Pixel Driving Circuit Modification Reset Voltage Brightness Uniformity
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Solution Overview
Problem
The existing pixel driving circuits in OLED display panels suffer from significant brightness differences between the first and second light-emitting stages, leading to poor display effects, especially in low-grayscale and low-frequency states, due to differing ramping speeds of the driving transistors, resulting in flickering and brightness uniformity issues.
Innovation Solution
A pixel driving circuit with a working timing sequence that includes a first light-emitting stage and a second light-emitting stage, where the first reset circuit transmits a modification reset voltage different from the initial reset voltage to the light-emitting circuit, adjusting the ramping speed to match that of the first stage, thereby reducing brightness differences and improving uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional pixel driving circuit is used with standard reset voltage, then the circuit structure is simple, but the brightness uniformity deteriorates due to different ramping speeds between first and second light-emitting stages
Solution Approach 1:
The patent changes the voltage parameter of the reset signal by introducing a modification reset voltage that is different from the initial reset voltage. This parameter change adjusts the ramping speed of the light-emitting circuit in the second light-emitting stage to match the first stage, thereby improving brightness uniformity without requiring fundamental structural changes to the pixel driving circuit.
2Manufacturing precision
If the same reset voltage is applied in both light-emitting stages, then the control signal is simple, but the brightness difference between stages increases due to different ramping speeds
Solution Approach 1:
The patent applies different reset voltages to different light-emitting stages: an initial reset voltage for the first light-emitting stage and a modification reset voltage for the second light-emitting stage. This local differentiation allows each stage to have optimized ramping speed control, improving brightness uniformity while maintaining relatively simple control signal structures.
3Ease of operation
If the ramping speed is not adjusted between stages, then the driving circuit operation is simple, but flickering occurs due to brightness differences
Solution Approach 1:
The patent introduces dynamic adjustment of the reset voltage parameter based on the light-emitting stage. By making the reset voltage adaptive (different values for different stages), the ramping speed is dynamically optimized to eliminate brightness differences and flickering, while the overall driving circuit operation remains relatively simple.
Data Source
AI summary
A pixel driving circuit, a method for driving the same and a display panel are provided. In an embodiment, the pixel driving circuit includes: a driving circuit; a light-emitting circuit including a first electrode and a first reset circuit. In an embodiment, a working timing sequence of the pixel driving circuit includes working periods, one of which includes first and second light-emitting stages. In an embodiment, the first and second light-emitting stages each include a reset stage and a light-emitting stage, wherein, during the reset stage of the first light-emitting stage, the first reset circuit transmits a first reset voltage to the first electrode of the light-emitting circuit and during the reset stage of the second light-emitting stage, the first reset circuit transmits a modification reset voltage to the first electrode of the light-emitting circuit, the modification reset voltage being different from the first reset voltage.