Timing Controller Pulse Scheduling for OLED Refresh-Rate Flicker
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Solution Overview
Problem
Flicker occurs when switching between different image refresh rates in OLED displays due to differences in threshold-compensated data voltages causing hysteresis effects among driving transistors, leading to display quality issues.
Innovation Solution
A timing controller is introduced with a first and second driving circuit, providing multiple pulses during a refresh frame for data writing and hysteresis reduction, and maintaining these pulses across hold frames to stabilize transistor characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple driving modes with different image refresh rates are used to adapt to different application scenes, then power consumption is reduced and display fluency is improved, but flicker occurs when switching between refresh rates
Solution Approach 1:
The patent performs preliminary threshold compensation and data voltage writing before the actual display refresh. By pre-compensating the transistor threshold voltages and pre-writing the data voltages to the pixel electrodes during the non-display period, the system ensures that when refresh rate switching occurs, the pixel circuits are already in a stable state, preventing flicker. This is achieved by extending the writing and compensation phases to occur before the display period begins.
Solution Approach 2:
The patent implements periodic threshold compensation and data writing operations that occur at fixed intervals independent of the display refresh rate. The writing and compensation circuits perform their functions in regular periodic cycles, ensuring that regardless of whether the display is running at 60Hz, 120Hz, or any other refresh rate, the pixel circuits receive consistent periodic treatment that maintains stability during transitions.
2Manufacturing precision
If threshold compensation processing is performed during each refresh frame, then display quality is improved, but additional time is required for data writing and compensation operations
Solution Approach 1:
The patent moves the threshold compensation and data writing operations from the temporal dimension (during the display period) to another dimension (the non-display period or idle time). By utilizing the time dimension that would otherwise be unused, the system performs compensation and writing operations without extending the actual display refresh time. This allows high-quality compensation to occur in parallel with or before the display updates, avoiding time loss in the critical display path.
Data Source
AI summary
The present disclosure provides a timing controller applied to a display device, where the display device includes a plurality of pixel circuits, a first driving circuit and a second driving circuit, each of the pixel circuits includes a driving transistor and a writing and compensation circuit; the first driving circuit is configured to sequentially output a first effective level signal to each of first control signal lines, according to a first driving start signal; the second driving circuit is configured to sequentially output a second effective level signal to each of second control signal lines, according to a second driving start signal; and the timing controller is configured to provide the first driving start signal and the second driving start signal during a refresh frame, where the number W of effective pulses in the first driving start signal is more than or equal to 2.