Display Pixel On-Bias Control Across Refresh and Skip Frames
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Solution Overview
Problem
Display apparatuses experience luminance deviations between refresh and skip frames due to leakage characteristic variations, particularly in low-speed driving, leading to flicker issues.
Innovation Solution
A display apparatus with a bias controller that applies different on-bias stress voltages in refresh and skip frames to pixels, adjusting the threshold voltage characteristic of the driving transistor, and uses pulse width modulation for emission control to minimize luminance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the data refresh cycle is increased to reduce power consumption, then power consumption is decreased, but luminance deviation between refresh frame and skip frame increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the on-bias stress voltage level based on the frame type (refresh frame vs. skip frame). In skip frames, a lower on-bias stress voltage is applied compared to refresh frames, which compensates for leakage characteristic variations and reduces luminance deviation while maintaining the extended refresh cycle for power savings.
2Productivity
If the number of skip frames is increased to implement low-speed driving, then data refresh cycle is increased, but luminance deviation becomes more considerable
Solution Approach 1:
The patent applies local quality by differentiating the on-bias stress voltage application based on the specific frame characteristics. Instead of using a uniform voltage level for all frames, the system applies higher on-bias stress voltage in refresh frames and lower on-bias stress voltage in skip frames, tailored to the specific requirements of each frame type to maintain luminance uniformity.
3Manufacturing precision
If on-bias stress voltage is applied in both refresh frame and skip frame, then luminance deviation is reduced, but device complexity increases
Solution Approach 1:
The patent applies dynamics by making the on-bias stress voltage adjustable rather than fixed. The bias controller dynamically selects the appropriate voltage level based on whether the current frame is a refresh frame or a skip frame, enabling the system to adapt to different operational conditions while managing control complexity through structured decision-making.
Data Source
AI summary
A display apparatus includes a display panel including a pixel, a source driver outputting a data voltage supplied to the pixel, in a refresh frame and stop the output of the data voltage in at least one skip frame succeeding the refresh frame, and a bias controller configured to output a first on-bias stress voltage to the pixel, in the refresh frame and output a second on-bias stress voltage to the pixel, in the at least one skip frame. The first and second on-bias stress voltages are applied to one electrode of a driving transistor included in the pixel so as to improve a luminance difference caused by a leakage characteristic variation of the pixel, and the first and second on-bias stress voltages are different so that a threshold voltage characteristic of the driving transistor differs in the refresh frame and the at least one skip frame.