Pixel Circuit External Compensation Method
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Solution Overview
Problem
Conventional pixel circuits face inefficiencies in detecting threshold voltage due to high parasitic capacitance, leading to prolonged detection times and uneven luminance display.
Innovation Solution
An external compensation method is introduced, where the real-time source potential of a driving transistor is detected through iterative processes within a controlled single iterative detection time, allowing for the determination of a compensation voltage to be applied, thereby improving threshold voltage detection and compensation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the initial gate-source voltage is reduced to decrease threshold voltage detection time, then the detection time decreases, but the source voltage rises more slowly due to greater parasitic capacitance effects
Solution Approach 1:
The detection process is divided into multiple discrete detection points (first detection point, second detection point, etc.) along the source voltage rise curve. By segmenting the continuous detection process into discrete points, the system can accurately track the voltage rise while maintaining efficient timing, resolving the contradiction between detection speed and measurement accuracy.
Solution Approach 2:
The system uses feedback by comparing the source voltage at different detection points to determine the threshold voltage. The second detection voltage is compared with the first detection voltage to calculate the threshold voltage, creating a feedback mechanism that improves detection accuracy without requiring excessively long detection times.
2Device complexity
If conventional threshold voltage detection is used, then the detection process is simple, but the detection time is prolonged due to high parasitic capacitance
Solution Approach 1:
The system performs preliminary actions by pre-charging the light-emitting element to a known voltage state before detection begins. The source voltage is initialized to a reference voltage, and the gate voltage is set to a predetermined level, allowing the detection process to start from a known state and complete more quickly.
Solution Approach 2:
The detection method dynamically adjusts the detection approach by using multiple detection points and adaptive timing. Rather than using a fixed detection method, the system dynamically determines threshold voltage based on the actual voltage rise characteristics observed at different detection points, optimizing the detection process for varying parasitic capacitance conditions.
Data Source
AI summary
The present disclosure discloses a pixel circuit and an external compensation method thereof. The external compensation method detects real-time source potentials of a driving transistor through n iterations, a single iterative detection time that can be set artificially to limit a time for each iteration to detect a real-time source potential of the driving transistor, until the real-time source potential of the driving transistor is equal to a target source potential, thereby improving threshold voltage detection efficiency of the driving transistor.