Display Pixel Circuit Using One Scan Signal for Uniform Luminance
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Solution Overview
Problem
Display devices, such as OLEDs, suffer from luminance non-uniformity due to varying threshold voltages of driving transistors, necessitating compensation operations that require initialization and emission signals.
Innovation Solution
A pixel design that eliminates the need for separate initialization and emission signals by using transistors of different types and a single scan signal to control transistor states, reducing the number of signal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If separate initialization and emission signals are used to control transistor states for uniform luminance, then luminance uniformity is improved, but device complexity and signal line requirements increase
Solution Approach 1:
The patent combines the initialization signal and emission signal into a single scan signal that sequentially controls multiple transistor groups. The scan signal first initializes the first group of transistors, then the second group, and finally the third group, eliminating the need for separate signal lines and reducing overall system complexity while maintaining luminance uniformity through coordinated transistor control
Solution Approach 2:
The scan signal serves multiple functions: it acts as an initialization signal for different transistor groups at different time points, and also serves as a control signal for the emission phase. This multi-functional approach replaces what would traditionally require separate dedicated signal lines, reducing device complexity while achieving uniform luminance control
2Manufacturing precision
If multiple signal lines are used for initialization and emission control, then transistor state control precision is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
By merging the initialization and emission control functions into a single scan signal that operates at different time points, the patent reduces the number of signal lines required. This simplification directly lowers manufacturing costs and reduces device complexity while maintaining precise control over transistor states through the sequential timing mechanism
3Device complexity
If a single scan signal controls multiple transistor groups sequentially, then device complexity is reduced, but control timing precision requirements increase
Solution Approach 1:
The scan signal operates in a periodic sequence, first initializing the first group of transistors, then the second group, and finally the third group before repeating the cycle. This periodic timing structure ensures that each transistor group is controlled at the appropriate moment, maintaining precise control timing while using a single signal line, thereby reducing device complexity without sacrificing control precision
Data Source
AI summary
A pixel includes a capacitor between a line transferring a first power supply voltage and a first node, a first transistor including a gate connected to the first node, a first terminal connected to a second node, and a second terminal connected to a third node, a second transistor including a gate receiving a scan signal, and a terminal connected to the second node, a third transistor including a gate receiving the scan signal, a first terminal connected to the third node, and a second terminal connected to the first node, a fourth transistor including a gate connected to the second node, and a terminal connected to the first node, a fifth transistor including a gate receiving the scan signal, a first terminal connected to the line, a sixth transistor including a terminal connected to the third node, and a light-emitting element connected to the terminal of the sixth transistor.