OLED Drive Circuit Simplification via Transistor Extraction
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Solution Overview
Problem
The existing drive circuits for organic electroluminescence display devices are complex and require multiple transistors, leading to increased power consumption and manufacturing challenges, particularly due to the frequent switching of transistors during threshold voltage canceling and write processing.
Innovation Solution
A simplified drive circuit configuration using a 2Tr/1C, 3Tr/1C, or 4Tr/1C structure, which includes a drive transistor, a write transistor, and a capacitor, with auxiliary bootstrap processing to reduce the number of transistor switchings and optimize threshold voltage canceling, write, and mobility correcting processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional drive circuit with multiple transistors (5Tr/1C) is used to perform threshold voltage canceling processing, then the threshold voltage control is effective, but the transistor switching frequency increases and power consumption increases
Solution Approach 1:
The patent extracts and eliminates redundant transistors from the conventional 5Tr/1C drive circuit, reducing it to a 2Tr/1C configuration. By removing unnecessary transistors (TR1, TR2, TR3) that were used for threshold voltage canceling, the circuit achieves the same threshold voltage control function with fewer components, thereby reducing power consumption and switching frequency.
Solution Approach 2:
The drive transistor TRD is designed to perform multiple functions: it serves as both the drive transistor for controlling the electroluminescence portion and as part of the threshold voltage canceling mechanism. The gate electrode of TRD is connected to one electrode of the capacitor portion, allowing the same transistor to participate in both drive operations and threshold voltage compensation, eliminating the need for separate dedicated transistors.
2Reliability
If a conventional drive circuit with multiple transistors is used, then the threshold voltage canceling processing can be performed, but the drive circuit configuration becomes complex
Solution Approach 1:
The patent removes redundant transistors (TR1, TR2, TR3) from the conventional 5Tr/1C configuration, extracting only the essential components needed for threshold voltage canceling. The simplified 2Tr/1C circuit retains the core functionality of threshold voltage compensation while eliminating unnecessary complexity in the drive circuit configuration.
Solution Approach 2:
The patent merges the functions of multiple transistors into a single drive transistor TRD. The gate electrode of TRD is connected to both the data line (for receiving video signals) and to one electrode of the capacitor portion (for threshold voltage canceling), combining what were previously separate functions into one integrated component.
3Reliability
If frequent transistor switching is performed for threshold voltage canceling and write processing, then the threshold voltage control is maintained, but the manufacturing efficiency decreases
Solution Approach 1:
By extracting and removing the redundant transistors (TR1, TR2, TR3) that caused frequent switching, the patent reduces the overall switching frequency in the drive circuit. The simplified 2Tr/1C configuration requires fewer switching operations to achieve the same threshold voltage control, thereby improving manufacturing efficiency and reducing production complexity.
4Use of energy by moving object
If a simplified drive circuit (2Tr/1C) is used, then the power consumption is reduced and configuration is simplified, but the threshold voltage canceling processing must be optimized
Solution Approach 1:
The patent implements preliminary threshold voltage canceling processing by connecting the gate electrode of the drive transistor TRD to one electrode of the capacitor portion C1. This preliminary action establishes the threshold voltage compensation mechanism in advance, allowing the simplified 2Tr/1C circuit to maintain effective threshold voltage control without requiring additional transistors or complex switching sequences.
Solution Approach 2:
The capacitor portion C1 provides feedback mechanisms that enable the drive transistor TRD to automatically compensate for threshold voltage variations. The connection between the gate electrode of TRD and the capacitor portion creates a feedback loop that maintains stable threshold voltage control, ensuring reliable operation of the simplified drive circuit.
Data Source
AI summary
Disclosed herein is a method of driving an organic electroluminescence emission portion, the driving method including the steps of: executing steps from preprocessing step to writing step for at least continuous three scanning time periods; applying a first node initialization voltage to corresponding one of the data lines, and supplying the video signal instead of the first node initialization voltage for each of the scanning time periods; applying the first node initialization voltage from the corresponding one of the data lines to the first node through the write transistor held in the ON state, thereby initializing the potential at the first node; and applying the first node initialization voltage from the corresponding one of the data lines to the first node through the write transistor held in an ON state, thereby holding the potential at the first node.