Display Gate Drive Circuit Using AC Pulses for Threshold Stability
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Solution Overview
Problem
Existing display devices using amorphous silicon transistors face challenges such as fluctuation in threshold voltage due to deterioration, leading to malfunction and increased power consumption.
Innovation Solution
The proposed solution involves a display device structure that applies an AC pulse to the gate electrode of a transistor through another transistor, effectively suppressing shifts in threshold voltage and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If amorphous silicon transistors are used in display devices, then manufacturing cost and power consumption are reduced, but threshold voltage fluctuation occurs due to deterioration
Solution Approach 1:
The patent applies periodic AC pulses to the gate electrode of the transistor to suppress threshold voltage shifts. By periodically applying these pulses during non-selection periods, the transistor's threshold voltage is stabilized without requiring continuous power input, thus resolving the contradiction between low power consumption and threshold voltage stability
Solution Approach 2:
The invention enables the transistor to self-correct its threshold voltage by applying AC pulses through a simple circuit configuration. The transistor essentially serves itself by having its threshold voltage stabilized through the AC pulse mechanism, eliminating the need for external intervention or complex compensation circuits
2Ease of manufacture
If amorphous silicon transistors are used in display devices, then manufacturing cost is reduced, but device reliability deteriorates due to threshold voltage shifts
Solution Approach 1:
Periodic AC pulses are applied to the gate electrode during non-selection periods to suppress threshold voltage shifts. This periodic intervention maintains transistor reliability throughout the display device's operation, ensuring consistent performance without increasing manufacturing complexity
Solution Approach 2:
The patent changes the electrical parameters applied to the transistor by introducing AC pulses with specific frequencies and amplitudes. This parameter change stabilizes the threshold voltage, thereby improving reliability while maintaining the simplicity and low cost of amorphous silicon transistor manufacturing
3Reliability
If AC pulse is applied to gate electrode through another transistor, then threshold voltage stability is improved, but device complexity increases
Solution Approach 1:
The patent uses another transistor as an intermediary to apply AC pulses to the gate electrode. This intermediary transistor simplifies the circuit configuration by using existing transistor components rather than requiring complex external pulse generation circuits, thus improving reliability without significantly increasing device complexity
Solution Approach 2:
The circuit configuration uses transistors that serve multiple functions: they act as switching elements for display operation and simultaneously serve to apply AC pulses for threshold voltage stabilization. This multi-functionality reduces the need for additional dedicated components, maintaining circuit simplicity while improving reliability
Data Source
AI summary
By applying an AC pulse to a gate of a transistor which easily deteriorates, a shift in threshold voltage of the transistor is suppressed. However, in a case where amorphous silicon is used for a semiconductor layer of a transistor, the occurrence of a shift in threshold voltage naturally becomes a problem for a transistor which constitutes a part of circuit that generates an AC pulse. A shift in threshold voltage of a transistor which easily deteriorates and a shift in threshold voltage of a turned-on transistor are suppressed by signal input to a gate electrode of the transistor which easily deteriorates through the turned-on transistor. In other words, a structure for applying an AC pulse to a gate electrode of a transistor which easily deteriorates through a transistor to a gate electrode of which a high potential (VDD) is applied, is included.