Scan Driver Light-Blocking Film Voltage Stabilization
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Solution Overview
Problem
Existing scan drivers using double-gate transistors are prone to erroneous operations due to sensitivity to characteristic variations, and traditional semiconductor materials like amorphous silicon and polycrystalline silicon have limitations in durability and scalability.
Innovation Solution
A scan driver design incorporating a first and second power line, pull-up and pull-down transistors, and light-blocking films to stabilize voltage signals, with the option of using double-gate transistors and oxide semiconductors, where the light-blocking films receive voltage signals from different power lines at specific times to reduce degradation and improve output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If double-gate transistors are used in the scan driver, then mobility and switching performance are improved, but the circuit becomes sensitive to characteristic variations causing erroneous operations
Solution Approach 1:
The patent applies preliminary action by pre-charging the light-blocking film to a first voltage level before the pull-up transistor switches. This pre-charging state prevents erroneous operations by ensuring the transistor is in a known stable state before switching occurs, thereby reducing sensitivity to characteristic variations while maintaining the mobility benefits of double-gate transistors
2Ease of manufacture
If amorphous silicon is used as the semiconductor layer, then manufacturing simplicity and low cost are achieved, but electrical reliability is not ensured
Solution Approach 1:
The patent changes the material parameter from amorphous silicon to oxide semiconductor, which maintains the low-temperature processing advantage (ease of manufacture) while significantly improving electrical reliability through the superior properties of oxide semiconductor materials
3Reliability
If polycrystalline silicon is used as the semiconductor layer, then electrical performance is improved, but high processing temperature and uniformity issues prevent large-scale application
Solution Approach 1:
The patent changes the semiconductor material from polycrystalline silicon to oxide semiconductor, which allows processing at lower temperatures while maintaining good electrical performance, thereby enabling large-scale manufacturing and improving uniformity across the display panel
4Duration of action of stationary object
If the light-blocking film receives voltage signals from power lines at different times, then photodegradation is reduced and transistor durability is improved, but the circuit complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-charging the light-blocking film to a first voltage level before the pull-up transistor switches. This pre-charging sequence reduces photodegradation and extends transistor durability while maintaining manageable circuit complexity through systematic timing control
Data Source
AI summary
Provided are a scan driver and a display device including the same. The scan driver includes a first power line configured to supply a first voltage signal, a second power line configured to supply a second voltage signal having a lower voltage level than the first voltage signal, a pull-up transistor configured to output a corresponding clock signal, among multiple clock signals, as a scan signal in response to a logic state of a first node, a pull-down transistor configured to output the second voltage signal from the second power line as the scan signal in response to a logic state of a second node, and a first light-blocking film overlapping the pull-up transistor or the pull-down transistor, and configured to receive the second voltage signal from the second power line and the first voltage signal from the first power line.