Display Substrate Shift Adjustment Structure for LTPO Transistor Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing LTPO process for display panels faces challenges with threshold voltage shifts in low temperature polysilicon and oxide transistors, leading to inoperability and increased power consumption due to incompatible processes and opposite shifting directions, making it difficult to adjust these shifts effectively.
Innovation Solution
A display substrate with a shift adjustment structure that introduces adjustment signals of opposite polarity to low temperature polysilicon and oxide transistors, allowing their threshold voltages to shift in opposite directions, reducing excessive inverse shifts and improving reliability and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LTPO process is used with both low temperature polysilicon and oxide transistors, then power consumption is reduced, but threshold voltage shifts in opposite directions cause inoperability
Solution Approach 1:
The patent applies preliminary anti-action by introducing adjustment signals of opposite polarity to the low temperature polysilicon and oxide transistors before the threshold voltage shifts can cause inoperability. This pre-compensating action counteracts the opposite shifting directions and prevents the harmful effect from occurring, thereby maintaining both low power consumption and transistor operability
Solution Approach 2:
The patent changes the polarity parameter of the adjustment signals applied to the transistors. By applying signals of opposite polarity to different transistor types, the threshold voltage shifts are controlled to move in opposite directions, compensating for the inherent opposite shifts caused by the LTPO process and maintaining transistor operability while preserving low power consumption benefits
2Reliability
If adjustment signals are applied to compensate threshold voltage shifts, then transistor reliability is improved, but device complexity increases
Solution Approach 1:
The adjustment signal source is designed to serve multiple functions: it generates adjustment signals for both low temperature polysilicon transistors and oxide transistors, and can selectively apply signals of appropriate polarity to different transistor types. This multi-functionality reduces the need for separate adjustment circuits for each transistor type, thereby improving reliability without proportionally increasing device complexity
Solution Approach 2:
The adjustment signal acts as an intermediary that mediates between the conflicting threshold voltage shifts of different transistor types. By introducing this intermediate control mechanism, the system can balance the opposite shifts without requiring fundamental changes to the transistor structures or process, thus improving reliability with minimal increase in complexity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A display substrate is provided. The display substrate includes a substrate (1), a first transistor (2) and a second transistor (3) on the substrate (1), directions of intrinsic threshold voltage shifts of the first transistor (2) and the second transistor (3) being opposite; and a shift adjustment structure (4) on the substrate (1). The shift adjustment structure (4) may be configured to input adjustment signals to the first transistor (2) and the second transistor (3) respectively to make threshold voltages of the first transistor (2) and the second transistor (3) shift in directions opposite to the directions of their intrinsic threshold voltage shifts respectively.