Display Apparatus Bottom Gate Transistor Kink Effect
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Solution Overview
Problem
Conventional display apparatuses suffer from a bright defect known as the kink effect when achieving low grayscale, which affects image quality and panel characteristics.
Innovation Solution
The display apparatus incorporates a first electrode used as a bottom gate by a driving thin-film transistor, along with additional transistors and capacitors, to manage voltage and data signals, preventing the kink effect by applying a voltage corresponding to the difference between the data signal and the threshold voltage of the transistor, and utilizing a second storage capacitor to improve panel characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional display apparatuses use standard thin-film transistor structures, then the device complexity is low, but a bright defect known as kink effect occurs at low grayscale levels
Solution Approach 1:
The transistor gate is divided into two separate electrodes: a first gate electrode and a second gate electrode. This segmentation allows independent control of voltage signals applied to each gate, enabling precise management of the transistor's threshold voltage to prevent the kink effect at low grayscale levels while maintaining standard transistor structures elsewhere in the display apparatus.
Solution Approach 2:
The invention changes the electrical parameters by applying different voltage signals to the first and second gate electrodes. By dynamically adjusting these voltage parameters, the threshold voltage of the thin-film transistor is controlled to avoid the kink effect region, thereby improving image quality without requiring fundamentally different transistor structures.
2Reliability
If additional transistors and capacitors are added to manage voltage signals, then the kink effect is prevented, but the device complexity increases
Solution Approach 1:
The first gate electrode serves multiple functions: it acts as a control electrode for the thin-film transistor and simultaneously functions as one of the electrodes for the storage capacitor. This multi-functionality reduces the need for separate dedicated capacitor electrodes, thereby limiting the increase in device complexity while still achieving reliable kink effect prevention and improved panel characteristics.
3Reliability
If a voltage corresponding to the difference between data signal and threshold voltage is applied to the first gate electrode, then the kink effect is minimized, but the manufacturing precision requirements increase
Solution Approach 1:
The first gate electrode acts as an intermediary element that mediates between the data signal and the threshold voltage. By applying a voltage corresponding to their difference through this intermediate electrode, the system achieves precise grayscale control and minimizes the kink effect without requiring extremely tight manufacturing tolerances on other components, as the gate electrode itself provides the necessary voltage adjustment functionality.
Data Source
AI summary
A display apparatus includes a first thin-film transistor including a semiconductor layer arranged on a substrate, a driving gate electrode arranged on the semiconductor layer, and a first electrode arranged between the substrate and the semiconductor layer, a second thin-film transistor transmitting a data signal received through a data line to the first thin-film transistor according to a first scan signal received through a first scan line, and a third thin-film transistor transmitting a first voltage to the first electrode according to a second scan signal received through a second scan line.