Mixed Transistor Pixel Circuit for Low-Frequency OLED Driving
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Solution Overview
Problem
Existing OLED display pixel circuits using only P-type transistors suffer from high leakage current, leading to flicker phenomena when driven at low frequencies, limiting their application due to increased power consumption and reduced resolution.
Innovation Solution
A pixel circuit design incorporating a combination of P-type and N-type transistors, where N-type transistors are used in the compensation circuit and drive circuit, reducing leakage current and enabling low-frequency driving without flicker, while also improving display panel resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If only P-type transistors are used in OLED pixel circuits, then the circuit design is simple and manufacturing is easier, but leakage current increases causing flicker at low driving frequencies
Solution Approach 1:
The patent applies different transistor types in different circuit regions: P-type transistors are used in the data writing circuit and emission control circuit where simplicity is important, while N-type transistors are used in the drive circuit and compensation circuit where low leakage current is critical. This local differentiation resolves the contradiction by optimizing each region for its specific function.
2Ease of manufacture
If P-type transistors are used in the drive circuit, then manufacturing is easier, but leakage current causes flicker phenomena at low driving frequencies
Solution Approach 1:
The patent changes the key parameter of transistor type from P-type to N-type specifically in the drive circuit and compensation circuit. N-type transistors have inherently lower leakage current characteristics, which eliminates the flicker problem at low driving frequencies while maintaining ease of manufacture through standard CMOS processing.
3Reliability
If N-type transistors are used in the drive circuit, then leakage current is reduced and low-frequency driving is enabled, but device complexity increases
Solution Approach 1:
The patent implements local quality by using N-type transistors only in the drive circuit and compensation circuit where low leakage is essential, while keeping P-type transistors in other circuits. This targeted approach achieves low-frequency driving capability without unnecessarily increasing overall device complexity.
4Device complexity
If P-type transistors are used throughout, then power consumption is higher, but the circuit structure remains simple
Solution Approach 1:
The patent changes the transistor type parameter in the drive and compensation circuits from P-type to N-type. This parameter change reduces leakage current and consequently reduces static power consumption, while the overall circuit structure remains relatively simple through selective application.
Data Source
AI summary
A pixel circuit, a method of driving a pixel circuit and a display panel. The pixel circuit (10) includes: a drive circuit (100), a data writing circuit (200), a compensation circuit (300), and a light emitting element (500). The drive circuit (100) includes a control terminal (130), a first terminal (110) and a second terminal (120), and is configured to control a drive current flowing through the first terminal (110) and the second terminal (120) for driving the light emitting element (500) to emit light. The data writing circuit (200) is configured to write a data signal to a first terminal (110) of the drive circuit (100) in response to a first scanning signal. The compensation circuit (300) is configured to store a data signal written by the data writing circuit (200) and compensate the drive circuit (100) in response to a second scanning signal. A first terminal (510) of the light emitting element (500) is configured to receive a drive current, and a second terminal (520) of the light emitting element (500) is connected to a second voltage terminal (VSS). The pixel circuit may realize a low-frequency driving.