OLED Display Substrate Reset Circuit for Threshold Voltage Shift
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Solution Overview
Problem
Existing OLED display devices suffer from short-term residual images due to the lag effect caused by threshold voltage shifts in driving transistors, especially when switching between different images.
Innovation Solution
The proposed display substrate incorporates a pixel circuit with a driving circuit, data writing circuit, first and second reset circuits, first and second light emission control circuits, and a light emitter element. The driving circuit is configured to control a driving current for light emission, with the first reset circuit applying a reset voltage to maintain a fixed bias state during initialization, thereby reducing the lag effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional driving circuit is used in OLED display, then the device can operate with simple structure, but short-term residual images occur due to threshold voltage shifts
Solution Approach 1:
The patent applies preliminary action by introducing a reset circuit that activates before the light emission phase to reset the threshold voltage of the driving transistor. This preliminary reset operation prevents the lag effect and short-term residual images by ensuring the transistor starts each frame with a known, stable threshold voltage, thereby resolving the contradiction between simple circuit structure and reliable image display.
2Device complexity
If the reset voltage is applied only during part of the initialization period, then the circuit operation is simplified, but the fixed bias state cannot be maintained throughout the entire initialization
Solution Approach 1:
The patent employs periodic action by applying the reset voltage in two distinct time periods within the initialization phase: first during a initial reset period, and then again during a second period before light emission. This periodic application of reset voltage maintains the fixed bias state throughout the entire initialization, ensuring stable transistor operation while managing circuit complexity through structured temporal control.
Data Source
AI summary
A display substrate and a display device. The display substrate includes a pixel circuit in which the driving circuit controls a driving current driving the light emitter element to emit light; the first light emission control circuit applies a first voltage to a first terminal of the driving circuit in response to a first light emission control signal; the second light emission control circuit applies the driving current to the light emitter element in response to a second light emission control signal; the first reset circuit applies a first reset voltage to the control terminal of the driving circuit in response to a first reset signal; the first reset signal and the first light emission control signal are simultaneously turn-on signals during a period; the first light emission control line and the second light emission control line extend along a first direction and are arranged in a second direction.