Source Driver Overdrive Circuit for 8K Display Signal Delay
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Solution Overview
Problem
In large screen display apparatuses, such as 8K TVs, signal delay along source lines causes variations in pixel charging rates, leading to degraded image quality due to increased wiring resistance, which existing overdrive methods fail to adequately address.
Innovation Solution
A source driver system that includes a latch unit, an overdrive arithmetic circuit, and a voltage output unit to calculate and apply drive voltages based on comparisons between adjacent data rows and distance from the source driver, ensuring consistent pixel charging across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the display panel screen size and definition are increased (e.g., 8K panel), then the display resolution and screen area are improved, but the wiring resistance of source lines increases causing signal delay and pixel charging rate variation
Solution Approach 1:
The patent applies local quality by differentiating the overdrive processing between proximal and distal regions of the source driver. Specifically, pixel portions in the distal region (further from the source driver) receive different overdrive processing compared to those in the proximal region, compensating for the increased signal delay and wiring resistance in the distal region. This is achieved by calculating different overdrive values based on the position of pixel portions along the source lines.
2Speed
If overdrive processing is performed based on comparison of previous and next gradation data, then the pixel charging rate is improved, but the difference in pixel charging rate based on load in the source line direction cannot be eliminated
Solution Approach 1:
The patent differentiates overdrive processing based on the positional relationship between pixel portions and the source driver. Pixel portions in the distal region receive enhanced overdrive processing compared to those in the proximal region, compensating for the cumulative effect of wiring resistance and signal delay. This positional differentiation eliminates the charging rate differences that would otherwise occur across the source line direction.
Solution Approach 2:
The patent performs preliminary determination of the pixel portion's position relative to the source driver before executing the overdrive processing. The position determination unit identifies whether pixel portions are in the proximal or distal region, and this information is used to select appropriate overdrive processing in advance, ensuring uniform charging rates across different regions.
3Productivity
If the horizontal scanning period is shortened due to increased screen size and definition, then the display refresh rate is maintained, but the signal delay increases making it difficult to charge pixels to the desired voltage level
Solution Approach 1:
The patent performs preliminary determination of pixel portion positions relative to the source driver before the overdrive processing is executed. This position determination is done in advance during the data input period, allowing the system to prepare appropriate overdrive values that compensate for signal delay, ensuring that pixels can be charged to the desired voltage level even within the shortened horizontal scanning period.
Solution Approach 2:
The patent changes the overdrive parameter values based on the position of pixel portions. By adjusting the overdrive voltage or timing parameters differently for proximal and distal pixel portions, the system compensates for the increased signal delay caused by shortened horizontal scanning periods, ensuring uniform voltage charging precision across the entire display panel.
Data Source
AI summary
A source driver includes a latch unit sequentially retrieving a video data signal for each data row corresponding to each of a first to n th horizontal scanning lines of the display panel, an overdrive arithmetic circuit calculating an overdrive value of the drive voltage applied to the pixel portions on an N th line based on a comparison result of comparing the data row corresponding to the N th line among the first to n th horizontal scanning lines and the data row corresponding to an (N−1) th line and a distance to the N th line from the source driver, and a voltage output unit generating the drive voltage applied to the pixel portions on the N th line based on the data row corresponding to the N th line and the overdrive value to output to the source line.