Emission Control Driver Stabilizes Pixel Voltage
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Solution Overview
Problem
The initial stage of driving a display device often experiences unstable internal voltages in emission control driver stages, leading to difficulties in controlling pixel emission and resulting in unintended flashing.
Innovation Solution
The emission control driver stages include an input unit to control node voltages, a first controller with transistors and capacitors to manage power supply voltages, and an output unit to stabilize the emission control signals, ensuring a gate-off voltage is maintained even at the initial stage of driving, thereby preventing pixel emission instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emission control driver stages are used, then the device structure is simple, but the internal voltages become unstable at the initial stage of driving, causing unintended pixel emission and flashing
Solution Approach 1:
The patent applies preliminary action by initializing the internal nodes (first node and second node) to specific voltages before the emission control driver begins normal operation. The input unit sets the first node to a first initial voltage and the second node to a second initial voltage in advance, ensuring that when the driver starts, the transistors are in known states that prevent unintended pixel emission. This preliminary initialization resolves the instability issue at the initial stage without requiring complex additional control circuits during operation.
Solution Approach 2:
The patent introduces an intermediary input unit that acts as a mediator between the power supply and the internal nodes of the emission control driver stage. This input unit specifically controls the voltage levels of the first node and second node, serving as an intermediate control layer that stabilizes the internal voltages before they affect the output emission control signals. By adding this intermediary control stage, the patent achieves voltage stability without significantly complicating the overall driver structure.
2Manufacturing precision
If the emission control driver stage structure is simplified, then the device complexity is reduced, but the output quality deteriorates due to unstable voltages causing unintended pixel emission
Solution Approach 1:
The input unit performs preliminary voltage setting on the first node and second node before the emission control driver operates. By pre-establishing appropriate voltage levels (first initial voltage and second initial voltage), the system ensures that the transistors (first transistor and second transistor) start in correct states, preventing unintended pixel emission from the beginning of operation. This preliminary action guarantees high output quality without adding complex control mechanisms during the emission control process.
3Reliability
If conventional stages are used without preliminary voltage control, then the device is easier to operate, but unintended flashing occurs due to unstable internal voltages at startup
Solution Approach 1:
The emission control driver stage is designed to automatically initialize its internal voltages through the input unit without requiring external intervention or complex startup procedures. The input unit self-manages the voltage initialization of the first node and second node, ensuring stable operation from the start. This self-service mechanism maintains ease of operation while eliminating unintended flashing, as the driver autonomously establishes the correct voltage states before normal operation begins.
Data Source
AI summary
A stage in an emission control driver of a display device includes an input unit to control a voltage of a first node and a second node in response to a first input signal supplied from a first input terminal and a second input signal supplied from a second input terminal, respectively; a first controller to control a voltage of a third node and a fourth node in response to a third input signal supplied from a third input terminal and the voltage of the second node; a second controller to control the voltage of the fourth node in response to the voltage of the first node; and an output unit to supply a voltage of a first power supply or a second power supply to an output terminal in response to the voltage of the third node or the voltage of the fourth node. The first controller includes a first transistor and a second transistor connected between the first power supply and the third node; and a third transistor connected between the first node and the third node, the first transistor being turned on in response to the voltage of the second power supply.