Display Shift Register Gate Pulsing for Threshold Voltage Stability
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Solution Overview
Problem
Conventional display devices using amorphous silicon transistors face issues with threshold voltage fluctuations, leading to malfunction, and require a reduction in the number of contact points between the display panel and driver IC to enhance efficiency and power consumption.
Innovation Solution
The implementation of a display device structure that applies an AC pulse to the gate electrode of transistors to suppress threshold voltage shifts, utilizing a CMOS switch with both n-channel and p-channel transistors to reduce power consumption and contact points, and employing a multi-gate structure to improve reliability and current flow.
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 fluctuations occur leading to malfunction
Solution Approach 1:
The patent applies periodic AC pulses to the gate electrode of transistors to suppress threshold voltage shifts. By periodically applying these pulses during non-selection periods, the transistor characteristics are maintained stable without requiring continuous high power input, thus resolving the contradiction between low power consumption and threshold voltage stability.
Solution Approach 2:
The patent changes the electrical parameters applied to the transistor gate by switching from DC voltage to AC pulsing. This parameter change allows the transistor to operate stably with reduced threshold voltage fluctuation while maintaining low average power consumption, as the AC pulses are applied only during specific non-selection periods rather than continuously.
2Productivity
If the number of contact points between display panel and driver IC is reduced, then efficiency is enhanced, but reliability may be compromised
Solution Approach 1:
The patent merges multiple signal functions into fewer contact points by implementing a shift register structure where a single contact point carries sequential signals through multiple transistor stages. This consolidation reduces the number of required contact points between display panel and driver IC while maintaining reliable signal transmission through the integrated shift register circuitry.
Solution Approach 2:
The patent makes each contact point multi-functional by designing the shift register to handle multiple signal types (input signals, clock signals, reset signals) through a single contact interface. This universal approach allows one contact point to serve multiple purposes, reducing the total number of contacts needed while preserving all necessary functions and reliability.
3Reliability
If AC pulse is applied to gate electrode to suppress threshold voltage shifts, then transistor performance is stabilized, but circuit complexity increases
Solution Approach 1:
The patent implements self-service by using the transistor's own gate electrode to apply the AC pulse to itself. The gate electrode receives an AC signal that directly modulates the transistor channel, creating a self-regulating mechanism that stabilizes threshold voltage without requiring external control circuits or additional components, thus minimizing circuit complexity while achieving performance stabilization.
4Use of energy by stationary object
If CMOS switch with both n-channel and p-channel transistors is used, then power consumption is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent uses periodic action to reduce power consumption in CMOS switches by applying AC pulses during non-selection periods. This periodic operation allows both n-channel and p-channel transistors to remain in high-impedance states most of the time, minimizing leakage current and power consumption, while the manufacturing process remains standard CMOS fabrication.
Solution Approach 2:
The patent changes the operating parameters of the CMOS switch from static DC levels to dynamic AC pulsing. This parameter change enables the complementary n-channel and p-channel transistors to operate in a manner that minimizes simultaneous conduction and reduces power consumption, while the manufacturing process uses conventional CMOS techniques without requiring special processing steps.
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.