics. The P-type transistor T3 is positioned to control current flow in one direction while the N-type transistor T4 handles complementary current control, creating locally optimized regions that collectively improve overall circuit efficiency and reliability
2Reliability
If more transistors are added to control current flow, then current control capability is improved, but leakage current increases and reliability decreases
Solution Approach 1:
The patent introduces a first connection line as an intermediary element that electrically connects the third transistor (T3) and fourth transistor (T4). This connection line is disposed on both transistors with an insulation layer interposed therebetween, allowing controlled current flow between the transistors while blocking unwanted leakage paths. The first connection line acts as a mediator that enables necessary current flow while preventing harmful leakage currents
Solution Approach 2:
The patent extracts and separates the current control functions into distinct P-type and N-type transistors (T3 and T4) with dedicated connection paths. By taking out the current control function from a single transistor and distributing it across two specialized transistors with controlled connections, the design achieves better current control while minimizing leakage through the first connection line structure
Data Source
AI summary
A pixel including a light emitting element, a first transistor connected between a first node and the light emitting element to control current flowing from a first power supply to a second power supply, a second transistor connected between a data line and the first transistor to be turned on by an ith first scan signal, a third transistor including a P-type TFT connected between the first transistor and the first node to be turned on by the ith first scan signal and, a fourth transistor including an N-type TFT connected between the first node and an initialization power supply line to be turned on by an i−1th scan signal, and a first connection line connected between the third and fourth transistors to electrically connect semiconductor patterns thereof, in which the first connection line is disposed on the third and fourth transistors and contacts the semiconductor patterns thereof.