Display Device Notch Area Luminance Uniformity via Touch Signal Timing
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Solution Overview
Problem
Display devices with notch areas experience differences in load connected to scan lines, leading to variations in pulse width and luminance, especially when touch driving signals are applied, causing defects like luminance differences and visible horizontal lines.
Innovation Solution
A display device design with a touch detector on the front surface of multiple display areas, where the touch driver circuit adjusts pulse width or timing of touch driving signals to synchronize with scan signals, reducing load differences and minimizing the impact of touch driving signals on pixels around the notch area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the display area is designed with a notch shape to accommodate sensor devices, then the display device can integrate various sensor functions (camera, illuminance sensor, infrared sensor), but the number of pixels connected to scan lines around the notch area becomes different from other areas, causing load differences and luminance variations
Solution Approach 1:
The patent applies local quality by setting different pulse widths for scan signals applied to scan lines in different display areas. Specifically, scan lines around the notch area (second and third display areas) receive scan signals with a first pulse width, while scan lines in other areas (first display area) receive scan signals with a second pulse width. This local differentiation compensates for the load differences caused by the notch shape, ensuring uniform luminance across the entire display area while maintaining the notch design for sensor integration.
2Adaptability or versatility
If touch driving signals are applied to the touch detector, then the touch function can be implemented, but the coupling effects cause larger luminance differences around the notch area when data lines are floating
Solution Approach 1:
The patent applies preliminary anti-action by timing the touch driving signal application to occur during the period when scan signals are being supplied to the scan lines. The touch driver circuit is configured to apply touch driving signals to the touch detector only when corresponding scan signals are supplied to the scan lines, preventing the data lines from floating during touch signal application. This preliminary coordination eliminates the harmful coupling effects that would otherwise cause luminance differences around the notch area.
3Manufacturing precision
If the pulse width of scan signals is varied to compensate for load differences, then luminance uniformity can be improved, but the complexity of the scan driver circuit increases
Solution Approach 1:
The patent applies segmentation by dividing the display area into multiple regions (first display area, second display area, and third display area) and applying different pulse widths to scan signals for different regions. The scan driver circuit is configured to supply scan signals with a first pulse width to scan lines in the second and third display areas (around the notch) and a second pulse width to scan lines in the first display area (other regions). This segmented approach achieves luminance uniformity while keeping the driver circuit complexity manageable through systematic regional differentiation.
Data Source
AI summary
The present disclosure relates to a display device that can reduce a difference between the load connected to scan lines around a notch area and the load connected to scan lines in the entire display area. According to an embodiment of the disclosure, a display device comprising a display panel comprising a display area that includes a first display area, and a second display area and a third display area disposed adjacent to the first area, a touch detector, a scan driver circuit, and a touch driver circuit supplying a touch driving signal to touch electrodes of the touch detector, wherein the touch driver circuit changes a pulse width or an output timing of the touch driving signal while images are displayed on at least one of the first to third display areas and supplies the touch driving signal to the touch electrodes.