Driving IC Output Buffer Transition Time Matching
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Solution Overview
Problem
The horizontal stripe phenomenon occurs in display panels due to significant differences in transition times of scan driving signals between different scan driving circuits, leading to visible artifacts at the junction of display areas.
Innovation Solution
A driving integrated circuit with a first and second output buffer, each generating start pulse signals for respective scan driving circuits, where the second buffer's driving ability is controlled to be less than the first, ensuring synchronized transition times across scan lines by adjusting the duty cycle and driving ability of the second buffer's signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the scan driving circuits use conventional shift registers with series connection, then the circuit structure is simple and easy to manufacture, but the transition time of scan driving signals becomes gradually larger across different stages, causing horizontal stripe phenomenon
Solution Approach 1:
The patent applies local quality by differentiating the driving capability of output buffers based on their position. The first output buffer (connected to the folded portion) is designed with higher driving capability than the second output buffer, allowing compensation for the accumulated transition time in the folded scan lines. This localized adjustment ensures uniform transition times across different display areas while maintaining the overall simple shift register structure.
Solution Approach 2:
The patent changes the driving capability parameter of the output buffers to compensate for signal degradation. By adjusting the driving capability (through transistor sizing, current control, or buffer staging) of the first output buffer relative to the second, the system compensates for the longer signal path and accumulated transition time in the folded display area, achieving uniform transition times without redesigning the entire shift register chain.
2Area of stationary object
If the rising time and falling time of scan driving signals differ significantly between different scan driving circuits, then the display can cover larger areas with multiple scan circuits, but horizontal stripe artifacts appear at the junction of display areas
Solution Approach 1:
The patent implements local quality by providing different driving capabilities to output buffers in different display areas. The first output buffer serving the folded portion has enhanced driving capability compared to the second output buffer, compensating for the longer signal propagation path. This localized differentiation allows the display to cover larger areas through multiple scan circuits while maintaining consistent transition times at the junction, eliminating horizontal stripe artifacts.
Solution Approach 2:
The patent applies preliminary anti-action by pre-compensating for the expected signal degradation in the folded display area. The first output buffer is designed with higher driving capability before the signal enters the folded scan lines, counteracting the accumulated transition time that would otherwise cause horizontal stripes at the display area junction.
Data Source
AI summary
A driving integrated circuit includes a first output buffer and a second output buffer. The first output buffer generates a first start pulse signal to a first scan driving circuit, so that the first scan driving circuit generates a first plurality of scan driving signals to a plurality of first scan lines of a display panel. The second output buffer generates a second start pulse signal to a second scan driving circuit, so that the second scan driving circuit generates a second plurality of scan driving signals to a plurality of second scan lines of the display panel. The earliest second scan line of the second scan lines is driven after the first scan lines are driven. A plurality of driving units of the second output buffer are respectively controlled to generate the second start pulse signal having a driving ability less than a driving ability of the first start pulse signal.